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Adhemerval Zanella 461cab1de7 linux: Add support for getrandom vDSO 
Linux 6.11 has getrandom() in vDSO. It operates on a thread-local opaque
state allocated with mmap using flags specified by the vDSO.

Multiple states are allocated at once, as many as fit into a page, and
these are held in an array of available states to be doled out to each
thread upon first use, and recycled when a thread terminates. As these
states run low, more are allocated.

To make this procedure async-signal-safe, a simple guard is used in the
LSB of the opaque state address, falling back to the syscall if there's
reentrancy contention.

Also, _Fork() is handled by blocking signals on opaque state allocation
(so _Fork() always sees a consistent state even if it interrupts a
getrandom() call) and by iterating over the thread stack cache on
reclaim_stack. Each opaque state will be in the free states list
(grnd_alloc.states) or allocated to a running thread.

The cancellation is handled by always using GRND_NONBLOCK flags while
calling the vDSO, and falling back to the cancellable syscall if the
kernel returns EAGAIN (would block). Since getrandom is not defined by
POSIX and cancellation is supported as an extension, the cancellation is
handled as 'may occur' instead of 'shall occur' [1], meaning that if
vDSO does not block (the expected behavior) getrandom will not act as a
cancellation entrypoint. It avoids a pthread_testcancel call on the fast
path (different than 'shall occur' functions, like sem_wait()).

It is currently enabled for x86_64, which is available in Linux 6.11,
and aarch64, powerpc32, powerpc64, loongarch64, and s390x, which are
available in Linux 6.12.

Link: https://pubs.opengroup.org/onlinepubs/9799919799/nframe.html [1]
Co-developed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Tested-by: Jason A. Donenfeld <Jason@zx2c4.com> # x86_64
Tested-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> # x86_64, aarch64
Tested-by: Xi Ruoyao <xry111@xry111.site> # x86_64, aarch64, loongarch64
Tested-by: Stefan Liebler <stli@linux.ibm.com> # s390x
2024-11-12 14:42:12 -03:00
..
alloc_buffer_alloc_array.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
alloc_buffer_allocate.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
alloc_buffer_copy_bytes.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
alloc_buffer_copy_string.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
alloc_buffer_create_failure.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
arena.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
Depend
dynarray_at_failure.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
dynarray_emplace_enlarge.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
dynarray_finalize.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
dynarray_resize_clear.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
dynarray_resize.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
dynarray-skeleton.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
dynarray.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
hooks.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
Makefile malloc: Link threading tests with $(shared-thread-library) 2024-08-20 16:16:25 +02:00
malloc-check.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
malloc-debug.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
malloc-internal.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
malloc.c linux: Add support for getrandom vDSO 2024-11-12 14:42:12 -03:00
malloc.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
mallocbug.c
mcheck-impl.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
mcheck-init.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
mcheck.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
mcheck.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
memusage.c Fix usage of _STACK_GROWS_DOWN and _STACK_GROWS_UP defines [BZ 31989] 2024-07-19 10:10:17 -04:00
memusage.sh Update copyright dates not handled by scripts/update-copyrights 2024-01-01 10:53:40 -08:00
memusagestat.c Update copyright dates not handled by scripts/update-copyrights 2024-01-01 10:53:40 -08:00
morecore.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
mtrace-impl.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
mtrace.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
mtrace.pl mtrace: make shell commands robust against meta characters 2024-06-24 09:33:49 +02:00
obstack.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
obstack.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
reallocarray.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
scratch_buffer_grow_preserve.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
scratch_buffer_grow.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
scratch_buffer_set_array_size.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
set-freeres.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
thread-freeres.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-aligned_alloc-lib.c malloc: avoid global locks in tst-aligned_alloc-lib.c 2024-07-22 11:54:46 +02:00
tst-aligned-alloc-random-thread-cross.c malloc: add multi-threaded tests for aligned_alloc/calloc/malloc 2024-07-22 11:54:46 +02:00
tst-aligned-alloc-random-thread.c malloc: add multi-threaded tests for aligned_alloc/calloc/malloc 2024-07-22 11:54:46 +02:00
tst-aligned-alloc-random.c malloc: Improve aligned_alloc and calloc test coverage. 2024-05-14 14:36:50 +00:00
tst-aligned-alloc-static.c aligned_alloc: conform to C17 2023-05-08 16:40:10 -04:00
tst-aligned-alloc.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-alloc_buffer.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-calloc.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-compathooks-off.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-compathooks-on.c
tst-dynarray-at-fail.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-dynarray-fail.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-dynarray-shared.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-dynarray.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-free-errno.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-aux-nothread.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-aux-thread.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-aux.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-aux.h Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-nothread.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-skeleton.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-static-nothread.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-static-thread.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-interpose-thread.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-mallinfo2.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc_info.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc-alternate-path.c malloc: New test to check malloc alternate path using memory obstruction 2024-06-04 18:00:29 +02:00
tst-malloc-backtrace.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc-check.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc-fork-deadlock.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc-random.c malloc: Improve aligned_alloc and calloc test coverage. 2024-05-14 14:36:50 +00:00
tst-malloc-stats-cancellation.c
tst-malloc-tcache-leak.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc-thread-exit.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc-thread-fail.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc-too-large.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc-usable-tunables.c
tst-malloc-usable.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-malloc.c malloc: Improve aligned_alloc and calloc test coverage. 2024-05-14 14:36:50 +00:00
tst-mallocalign1.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-mallocfork2.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-mallocfork3.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-mallocfork.c
tst-mallocstate.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-mallopt.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-memalign-2.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-memalign-3.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-memalign.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-mtrace.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-mtrace.sh Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-mxfast.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-obstack.c
tst-posix_memalign.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-pvalloc-fortify.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-pvalloc.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-realloc.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-reallocarray.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-safe-linking.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-scratch_buffer.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-tcfree1.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-tcfree2.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-tcfree3.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
tst-trim1.c
tst-valloc.c Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
Versions Remove unused scratch_buffer_dupfree 2022-10-28 18:43:58 +01:00