Describe AArch64 specific flags PKEY_DISABLE_READ and PKEY_DISABLE_EXECUTE that
are available on AArch64 systems with enabled Stage 1 permission overlays
feature introduced in Armv8.9 / 9.4 (FEAT_S1POE).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This patch adds support for memory protection keys on AArch64 systems with
enabled Stage 1 permission overlays feature introduced in Armv8.9 / 9.4
(FEAT_S1POE) [1].
1. Internal functions "pkey_read" and "pkey_write" to access data
associated with memory protection keys.
2. Implementation of API functions "pkey_get" and "pkey_set" for
the AArch64 target.
3. AArch64-specific PKEY flags for READ and EXECUTE (see below).
4. New target-specific test that checks behaviour of pkeys on
AArch64 targets.
5. This patch also extends existing generic test for pkeys.
6. HWCAP constant for Permission Overlay Extension feature.
To support more accurate mapping of underlying permissions to the
PKEY flags, we introduce additional AArch64-specific flags. The full
list of flags is:
- PKEY_UNRESTRICTED: 0x0 (for completeness)
- PKEY_DISABLE_ACCESS: 0x1 (existing flag)
- PKEY_DISABLE_WRITE: 0x2 (existing flag)
- PKEY_DISABLE_EXECUTE: 0x4 (new flag, AArch64 specific)
- PKEY_DISABLE_READ: 0x8 (new flag, AArch64 specific)
The problem here is that PKEY_DISABLE_ACCESS has unusual semantics as
it overlaps with existing PKEY_DISABLE_WRITE and new PKEY_DISABLE_READ.
For this reason mapping between permission bits RWX and "restrictions"
bits awxr (a for disable access, etc) becomes complicated:
- PKEY_DISABLE_ACCESS disables both R and W
- PKEY_DISABLE_{WRITE,READ} disables W and R respectively
- PKEY_DISABLE_EXECUTE disables X
Combinations like the one below are accepted although they are redundant:
- PKEY_DISABLE_ACCESS | PKEY_DISABLE_READ | PKEY_DISABLE_WRITE
Reverse mapping tries to retain backward compatibility and ORs
PKEY_DISABLE_ACCESS whenever both flags PKEY_DISABLE_READ and
PKEY_DISABLE_WRITE would be present.
This will break code that compares pkey_get output with == instead
of using bitwise operations. The latter is more correct since PKEY_*
constants are essentially bit flags.
It should be noted that PKEY_DISABLE_ACCESS does not prevent execution.
[1] https://developer.arm.com/documentation/ddi0487/ka/ section D8.4.1.4
Co-authored-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
ThunderX1 and ThunderX2 have been retired for a few years now.
So let's remove the thunderx{,2} specific versions of memcpy.
The performance gain or them was for medium and large sizes
while the generic (aarch64) memcpy will handle just slightly worse.
Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Two of the architecture bits/fenv.h headers define femode_t if
__GLIBC_USE (IEC_60559_BFP_EXT), instead of the correct condition
__GLIBC_USE (IEC_60559_BFP_EXT_C23) (both were added after commit
0175c9e9be, but were probably first
developed before it and then not updated to take account of its
changes). This results in failures of the installed headers check for
fenv.h when building with GCC 15 (defaults to -std=gnu23 - we don't
yet have an installed-headers test specifically for C23 mode and don't
yet require a compiler with such a mode for building glibc) together
with a combination of options leaving C23 features enabled, since the
declarations of functions using femode_t use the correct conditions;
see
<https://sourceware.org/pipermail/libc-testresults/2024q4/013163.html>.
Fix the conditionals to get <fenv.h> to work correctly in C23 mode
again.
Tested with build-many-glibcs.py (arc-linux-gnu, arch-linux-gnuhf,
or1k-linux-gnu-hard, or1k-linux-gnu-soft).
Update the inline asm syscall wrappers to match the newer register constraint
usage in INTERNAL_VSYSCALL_CALL_TYPE. Use the faster mfocrf instruction when
available, rather than the slower mfcr microcoded instruction.
Nameless function parameters have only been added to ISO C with the C23
revision of the language standard. Give names to the unused parameters
of the stub 'dladdr' implementation then so as to make compilation happy
with the earlier language definitions, fixing errors such as:
tst-printf-format-skeleton.c:374:9: error: parameter name omitted
374 | dladdr (const void *, Dl_info *)
reported by older compilers.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
The remaining_to_add variable can be 0 if (current_used + count) wraps,
This is caught by GCC 14+ on hppa, which determines from there that
target_seg could be be NULL when remaining_to_add is zero, which in
turns causes a -Wstringop-overflow warning:
In file included from ../include/atomic.h:49,
from dl-find_object.c:20:
In function '_dlfo_update_init_seg',
inlined from '_dl_find_object_update_1' at dl-find_object.c:689:30,
inlined from '_dl_find_object_update' at dl-find_object.c:805:13:
../sysdeps/unix/sysv/linux/hppa/atomic-machine.h:44:4: error: '__atomic_store_4' writing 4 bytes into a region of size 0 overflows the destination [-Werror=stringop-overflow=]
44 | __atomic_store_n ((mem), (val), __ATOMIC_RELAXED); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
dl-find_object.c:644:3: note: in expansion of macro 'atomic_store_relaxed'
644 | atomic_store_relaxed (&seg->size, new_seg_size);
| ^~~~~~~~~~~~~~~~~~~~
In function '_dl_find_object_update':
cc1: note: destination object is likely at address zero
In practice, this is not possible as it represent counts of link maps.
Link maps have sizes larger than 1 byte, so the sum of any two link map
counts will always fit within a size_t without wrapping around.
This patch therefore adds a check on remaining_to_add == 0 and tell GCC
that this can not happen using __builtin_unreachable.
Thanks to Andreas Schwab for the investigation.
Closes: BZ #32245
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: John David Anglin <dave.anglin@bell.net>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
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
Add a new test tst-faccessat-setuid that iterates through real and
effective UID/GID combination and tests the faccessat() interface for
default and AT_EACCESS flags.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Use libsupport convenience functions and macros instead of the old
test-skeleton. Also add a new xdup() convenience wrapper function.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Add xdup as the error-checking version of dup for test cases.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
When building with e.g. -std=c99 and _ATFILE_SOURCE, stat.h was missing
including bits/types/struct_timespec.h to get the struct timespec
declaration for utimensat.
For instance, 1073741906 leads to system 16, subsystem 0 and code 82,
which is in range (max_code is 122), but not defined. Return EINVAL in
that case, like
A static analyzer apparently reported an uninitialized use of the
variable result in sem_open in the case where the file is required to
exist but does not exist.
The report appears to be correct; set result to SEM_FAILED in that
case, and add a test for it.
Note: the test passes for me even without the sem_open fix, I guess
because result happens to get value SEM_FAILED (i.e. 0) when
uninitialized.
Tested for x86_64.
Per the rseq syscall documentation, 3 fields are required to be
initialized by userspace prior to registration, they are 'cpu_id',
'rseq_cs' and 'flags'. Since we have no guarantee that 'struct pthread'
is cleared on all architectures, explicitly set those 3 fields prior to
registration.
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
The declaration of found_other_class could be jumped
over via the goto just above it, but the code jumped
to uses found_other_class. Move the declaration
up a bit to ensure it's properly declared and initialized.
The commit 9247f53219 triggered some regressions on loongarch and
riscv:
math/test-float-log10
math/test-float32-log10
And it is due a wrong sync with CORE-MATH for special 0.0/-0.0
inputs.
Checked on aarch64-linux-gnu and loongarch64-linux-gnu-lp64d.
Wire vasprintf into test infrastructure for formatted printf output
specifiers.
Owing to mtrace logging these tests take amounts of time to complete
similar to those of corresponding asprintf tests, so set timeouts for
the tests accordingly, with a global default for all the vasprintf
tests, and then individual higher settings for double and long double
tests each.
Reviewed-by: DJ Delorie <dj@redhat.com>
