AnyPS5/docs/dev/debt/libkernel.md

# libkernel technical debt

### Silent stubs

- [scePthreadMutexattrSetprotocol](../../../core/libs/prx/libkernel/Pthread/src/Mutex.cpp) (libkernel) - accepts 0 to 2 as a PS5 (firmware 13.60) does and returns `EINVAL` otherwise, but the protocol is not stored or applied: priority inheritance and protection are not modelled. On the console a null or uninitialized mutex attribute returns `EINVAL` from the SCE attribute calls, `scePthreadMutexInit` takes an uninitialized attribute as the default one, and a destroyed mutex returns `EINVAL` from `scePthreadMutexDestroy`; a null mutex pointer crashed the payload and still throws
- [pthread_mutexattr_setprotocol, pthread_mutexattr_setprioceiling, pthread_mutexattr_getprioceiling](../../../core/libs/prx/libkernel/Pthread/Posix/Mutex.cpp) (libkernel) - the protocol and the priority ceiling are stored and reported as in FreeBSD's [libthr](https://github.com/freebsd/freebsd-src/blob/main/lib/libthr/thread/thr_mutexattr.c) (the ceiling is set or read only under `PTHREAD_PRIO_PROTECT`, and setting a protocol resets it to the highest `SCHED_RR` priority), but mutexes do not apply them: a priority-inherit or priority-protect mutex locks like a normal one and does not change its owner's priority
- [sceKernelGetMainSocId and sceKernelGetCpumode](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) both return 0, and [sceKernelGetCpuFrequency](../../../core/libs/prx/libkernel/Time/Time.cpp) returns the host TSC frequency measured for `sceKernelGetTscFrequency`, not the console CPU clock. The PS5's SoC id and CPU mode are unknown; shadPS4's PS4 values are [0x710f10/0x740f30 and 0, 2 or 5 from the param.sfo CPU-mode flags](https://github.com/shadps4-emu/shadPS4/blob/e0a466753a1a/src/core/libraries/kernel/process.cpp). PPSA99203 only logs them (`[console] main SoC id: result=%#x out=%#x`, `CPU: %llu Hz, cpumode %d`), passing a pointer that `sceKernelGetMainSocId` leaves untouched
- [sceKernelEnableDmemAliasing](../../../core/libs/prx/libkernel/DirectMemory/Export.cpp) (libkernel) returns 0 and changes nothing: direct memory can always be mapped more than once here, as `DoMapDirect` in [DirectMemory.cpp](../../../core/libs/prx/libkernel/DirectMemory/DirectMemory.cpp) only checks that the physical pages are allocated, so there is no aliasing to turn on. [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/e0a466753a1aacbc8db8253be685bf7ab4d9daae/src/core/libraries/kernel/memory.cpp#L39-L43) (PS4) sets a flag there that lifts the `EBUSY` its [`sceKernelMapDirectMemory2`](https://github.com/shadps4-emu/shadPS4/blob/e0a466753a1aacbc8db8253be685bf7ab4d9daae/src/core/libraries/kernel/memory.cpp#L299-L301), and [`sceKernelMapDirectMemory` for SDK 2.50 and later](https://github.com/shadps4-emu/shadPS4/blob/e0a466753a1aacbc8db8253be685bf7ab4d9daae/src/core/libraries/kernel/memory.cpp#L237-L242), return for direct memory that is [already mapped](https://github.com/shadps4-emu/shadPS4/blob/e0a466753a1aacbc8db8253be685bf7ab4d9daae/src/core/memory.cpp#L548-L553); that check is not applied here. The no-argument `int` signature follows shadPS4 and ProsperoEden (PPSA99008), which calls it before mapping the same direct memory again. Whether the PS5 refuses such a mapping without the call is unverified
- [sceKernelInternalMemoryGetAvailableSize](../../../core/libs/prx/libkernel/DirectMemory/Export.cpp) (libkernel) reports 0 bytes and returns 0: what the console's internal memory pool holds and how large it is are unknown. The `int (size_t*)` signature is from [xUtilty](https://github.com/Backporter/xUtilty/blob/328a856af1ef/source/SystemWrapper.cpp#L85) (PS4). PPSA99203 calls it once beside `sceKernelAvailableFlexibleMemorySize` while starting its GS renderer and never reads the result ([GS.cpp](https://github.com/Swordpdf/PS5SX2/blob/b4cf55e87c34/pcsx2/GS/GS.cpp#L233-L247))
- [sceKernelIsThreadSanitizerEnabled](../../../core/libs/prx/libkernel/System/src/Sanitizer.cpp) (libkernel, NID `LzoM-wVLJDE`) returns 0, as `sceKernelIsAddressSanitizerEnabled` does: a converted title never runs under the thread sanitizer, so a title that checks it skips the [libSceDbgThreadSanitizer](../../../core/libs/prx/libSceDbgThreadSanitizer/Export.cpp) annotation calls, which throw. PPSA23226's bundled `libSceJobManager_nosubmission.prx` makes those calls only when it reports nonzero

### Unknown function info

- [getlogin_r](../../../core/libs/prx/libkernel/System/src/Login.cpp) (libkernel) returns the host effective account name: `GetUserNameW` as UTF-8 on Windows and `getpwuid_r(geteuid())` on POSIX. A valid account returns a name even without a login session; host `getlogin_r`, `USER` and `LOGNAME` are not consulted. The console's login name and behaviour without a session are unknown. Account lookup or encoding failures, a missing or empty account name, and POSIX account records exceeding the 16 KiB lookup buffer throw; there is no replacement name or retry. A short guest buffer returns `ERANGE` without modifying it, and a null output returns `EFAULT`.
- [sceCoredumpGetThreadContextInfo](../../../core/libs/prx/libkernel/System/src/Coredump.cpp) (libkernel, NID `ShChva57wIM`) - declared as a throwing stub. The pointer and size arguments and integer return type follow [SharpProspero's PS5 bindings](https://github.com/SvenGDK/SharpProspero/blob/5dfdb4b0b166e83dc9ae275001afb695f12c7174/src/SharpProspero/Interop/Kernel/KernelSystem.cs). The context structure and console behavior are unverified; the stub does not read or write caller memory. PPSA01736 imports it
- [sceKernelGetSystemSwVersion](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) reports baseline system software version `0x01000000` ("01.000.000") for ProsperoStore (PPSA99000). The 0x28-byte layout (`uint64_t size` at 0, `versionString` at 8 and `version` at 0x24) matches [ProsperoStore's caller](https://github.com/blackbearreloaded/ProsperoStore/blob/20584011/src/diag/trace.cpp#L20-L26), [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/811bfcd7d1/src/core/libraries/kernel/kernel.h#L45-L49), [fpPS4](https://github.com/red-prig/fpPS4/blob/04cefd43e6/kernel/ps4_libkernel.pas#L502-L506) and [OpenOrbis](https://github.com/OpenOrbis/OpenOrbis-PS4-Toolchain/blob/0a1aaf9dd4/include/orbis/_types/kernel.h#L256-L260). These sources support the structure layout, but not the reported version value: the console firmware version remains unverified. The checks are unverified too: a null pointer returns `SCE_KERNEL_ERROR_EFAULT` and a `size` other than 0x28 returns `SCE_KERNEL_ERROR_EINVAL`, while shadPS4 returns success for null and never reads `size`.
- [kern.rng_pseudo](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) - `sysctlbyname` fills the whole output buffer with bytes from the host's `std::random_device` and leaves the length unchanged; a write returns -1 with `EPERM` and a call without an output buffer throws. The only caller seen is mbedTLS's `mbedtls_hardware_poll` in the catalog's ProsperoLight boilerplate, which asks for 64-byte blocks and fails if fewer come back. The console's generator, its per-call maximum and its answer to a size query are unknown
- [sysconf](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) - `_SC_CLK_TCK` returns 128, FreeBSD's `CLK_TCK` as its [`sysconf`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/lib/libc/gen/sysconf.c#L100-L101) returns it ([`time.h`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/include/time.h#L48-L54)); the console's value is not checked, and no `times` reports ticks at that rate. CPython's `posix` module stops its import with "cannot read ticks_per_second" when the value is below 1, as the Python in PS5MC (PPSA99420) does. Names other than `_SC_CLK_TCK`, `_SC_PAGESIZE`, `_SC_NPROCESSORS_CONF`, `_SC_NPROCESSORS_ONLN` and `_SC_PHYS_PAGES` fail with `EINVAL`
- [kern.sdk_version](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) - `sysctlbyname` reports the system software version as the 4-byte value `0x01000000` (1.00), the value `sceKernelGetSystemSwVersion` reports; a write returns -1 with `EPERM`. The major version is byte 3 and the minor version byte 2, in hex digits that read as decimal (13.60 is `0x1360xxxx`), as [Capy Mobile](https://github.com/khalifa007/CapyMobile/blob/2758c016/src/ps5/platform.c#L64-L71) (PPSA92280), [remote_lua_loader](https://github.com/n0llptr/remote_lua_loader/blob/7c2840e475/savedata/misc.lua#L195-L209) and the [lapse payload](https://github.com/NetflixNHack/Netflix-N-Hack/blob/605eb93ba5/PS4/payloads/lapse.js#L436-L450) read it. Capy Mobile only displays it. The console's firmware version is not modeled and the low two bytes are unknown
- [sceKernelGetProsperoSystemSwVersion](../../../core/libs/prx/libkernel/System/src/SoftwareVersion.cpp) (libkernel) reports system software version `0x01000000` ("01.000.000"); the console's firmware version is not modeled. The 0x28-byte block (a 64-bit size at 0, the version string at 8 and the packed version at 0x24) follows [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/main/src/SharpProspero/Interop/Kernel/KernelSystem.cs), which Prospero Multi Tools (PPSA99110) and Prospero Explorer (PPSA99109) are built with and which sets the size to 40, and the same fields in [etaHEN](https://github.com/etaHEN/etaHEN/blob/main/Source%20Code/daemon/include/ipc.hpp) and [shsrv](https://github.com/ps5-payload-dev/shsrv/blob/master/sh.c). A size other than 0x28 returns `SCE_KERNEL_ERROR_EINVAL` without writing; whether the console checks the size is unverified, since etaHEN and shsrv declare a 0x30-byte block and do not set it
- [sceKernelGetAllowedSdkVersionOnSystem](../../../core/libs/prx/libkernel/System/src/SoftwareVersion.cpp) (libkernel) reports the system software version with the 12 patch bits set, `0x01000fff`, as [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/98fd0689/src/core/libraries/kernel/kernel.cpp) does on the PS4 and as [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/main/src/SharpProspero/Interop/Kernel/KernelSystem.cs) describes it, which Prospero Explorer (PPSA99109) reads it through; a null pointer returns `SCE_KERNEL_ERROR_EINVAL`. The console's value and its errors are unverified
- [getuid, geteuid, getgid, getegid and issetugid](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) report the root identity (0) and a process that never changed credentials (`issetugid` 0), as a jailbroken process has; the host user and group are not exposed to the guest. The values a title sees on a console are unverified
- [sceKernelGetAppInfo](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - only `app_id` and the title ID (offset 0x10, up to 9 characters plus a terminator) are written; callers declare the structure with different sizes, so the rest is left alone. `app_id` is 1, the running title's id in libSceSystemService, which is a guess, not something measured. The error codes follow shadPS4: `EPERM` for another process, and 0 without writing anything for a null pointer.
- [AMPR object layout and compact gathers](../../../core/libs/prx/libkernel/Apr/include/AprCommandBuffer.hpp) - the 24-byte object and offsets (type 0, cursor 4, count 8, capacity 12, pointer 16) follow [ampr_emu assertions](https://github.com/drakmor/ampr_emu/blob/cfa85df379f6eeeb165d7badf9b648e266fe77b7/include/ampr_emu_command_buffer_types.h#L138-L143) and its [C declaration](https://github.com/drakmor/ampr_emu/blob/cfa85df379f6eeeb165d7badf9b648e266fe77b7/include/ampr.h#L41-L47). AnyPS5 represents the 32-bit type word as low 16-bit type and high 16-bit recording flags. Command encoding is AnyPS5 internal: opcode 29 and three 32-bit words encode the high offset byte, length minus one and low offset word. The 12-byte size reduces HFW's 1 MiB buffer pressure; it is not a claim about console opcode encoding. Existing 40-bit offsets and lengths 1 through 2^32 are retained; console behavior outside those limits is unverified.
- [APR resolve ForEach result](../../../core/libs/prx/libkernel/Apr/src/Apr.cpp) (libkernel) - `sceKernelAprResolveFilepathsToIdsAndFileSizesForEach` returns the number of paths that resolved, with the per-path status in `results` and the failed ids/sizes set to the invalid id and 0. The [ampr_emu](https://github.com/drakmor/ampr_emu) bridge passes the count of its resolver through and does not show what is counted; counting successes is not confirmed on a title. The guest errno of the failing non-`ForEach` resolves is set through `__error_nid_postfix`
- [AMPR counter access](../../../core/libs/prx/libkernel/Apr/src/Apr.cpp) (libSceAmpr) - signatures and checks of `WaitOnCounter_04_00`, `WriteCounter_04_00`, `ConstructNop` and `ConstructMarker` taken from the [ampr_emu](https://github.com/drakmor/ampr_emu) reimplementation, which hands counter commands to the console and does not show their effect. The counters are taken as 32 bits each: the 8-byte access of counter n spans n (low) and n + 1 (high), the 2- and 1-byte accesses select a half or a byte of the counter by its offset, waits compare at the access width (signed and wrapped compares included), the AND mask applies to both sides and the atomic writes wrap within the access. The `ConstructNop` type is not recorded
- [APR gather and scatter reads](../../../core/libs/prx/libkernel/Apr/src/Apr.cpp) (libSceAmpr) - signatures, argument checks and the read cursor taken from the [ampr_emu](https://github.com/drakmor/ampr_emu) reimplementation, not confirmed on a title: each read leaves the file, the next file offset and the next destination; a gather reads that file at a new offset into the next destination, a scatter continues in the file into a new destination, a gather-scatter takes both. Recording one needs a read file since the last `ResetGatherScatterState`; like ampr_emu, `sceAmprCommandBufferReset` keeps that state, and a gather or scatter with no read before it in the submitted buffer throws instead of returning `SCE_AMPR_ERROR_APR_INVALIDGATHERSCATTERSTATE`
- [AMM map, map direct and unmap](../../../core/libs/prx/libkernel/Apr/src/Apr.cpp) (libSceAmpr) - signatures and the protection mask (CPU, GPU, AMPR and ACP read and write) taken from the [ampr_emu](https://github.com/drakmor/ampr_emu) reimplementation, which hands the remaining checks and the mapping to the console kernel; the mapper model taken from [PS5PCEM](https://github.com/iStark/PS5PCEM): `sceAmprAmmGiveDirectMemory` usage 1 gives the allocated direct memory to the pool plain maps take pages from, usage 0 only allocates it. Not confirmed on a title. The AMM virtual address ranges are a 32 GiB range and a 32 GiB multimap range reserved on first use at the top of the guest arena, above the addresses that maps without `MAP_FIXED` are given lowest first and that titles derive their next hints from; the console's addresses are not known (ampr_emu takes them from `sceKernelMapperGetParam`), and a reservation that cannot be made there throws. Maps outside them throw. Addresses, sizes and direct offsets must be 16 KiB aligned. The memory type and the GPU mask are ignored, AMPR and ACP access maps as CPU access, unmapped pages go back to the pool and stay reserved. Submission runs the buffer before returning, the submit result is always 0 and a failing command throws; the AMM measures return errors sign-extended, as ampr_emu does. A map returns its target to the reservation before releasing the old pages, so pool exhaustion leaves that target reserved; mapping failure also restores the reservation before returning newly taken pages to the pool. The console's map failure and rollback behavior is unverified. `sceAmprAmmGetVirtualAddressRanges` throws for a null output
- [AMM remap, multimap and protection changes](../../../core/libs/prx/libkernel/Apr/src/Apr.cpp) (libSceAmpr) - signatures and the protection and mask checks taken from ampr_emu; the effects are inferred from the names, not confirmed on a title. A remap moves every page of a fully mapped range to the new address with the given protection and leaves the old range reserved; a multimap maps the same pages at a second address, anywhere in the AMM ranges, and a pool page goes back to the pool once its last mapping is unmapped; a multimap onto its own source range throws. A protection change sets the masked bits on every page of a fully mapped range; the memory type is recorded and ignored. A command on a range that is not fully mapped throws
- [AMM PRT ranges](../../../core/libs/prx/libkernel/Apr/src/Apr.cpp) (libSceAmpr) - signatures, checks and their order taken from ampr_emu, where `MapAsPrt` is a map with the PRT flag and protection 0 and `AllocatePaForPrt` a memory type and protection change with mask 1019, both checking the buffer memory after its size; the effects are inferred from the names, not confirmed on a title. Unbacked PRT pages are zero-filled pages with GPU read access, so CPU reads see zeros instead of faulting and GPU writes fault instead of being dropped. `AllocatePaForPrt` backs each unbacked page with a pool page and sets the type and protection of backed ones; `RemapIntoPrt` moves a fully mapped range into a PRT range, its opcode argument (1011 when 0, as in ampr_emu) is recorded and ignored; `UnmapToPrt` returns the pages to the pool and zero-fills them again. A plain map, unmap or remap over a PRT range ends it; `AllocatePaForPrt`, `RemapIntoPrt` or `UnmapToPrt` outside a PRT range throws
- [AMM kernel write commands](../../../core/libs/prx/libkernel/Apr/src/Apr.cpp) (libkernel) - signatures of `sceKernelWriteModifyMtypeProtectCommand` and `sceKernelWriteRemapIntoPrtCommand` taken from [ampr_emu's libkernel hook targets](https://github.com/drakmor/ampr_emu/blob/cfa85df379f6eeeb165d7badf9b648e266fe77b7/include/ampr_libkernel_hook_targets.h), which forward to the real kernel; the measure mode (`dst` null reports the size, `outSize` null skips the report) follows ampr_emu's measure-then-record calls, not confirmed on a title. The range, protection and mask checks mirror the `libSceAmpr` siblings, and the recorded bytes match them exactly so the submitted buffer executes on the existing paths
- [sceCoredumpWriteUserString](../../../core/libs/prx/libkernel/System/src/Coredump.cpp) - imported by PPSA16064, not called during its start-up and added without an implementation; unknown signature
- [sceKernelInternalMemoryGetModuleSegmentInfo](../../../core/libs/prx/libkernel/Module/src/ModuleInfo.cpp) (libkernel) - the `(InternalSegmentInfo* result)` signature, the 16-byte `{address, size}` result and the choice of the main program's first segment follow [fpPS4](https://github.com/red-prig/fpPS4/blob/04cefd43e6fddd1ab033e7980cd356d14c964905/kernel/ps4_libkernel.pas#L343-L355) only, which fills it through its `sceKernelGetLibkernelTextLocation` from the first segment of `eboot.bin`; whether the console reports that segment, the text of libkernel itself or the calling module's is unknown. The segment is the first one `sceKernelGetModuleInfo` reports for the main program, and 0 is returned. A null result throws. 44 audited titles that bundle their own `libc.prx` import it; no call has been observed
- [sceKernelGetModuleInfoForUnwind](../../../core/libs/prx/libkernel/Module/src/Module.cpp) (libkernel) - on Linux the tables come from `sceKernelGetModuleInfoFromAddr`, whose `eh_frame_size` includes the zero terminator, as measured on firmware 13.60 (reported in [#2419](https://github.com/boykopovar/AnyPS5/issues/2419), not reproduced here); on Windows it is assumed to stop before the terminator. LLVM libunwind's `CFI_Parser::findFDE` stops at the terminator or the length, whichever comes first, so it finds the same FDEs either way. Only the main executable and `.guest.prx` images report tables; other host images report none, as on Windows
- [sceKernelGetModuleInfoFromAddr](../../../core/libs/prx/libkernel/Module/src/ModuleInfo.cpp) (libkernel) - the 0x1A8-byte info layout follows the [shadPS4](https://github.com/shadps4-emu/shadPS4) reimplementation; a title's `libc.prx` reads only `id` (PPSA14632). The meaning of `flags` is unknown; only 2 is accepted. The input `st_size` is ignored, because PPSA21703's `libc.prx` passes an uninitialized 0x1A8-byte buffer; the full size is written back. The id is the `sceKernelLoadStartModule` handle of an image opened through the loader and otherwise a stable id from the same range. The name is the host file name without `.guest.prx`. An image with more than 4 load segments (the converted executable has 7) reports its first 4. `tls_offset` is 0 and `ref_count` is 1, as the host loader exposes neither. On Windows the module is the PE image holding the address: a relinked image reports its `.elf` sections as segments and the eh_frame_hdr recorded in `.ehmeta`, any other image its first 4 sections with memory access and the `.ehfram` section without an eh_frame_hdr; the TLS fields and `init_proc_addr`/`fini_proc_addr` are 0
- [sceKernelGetModuleList](../../../core/libs/prx/libkernel/Module/src/ModuleInfo.cpp) (libkernel) - lists the main program and every loaded `.prx` image in load order; host runtime libraries are left out. The handles are the ids `sceKernelGetModuleInfoFromAddr` reports, not the console's. The `(int32_t* handles, size_t count, size_t* actual)` signature and returning `ENOMEM` without writing `actual` after filling the first `count` handles when more images are loaded follow [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/0fe263a4760dfbfa973366890061749b4af0de97/src/core/libraries/kernel/process.cpp#L244-L264); whether the console writes any handles in that case is unknown
- [sceKernelGetModuleInfo](../../../core/libs/prx/libkernel/Module/src/ModuleInfo.cpp) (libkernel) - the 0x160-byte layout (`st_size`, `name[256]`, 4 segments, `segment_count`, `fingerprint[20]`) follows [fpPS4](https://github.com/red-prig/fpPS4/blob/04cefd43e6fddd1ab033e7980cd356d14c964905/sys/sys_types.pas#L319-L337) and [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/0fe263a4760dfbfa973366890061749b4af0de97/src/core/module.h#L15-L31). Only that `st_size` is accepted, as in shadPS4; other sizes return `EINVAL`, a null pointer `EFAULT` and a handle `sceKernelGetModuleList` does not list `ESRCH`. Name and segments are the ones `sceKernelGetModuleInfoFromAddr` reports, on Windows from the same PE sections, so `prot` uses the read/write/execute bits 1/2/4, while fpPS4 and shadPS4 store the ELF `p_flags`. The fingerprint is left zero, as the host image does not carry it
- [sceKernelGetModuleList2 and sceKernelGetModuleInfo2](../../../core/libs/prx/libkernel/Module/src/ModuleInfo.cpp) (libkernel) - the title-module variants follow [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/main/src/core/libraries/kernel/process.cpp): `sceKernelGetModuleList2` lists what `sceKernelGetModuleList` lists without system libraries, and `sceKernelGetModuleInfo2` answers `EPERM` for a system library after the `EFAULT`, `EINVAL` and `ESRCH` checks of `sceKernelGetModuleInfo`. A system library here is a loaded `.prx` image that is not a relinked title module (`.guest.prx`); the main program and the title's own modules are listed. Not verified on the console. PPSA34063 imports both and fails to load without them
- [sceKernelGetLibkernelTextLocation](../../../core/libs/prx/libkernel/Module/src/ModuleInfo.cpp) (libkernel) - the `(void** address, std::size_t* size)` signature and the choice of the main program's first segment follow [fpPS4](https://github.com/red-prig/fpPS4/blob/04cefd43e6fddd1ab033e7980cd356d14c964905/kernel/ps4_libkernel.pas#L338-L348); whether the console reports that segment, the text of libkernel itself or the calling module's is unverified. The segment is the first one `sceKernelGetModuleInfo` reports for the main program, and 0 is returned. A null argument throws.
- [sceKernelReleaseFlexibleMemory](../../../core/libs/prx/libkernel/DirectMemory/Export.cpp) (libkernel) - unmaps the range like sceKernelMunmap, as fpPS4 and prosper do; whether the console keeps the virtual range reserved after releasing its pages is unverified
- [sceKernelAvailableFlexibleMemorySize](../../../core/libs/prx/libkernel/DirectMemory/Export.cpp) (libkernel) - the segments of the title's executable and of its `.guest.prx` modules count against the configured flexible-memory budget (448 MiB by default) while loaded, for this size and for flexible maps. A title may declare a larger budget through `kernel.flexibleMemorySize` in `param.json`; this does not reduce the 13.5 GiB direct-memory size. Rejection of zero or a value not aligned to 16 KiB has not been measured on a console. This segment-accounting model follows [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/3a9f57265d28975658f1ca941daa5c879c7a74bd/src/core/module.cpp#L165), which maps every segment of a module outside its system module directory as flexible memory on the PS4. [Counted](../../../core/libs/prx/libkernel/Module/src/ModuleInfo.cpp) are the segments the title's ELF gives permissions, each rounded to 16 KiB pages; not counted are segments without permissions, the relinker's own blocks (on Linux both are the read/write/execute `PT_LOAD`s, plus the header block at file offset 0; on Windows everything outside the `.elf` sections) and the host system libraries. The Linux image carries no marker for the relinker's blocks, so they are told apart by those flags and that offset only: a title segment that is writable and executable, or starts at file offset 0, is not counted. A module whose segments exceed what is left still loads, and the available size then reads 0; shadPS4 fails the segment map instead ([memory.cpp](https://github.com/shadps4-emu/shadPS4/blob/3a9f57265d28975658f1ca941daa5c879c7a74bd/src/core/memory.cpp#L519-L524) returns `EINVAL`, [module.cpp](https://github.com/shadps4-emu/shadPS4/blob/3a9f57265d28975658f1ca941daa5c879c7a74bd/src/core/module.cpp#L168-L169) asserts). Which segments the PS5 charges, its rounding, whether system modules use the title's budget and when an unload releases the charge are not measured. PPSA15508 subtracts the reported size and a 10 MiB module allowance from its own 448 MiB budget at start-up and stops when the result exceeds its 146 MiB code and data limit ([#2883](https://github.com/boykopovar/AnyPS5/issues/2883))
- [Memory protection bits 0x100 and 0x200](../../../core/libs/prx/libkernel/DirectMemory/DirectMemory.cpp) (libkernel) - taken as audio coprocessor (ACP) read and write, as in the [KytyPS5](https://github.com/KytyPS5/KytyPS5) and [etaHEN](https://github.com/etaHEN/etaHEN) headers; the coprocessor work runs on the host CPU, so they grant host read and read/write access like the GPU bits
- [_umtx_op](../../../core/libs/prx/libkernel/SyncOnAddress/src/SyncOnAddress.cpp) (libkernel) - `UMTX_OP_WAIT`, `UMTX_OP_WAKE`, `UMTX_OP_WAIT_UINT`, `UMTX_OP_WAIT_UINT_PRIVATE`, `UMTX_OP_WAKE_PRIVATE` and `UMTX_OP_NWAKE_PRIVATE` follow FreeBSD 11's [kern_umtx.c](https://github.com/freebsd/freebsd-src/blob/stable/11/sys/kern/kern_umtx.c): a timeout whose size argument is at most 16 is a relative `timespec`, a larger one an `_umtx_time`, and a wake of 0 or fewer wakes one waiter. `UMTX_OP_NWAKE_PRIVATE` reads the value as an `int` count of pointers at the object and wakes every waiter on each one; a count of 0 or fewer reads nothing, and a null list fails with `EFAULT`, where FreeBSD's `copyin` would also fail for any other unreadable list. Waiters share the queue of `sceKernelSyncOnAddressWait`. Operation 0 fails with `EOPNOTSUPP` and operations above 26 with `EINVAL`, as in FreeBSD 11; `UMTX_OP_WAIT_UINT` with a value that does not fit in 32 bits returns 0 at once, as FreeBSD's zero-extended compare does. Operation 1 throws, since PPSA12544's call_once uses it in a way FreeBSD rejects; the other operations throw, and so does a misaligned object. PPSA12544's `libc.prx` passes `UMTX_OP_WAIT` and `UMTX_OP_WAIT_UINT` a pointer to a 4-byte microsecond timeout with size argument 0, which FreeBSD reads as a `timespec`, and waits for a running call_once with operation 1; its `PS5Util.prx` passes a `timespec`. Whether the console reads a microsecond timeout there, and what operation 1 does on it, is unverified. A libc call cannot be told apart from a `timespec` call by the size argument alone, so a timeout with size argument 0 is read as a `timespec` and only throws when it is not a valid one (negative seconds, nanoseconds outside [0, 1e9)), which is where FreeBSD would return `EINVAL`; a microsecond value that happens to read as a valid `timespec` is waited on as one
- [sceKernelSyncOnAddressWait](../../../core/libs/prx/libkernel/SyncOnAddress/src/SyncOnAddress.cpp) (libkernel) - the only known caller passes a null timeout and a name string as the fourth argument; the timeout is assumed to point to microseconds like the other kernel waits, and the name is ignored
- [sceKernelSyncOnAddressWait8 / sceKernelSyncOnAddressWait16 / sceKernelSyncOnAddressWait32 / sceKernelSyncOnAddressWait64](../../../core/libs/prx/libkernel/SyncOnAddress/src/SyncOnAddress.cpp) (libkernel) - libc's `__std_atomic_wait_direct_8/16/32/64` pass a microsecond timeout or null and ignore the result; the by-value comparand, return values and the 2- and 8-byte alignment of Wait16 and Wait64 are assumed
- [scePthreadRwlockDestroy, pthread_rwlock_destroy](../../../core/libs/prx/libkernel/Pthread/src/Rwlock.cpp) (libkernel) - measured on a PS5 (firmware 13.60): destroying a rwlock returns 0 whether it is free or held for reading or writing, and leaves 1 in the handle; every call on that handle then returns `EINVAL` until it is initialized again, and a zero handle is initialized on first use by the `scePthreadRwlock` calls as by the POSIX ones. A rwlock destroyed while held is not freed, so its memory leaks. Destroying a rwlock while another thread is acquiring it is not guarded
- [scePthreadCondWait / scePthreadCondTimedwait](../../../core/libs/prx/libkernel/Pthread/src/Cond.cpp) (libkernel) - before waiting, FreeBSD libthr's [`cond_wait_common`](https://github.com/freebsd/freebsd-src/blob/main/lib/libthr/thread/thr_cond.c#L1992-L2029) checks ownership through [`_mutex_owned`](https://github.com/freebsd/freebsd-src/blob/main/lib/libthr/thread/thr_mutex.c#L1166-L1178): an unowned mutex returns `EPERM`, while its destroyed marker returns `EINVAL`. An untouched adaptive static initializer (slot value 1) therefore returns `EPERM`; the test covers this, an uninitialized slot, a mutex owned by another thread, and the destroyed marker for both timed and untimed sce and POSIX waits. A recursive mutex locked several times is released completely for the wait and relocked to the same depth afterwards, as FreeBSD libthr does (`_mutex_cv_unlock`, `_mutex_cv_lock`). These FreeBSD-derived behaviors remain unverified on console hardware
- [sceKernelAioSubmitReadCommandsMultiple / sceKernelAioSubmitWriteCommandsMultiple / sceKernelAioWaitRequests / sceKernelAioPollRequests / sceKernelAioCancelRequest / sceKernelAioCancelRequests / sceKernelAioDeleteRequests](../../../core/libs/prx/libkernel/Aio/src/Aio.cpp) (libkernel) - behaviour from shadPS4 (one id per request for the Multiple submits, cancel turns any request aborted and id 0 reports processing, wait mode 2 returns once one request completed, poll copies every state without waiting); the 128 requests or ids per batch limit is from SharpProspero, with an unknown error, so larger batches throw; wait modes other than 1 (and) and 2 (or) throw; null pointers, negative counts and invalid ids return the codes the single-request siblings use, checked before any state is written
- [scePthreadAttr setters and getters](../../../core/libs/prx/libkernel/Pthread/src/Attr.cpp) (libkernel) - measured on a PS5 (firmware 13.60): a null or uninitialized attribute returns `EINVAL`, as does a null output of the stack size, detach state and scheduling parameter getters; a policy other than 1 and 3, an inheritance other than 0 and 4, or a priority outside 256 to 767 (or a null parameter) returns `ENOTSUP` (`0x8002002D`); a detach state other than 0 and 1 and a stack size below 16384 return `EINVAL`; any affinity mask is accepted. A null attribute pointer to `scePthreadAttrInit` and a null output of `scePthreadAttrGetaffinity` crashed the payload, so they still throw. A new attribute holds a 64 KiB stack size on the console and 1 MiB here, which the host code that runs on guest threads needs
- [sceKernelGetAvailableCpumask](../../../core/libs/prx/libkernel/Pthread/src/Thread.cpp) (libkernel) - returns the default thread affinity, 0x1FFF (CPUs 0 to 12), as KytyPS5 does. Titles pin threads within it (PPSA02664 passes 0x1FFB, Hades II PPSA36082 0x3 and 0x3F); whether CPU 13 is available to a title is not confirmed
- [sceKernelGetCurrentCpu](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - guest affinities are not applied to host threads, so the host CPU index is mapped into the calling thread's affinity clipped to `sceKernelGetAvailableCpumask` (the available mask when they do not overlap): host CPU n reports the (n modulo the CPU count)-th CPU of that mask, so a thread pinned to one CPU reports that CPU, as a FreeBSD `cpuset` guarantees on the console. Which CPU the console reports for a thread allowed on several is not known; shadPS4 returns 0
- [pthread_attr_setsolosched_np](../../../core/libs/prx/libkernel/Pthread/Posix/Attr.cpp) (libkernel) takes `(attr, int)` and stores the value through `scePthreadAttrSetsolosched`, returning `EINVAL` (22) for a null or uninitialized attribute like the other POSIX attribute setters. Only the name is public (aerolib `2+pVfgiEd7A`); the signature and behaviour follow the SCE twin, which [KytyPS5](https://github.com/KytyPS5/KytyPS5/blob/947627d10d4ef4b68ba3c0189aab6c368e70a8d2/src/kernel/pthread.cpp#L2188-L2199) and [sharpemu](https://github.com/sharpemu/sharpemu/blob/a2983692930564815a77f81e74c151268f5b935f/src/SharpEmu.Libs/Kernel/KernelPthreadExtendedCompatExports.cs#L891-L913) store as an `int` without a range check, and [PS5PCEM](https://github.com/iStark/PS5PCEM/blob/71de7681f06c5db59a1120a3bb554c86780c3f5f/src/hle/libs/kernel_threading.zig#L1396-L1398) implements this alias over it. On a PS5 (firmware 13.60) only 0 and 16 are accepted; every other value returns `ENOTSUP` (45, `0x8002002D` from the SCE call) and keeps the stored one, and the SCE calls return `EINVAL` for a null or uninitialized attribute. PPSA15878 passes 16. Threads created from the attribute are not scheduled differently; what solo scheduling does on the console is unknown. Returnal (PPSA01285 v03.000.005) stopped on it with `what(): pthread_attr_setsolosched_np_nid_postfix not implemented` (#2872, #1155); LEGO Horizon Adventures (PPSA14632, #734) and Palworld (PPSA23126, #2598) import it
- [sceKernelMapFlexibleMemory / sceKernelMapNamedFlexibleMemoryInternal](../../../core/libs/prx/libkernel/DirectMemory/Export.cpp) (libkernel) - flag 0x8000 is accepted and ignored; its meaning is not established. KytyPS5 (`GUEST_MAP_UNKNOWN_8000`) and sharpemu accept it without reading it. Every known caller is an SDK 9 `libc.prx` heap, which passes it with read/write protection and uses the mapping as an older `libc.prx` uses `sceKernelMapNamedFlexibleMemory` with flags 0: through the Internal variant in Astro Bot PPSA21564, through `sceKernelMapFlexibleMemory` in Animal Well PPSA22520 01.000.011
- [sceKernelMtypeprotect](../../../core/libs/prx/libkernel/DirectMemory/DirectMemory.cpp) (libkernel) - sets the memory type of the direct mappings in the page-rounded range and of the direct memory behind them, as shadPS4 and prosper do (KytyPS5 ignores the type); the type is not validated, flexible pages in the range only get the protection, and a later map of the retyped direct memory reports the type it was allocated with. `sceKernelBatchMap2` operation 4 takes the same path with the entry type
- [Map hints inside a reservation](../../../core/libs/prx/libkernel/DirectMemory/DirectMemory.cpp) (libkernel) - `sceKernelMapDirectMemory` and the flexible and anonymous maps place a mapping without `MAP_FIXED` at its hint address when the whole range lies in a range still reserved by `sceKernelReserveVirtualRange`, as if `MAP_FIXED` were set. Taken from PPSA01474, which reserves 64 GiB and then maps its heaps inside it with hints and no `MAP_FIXED`, and uses the hint addresses afterwards; not measured on the console. Hints outside a reservation, or over a range that is partly mapped, stay hints
- [_sceKernelRtldThreadAtexitIncrement, _sceKernelRtldThreadAtexitDecrement](../../../core/libs/prx/libkernel/System/src/Rtld.cpp) (libkernel) - the argument is the `dso` address a title's `libc.prx` passes to `__cxa_thread_atexit` (PPSA14632), which fails when Increment returns nonzero. As in the [fpPS4](https://github.com/red-prig/fpPS4) reimplementation, Increment takes a reference on the loaded image containing the address and Decrement releases one; the variants without the leading underscore are assumed to match
- [tcgetattr, tcsetattr](../../../core/libs/prx/libkernel/File/src/Terminal.cpp) (libkernel) - every file and pipe descriptor is taken as not a terminal (`ENOTTY`), and a socket gets `EADDRNOTAVAIL` for `AF_INET` and `EOPNOTSUPP` otherwise, as FreeBSD's `in_control` and `pru_control_notsupp` answer a termios ioctl; what descriptors 0 to 2 of a title are on the console, and whether any of them is a terminal there, is unknown
- [select](../../../core/libs/prx/libkernel/Socket/src/Socket.cpp) (libkernel) - descriptor 0 is never reported readable and descriptors 1 and 2 are always writable, as for a console title with no input; reads from descriptor 0 still go to the host stdin. `/dev/random` and `/dev/urandom` are always readable and writable, as FreeBSD reports a seeded random device. Guest sockets and libSceNet sockets are polled; other descriptors throw on Windows and are polled through the host on Linux. Dungeons (PPSA16064) selects on descriptor 0
- [select](../../../core/libs/prx/libkernel/Socket/src/Socket.cpp) (libkernel) - a descriptor the socket poller reports as unknown that is below `GuestSockets::FirstDescriptor` is polled on the host instead of throwing, except on Windows where it still throws; an invalid host descriptor fails with `EBADF`, and mixed host and socket sets are polled in short alternating slices so neither side waits out the full slice alone. Wobbly Life (PPSA29413) selects on file descriptors while streaming its bundles
- [__progname](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - unknown data export
- [environ](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - data export pointing to a fixed empty environment so titles that import it load; it is not the environment libc's `getenv` reads, so it lists none of those variables and `setenv`/`putenv` changes do not appear in it
- [seteuid, setegid, setuid, setreuid, setregid, setgroups, getgroups](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - the guest process is assumed to run as root, with real, effective and saved user and group ids 0. As in FreeBSD's `sys_seteuid`, `sys_setegid`, `sys_setuid`, `sys_setreuid` and `sys_setregid`, id 0 (or -1 for an unchanged `setreuid`/`setregid` id) is then accepted without a privilege check and changes no credential, so 0 is returned; any other id would change an id, which is not modelled, and throws. `setgroups` keeps the supplementary group list as `kern_setgroups` does (`NGROUPS_MAX` 1023, an empty list leaves the effective group as the only entry, a first entry other than 0 would change the effective group and throws) and `getgroups` reports it. The ids and privileges a title has on a console are unverified
- [pthread_barrierattr_setpshared](../../../core/libs/prx/libkernel/Pthread/Posix/Barrier.cpp) (libkernel) - PTHREAD_PROCESS_SHARED is accepted on the assumption that the console follows FreeBSD 11.0 libthr, which accepts it (9.0 rejects it with EINVAL); unverified on hardware. Guest code runs in one process, so a shared barrier behaves as a private one
- [pthread_getname_np](../../../core/libs/prx/libkernel/Pthread/Posix/Thread.cpp) (libkernel) - a thread that has already been joined returns `ESRCH` (3) on a PS5 (firmware 13.60), but its object is freed after the join here, so the pointer cannot be told apart from a live thread and its name is read as for a live one
- [sceKernelGetOperationMode](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - the signature `(int* mode, int* submode)` comes from PPSA12544, which logs both values after the call and ignores the result. A homebrew payload on a PS5 (firmware 13.60) reads mode 2 and submode 0, nothing else is written, and the result register holds no status, so the function is taken to return nothing. Whether a title process reads the same values is unverified. Null outputs throw
- [sceCoredumpGetStopInfoCpu](../../../core/libs/prx/libkernel/System/src/Coredump.cpp) (libkernel) takes `(void* info, size_t size)` as in the [Orbital type database](https://github.com/AlexAltea/orbital/blob/cc408367da6a6ebbf5ac1ac559fefeadc73b2831/tools/ida/db_types.json); the 16-byte, 8-byte-aligned block follows [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/5dfdb4b0b166e83dc9ae275001afb695f12c7174/src/SharpProspero/Interop/Kernel/KernelSystem.cs), which places coredump reads inside the handler. The handler is never invoked here, so a well-formed request returns `NOT_IN_COREDUMP_HANDLER` without reading or writing the block. Its value `0x81180003` follows [shadPS4](https://github.com/shadps4-emu/shadPS4/blob/e0a466753a1aacbc8db8253be685bf7ab4d9daae/src/core/libraries/kernel/coredump/coredump_error.h) and the NHL 27 (PPSA34063) call site reported in [#4275](https://github.com/boykopovar/AnyPS5/discussions/4275), not a PS5 measurement. The console validation order is unverified: null, unaligned or wrapping buffers and sizes other than 16 throw instead of guessing an argument error. Information from an active coredump handler remains unsupported
- [sceCoredumpAttachMemoryRegion, sceCoredumpAttachUserMemoryFile](../../../core/libs/prx/libkernel/System/src/Coredump.cpp) (libkernel) - both take `(uint32_t userValue, const void* mem, size_t size)`: for the first, the IDA type database of [Orbital](https://github.com/AlexAltea/orbital/blob/master/tools/ida/db_types.json) and the [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/main/src/SharpProspero/Interop/Kernel/KernelSystem.cs) bindings agree; the second has only SharpProspero (the PS4 5.05 firmware does not export it, so Orbital has no entry) and is described there as attaching the region as an unnamed user file. Not confirmed on a title; the RED engine's PS4 crash handler ([Vangaurd](https://github.com/vurimad/Vangaurd/blob/main/source/imported/common/redSystem/src/errorHandlerImplErrorHooksOrbis.cpp)) calls the sibling `sceCoredumpAttachMemoryRegionAsUserFile(999, buffer, bytes, name)` from inside its handler. Attaching belongs inside the core dump handler, which the system runs on its own thread after the process stops (SharpProspero's remark, the RED engine's usage and `SCE_COREDUMP_ERROR_NOT_IN_COREDUMP_HANDLER`, "function was not called from registered core dump handler", in the Vita's SceCoredump error table, [RivetDB](https://github.com/CreepNT/RivetDB/blob/master/rivetdb.json)). The handler is never invoked here, so every call is outside it and returns that error; nothing is recorded, as there is no dump to attach to. Its value `0x81180003` comes from shadPS4 (PS4), not confirmed on a PS5: [fpPS4](https://github.com/red-prig/fpPS4/blob/master/kernel/ps4_libkernel.pas) has `NOT_REGISTERED` 0x81180001 and `ALREADY_REGISTERED` 0x81180002, shadPS4's `coredump_error.h` has `NOT_IN_COREDUMP_HANDLER` = 0x81180003, and the Vita table numbers `PARAM` 0, `NOT_REGISTERED` 1, `ALREADY_REGISTERED` 2 and `NOT_IN_COREDUMP_HANDLER` 3. Whether the console checks the region before the calling context is unknown, so a null, empty or wrapping region throws. `userValue` is not interpreted; SharpProspero names its bits 31 and 30 as truncation flags for the user file variants
- [sceCoredumpWriteUserData, sceCoredumpDebugTextOut](../../../core/libs/prx/libkernel/System/src/Coredump.cpp) (libkernel) - the signatures `ssize_t (const void* data, size_t size)` and `void (const char* str, int len)` follow the [Orbital](https://github.com/AlexAltea/orbital/blob/cc408367da6a6ebbf5ac1ac559fefeadc73b2831/tools/ida/db_types.json) IDA type database and the [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/5dfdb4b0b166e83dc9ae275001afb695f12c7174/src/SharpProspero/Interop/Kernel/KernelSystem.cs) bindings ("Repeated calls append", "The bytes written, or a negative error code"). User data is written from inside the core dump handler: the Vita's [`sceCoredumpWriteUserData`](https://github.com/vitasdk/vita-headers/blob/e66ebe90b73d1fa4cce005a5b2072cec27322544/include/psp2/coredump_nounlink.h) returns `0x800A0003` ("No user-data capture is active") outside it, and the RED engine's PS4 crash handler ([Vangaurd](https://github.com/vurimad/Vangaurd/blob/4f86d2b0e1a6c0d50526152c517a0292b1a68af4/source/imported/common/redSystem/src/errorHandlerImplErrorHooksOrbis.cpp)) makes all its coredump calls, `sceCoredumpDebugTextOut` included, from its handler. The handler is never invoked here, so `sceCoredumpWriteUserData` returns `SCE_COREDUMP_ERROR_NOT_IN_COREDUMP_HANDLER` (0x81180003 in shadPS4's [`coredump_error.h`](https://github.com/shadps4-emu/shadPS4/blob/e0a466753a1aacbc8db8253be685bf7ab4d9daae/src/core/libraries/kernel/coredump/coredump_error.h), PS4 numbering) sign-extended to 64 bits and keeps nothing; whether the console checks the buffer before the calling context is unknown, so a null, empty or wrapping buffer throws. `sceCoredumpDebugTextOut` returns nothing; its text, which goes into the report on the console, is printed to stderr with the `[coredump]` prefix of `sceKernelDebugWriteCppExceptionInfo`, and a negative length or a null text with a nonzero length throws. No title is seen calling either: 007 First Light (PPSA11386) imports `sceCoredumpWriteUserData` and does not call it before its stop (#2523)
- [sceCoredumpAttachUserFile, sceCoredumpAttachMemoryRegionAsUserFile](../../../core/libs/prx/libkernel/System/src/Coredump.cpp) (libkernel) - the signatures `int (uint32_t userValue, const char* path)` and `int (uint32_t userValue, const void* mem, size_t size, const char* name)` follow the [Orbital](https://github.com/AlexAltea/orbital/blob/cc408367da6a6ebbf5ac1ac559fefeadc73b2831/tools/ida/db_types.json) IDA type database and the [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/5dfdb4b0b166e83dc9ae275001afb695f12c7174/src/SharpProspero/Interop/Kernel/KernelSystem.cs) bindings. The crash handler calls both from inside its core dump handler, `sceCoredumpAttachUserFile(priority, absolutePath)` and `sceCoredumpAttachMemoryRegionAsUserFile(999, buffer, bytes, "LoggerQueueCrashDump.txt")`. The handler is never invoked here, so both return `SCE_COREDUMP_ERROR_NOT_IN_COREDUMP_HANDLER` (0x81180003, PS4 numbering from shadPS4) and attach nothing; whether the console checks the arguments before the calling context is unknown, so a null path or name and a null, empty or wrapping region throw. An empty path or name is passed through to that error, and `userValue` is not interpreted. No title is seen calling either
- [sceKernelAddTimerEvent](../../../core/libs/prx/libkernel/Equeue/Equeue.cpp) (libkernel) - `usec` is taken as the period in microseconds; re-adding an existing timer keeps its pending expiration count and restarts the period from the time of the call, where FreeBSD 12+ `filt_timertouch` clears pending expirations on `EV_ADD`; `usec == 0` fires on every wait. None of this is confirmed on a PS5 title
- [sceKernelWaitEqueue](../../../core/libs/prx/libkernel/Equeue/Equeue.cpp) (libkernel) - a level-triggered user event (`sceKernelAddUserEvent`) is reported at most once per call, as in FreeBSD `kqueue_scan` (`sys/kern/kern_event.c`), which re-queues a reported knote without `EV_CLEAR` or `EV_DISPATCH` behind the scan marker, and kevent(2), where several triggers do not produce several kevents. Not measured on a console. Events are scanned in list order and the list is not rotated, so when `num` is smaller than the number of ready level events the later ones can starve, where FreeBSD moves a reported level knote to the tail. Several completions of one AMPR or VideoOut event within one call are returned as separate entries, where FreeBSD would aggregate them; the Orbis behaviour is unconfirmed
- [AC1FtjqMCL0](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [0iEKNAvT600](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [2cELEBPdYQ0](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [5xYxiOtOccA](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [6W+shIH315Q](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [7ilObq815O4](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [7iq7Hfs8HBk](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [AMJZhpC+siY](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [E9XkHowt+dY](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [GADjreszOgM](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [Giyg2xGrXDU](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [KC3y21wrqzc](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [Qb8wS4GZUsw](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [aAQZSjb2fho](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [pnz21I6VjDs](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [qk043QPsrZU](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [uDGXwUKqi8s](../../../core/libs/prx/libkernel/Unimplemented.cpp) (libkernel) - unknown name, signature
- [sceKernelGetCpuTemperature, sceKernelGetSocSensorTemperature](../../../core/libs/prx/libkernel/System/src/ThermalSensors.cpp) (libkernel) - read the host's thermal sensors: on Linux from `/sys/class/hwmon` and `/sys/class/thermal`, on Windows from the ACPI thermal zones (`MSAcpi_ThermalZoneTemperature` over WMI) and the storage temperature property of the first physical drive. Sensor 0 is the CPU/package value, 1 the first other value and 2 an NVMe value; a host that exposes none reports every sensor as unsupported (`EINVAL`). The console's SoC channel count and meanings are hardware-dependent and differ from the host's, the host sensors are not the console's, the ACPI reading is unavailable on many machines, and the storage temperature property is numbered 52 on Windows 10 2004 and later and 22 before it, so the mapping, the values and the unsupported-input error are unverified; the storage channel was checked against the drive's own SMART composite temperature on one NVMe host (`StorageDeviceTemperatureProperty`, 36 °C on a WD_BLACK SN7100). `sceKernelGetCpuTemperature` reports sensor 0. PPSA99058 and PPSA99420 call both
- [LinuxProtFromSce](../../../core/libs/prx/libkernel/DirectMemory/DirectMemory.cpp) (libkernel) - protection bits 0x100 and 0x200 are accepted and assumed not to affect host CPU access; host protection is derived only from the read, write and execute bits
- [sched_get_priority_max, sched_get_priority_min](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - measured on a PS5 (firmware 13.60): `SCHED_FIFO` (1) and `SCHED_RR` (3) report a maximum of 767 and a minimum of 256, and every other policy, `SCHED_OTHER` (2) included, returns -1 with `EINVAL`. `pthread_setschedparam` and `scePthreadSetschedparam` accept those two policies with a priority of 256 to 767 or 896 to 959 and keep the policy, as measured; a created thread takes the policy of explicit scheduling attributes, or its creator's when it inherits. When it inherits, it still takes the priority of its attributes, where the console gives it its creator's priority
- [inet_pton, inet_ntop](../../../core/libs/prx/libkernel/Socket/src/AddressConversion.cpp) (libkernel) - the text forms are assumed to be those of FreeBSD 11.4 and are unverified on a console: `inet_pton` accepts only four decimal parts without leading zeros for `AF_INET` and the RFC 4291 forms for `AF_INET6` (one `::` standing for at least one group, a dotted-quad tail only as the last 32 bits, no zone id), and `inet_ntop` prints lowercase hex with the first longest run of two or more zero groups compressed, and a dotted tail only for `::a.b.c.d` and `::ffff:a.b.c.d`. They no longer depend on the host resolver library
- [sceKernelIsThreadSanitizerEnabled](../../../core/libs/prx/libkernel/System/src/Sanitizer.cpp) (libkernel, NID `LzoM-wVLJDE`) - no source gives the signature; `int (void)` is assumed from `sceKernelIsAddressSanitizerEnabled` and from PPSA23226's bundled `libSceJobManager_nosubmission.prx`, which passes no arguments and tests only the 32-bit result

### Functional

- [JIT shared memory](../../../core/libs/prx/libkernel/DirectMemory/Jit.cpp) (libkernel) - `sceKernelJitCreateSharedMemory`, `sceKernelJitCreateAliasOfSharedMemory` and `sceKernelJitMapSharedMemory` take the signatures of [Orbital](https://github.com/AlexAltea/orbital)'s `tools/ida/db_types.json` (name, length, maximum protection, descriptor out; descriptor, maximum protection, descriptor out; descriptor, protection, address in and out), which ps4sdk, ps5-jar-loader and the call sites in RetroArch PPSA99169, XPSemu PPSA97358 and VLC PPSA85300 match; SharpProspero declares the alias as returning the descriptor. The object is a host anonymous file shared by its descriptors (a `memfd` on Linux, a delete-on-close temporary file mapped as an executable section on Windows), the alias is a duplicate descriptor, and every map maps the whole object, so writes through one view show through the others; a non-null address is a hint, as in `mmap` without `MAP_FIXED`. Not measured on the console: a length that is zero or not a multiple of 16 KiB and protection bits other than CPU read, write and execute are `EINVAL`; an alias or a map asking for more than the descriptor's maximum protection (write and execute counting as read) is `EACCES`, as FreeBSD 11's `vm_map_protect` treats a protection past `max_protection`; a descriptor that is not a JIT object is `EBADF`. The name is ignored, the objects do not count against the flexible memory budget, `mprotect` of a view is not limited to the maximum protection, and `mmap` of the descriptors is unsupported, as for `shm_open`. On Linux the `memfd` is created without `MFD_EXEC`, which Linux 6.3 added and older kernels reject with `EINVAL`, and relies on the protection of the mapping: the flag only sets the file's execute permission bits, and the direct memory `memfd` is mapped executable the same way; a host with `vm.memfd_noexec` set to 2 refuses the creation and the call throws
- [kqueue and kevent](../../../core/libs/prx/libkernel/Equeue/src/Kqueue.cpp) (libkernel) follow FreeBSD 11's [`kern_event.c`](https://github.com/freebsd/freebsd-src/blob/34bd34750187bae02a0086402c78c031c59dd8b3/sys/kern/kern_event.c) (`kqueue_kevent`, `kqueue_register`, `kqueue_scan`, the timer and user filters) over the event queue; nothing is measured on a console. The descriptor is a host null device registered as the kqueue: `close` and `sceKernelClose` close the queue and `dup`/`dup2` of it throw, but `read`, `write` and `fstat` act on the null device instead of failing with `EOPNOTSUPP` or reporting `S_IFIFO`. Read and write events are supported on guest sockets only, plus the timer, user and [vnode](../../../core/libs/prx/libkernel/Equeue/src/FileEvent.cpp) filters; other filters, `EV_DISABLE`, `EV_DISPATCH`, `EV_FORCEONESHOT`, `NOTE_LOWAT`, `EV_CLEAR` on a socket, `EVFILT_READ` on another kqueue, a `NOTE_NSECONDS` period above one second with a fraction (11.0 converts the fraction with the microsecond macro), any change to an existing timer (11.0 keeps the armed expiry and applies the new period after it, 11.4's `filt_timertouch` restarts it) and a negative `nevents` throw. A new user event keeps its `fflags` unmasked and is not triggered by `NOTE_TRIGGER`, because `filt_userattach` reads the already cleared `kn_fflags`. The timer limit `kq_calloutmax` (`ENOMEM`) is not enforced, and closing a kqueue wakes a thread waiting on it in `kevent` with `EBADF`, where `kqueue_drain` makes the close wait for that thread. A level-triggered event is reported once per call and moved behind the other events, as in `kqueue_scan`; the `sceKernel*Equeue` calls keep their own collection loop
- [EVFILT_VNODE, sceKernelAddFileEvent and sceKernelDeleteFileEvent](../../../core/libs/prx/libkernel/Equeue/src/FileEvent.cpp) (libkernel) watch the host file or directory behind the descriptor and turn host changes into FreeBSD 11 vnode hints, which [`filt_vfsvnode`](https://github.com/freebsd/freebsd-src/blob/34bd34750187bae02a0086402c78c031c59dd8b3/sys/kern/vfs_subr.c#L5032) adds whole when they share a bit with the requested `fflags`: a write that grows a file is `NOTE_WRITE | NOTE_EXTEND`, another write `NOTE_WRITE`, a shrinking truncate or an attribute change `NOTE_ATTRIB`, a higher link count `NOTE_LINK`, a lower one or a pending delete `NOTE_DELETE`, a new path `NOTE_RENAME`; in a directory, an entry created, removed or renamed is `NOTE_WRITE`, with `NOTE_LINK` for a subdirectory, and on Linux an entry moved from or to another directory adds `NOTE_EXTEND`; inotify queues the two halves of a rename one after the other, so a watcher woken by the first can read it alone, and a half read without the other is classified only after a `getdents64` on the watched directory, which takes the directory lock that `rename` holds until both halves are queued ([`do_renameat2`](https://github.com/torvalds/linux/blob/v6.8/fs/namei.c#L4975) around `vfs_rename` and its `fsnotify_move`, [`iterate_dir`](https://github.com/torvalds/linux/blob/v6.8/fs/readdir.c#L103)), an ordering taken from the kernel source, not from inotify(7), which promises none; a directory registered with `NOTE_EXTEND` on Windows is accepted, as `vfs_kqfilter` does not check it, but never receives it, because the directory handle cannot tell a move between directories from a removal plus an addition. FreeBSD's hints depend on the filesystem and the console's filesystems are not known: a growing `ftruncate` reports `NOTE_WRITE | NOTE_EXTEND` where `vop_setattr_post` reports `NOTE_ATTRIB`, and on Windows `utimes` on a file reports `NOTE_WRITE`. Windows uses `FindFirstChangeNotification` on the parent directory (and on a watched directory itself) and compares `GetFileInformationByHandleEx` snapshots at least every 50 ms, because a write through an open handle is reported only when the handle is flushed or closed, so file hints can arrive 50 ms late; Linux uses inotify on the file and is not run. `NOTE_REVOKE`, `NOTE_OPEN`, `NOTE_CLOSE`, `NOTE_CLOSE_WRITE`, `NOTE_READ`, unknown bits and descriptors other than files, directories, pipes and sockets throw. `sceKernelAddFileEvent(eq, fd, watch, udata)` and `sceKernelDeleteFileEvent(eq, fd)` take the [OpenOrbis](https://github.com/OpenOrbis/OpenOrbis-PS4-Toolchain/blob/0a1aaf9d/include/orbis/libkernel.h#L35) and [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/5dfdb4b0/src/SharpProspero/Interop/Kernel/KernelEqueue.cs#L164) signatures; `watch` is taken as the `fflags` and the event is added with `EV_CLEAR`, neither confirmed on a title
- [sem_timedwait](../../../core/libs/prx/libkernel/Pthread/Posix/Sem.cpp) (libkernel) consumes an available count before checking the timeout and waits indefinitely for a null timeout, following FreeBSD 11's `sem_timedwait`. Console behavior for null and invalid timeouts when a count is available is unverified.
- [tcsendbreak, tcdrain, tcflush, tcflow, tcgetpgrp, tcsetpgrp](../../../core/libs/prx/libkernel/File/src/Terminal.cpp) (libkernel) follow FreeBSD 11.4's [`termios.c`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/lib/libc/gen/termios.c): `tcflush` answers `EINVAL` for a queue other than `TCIFLUSH`, `TCOFLUSH` or `TCIOFLUSH` and `tcflow` for an action outside `TCOOFF`..`TCION` before the descriptor is looked at, and every other call fails as its terminal ioctl does on a descriptor that is not a terminal, with the errors `tcgetattr` gives, so `tcsendbreak` never reaches its 0.4 s pause. FreeBSD's `pipe_ioctl` answers `TIOCGPGRP` and `TIOCSPGRP` on a pipe or FIFO with the descriptor's SIGIO owner, which is not modelled, so `tcgetpgrp` and `tcsetpgrp` throw on a host pipe or FIFO above descriptor 2; descriptors 0 to 2 are taken as non-terminals that are not pipes, whatever the host attaches to them, so a pipe the guest creates on a freed descriptor 0 to 2 gets `ENOTTY` there. The PS5 `libkernel` is assumed to use this FreeBSD code, and `tcdrain` is not a cancellation point here
- [Windows file timestamps](../../../core/libs/prx/libkernel/File/include/WindowsFileTime.hpp) use the host filesystem's timestamp range and resolution. `utimes`, `futimes`, and `lutimes` reject timestamps outside nonnegative signed 64-bit Windows file-time ticks with `EINVAL`, including exactly 1601-01-01 00:00:00 UTC, whose zero value means "leave unchanged" to `SetFileTime`. Guest directory descriptors still resolve through their recorded path. Filesystems with coarser timestamp resolution cannot retain every guest microsecond
- [Windows file identity](../../../core/libs/prx/libkernel/File/src/NativeStat.cpp) (libkernel) - `stat` and `fstat` report the volume serial number as `st_dev` and the 64-bit file index folded into the guest's 32-bit `st_ino` (never 0), so two different files can in principle share an `st_ino`; the fold is not taken from a reference. `st_nlink` is clamped to 65535, the width of the guest field. The call keeps the `_wstat64` values when `GetFileInformationByHandle` fails
- [setitimer](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) follows FreeBSD's `sys_setitimer` and `kern_setitimer`: `EINVAL` for timers other than `ITIMER_REAL`, `ITIMER_VIRTUAL` and `ITIMER_PROF`, and for a value, or the interval of a non-zero value, with a negative field, `tv_usec` of 1000000 or more, or more than `INT32_MAX / 2` seconds; a null value reads the timer as `getitimer` does, with `EFAULT` when the output is null too. `ITIMER_REAL` shares the timer thread of `alarm`, which clears its interval: a zero value disarms it, the previous value is returned, and each expiry re-arms it by `it_interval`. An expiry delivers nothing: with `SIG_IGN` it is dropped, with the default disposition the process exits with status 142, and with a handler, or with `SIGALRM` blocked, it throws, since guest `SIGALRM` handlers are never run and signals are never left pending. The value is not raised to `tick / 16` as `itimerfix` does, and an interval below 1 ms throws, since the console's `hz`, and so that rounding, is unknown (1 ms covers any `hz` of 63 or more). `ITIMER_VIRTUAL` and `ITIMER_PROF` throw when armed, as process CPU time is not accounted, and read and disarm as zero. PPSA99420 imports it and fails to load without it
- On Linux, [direct memory](../../../core/libs/prx/libkernel/DirectMemory/DirectMemory.cpp) lives in one sparse memfd at file offset = physical address, so the [GPU imports](../../../core/libs/prx/libSceAgcDriver/Graphics/src/GuestBufferMemory.cpp) can share one udmabuf buffer object per 64 MiB of it. Released direct memory is not punched out of the file, because a live import of its chunk pins the pages and the GPU would keep reading the old ones: its pages stay committed (the process keeps the high-water mark of the direct memory it used) and are zeroed when the range is allocated again.
- [system](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) runs no command. It follows FreeBSD 11's `lib/libc/stdlib/system.c` for a sandbox without `/bin/sh`: a null command returns 1 unconditionally, as that version does, and any command returns the wait status of a child that could not exec the shell and called `_exit(127)` (`0x7f00`). Whether the console's application sandbox has no shell, and whether `vfork` succeeds there (FreeBSD returns -1 when it fails), is unverified
- [sceKernelWriteThrottlingStatus](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) reports no write throttling: the host SSD has no write budget, so the first qword of the 32-byte status is set to `UINT32_MAX` and the rest is zeroed. PPSA17221 reads only that qword: it multiplies it by 64 KiB and compares the product with byte thresholds up to 0x4AF00000 to pick one of five tiers. When the call fails the title assumes 0x4B000001 bytes, which selects the same top tier as `UINT32_MAX`. What the value measures on hardware (a remaining budget or a rate) and the meaning of the other three qwords are unknown
- [Windows directory descriptors](../../../core/libs/prx/libkernel/File/src/DirectoryDescriptor.cpp) (libkernel) take one snapshot of the directory, on the first `getdents`, `getdirentries` or non-zero `lseek` (`SEEK_SET` or `SEEK_CUR`), and keep it until it is discarded; `lseek` to offset 0 only discards the snapshot, and the next read lists the directory again, so every rewind costs O(entries) on the next read. `lseek` takes the offset as an entry index and `SEEK_CUR` with offset 0 only reports the index. `SEEK_END` throws, where the NUL descriptor used to return 0, because FreeBSD defines it relative to the directory size, which is not modelled. A negative result returns `EINVAL` and a `SEEK_CUR` offset that overflows returns `EOVERFLOW`, as FreeBSD `vn_seek` reports them. Names whose UTF-8 encoding exceeds the one-byte `d_namlen` limit are not representable in this guest directory-record layout: `getdents` returns `ENAMETOOLONG` without consuming the entry. Repeated calls therefore report the same error and entries after that name cannot be reached through this descriptor; FreeBSD's `getdents` behavior for host filenames that exceed its `MAXNAMLEN` is not verified. `getdirentries` still reports 0 through `basep` instead of the position of the block it read, so only 0 and values returned by `lseek` are valid offsets; FreeBSD offsets are filesystem cookies
- [/dev/random and /dev/urandom](../../../core/libs/prx/libkernel/File/src/RandomDevice.cpp) (libkernel) opened for reading return a descriptor backed by the host null device whose reads are filled with host OS entropy (`getentropy`, `rand_s` on Windows); both paths behave the same, never block, and positioned reads ignore the offset (FreeBSD `random(4)`). Only the exact paths are recognised, `fstat`, `lseek` and `mmap` see the null device, and opening them for writing throws
- [pthread_attr_getinheritsched, pthread_attr_setinheritsched, pthread_attr_getscope, pthread_attr_setscope, pthread_attr_getstackaddr](../../../core/libs/prx/libkernel/Pthread/Posix/Attr.cpp) (libkernel) follow FreeBSD 11 libthr ([thr_attr.c](https://github.com/freebsd/freebsd-src/blob/5ed7eb0d97ba4436218e810f61bd059acba984c2/lib/libthr/thread/thr_attr.c), [thr_create.c](https://github.com/freebsd/freebsd-src/blob/5ed7eb0d97ba4436218e810f61bd059acba984c2/lib/libthr/thread/thr_create.c)), not measured on the console: the scope defaults to `PTHREAD_SCOPE_SYSTEM` (2), only it and `PTHREAD_SCOPE_PROCESS` (0) are accepted and other values return `EINVAL`, and an inherit value other than `PTHREAD_INHERIT_SCHED` (4) or `PTHREAD_EXPLICIT_SCHED` (0) returns `ENOTSUP`. `pthread_attr_getstackaddr` returns the configured stack address pointer (null by default). A null output of `pthread_attr_getinheritsched` throws, since libthr writes through it unchecked. A thread keeps the scope it was created with, taken from the creating thread under `PTHREAD_INHERIT_SCHED`, and `pthread_attr_get_np` and `scePthreadAttrGet` report it, but every guest thread is a host thread at system scope, so process scope changes nothing
- [Shared memory](../../../core/libs/prx/libkernel/File/src/SharedMemory.cpp) (libkernel) on Linux implements anonymous and named objects, bounded descriptor writes and seeks, and `shm_unlink` with effective read/write permission checks from FreeBSD 11. Named paths up to 1023 bytes use `/anyps5-shm-` plus SHA-1; collisions are not detected, and the namespace is shared across processes in the host mount namespace. Named creation applies the guest umask without changing the host mask. Linux procfs and `/dev/shm` are required. Operations use an advisory directory lock; external host operations bypass it, unrelated objects serialize, and descriptor operations require two spare host descriptors and compare device/inode with the initial descriptor identity on both the pinned-object and ordinary-file fallback paths. [Guest mappings](../../../core/libs/prx/libkernel/DirectMemory/PosixMemory.cpp) support shared and private mappings of these descriptors through the allocation tracker and pin a duplicate descriptor during validation and mapping; mapping requires one spare host descriptor; file-backed mappings use the write-watch scan fallback because aliases and descriptor writes bypass per-mapping tracking. Named objects and file-backed mappings on Windows remain unsupported. Invalid non-null name pointers, console behaviour and title compatibility remain unverified.
- [sceKernelAddReadEvent and sceKernelAddWriteEvent](../../../core/libs/prx/libkernel/Equeue/Equeue.cpp) (libkernel): a write event reports the socket's send buffer size (`SO_SNDBUF`) in `data`, not the free space left in it, as Windows has no query for that space. Only guest sockets are supported; other descriptors and a low watermark above 1 throw
- [close](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) and [setsockopt](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) reach a [libSceNet](../../../core/libs/prx/libSceNet/Export.cpp) socket through hooks libSceNet registers, as `select` polls them; the other libkernel socket calls do not. libSceNet numbers its sockets from 32 in its own table, so a CRT file descriptor and a socket can share a number; `close` then closes the socket. On the console both are one kernel descriptor space
- [sceKernelPread, sceKernelPwrite, sceKernelPreadv, sceKernelPwritev](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) on Windows transfer at the given offset with an overlapped `ReadFile`/`WriteFile` and restore the descriptor's file pointer afterwards, so a concurrent `read`/`write` on the same descriptor can see the moved pointer in between, unlike on the console. Handles that are not disk files return `ESPIPE`. `readv` on a pipe or console handle stops after the first iovec read, a short read the console is assumed to allow; each iovec is transferred separately, so a failure after the first transfer returns the bytes already done
- [sceKernelAioSubmitReadCommands, sceKernelAioSubmitWriteCommands and their Multiple variants](../../../core/libs/prx/libkernel/Aio/src/Aio.cpp) (libkernel) on Windows transfer through the same positioned path as `sceKernelPread`/`sceKernelPwrite` and restore the descriptor's file pointer afterwards; positioned transfers, plain transfers and seeks of one descriptor are serialized per descriptor (shared across duplicated descriptors), so a concurrent transfer observes a stable file pointer
- [sceKernelAioSetParam](../../../core/libs/prx/libkernel/Aio/src/Aio.cpp) (libkernel) writes the five values into the 20-byte scheduling struct the first argument points to, following the declarations in [Orbital](https://github.com/AlexAltea/orbital/blob/cc408367da6a6ebbf5ac1ac559fefeadc73b2831/tools/ida/db_types.json), [SharpProspero](https://github.com/SvenGDK/SharpProspero/blob/5dfdb4b0b166e83dc9ae275001afb695f12c7174/src/SharpProspero/Interop/Kernel/KernelAio.cs) and [ampr_emu](https://github.com/drakmor/ampr_emu/blob/cfa85df379f6eeeb165d7badf9b648e266fe77b7/ps5/include/sce/_fs.h). Whether the console checks the values is unknown, so a null struct, a scheduling window or delayed count limit outside 0..128, a split flag other than 0 or 1 and a split size or chunk size above 0x1000000 (SharpProspero's maximums) throw. The scheduling settings are not used: `sceKernelAioInitializeImpl` ignores the struct and requests run synchronously on submit
- [sceKernelGetFsSandboxRandomWord](../../../core/libs/prx/libkernel/System/src/Sandbox.cpp) (libkernel) returns a fixed directory name, `gkbHtXc3Wq`. On the console the name is the process's randomized path (syscall 602, `randomized_path`), and the sandbox exposes system files under it, such as `common/lib` and `common/cert`. Nothing is mounted under the name here, so `/gkbHtXc3Wq/common/...` resolves under the guest root like any other path and does not exist
- [getcontext and setcontext](../../../core/libs/prx/libkernel/System/src/UserContext.cpp) (libkernel) and [makecontext](../../../core/libs/prx/libSceLibcInternal/UserContext.cpp) (libSceLibcInternal) use FreeBSD 11's amd64 `ucontext_t` (`mcontext` at 0x10, `mc_len` 800, `uc_link` at 0x330, `uc_stack` at 0x338, 0x370 bytes), the layout homebrew built against FreeBSD's headers passes: PPSA99039's OpenSSL `ASYNC` (`crypto/async/arch/async_posix.c`) captures into a 0x370-byte stack buffer. `getcontext` writes the 0x330 bytes before `uc_link`, as FreeBSD's `UC_COPY_SIZE`. The console's own layout for these functions is not verified; the exception handler's context is a different one (see `sceKernelRaiseException`)
- [getcontext and setcontext](../../../core/libs/prx/libkernel/System/src/UserContext.cpp) (libkernel) keep the 512-byte FXSAVE image in `mc_fpstate` (x87, MXCSR, XMM0-15), so the upper halves of YMM0-15 are neither saved nor restored, and `getcontext` leaves `mc_xfpustate` and `mc_xfpustate_len` 0. `getcontext` sets `mc_fpformat` and `mc_ownedfp` to FreeBSD's `_MC_FPFMT_XMM` and `_MC_FPOWNED_FPU`, `mc_cs` and `mc_ss` to the host selectors, and `mc_flags`, `mc_fsbase` and `mc_gsbase` to 0. `setcontext` loads `mc_fpstate` whatever `mc_fpformat` and `mc_ownedfp` say, and restores neither the segment selectors, `mc_fsbase` and `mc_gsbase` nor the extended state, which FreeBSD restores when `mc_flags` asks for them
- [setcontext](../../../core/libs/prx/libkernel/System/src/UserContext.cpp) (libkernel) and [longjmp](../../../core/libs/prx/libc/src/JumpBuffer.cpp) (libc) on Windows set the thread's stack bounds in the TEB to the stack they switch to: a `makecontext` stack, or else the committed region around the target stack pointer. A switch to any other guest stack, such as a context built by hand, gets the bounds of that region only
- [sceKernelInstallExceptionHandler](../../../core/libs/prx/libkernel/System/src/Exception.cpp) records the handler, but a host fault still ends the process: only signals raised with `sceKernelRaiseException` are delivered. Unity's PS5Util module installs a SIGUSR1 handler that reads `uc_mcontext.mc_rsp` (offset 0xf8 of the context) and raises SIGUSR1 on other threads to stop them for garbage collection
- [sceKernelRaiseException](../../../core/libs/prx/libkernel/System/src/Exception.cpp) on Linux sends the host SIGUSR1, which the library takes over, to the target thread, so the handler runs wherever the thread was interrupted, emulator code included. On the console kernel objects are system calls and libthr defers signals while a thread holds its internal locks; here a handler that needs a host lock the interrupted code holds deadlocks, and a thread that the handler keeps waiting keeps its host locks. Host waits resume after the handler. The host calls Linux does not restart end early: sleeps that do not retry return before their time, and the poll of `sceNetEpollWait` and socket calls with a send or receive timeout return `EINTR` to the guest
- [sceKernelRaiseException](../../../core/libs/prx/libkernel/System/src/Exception.cpp) builds the handler's `ucontext` with FreeBSD's amd64 layout (16-byte sigmask, `mcontext` at 0x40, `mc_rsp` at 0xf8); the console's layout is not verified beyond the fields PS5Util reads
- [sceKernelRaiseException](../../../core/libs/prx/libkernel/System/src/Exception.cpp) does not consult the target thread's signal mask
- [pthread_sigmask](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) shares the process-wide mask of `sigprocmask` and `_sigprocmask`, which keeps only the first 32 signals; FreeBSD keeps a mask per thread
- [sceKernelRaiseException](../../../core/libs/prx/libkernel/System/src/Exception.cpp) reaches a thread that waits in an alertable `TimedWait` wait through an APC. A thread blocked anywhere else, including all waits under `APS5_COARSE_TIMED_WAITS` and host waits inside the emulator, is redirected and runs the handler only when that wait returns
- [sceKernelRaiseException](../../../core/libs/prx/libkernel/System/src/Exception.cpp) on Windows runs the handler wherever the target thread was interrupted. It waits only while the thread is inside winpthreads or restoring a context through `NtContinue`, and throws if that lasts 1 s, so a handler that calls into other host code the thread was interrupted in, such as the C runtime's heap or a lock of the emulator, can deadlock on it or reenter it
- [sigaltstack](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) records each thread's alternate signal stack and reports it back, following FreeBSD's `kern_sigaltstack` (`EINVAL` for flags other than `SS_DISABLE`, `ENOMEM` below `MINSIGSTKSZ` 2048), but handlers never run on it, so `SS_ONSTACK` and `EPERM` are never reported
- [sigpending](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) reports the intersection of the process-wide pending set of `sigtimedwait` and the blocked mask of `_sigprocmask`, as FreeBSD's `sys_sigpending` intersects the pending list with `td_sigmask`, and returns -1 with `EFAULT` for a null set. Because `_sigprocmask` keeps only the first 32 signals, signals 33 to 128 are never blocked and never appear in the set, and setting `SIG_IGN` (or `SIG_DFL` on a signal whose default action is to ignore) does not clear a signal that was already marked pending. PPSA99420 imports it
- [scePthreadJoin, scePthreadCreate](../../../core/libs/prx/libkernel/Pthread/src/Thread.cpp) (libkernel) - on a PS5 (firmware 13.60) joining a thread a second time returns `ESRCH` (`0x80020003`); here a joined thread is released, so a second join reads freed memory. A null entry crashed the payload and still throws. Joining the calling thread returns `EDEADLK` and a zeroed attribute creates a default thread, as on the console
- [Thread cancellation](../../../core/libs/prx/libkernel/Pthread/src/Thread.cpp) (libkernel) follows FreeBSD libthr (states and types 0/1 and 0/2, `PTHREAD_CANCELED` 1, the `_pthread_cleanup_info` node layout), not measured on the console. A request is acted on only in `scePthreadTestcancel`, the condition variable, `sem` and `scePthreadSem` waits, `scePthreadJoin` and the sleeps, and their POSIX names; file and socket calls are not cancellation points. A sleep is not interrupted: the thread exits when it ends. The asynchronous type acts like the deferred one, except at the two set calls.
- [cpuset_setaffinity](../../../core/libs/prx/libkernel/Pthread/Posix/Thread.cpp) (libkernel) - only the calling thread or the calling process is handled; other levels (ROOT/CPUSET), other scopes (CPUSET/JAIL) and other threads throw as unmodelled, invalid levels or scopes return `EINVAL` and unknown thread or process IDs return `ESRCH`, following FreeBSD's `cpuset_setaffinity`. Bits outside `sceKernelGetAvailableCpumask` are dropped, and a mask with none of those bits fails with `EDEADLK`, as FreeBSD does when the new set has no CPU in common with the parent set
- [cpuset_getaffinity](../../../core/libs/prx/libkernel/Pthread/Posix/Thread.cpp) (libkernel) - only the calling thread or the calling process is handled; other levels (ROOT/CPUSET), other scopes (CPUSET/JAIL) and other threads throw as unmodelled, invalid levels or scopes return `EINVAL` and unknown thread or process IDs return `ESRCH`, following FreeBSD's `cpuset_getaffinity`. For the process the mask is the union of the affinities of the live guest threads, as [FreeBSD 11.4](https://github.com/freebsd/freebsd-src/blob/d106002967eff712894ab8b5337bbbff106ce5e0/sys/kern/kern_cpuset.c#L1150-L1156) ORs the mask of every thread in the process; threads the guest did not create through libkernel are not included, and the console result is unverified
- [pthread_setaffinity_np](../../../core/libs/prx/libkernel/Pthread/Posix/Thread.cpp) (libkernel) - follows [FreeBSD 11.4](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/lib/libthr/thread/thr_affinity.c#L41-L62) libthr over `kern_cpuset_setaffinity` for the calling thread and any live guest thread: a size other than the 32-byte `cpuset_t` returns `ERANGE`, an unknown or finished thread `ESRCH`. Bits outside `sceKernelGetAvailableCpumask` are dropped and a mask with none of those bits returns `EDEADLK`, as `cpuset_setaffinity` does; the affinity is recorded on the guest thread and not applied to the host thread, and the console result is unverified
- [dup and dup2](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) throw for the combinations they do not model: `dup2` of a guest socket onto descriptors 0 to 2, whose host streams libc writes without the socket table, and on Windows duplicating a directory descriptor. Guest sockets share one socket object between the duplicates; the numbers come from the host descriptor table like those of files. The errno values for descriptor exhaustion are not verified against the console.
- [waitpid](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) returns -1 with `ECHILD` (`EINVAL` for unknown options): nothing here creates a child process; child processes would need a real `waitpid`.
- [execv](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) throws: replacing the process image is not supported, the same as `execvp`. PPSA97358 imports it and fails to load without it.
- [execve](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) throws like `execvp`: replacing the process image is not supported. The console behavior for invalid arguments and executable path lookups is not modeled.
- [kern.proc.pathname](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) returns `/app0/eboot.bin` for pid -1 and the calling process, following FreeBSD's `sysctl_kern_proc_pathname`; the exact pathname on retail consoles remains unverified.
- [machdep.cacheline_size](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) returns -1 with `ENOENT`, matching FreeBSD amd64 where this sysctl OID is not defined.
- [hw.model](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) reports the host CPU's name, built as FreeBSD 11 builds `hw.model`: the CPUID brand string (leaves 0x80000002 to 0x80000004) without leading spaces ([identcpu.c](https://github.com/freebsd/freebsd-src/blob/release/11.0.0/sys/x86/x86/identcpu.c#L683-L691)). Trailing padding stays, as it does there, so an AMD host's name ends in spaces. The name a PS5 reports is unknown. A write returns -1 with `EPERM`. A host without an x86 CPUID brand string, such as an Apple Silicon Mac, throws. PPSA99203 only prints it (`[console] hw.model: %s`)
- [machdep.tsc_freq](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) reports the host TSC frequency that `sceKernelGetTscFrequency` measures, as a 64-bit value like FreeBSD 11's [`sysctl_machdep_tsc_freq`](https://github.com/freebsd/freebsd-src/blob/release/11.0.0/sys/x86/x86/tsc.c#L658-L676). FreeBSD lets root write it to change the TSC timecounter's frequency; a write here returns -1 with `EPERM`. PPSA99203 reads it at start-up and measures the TSC itself when the value is 100 MHz or less
- [getrlimit](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) - `RLIMIT_CPU`, `RLIMIT_FSIZE`, `RLIMIT_CORE`, `RLIMIT_SBSIZE`, `RLIMIT_VMEM`/`AS`, `RLIMIT_NPTS`, `RLIMIT_SWAP`, `RLIMIT_KQUEUES` and `RLIMIT_UMTXP` report infinity as in FreeBSD's process-0 defaults, and `RLIMIT_DATA` mirrors the host limit. `RLIMIT_STACK`, `RLIMIT_RSS`, `RLIMIT_MEMLOCK`, `RLIMIT_NPROC` and `RLIMIT_NOFILE` throw because no console values are established.
- [setrlimit](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) validates the resource and input in FreeBSD order, maps negative limits to infinity, and lowers a soft limit above the hard limit. A request succeeds only when its normalized values match `getrlimit`; changing limits throws because guest limit state is not stored.
- [execvp](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) throws: replacing the process image is not supported. PPSA85300 imports it and fails to load without it; its `fork` and `vfork` fail with `ENOSYS` ([libc_missing.c](https://github.com/ZiZc3/VLC/blob/f3253020a64368153233ede29183014c0b6c8979/ps5/compat/libc_missing.c#L290-L292)), so the child process that would call it is never created.
- [socketpair](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) - the pair is the host's `AF_UNIX` pair on Linux and, on Windows, a loopback TCP connection for `SOCK_STREAM` or two connected UDP sockets for `SOCK_DGRAM`; `SOCK_SEQPACKET` throws on Windows. A datagram sent to a full receiver gets `ENOBUFS` on the console, waits or gets `EAGAIN` on Linux and is dropped on Windows, and on Windows a datagram `recv` after the peer closed reports `ECONNRESET` instead of the console's `ENOTCONN`, and a stream `send` after the peer closed reports `ECONNABORTED` instead of the console's `EPIPE`. `read` and `write` on a pair end go to the host like on every guest socket. `getpeername` on a pair end succeeds after the peer closed, where the console returns `ENOTCONN`, and `connect`, `bind` and `sendto` with an address on a pair end report an address-family error instead of the console's `EISCONN`. On Windows `poll` on a stream end reports `POLLHUP` without `POLLIN` after the peer's `shutdown(SHUT_WR)` or `close`, where the console reports `POLLIN`, with `POLLHUP` only after `close`
- [UDP recv/recvfrom](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) and [sceNetRecv/sceNetRecvfrom](../../../core/libs/prx/libSceNet/Export.cpp) translate Windows WSAEMSGSIZE into the copied byte count for datagram sockets, including MSG_PEEK, and retain the sender address. This follows FreeBSD 11.4 recv(2) and Winsock's documented truncated-datagram behavior; console behavior and existing title impact are unverified.
- [send, sendto](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) - send and sendto without an address on an unconnected datagram socket map Windows `WSAENOTCONN` to FreeBSD's `EDESTADDRREQ` (39).
- [read, write and vector I/O](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) on a guest socket use `recv` and `send` without flags; `sceKernelReadv` and `sceKernelWritev` gather or scatter through one socket operation, preserving stream short reads and datagram boundaries. The positioned `pread`, `pwrite`, `preadv` and `pwritev` forms, and their `sceKernel` forms, return `ESPIPE` for an open guest socket and `EBADF` for a closed one. `EPIPE` from a write raises the host's `SIGPIPE` on Linux, which the guest can neither ignore nor suppress: `signal(SIGPIPE, SIG_IGN)` and `sigaction` record the disposition, as they do for every number from 1 to 128, but only the six signals with host equivalents (2, 4, 6, 8, 11 and 15) take effect on the host or are delivered, so the host `SIGPIPE` is not stopped; `SO_NOSIGPIPE` is not an option here, and raises nothing on Windows; a `write` longer than `INT_MAX` bytes is `EMSGSIZE` where the console sends it. AIO on a guest socket still goes to the host, which has no such descriptor
- [Socket descriptor numbers](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel, libSceNet) - `socket`, `accept`, `socketpair`, `dup`, `sceNetSocket` and `sceNetAccept` take the lowest free number of the host descriptor table that files use, as FreeBSD 11.4 `fdalloc` takes the lowest free entry of the one process table (`kern_descrip.c`), so every number stays below `FD_SETSIZE` (1024) while fewer than 1024 descriptors are open. The number holds a zero-access `NUL` handle on Windows and a duplicate of the host socket on Linux, and the socket tables map it to the socket. The host table also holds the runtime's own files, so the numbers differ from the console's; the first number `socket` and `sceNetSocket` return on a console and its `getdtablesize` are not measured. Paths that bypass the socket tables see the placeholder: libc `fdopen` on a socket opens it, libkernel `fstat` on a socket throws, and libkernel `close` of a libSceNet socket releases the number but leaves the libSceNet socket open. Palworld (PPSA23126), The Mound (PPSA26223) and Dying Light 2 (PPSA02262) set socket bits in a 1024-bit `fd_set`
- [poll](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) waits on guest sockets and pipes, through `WSAPoll` on Windows and `poll` on Linux; the `pollfd` layout and flag values are FreeBSD's. `WSAPoll` rejects `POLLPRI`, so on Windows a socket's `POLLPRI` is asked as `POLLRDBAND` and `POLLIN` as `POLLRDNORM`; Winsock reports urgent data until it is read with `MSG_OOB`, where FreeBSD 11.4's `sopoll_generic` stops once the normal stream passes the mark. Guest `send` and `recv` refuse `MSG_OOB` with `EOPNOTSUPP`, so urgent data can only come from an outside peer and Windows keeps reporting `POLLPRI` after the stream passes the mark. A pipe follows FreeBSD's `pipe_poll`: the read end is readable when data is buffered, either end reports `POLLHUP` once the other end is closed, with the requested `POLLIN` and `POLLRDNORM` bits and without `POLLOUT`, which `pollscan` clears, and the write end is writable when `PIPE_BUF` (512) bytes are free on Windows, or when the host kernel says so on Linux. `POLLOUT` on a read end throws: FreeBSD opens both ends for reading and writing and reports it writable, and host pipes are one-way. Windows pipes cannot be waited on, so while a pipe is polled `poll` checks it with `NtQueryInformationFile` and waits on the sockets in slices of 1 ms. A closed descriptor reports `POLLNVAL`, and an open descriptor that is neither a guest socket nor a pipe (files, stdio, libSceNet sockets) throws, as do event bits other than `POLLIN`, `POLLPRI`, `POLLOUT`, `POLLRDNORM`, `POLLRDBAND` and `POLLWRBAND` (the `POLLERR`, `POLLHUP` and `POLLNVAL` bits are ignored in `events`), an infinite timeout with no socket or pipe to wait on. A closed socket descriptor reports `POLLNVAL`; the console's limit on the descriptor count is unknown and not checked
- [Socket error numbers](../../../core/libs/prx/libkernel/Socket/include/SocketError.hpp) (libkernel) - a host socket error becomes the FreeBSD 11 `errno.h` number of the same name; the numbers are not checked on the console. Winsock `WSAESHUTDOWN` becomes `EPIPE`, as a send after `shutdown` does on FreeBSD, and a host error with no FreeBSD socket counterpart becomes `EIO`. A nonblocking `connect` in progress reports `EINPROGRESS` on Linux but `EAGAIN` on Windows (`WSAEWOULDBLOCK`), where FreeBSD reports `EINPROGRESS`. On Windows a refused nonblocking `connect` is never reported (`SO_ERROR` is unsupported), so a repeated one keeps reporting `EALREADY` where FreeBSD reports `ECONNREFUSED`. A receive after `shutdown(SHUT_RD)` reports `EPIPE` on Windows where FreeBSD returns 0
- [connect to AF_UNSPEC](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) dissolves a datagram association as FreeBSD 11.4's `udp_disconnect()` does, which resets the local address to the wildcard address and keeps the port. On Linux a socket bound to an explicit port keeps its local address as well (`127.0.0.1:<port>` stays `127.0.0.1:<port>`), because a bound socket cannot be bound again; one bound to port 0 is bound again to the wildcard address with the port it had
- [msync](../../../core/libs/prx/libkernel/DirectMemory/PosixMemory.cpp) (libkernel) follows FreeBSD 11's `kern_msync` and `vm_map_sync`, not measured on the console: the address is rounded down to the page, a range that wraps is `EINVAL`, as is `MS_ASYNC` with `MS_INVALIDATE`, and a range whose start or any page is not mapped (as `sceKernelVirtualQuery` reports it, reservations included) is `ENOMEM`; a page unmapped from inside a larger mapping still counts as mapped there, since `sceKernelVirtualQuery` keeps reporting the whole mapping. The guest has no file mappings, so a successful call writes nothing back. `MS_INVALIDATE` on a mapped range throws: FreeBSD returns `EBUSY` when the range holds `mlock`ed pages, and locked pages are not tracked
- [madvise](../../../core/libs/prx/libkernel/DirectMemory/PosixMemory.cpp) (libkernel) accepts `MADV_PROTECT` (10) as a no-op hint without modifying process protection. FreeBSD 11's `kern_madvise` (`sys/vm/vm_mmap.c`) handles it before the address check, ignores the address and length, and calls `kern_procctl(..., PROC_SPROTECT, PPROT_SET)`, which requires `PRIV_VM_MADV_PROTECT` and fails with `EPERM` without it. Returning 0 unconditionally assumes the calling process is privileged. Console behaviour is unverified
- [mlockall](../../../core/libs/prx/libkernel/DirectMemory/PosixMemory.cpp) (libkernel) returns `EINVAL` for zero or unknown flags. Valid `MCL_CURRENT` throws because it would lock host stacks, heaps, modules and driver mappings along with guest memory; `MCL_FUTURE` throws because later mappings are not tracked for locking. On main, XPSemu (PPSA97358) fails to load at this import; its `MCL_CURRENT | MCL_FUTURE` calls execute only when `-overcommit mem-lock=on` is enabled. The call has not been observed in a run with this implementation.
- [sigtimedwait](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) waits on a process-wide pending set instead of throwing: a signal raised while blocked stays pending and is taken by `sigwait`, `sigwaitinfo` or `sigtimedwait`, delivered to the handler when `_sigprocmask` unblocks it, or delivered by `pause`. The set covers all 128 signals and the lowest number that is pending and in the set is selected (FreeBSD specifies the lowest number only among real-time signals). Selection, `EAGAIN` on timeout, `EINVAL` for a `tv_nsec` outside 0 to 1000000000 while nothing is pending and `NULL` timeout blocking indefinitely follow FreeBSD's [sigtimedwait(2)](https://man.freebsd.org/cgi/man.cgi?query=sigtimedwait). `sigwait` returns 0 with the number in its output, as POSIX specifies, and `sigwaitinfo` and `sigtimedwait` return the number, as FreeBSD does. The guest `siginfo_t` follows FreeBSD 11's `sys/sys/siginfo.h`: 80 bytes, `si_signo` at 0, `si_code` at 8, `si_pid` at 12, `si_uid` at 16, `si_addr` at 24, `si_value` at 32 and `si_band` at 40; only `si_signo`, `si_code` (`SI_USER`) and `si_pid` (the guest pid) are written, `si_uid` stays 0 because no uid is modelled, and the console's layout is not verified. PPSA85300 imports `sigtimedwait` and fails to load without it; its only call site is VLC's `vlc_writev` ([filesystem.c](https://github.com/videolan/vlc/blob/6de05adcbaf2e8b85fe86aad4169393098628119/src/posix/filesystem.c#L243-L278)), which polls with a zero timeout to drain a `SIGPIPE` only after `writev` fails with `EPIPE`. The waits are not cancellation points and an unblocked caught signal does not interrupt them with `EINTR`, where FreeBSD's `sigwaitinfo` and `sigtimedwait` may return it. `SIGPIPE` has no host equivalent and is never raised by a host write here (see `read, write and vector I/O`), so VLC's drain finds nothing
- [pause, sigwait, sigwaitinfo](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) take the pending set of `sigtimedwait` instead of throwing. `pause` waits for a pending signal that is not blocked and whose disposition can be delivered, runs its handler on the calling thread and returns -1 with `EINTR`; an ignored signal is discarded and the wait continues, and it never returns for a signal whose handler cannot run. A signal whose registered handler has `SA_SIGINFO` still throws, and one whose disposition is the default action and that has no host equivalent (every signal except 2, 4, 6, 8, 11 and 15) is neither delivered nor discarded: it stays pending until a wait takes it, where FreeBSD runs the default action, which terminates the process for most of them. PPSA68091, PPSA99169, PPSA99420 and PPSA97358 import them and fail to load without them. PPSA68091 calls `pause` at one site (0x8F7266), in a loop that waits while a global holds another thread's `errno` address. PPSA99169 only stores the address of `pause` in a table of symbol addresses (0x30DB1). PPSA99420 calls `pause` at 0x3BD80F6 and 0x3C9E220, `sigwait` at 0x3C9E4C7 and `sigwaitinfo` at 0x3C9E588. PPSA97358 calls `sigwait` from QEMU's `sigwait_compat` thread ([compatfd.c](https://github.com/ZiZc3/XPSemu/blob/8eec07b4e31f66dce8e0b05c1ca1281af303e933/util/compatfd.c#L28-L53)), which `qemu_signal_init` ([main-loop.c](https://github.com/ZiZc3/XPSemu/blob/8eec07b4e31f66dce8e0b05c1ca1281af303e933/util/main-loop.c#L110-L147)) starts for `SIGIO`, `SIGALRM` and `SIGBUS` when the main loop is created, so it reaches the wait at start-up, and from the vCPU thread of the dummy accelerator ([dummy-cpus.c](https://github.com/ZiZc3/XPSemu/blob/8eec07b4e31f66dce8e0b05c1ca1281af303e933/accel/dummy-cpus.c#L48-L56)). None of the four waits is a cancellation point
- [getsid](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) returns the calling process ID for pid 0 and the calling process, and `ESRCH` for other process IDs, assuming the single guest process is its own session leader. PPSA74126 imports it and fails to load without it
- [sigaction](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) records the handler, flags and mask of every signal from 1 to 128 and reports them back, following FreeBSD's `sigaction` (`EINVAL` for other signals, and for a handler on `SIGKILL` or `SIGSTOP`); `signal` records its handler with `SA_RESTART`, as FreeBSD's libc does. Only handlers without `SA_SIGINFO` on the signals `signal` already delivers (`SIGINT`, `SIGILL`, `SIGABRT`, `SIGFPE`, `SIGSEGV`, `SIGTERM`) run, the same way `signal` handlers do; their mask and flags are not applied. `SA_SIGINFO` handlers are recorded but never called, since that needs FreeBSD's `siginfo_t` and `ucontext_t`, and neither are the handlers of other signals (`SIGBUS`, `SIGHUP`, ...), whether they are set by `sigaction` or by `signal`, which records them too (every number from 1 to 128, with `SA_RESTART` and an empty mask replacing what `sigaction` stored; `SIGKILL` and `SIGSTOP` accept only the default handler in both calls, as in FreeBSD's `kern_sigaction`). `raise` and `kill` accept every number from 1 to 128 now: a blocked one stays pending on the set of `sigtimedwait`, an unblocked one whose handler is registered runs it on the calling thread, and an unblocked one that has no host equivalent and no handler still fails with `EINVAL`, where FreeBSD runs its default action. `raise` of an `SA_SIGINFO` handler still throws instead of terminating
- [kill, killpg](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) follow FreeBSD's `kern_kill` and `killpg1` for the only guest process: `EINVAL` for signals outside 0 to 128 and for negative `killpg` process groups, signal 0 only checks that the target exists, and its own pid, 0 and minus its own pid (the guest is taken to lead its own process group) signal it through `raise`, so they share `raise`'s limits above. Any other pid, and -1, which skips the caller, report `ESRCH`, so `EPERM` is never reported
- [sceKernelFcntl](../../../core/libs/prx/libkernel/File/src/Open.cpp) (libkernel) runs the POSIX `fcntl` below and returns its guest errno as `SCE_KERNEL_ERROR_*`, the form the other `sceKernel` file exports use. The return values and error codes are unverified on a console
- [fcntl](../../../core/libs/prx/libkernel/File/src/DescriptorControl.cpp) (libkernel) follows FreeBSD 11.4's [`kern_fcntl`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_descrip.c#L479-L799) and [`kern_dup`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_descrip.c#L812) on file, directory, pipe and character device descriptors; a socket keeps the libSceNet path (`F_GETFL`, `F_SETFL` with `O_NONBLOCK`, `EINVAL` for every other command, `F_GETFD` and `F_SETFD` included). The close-on-exec flag and the status flags live in a guest table, the status flags shared by `dup`, `dup2` and `F_DUPFD` as in an open file description; a descriptor the table has not seen, such as 0 to 2, starts from the host's flags, since the console's are not known. `F_GETFL` takes the access mode from the host (the granted access of the handle on Windows), so pipe ends report `O_RDONLY` and `O_WRONLY` where FreeBSD's bidirectional pipes report `O_RDWR`. `F_DUPFD` and `F_DUPFD_CLOEXEC` return the lowest free host descriptor at or above the start, so the bound is the host table (`EMFILE` on Windows, `EINVAL` past `RLIMIT_NOFILE` on Linux), not the console's unknown `RLIMIT_NOFILE` and `kern.maxfilesperproc`. `O_NONBLOCK` switches a host pipe (`PIPE_NOWAIT` on Windows, where an empty read and a full write then report `EAGAIN`) and is only recorded on files, directories and the random device, as their reads never block; on a Windows console or other character device it throws. Changing `O_APPEND` on a Windows file, changing `O_FSYNC` on a file, `O_ASYNC` on a pipe or character device (`SIGIO` is not delivered), `F_GETOWN`, `F_SETOWN` and `F_SETLK_REMOTE` throw; `O_DIRECT`, `F_RDAHEAD` and `F_READAHEAD` are recorded as the hints they are. Record locks (`F_GETLK`, `F_SETLK`, `F_SETLKW` and their forms without `l_sysid`) use the host's POSIX locks on Linux, where `F_GETLK` with `F_UNLCK` throws. On Windows they follow [`kern_fcntl`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_descrip.c#L607-L752) and [`lf_advlockasync`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_lockf.c#L433-L487) for the one guest process, which owns every lock: `EOVERFLOW` for an `SEEK_CUR` start past `OFF_MAX`, then `EBADF` for `F_RDLCK` without read access or `F_WRLCK` without write access and `EINVAL` for another type, then `EINVAL` and `EOVERFLOW` for the range; as [`lf_blocks`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_lockf.c#L866) never lets locks of one owner conflict, whichever descriptor or thread asks, `F_SETLK` and `F_SETLKW` then succeed without waiting and `F_GETLK` reports `F_UNLCK`, so no lock list is kept and merging, splitting and the release on close have nothing to change. Nothing is held on the host, since Windows byte-range locks are mandatory and would fail the guest's own reads and writes through other descriptors, so other host processes neither see these locks nor are seen; a lock from the end of a directory throws. The return values and error codes are unverified on a console
- [ioctl, _ioctl](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) handle only `FIONBIO` and `FIONREAD` on a socket, and any other request there fails with `ENOTTY`. On the other descriptors they follow FreeBSD's [`kern_ioctl`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/sys_generic.c#L758), [`vn_ioctl`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/vfs_vnops.c#L1488) and [`pipe_ioctl`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/sys_pipe.c#L1346): `FIONBIO` sets `O_NONBLOCK` as `fcntl` does, and `FIONREAD` reports the size past the offset of a file, the queued bytes of a pipe's read end, 0 on its write end and `ENOTTY` on the random device, while it throws on a directory or another character device. Every termios request (group `t`, `TIOCGWINSZ` included) fails with `ENOTTY`, since those descriptors are taken as not a terminal, as in `tcgetattr`, and any other request throws. Stremio Plus (PPSA74126) imports `_ioctl` for its statically linked `tc*` functions, which send `TIOCGETA`, `TIOCSETA`, `TIOCSPGRP` and the other termios requests
- [sendfile](../../../core/libs/prx/libkernel/Socket/src/Udp.cpp) (libkernel) follows FreeBSD 11's `sendfile` for a connected stream socket: headers, the file from `offset` (to its end when `nbytes` is 0) and trailers, the file offset left unchanged, `EAGAIN` with `*sbytes` set after a partial send on a non-blocking socket. It reads the file through `sceKernelPread` in 64 KiB blocks and sends each with `send`. A socket as the file fails with `EINVAL`, as on FreeBSD, but any other descriptor `sceKernelPread` reads, such as `/dev/urandom`, is sent where FreeBSD requires a regular file or shared memory, and a file descriptor as the socket fails with `EBADF`, as for `send`, where FreeBSD answers `ENOTSOCK`. `flags` are ignored: reads complete before sending, so `SF_NODISKIO` never fails with `EBUSY`, and `SF_SYNC` returns once the data is queued on the socket rather than sent. PS5MC (PPSA99420) imports it
- [pthread_kill](../../../core/libs/prx/libkernel/System/src/Signals.cpp) (libkernel) returns the error number like FreeBSD's `pthread_kill`: `EINVAL` for signals outside 0 to 128 and `ESRCH` for a null thread. Signal 0 reports any other thread handle as existing, without checking that the thread is still alive. A signal to the calling thread goes through `raise`, so it shares `raise`'s limits; a signal to another thread is left on the pending set for whichever thread waits for or unblocks it, since it is not delivered to the chosen thread, and a handle that is not a live guest thread returns `ESRCH` without touching it
- [select](../../../core/libs/prx/libkernel/Socket/src/Socket.cpp) (libkernel) validates `tv_usec` but saturates a valid timeout beyond the remaining `steady_clock` range at `time_point::max()`, so the wait can continue effectively indefinitely. The console's behavior for a valid timeout outside the host clock's range is unknown.
- [_fstatfs](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) fills the FreeBSD 11 `struct statfs` of the PS5 payload SDK with the host volume that holds the file: block size, transfer size, total, free and available blocks, maximum name length and the read-only, `nosuid` and `noexec` flags (on Windows only read-only, and `f_files` and `f_ffree` are 0, as NTFS has no fixed number of files). The filesystem type number and name, mount paths, owner, filesystem id and I/O counters are left 0 or empty, since they would describe a host mount, not a console one. Sockets and pipes return `EINVAL`, as FreeBSD's `getvnode` does; a Windows descriptor that is neither a file nor a pipe throws. Stremio Plus (PPSA74126) reads the free space before a download and only logs the other fields
- [pthread_spin_init, pthread_spin_destroy, pthread_spin_lock, pthread_spin_trylock, pthread_spin_unlock](../../../core/libs/prx/libkernel/Pthread/Posix/Spinlock.cpp) (libkernel) follow FreeBSD 11.4 libthr [`thr_pspinlock.c`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/lib/libthr/thread/thr_pspinlock.c) and the owner checks of its [`thr_umtx.h`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/lib/libthr/thread/thr_umtx.h#L80-L175), unverified on the console: `EINVAL` for a null or destroyed lock and a `pshared` other than 0 or 1, `EBUSY` from `trylock` while any thread holds it, `EPERM` from `unlock` by a thread that does not hold it. `PTHREAD_PROCESS_SHARED` allocates a private lock, as guest code runs in one process. libthr spins forever when the holder locks again; here that call throws
- [sceKernelGetEventError](../../../core/libs/prx/libkernel/Equeue/src/EventAccessors.cpp) (libkernel) returns the event's `data` as an `int` when `EV_ERROR` (0x4000) is set in `flags` and 0 otherwise, as [KytyPS5](https://github.com/KytyPS5/KytyPS5/blob/947627d10d4ef4b68ba3c0189aab6c368e70a8d2/src/kernel/eventQueue.cpp#L663) does and as FreeBSD 11's [kevent](https://github.com/freebsd/freebsd-src/blob/release/11.0.0/sys/kern/kern_event.c#L1005) reports a failed change (`flags = EV_ERROR`, errno in `data`). [fpPS4](https://github.com/red-prig/fpPS4/blob/04cefd43e6fddd1ab033e7980cd356d14c964905/kernel/ps4_queue.pas#L643) instead returns `fflags` plus `0x80020000` when `fflags` is nonzero. Whether the console reads `data` or `fflags` and returns the raw errno or an SCE error code is unverified. No event delivered by the equeue here carries `EV_ERROR`, so the call returns 0 for every event `sceKernelWaitEqueue` reports
- [pthread_cond_reltimedwait_np](../../../core/libs/prx/libkernel/Pthread/Posix/Cond.cpp) (libkernel) takes `(cond, mutex, usec)`, a relative timeout in microseconds, and is `scePthreadCondTimedwait` with POSIX error numbers. FreeBSD 11.4 has no such function; the signature comes only from shadPS4, which registers one function for this NID and for `scePthreadCondTimedwait` ([`condvar.cpp`](https://github.com/shadps4-emu/shadPS4/blob/3a9f57265d28975658f1ca941daa5c879c7a74bd/src/core/libraries/kernel/threads/condvar.cpp#L229-L234)). shadPS4 reads a 64-bit count; here it is the 32-bit `SceKernelUseconds` of the SCE twin, as for `sem_reltimedwait_np`. Unverified on the console
- [sysctl kern.arandom](../../../core/libs/prx/libkernel/System/src/SystemConfiguration.cpp) (libkernel) serves FreeBSD 11's MIB {1, 37} (CTL_KERN, KERN_ARANDOM) and the "kern.arandom" sysctlbyname lookup through std::random_device, returning min(*oldLength, 256) random bytes. Following FreeBSD's sysctl_kern_arnd, a null buffer reports min(*oldLength, 256) without writing, a null length returns 0 without writing, and requests with a new value return EPERM (1) as the node is read-only. Cryptographic quality depends on the host's random device implementation.
- [pthread_atfork](../../../core/libs/prx/libkernel/Pthread/Posix/Atfork.cpp) (libkernel) appends the three handlers to a process-wide list and returns 0, or `ENOMEM` when the entry cannot be allocated, as FreeBSD 11.4's [`_pthread_atfork`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/lib/libthr/thread/thr_fork.c#L78-L100) does; null handlers are accepted. The handlers never run: `fork` throws and `vfork` is absent, so no child process is created. Handlers of a module that is unloaded stay in the list, where FreeBSD's `__pthread_cxa_finalize` removes them. PPSA97358 has a source-level call from the constructor `rcu_init` ([rcu.c](https://github.com/ZiZc3/XPSemu/blob/8eec07b4e31f66dce8e0b05c1ca1281af303e933/util/rcu.c#L488-L495)), but current-main runtime reachability is unverified; XPSemu currently stops first at the unresolved `mlockall` import (#4386)
- [sceKernelGetPageTableStats](../../../core/libs/prx/libkernel/DirectMemory/Export.cpp) (libkernel) - reports 2048 page-table entries on each side (a 4 GiB pool of 2 MiB entries, the constants of [KytyPS5](https://github.com/KytyPS5/KytyPS5/blob/main/src/kernel/memory.cpp)) and all of them available: no entries are counted as used, so a title never sees page-table pressure. KytyPS5 counts the 2 MiB entries of the committed CPU- or GPU-accessible ranges as used, which this port does not do. The four `int*` arguments follow OpenOrbis' `libkernel.h`, the Orbital type database and SharpProspero; a null pointer returns `SCE_KERNEL_ERROR_EFAULT` as in KytyPS5. None of the values is measured on a console. PPSA30601 (Resonance) calls it during start-up
- [clock_settime](../../../core/libs/prx/libkernel/Time/Time.cpp) (libkernel) validates like FreeBSD 11.4's [`kern_clock_settime`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_time.c#L396-L412) for a root caller: `EFAULT` for a null time, `EINVAL` for any clock but `CLOCK_REALTIME`, a negative second count or a nanosecond count outside 0 to 999999999. A valid `CLOCK_REALTIME` request throws, naming the requested time, since the host clock is never set and no guest clock offset is kept. FreeBSD checks `PRIV_CLOCK_SETTIME` first, which a jailed process fails with `EPERM`; whether a title holds it on the console is unverified. PS5MC (PPSA99420) imports it; no call site is known
- [chflags](../../../core/libs/prx/libkernel/File/src/Stdio.cpp) (libkernel) follows FreeBSD 11.4's [`kern_chflagsat`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/vfs_syscalls.c#L2366-L2383) and UFS's [`ufs_setattr`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/ufs/ufs/ufs_vnops.c#L509-L556) for a root caller: the path lookup reports `EFAULT`, `ENOENT` and `ENOTDIR`, a flag outside the 17 UFS stores (`VNOVAL` included) `EOPNOTSUPP`, and `SF_SNAPSHOT` `EPERM`. Neither host keeps BSD file flags, so every file is taken to have none (`stat` reports `st_flags` 0): flags 0 succeed without touching the file, and any other flag throws, naming the flags. `UF_READONLY`, `UF_HIDDEN`, `UF_SYSTEM` and `UF_ARCHIVE` are FreeBSD's names for the Windows attributes but are not mapped to them: UFS stores them without enforcing them, `FILE_ATTRIBUTE_READONLY` already carries the owner write bit of `chmod` on Windows, and Linux has no equivalent a process can set without `CAP_LINUX_IMMUTABLE`. The console's filesystem types, `EROFS` on read-only mounts and the change-time update are not modelled
- [getpriority](../../../core/libs/prx/libkernel/System/src/Process.cpp) (libkernel) follows FreeBSD 11.4's [`sys_getpriority`](https://github.com/freebsd/freebsd-src/blob/8c639945a44588f6cfdddfb057bb5aad88735da0/sys/kern/kern_resource.c#L93-L165) for the only guest process, which is taken to run at nice 0: `PRIO_PROCESS` and `PRIO_PGRP` with 0 or its own pid (the guest is taken to lead its own process group, see `kill`) and `PRIO_USER` with 0 or its user id 0 return 0, any other id fails with `ESRCH` and any other `which` with `EINVAL`. As in FreeBSD's libc, where `getpriority` is the bare system call, errno is left unchanged on success. The nice value of a title process on the console is unverified, and the host nice of the process or of the threads `APS5_THREAD_PRIORITY=high` raises is not reported