* feat(libkernel): implement sceKernelReleaseFlexibleMemory
Unmaps the range through sceKernelMunmap, which returns its pages to
the flexible memory budget, as fpPS4 and prosper do.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* test(libkernel): keep the flexible memory release check apart from the batch map checks
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Release direct memory only when the whole range is allocated: a misaligned
start or length returns EINVAL, a zero length succeeds, and a range that
leaves direct memory or covers an unallocated page returns ENOENT without
releasing anything, as in shadPS4. The check and the release run under
the pool lock.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A range reserved with sceKernelReserveVirtualRange is registered as not
readable, and sceKernelVirtualQuery only searched readable registrations,
so a query inside a reservation fell back to the host and returned EACCES.
Reserved ranges are now tracked until a direct or flexible mapping or an
unmap covers them, and a query inside one succeeds with the reserved piece
as its extent, protection 0 and is_committed clear. PPSA12544's allocator
queries a reservation before committing it and treated the error as a
failed commit, then wrote to the inaccessible range.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
On Windows the guest arena ended at 0x72_0000_0000: #231 kept its
448 GiB size after #153 had moved its start down to 0x2_0000_0000.
Titles map fixed addresses up to the application map area end,
0xFC_0000_0000 (SCE_KERNEL_APP_MAP_AREA_END_ADDR on the PS4), and a
direct memory mapping above the old end threw "shared mapping outside
the guest arena".
The arena is now reserved up to 0xFC_0000_0000. The out-of-arena
errors name the address and length, and a fixed mapping over a used
arena range says whether it hit a host region. guest_memory maps
direct memory at the last two pages below the end, reads it through
an alias and checks that a mapping at the end is refused.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
ForgetDirectMemory erased the physical pages but left g_directMappings entries pointing at the dead backing, so sceKernelVirtualQuery kept reporting is_direct with a stale physical offset. Erase (and split, on the phys axis) the affected mapping tracking on release; mapped views are untouched, so no new faults are introduced.
Lock the guest pages of the range with VirtualLock or mlock, following FreeBSD mlock(2): the range is widened to guest pages, a zero length succeeds, a wrapping range is EINVAL and a range that is not mapped and accessible is ENOMEM. The Windows working set limits and the Linux RLIMIT_MEMLOCK soft limit are raised when the lock needs it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
libkernel did not export sceKernelMapNamedFlexibleMemoryInternal, which
the libc bundled with SDK 9 titles imports. It now forwards to
sceKernelMapNamedFlexibleMemory: the mapping counts against the flexible
budget, gets the range name and is released by sceKernelMunmap. Older
libc builds call the public function at the same sites with the same
arguments and result handling.
The known callers pass flag 0x8000, whose meaning is unknown. It is
still rejected as an unsupported mapping flag and is recorded in
TechnicalDebt.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A file read into guest memory is a host write: before the I/O it pins the shared pages it
covers, which reopens any page armed for write tracking and keeps write tracking from arming
it again until the read ends, when the pages count as written. A destination the guest cannot
write fails with EFAULT before any I/O; read and pread throw as for any failed read, AIO
reports SCE_KERNEL_ERROR_EFAULT, and APR throws. APR also throws when a read ends before the
requested size.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
std::tmpfile() places the shared direct memory backing in /tmp, so a
title's direct memory counts against that filesystem's size (a tmpfs is
half of RAM by default): once /tmp fills, touching a backing page raises
SIGBUS. memfd_create gives the same shared memory pages without a
filesystem or its size limit.
Both ignored the flags and the requested address and reserved wherever the arena
had room, so a title that reserves a fixed range (Marvel's Wolverine passes
0x400010, MAP_FIXED | MAP_NO_COALESCE) and then uses the address it asked for
touched memory it never reserved. A fixed reservation now lands at the address,
after checking the range is free; other reservations are placed as before.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
GuestMemory::CollectWrites was built on the Windows arena's MEM_WRITE_WATCH
and answered 0 on Linux, so every cached copy of guest memory (textures,
resident render targets, buffers, DCC key proofs) read as changed at every
check: resident targets were stored and re-uploaded at every refresh and
unit shadows stayed off. Astro Bot's intro ran at ~3 fps.
libc gains GuestWriteWatch, the Linux counterpart of GetWriteWatch. Every
guest mapping libkernel makes (MapAligned: fixed, hinted and aligned) is
registered with one userfaultfd in asynchronous write-protect mode
(UFFD_FEATURE_WP_ASYNC: the kernel lifts a page's protection on its first
write without a handler thread, for user and kernel-mode writes alike), and
PAGEMAP_SCAN with PM_SCAN_WP_MATCHING reports the pages written since the
last scan of a range and protects them again in one call. Unmap forgets
the range. Direct memory is mapped from shared backings over its
reservation and a fixed remap replaces the mapping, so both register the
new mapping afresh. The watch is per mapping: a write through one mapping
of shared physical pages is not seen at another, so physical pages mapped
at more than one address leave the watch in every mapping of them.
A registered mapping reads as written until a collect covers it. The watch
keeps that itself instead of relying on how the kernel classifies pages
never faulted in: Linux 6.17 reports a range without page tables as not
written and leaves it unprotected, 7.2 reports it as written. The first
collect of a fresh range reports it written and write-protects it with
UFFDIO_WRITEPROTECT, which puts markers on its unpopulated pages
(UFFD_FEATURE_WP_UNPOPULATED), so from then on only real writes report.
Fallback: the userfaultfd is opened with UFFD_USER_MODE_ONLY where
vm.unprivileged_userfaultfd restricts it, and a probe at startup checks the
mechanism on scratch pages (a populated and an unpopulated page written
after protection report exactly, untouched ones do not). Without it (kernel
older than 6.7, no userfaultfd permission, headers without PAGEMAP_SCAN, or
APS5_NO_WRITE_WATCH=1) the watch reports unavailable and the tracker stays
unwatched exactly as before: CollectWrites answers 0 and callers compare
bytes. A range with a page outside the registered mappings also answers 0,
and a protection or scan that fails reports its remaining pages as written
and answers 0.
The driver's tracker keeps its contract and generations. On Linux its
block stamps live in 4 GiB leaves over the user address space, made on
first stamp, instead of the arena's flat arrays; the collect memo now works
on both platforms. GuestMemory::WriteWatched and Watched replace the arena
queries in UnitShadowEnabled and ShadowDestinationFor, so unit shadows run
on Linux over watched memory and stay off everywhere else. The Windows
arena path is unchanged apart from going through the same stamp helpers.
Host imports: a driver may lift the write protection of imported pages
itself. amdgpu validates the userptr BO behind a VK_EXT_external_memory_host
import with a writable HMM fault on every submission after the pages were
protected again, so PAGEMAP_SCAN reports them as written with no CPU store,
and a resident display image read as written at every present (found by
Pacuka on an RX 6650 XT with RADV: the presented image went black). NVIDIA
pins the pages once at the import and stays exact from then on. A probe at
device setup decides per device: it maps and watches scratch pages, collects
them clean, imports them, collects, submits a GPU copy that reads the import,
waits, and collects again. Pages written after the submission mean imports
resolve write protection: every import from then on takes its range off the
watch (GuestMemory::Unwatch) before it is made, so Watched is false for it,
CollectWrites answers 0 and callers compare bytes; GPU writes to watched
memory keep their MarkWritten stamps. The result is logged once:
"[write-watch] host imports resolve write protection: yes/no". A probe that
cannot run takes the unwatch side. APS5_WRITE_WATCH_IMPORTS=watch|unwatch
overrides the probe (default probe; anything else throws), and
APS5_NO_WRITE_WATCH=1 still turns the watch off. On the RTX 4090 the probe
reads 0 of 4 pages written after the GPU read (4 after the import itself),
so imports stay watched there.
The import itself lifts the protection once where imports stay watched:
on the RTX 4090 the pinning at vkAllocateMemory reports every imported page
as written (4 of 4 in the probe), with no CPU store. Such a report would
read as a CPU write over any GPU results pending in the range and drop
them. So every import of a watched range is made inside an import window
(GuestMemory::ImportWatched), under the tracker lock: the range is
collected right before the import, so earlier CPU writes are stamped as
usual, and again right after it, and what the window reports is stamped
"maybe written". Readers without pending results see it as a change
(UnchangedSince fails, ChangedBlocks reports it), so caches re-upload or
compare. Decisions about pending GPU results read it as untracked:
ChangedBlocks reports BlockMaybeWritten apart from BlockWritten, and the
drop rule, the write-back's keep blocks, the alias checks, the unit
shadow's stale drop and the whole-image stale checks (through the new
WrittenSince, which also answers false for a range off the watch) store
the results instead of dropping them. A real CPU store racing an import
also races the pending GPU writes to the same memory, which has no
defined order on hardware either, so the GPU results winning is
acceptable. From the second collect on the range is protected again and
watched normally. A range the watch does not cover whole, or a collect of
the window that fails, is taken off the watch instead.
An unwatched import stays off the watch for the rest of its mapping: a
remap registers the range afresh, the import kept over it takes it off
again at the next reconcile, and a re-import after an unmap follows the
decision. Unwatch invalidates the collect memo, so a collect memoized
before the import answers 0. A range that leaves the watch while a storage
image holds a generation for it no longer reads as CPU-written:
ChangedBlocks now tells whether the range is watched, and the drop rule,
the write-back's keep blocks and the alias borrow treat an unwatched range
as untracked (stored, never dropped), as a generation of 0 is.
Tests: guest_memory checks the watch through libkernel mappings (a CPU
store, a read, a kernel write through read(), another thread, a memcpy
across pages, an mprotect cycle, a partial munmap and a fixed remap) and
over a fresh 2 MiB-aligned mapping without page tables, checks direct
memory (watched, an alias takes the shared pages off the watch in both
mappings, a fixed direct remap over flexible memory is watched afresh), and
names the failing line and the reported pages. The recorder tests allocate watched
memory on both platforms, so the UnchangedSince, key proof, close race and
unit shadow tests run on Linux, and the storage refresh test gains a
watched variant: results kept on the GPU reach a CPU reader, and a plain
CPU store into one unit with newer results pending is found by the watch
alone. The recorder tests now also run the real import probe, check the
decision with the result injected (unwatch: an import leaves the watch, a
memoized collect, a partly imported range and the unimported neighbour
answer as they should, MarkWritten stamps only watched memory, a remap and
a re-import after an unmap follow the decision; watch: the import stays
watched and stamped), and check that results pending when their memory
leaves the watch are stored rather than dropped. A further test imports the
memory of a storage image with results pending in watch mode: the
results survive the import window and reach guest memory, a cache
generation taken before the import sees a change, the window reads as
maybe written and not as a CPU store, and a CPU store after it reads as
one again. Unit shadows and the
watched storage refresh report themselves as not run when imports are
compared.
Since direct memory mapped at two addresses is shared read-only instead of
refused, the guest memory test expected an exception that no longer comes.
It now maps the second view, reads the first view's bytes through it, and
writes through the first view once the second is gone, which faults unless
its protection came back.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Only the lines this branch added lose their comments; the commits before
keep them, with the reasoning behind each change, for whoever digs into
that code later.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
libkernel:
- direct memory keeps its contents per physical page across unmap and
remap; a page mapped at two live addresses at once throws
- sceKernelDirectMemoryQuery answers from tracked allocations
- SCE protections read back as set, GPU and AMPR bits included
- APR prefix path resolve, file size and stat by id, positional reads,
fsync/pread/pwrite; directories open as descriptors on Windows
- sceKernelCheckReachability, getpeername, shutdown
- Dinkumware C11 threads (_Mtx_*, _Cnd_*, _Thrd_*) in the title libc
layout; any pthread stack size, rounded at thread creation
libc:
- unaddressed guest mappings go to the system-managed area from
0x2_0000_0000, leaving the application area to fixed mappings
- the process starts in /app0
- guest sscanf on Windows; a null %s prints as (null) as on FreeBSD
- localeconv, _FNan, _FDtest, _FExp, __udivti3, wcsncpy_s, aligned
operator new, _Throw_Cpp_error
Tests: direct memory following physical pages, guest formatting.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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