Joseph Myers [Mon, 22 Nov 2021 15:30:12 +0000 (15:30 +0000)]
Update kernel version to 5.15 in tst-mman-consts.py
This patch updates the kernel version in the test tst-mman-consts.py
to 5.15. (There are no new MAP_* constants covered by this test in
5.15 that need any other header changes.)
DJ Delorie [Wed, 30 Mar 2022 21:44:02 +0000 (17:44 -0400)]
posix/glob.c: update from gnulib
Copied from gnulib/lib/glob.c in order to fix rhbz 1982608
Also fixes swbz 25659
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 7c477b57a31487eda516db02b9e04f22d1a6e6af)
Carlos O'Donell [Tue, 26 Apr 2022 14:52:41 +0000 (10:52 -0400)]
i386: Regenerate ulps
These failures were caught while building glibc master for Fedora
Rawhide which is built with '-mtune=generic -msse2 -mfpmath=sse'
using gcc 11.3 (gcc-11.3.1-2.fc35) on a Cascadelake Intel Xeon
processor.
Noah Goldstein [Sat, 25 Dec 2021 00:54:41 +0000 (18:54 -0600)]
x86: Optimize L(less_vec) case in memcmp-evex-movbe.S
No bug.
Optimizations are twofold.
1) Replace page cross and 0/1 checks with masked load instructions in
L(less_vec). In applications this reduces branch-misses in the
hot [0, 32] case.
2) Change controlflow so that L(less_vec) case gets the fall through.
Change 2) helps copies in the [0, 32] size range but comes at the cost
of copies in the [33, 64] size range. From profiles of GCC and
Python3, 94%+ and 99%+ of calls are in the [0, 32] range so this
appears to the the right tradeoff.
Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit abddd61de090ae84e380aff68a98bd94ef704667)
Noah Goldstein [Fri, 3 Dec 2021 23:29:25 +0000 (15:29 -0800)]
x86-64: Use notl in EVEX strcmp [BZ #28646]
Must use notl %edi here as lower bits are for CHAR comparisons
potentially out of range thus can be 0 without indicating mismatch.
This fixes BZ #28646.
Noah Goldstein [Wed, 10 Nov 2021 22:18:56 +0000 (16:18 -0600)]
x86: Shrink memcmp-sse4.S code size
No bug.
This implementation refactors memcmp-sse4.S primarily with minimizing
code size in mind. It does this by removing the lookup table logic and
removing the unrolled check from (256, 512] bytes.
The current memcmp-sse4.S implementation has a large code size
cost. This has serious adverse affects on the ICache / ITLB. While
in micro-benchmarks the implementations appears fast, traces of
real-world code have shown that the speed in micro benchmarks does not
translate when the ICache/ITLB are not primed, and that the cost
of the code size has measurable negative affects on overall
application performance.
See https://research.google/pubs/pub48320/ for more details.
Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 2f9062d7171850451e6044ef78d91ff8c017b9c0)
Noah Goldstein [Mon, 1 Nov 2021 05:49:52 +0000 (00:49 -0500)]
x86: Double size of ERMS rep_movsb_threshold in dl-cacheinfo.h
No bug.
This patch doubles the rep_movsb_threshold when using ERMS. Based on
benchmarks the vector copy loop, especially now that it handles 4k
aliasing, is better for these medium ranged.
H.J. Lu [Fri, 29 Oct 2021 19:56:53 +0000 (12:56 -0700)]
x86-64: Remove Prefer_AVX2_STRCMP
Remove Prefer_AVX2_STRCMP to enable EVEX strcmp. When comparing 2 32-byte
strings, EVEX strcmp has been improved to require 1 load, 1 VPTESTM, 1
VPCMP, 1 KMOVD and 1 INCL instead of 2 loads, 3 VPCMPs, 2 KORDs, 1 KMOVD
and 1 TESTL while AVX2 strcmp requires 1 load, 2 VPCMPEQs, 1 VPMINU, 1
VPMOVMSKB and 1 TESTL. EVEX strcmp is now faster than AVX2 strcmp by up
to 40% on Tiger Lake and Ice Lake.
H.J. Lu [Fri, 29 Oct 2021 19:40:20 +0000 (12:40 -0700)]
x86-64: Improve EVEX strcmp with masked load
In strcmp-evex.S, to compare 2 32-byte strings, replace
VMOVU (%rdi, %rdx), %YMM0
VMOVU (%rsi, %rdx), %YMM1
/* Each bit in K0 represents a mismatch in YMM0 and YMM1. */
VPCMP $4, %YMM0, %YMM1, %k0
VPCMP $0, %YMMZERO, %YMM0, %k1
VPCMP $0, %YMMZERO, %YMM1, %k2
/* Each bit in K1 represents a NULL in YMM0 or YMM1. */
kord %k1, %k2, %k1
/* Each bit in K1 represents a NULL or a mismatch. */
kord %k0, %k1, %k1
kmovd %k1, %ecx
testl %ecx, %ecx
jne L(last_vector)
with
VMOVU (%rdi, %rdx), %YMM0
VPTESTM %YMM0, %YMM0, %k2
/* Each bit cleared in K1 represents a mismatch or a null CHAR
in YMM0 and 32 bytes at (%rsi, %rdx). */
VPCMP $0, (%rsi, %rdx), %YMM0, %k1{%k2}
kmovd %k1, %ecx
incl %ecx
jne L(last_vector)
It makes EVEX strcmp faster than AVX2 strcmp by up to 40% on Tiger Lake
and Ice Lake.
Noah Goldstein [Sat, 23 Oct 2021 05:26:47 +0000 (01:26 -0400)]
x86: Replace sse2 instructions with avx in memcmp-evex-movbe.S
This commit replaces two usages of SSE2 'movups' with AVX 'vmovdqu'.
it could potentially be dangerous to use SSE2 if this function is ever
called without using 'vzeroupper' beforehand. While compilers appear
to use 'vzeroupper' before function calls if AVX2 has been used, using
SSE2 here is more brittle. Since it is not absolutely necessary it
should be avoided.
It costs 2-extra bytes but the extra bytes should only eat into
alignment padding. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit bad852b61b79503fcb3c5fc379c70f768df3e1fb)
1. change control flow for L(more_2x_vec) to fall through to loop and
jump for L(less_4x_vec) and L(less_8x_vec). This uses less code
size and saves jumps for length > 4x VEC_SIZE.
2. For EVEX/AVX512 move L(less_vec) closer to entry.
3. Avoid complex address mode for length > 2x VEC_SIZE
4. Slightly better aligning code for the loop from the perspective of
code size and uops.
5. Align targets so they make full use of their fetch block and if
possible cache line.
6. Try and reduce total number of icache lines that will need to be
pulled in for a given length.
7. Include "local" version of stosb target. For AVX2/EVEX/AVX512
jumping to the stosb target in the sse2 code section will almost
certainly be to a new page. The new version does increase code size
marginally by duplicating the target but should get better iTLB
behavior as a result.
test-memset, test-wmemset, and test-bzero are all passing.
Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit e59ced238482fd71f3e493717f14f6507346741e)
x86: Optimize memcmp-evex-movbe.S for frontend behavior and size
No bug.
The frontend optimizations are to:
1. Reorganize logically connected basic blocks so they are either in
the same cache line or adjacent cache lines.
2. Avoid cases when basic blocks unnecissarily cross cache lines.
3. Try and 32 byte align any basic blocks possible without sacrificing
code size. Smaller / Less hot basic blocks are used for this.
Overall code size shrunk by 168 bytes. This should make up for any
extra costs due to aligning to 64 bytes.
In general performance before deviated a great deal dependending on
whether entry alignment % 64 was 0, 16, 32, or 48. These changes
essentially make it so that the current implementation is at least
equal to the best alignment of the original for any arguments.
The only additional optimization is in the page cross case. Branch on
equals case was removed from the size == [4, 7] case. As well the [4,
7] and [2, 3] case where swapped as [4, 7] is likely a more hot
argument size.
dlfcn: Do not use rtld_active () to determine ld.so state (bug 29078)
When audit modules are loaded, ld.so initialization is not yet
complete, and rtld_active () returns false even though ld.so is
mostly working. Instead, the static dlopen hook is used, but that
does not work at all because this is not a static dlopen situation.
Commit 466c1ea15f461edb8e3ffaf5d86d708876343bbf ("dlfcn: Rework
static dlopen hooks") moved the hook pointer into _rtld_global_ro,
which means that separate protection is not needed anymore and the
hook pointer can be checked directly.
The guard for disabling libio vtable hardening in _IO_vtable_check
should stay for now.
Joan Bruguera [Mon, 11 Apr 2022 17:49:56 +0000 (19:49 +0200)]
misc: Fix rare fortify crash on wchar funcs. [BZ 29030]
If `__glibc_objsize (__o) == (size_t) -1` (i.e. `__o` is unknown size), fortify
checks should pass, and `__whatever_alias` should be called.
Previously, `__glibc_objsize (__o) == (size_t) -1` was explicitly checked, but
on commit a643f60c53876b, this was moved into `__glibc_safe_or_unknown_len`.
A comment says the -1 case should work as: "The -1 check is redundant because
since it implies that __glibc_safe_len_cond is true.". But this fails when:
* `__s > 1`
* `__osz == -1` (i.e. unknown size at compile time)
* `__l` is big enough
* `__l * __s <= __osz` can be folded to a constant
(I only found this to be true for `mbsrtowcs` and other functions in wchar2.h)
In this case `__l * __s <= __osz` is false, and `__whatever_chk_warn` will be
called by `__glibc_fortify` or `__glibc_fortify_n` and crash the program.
This commit adds the explicit `__osz == -1` check again.
moc crashes on startup due to this, see: https://bugs.archlinux.org/task/74041
Minimal test case (test.c):
#include <wchar.h>
int main (void)
{
const char *hw = "HelloWorld";
mbsrtowcs (NULL, &hw, (size_t)-1, NULL);
return 0;
}
Build with:
gcc -O2 -Wp,-D_FORTIFY_SOURCE=2 test.c -o test && ./test
This is necessary to place the libio vtables into the RELRO segment.
New tests elf/tst-relro-ldso and elf/tst-relro-libc are added to
verify that this is what actually happens.
The new tests fail on ia64 due to lack of (default) RELRO support
inbutils, so they are XFAILed there.
Hopefully, this will lead to tests that are easier to maintain. The
current approach of parsing readelf -W output using regular expressions
is not necessarily easier than parsing the ELF data directly.
This module is still somewhat incomplete (e.g., coverage of relocation
types and versioning information is missing), but it is sufficient to
perform basic symbol analysis or program header analysis.
The EM_* mapping for architecture-specific constant classes (e.g.,
SttX86_64) is not yet implemented. The classes are defined for the
benefit of elf/tst-glibcelf.py.
The 404656009b reversion did not setup the atomic loop to set the
cancel bits correctly. The fix is essentially what pthread_cancel
did prior 26cfbb7162ad.
Checked on x86_64-linux-gnu and aarch64-linux-gnu.
nptl: Handle spurious EINTR when thread cancellation is disabled (BZ#29029)
Some Linux interfaces never restart after being interrupted by a signal
handler, regardless of the use of SA_RESTART [1]. It means that for
pthread cancellation, if the target thread disables cancellation with
pthread_setcancelstate and calls such interfaces (like poll or select),
it should not see spurious EINTR failures due the internal SIGCANCEL.
However recent changes made pthread_cancel to always sent the internal
signal, regardless of the target thread cancellation status or type.
To fix it, the previous semantic is restored, where the cancel signal
is only sent if the target thread has cancelation enabled in
asynchronous mode.
The cancel state and cancel type is moved back to cancelhandling
and atomic operation are used to synchronize between threads. The
patch essentially revert the following commits:
8c1c0aae20 nptl: Move cancel type out of cancelhandling 2b51742531 nptl: Move cancel state out of cancelhandling 26cfbb7162 nptl: Remove CANCELING_BITMASK
However I changed the atomic operation to follow the internal C11
semantic and removed the MACRO usage, it simplifies a bit the
resulting code (and removes another usage of the old atomic macros).
Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
and powerpc64-linux-gnu.
Stefan Liebler [Wed, 13 Apr 2022 12:36:09 +0000 (14:36 +0200)]
S390: Add new s390 platform z16.
The new IBM z16 is added to platform string array.
The macro _DL_PLATFORMS_COUNT is incremented.
_dl_hwcaps_subdir is extended by "z16" if HWCAP_S390_VXRS_PDE2
is set. HWCAP_S390_NNPA is not tested in _dl_hwcaps_subdirs_active
as those instructions may be replaced or removed in future.
tst-glibc-hwcaps.c is extended in order to test z16 via new marker5.
A fatal glibc error is dumped if glibc was build with architecture
level set for z16, but run on an older machine. (See dl-hwcap-check.h)
On hppa, a function pointer returned by la_symbind is actually a function
descriptor has the plabel bit set (bit 30). This must be cleared to get
the actual address of the descriptor. If the descriptor has been bound,
the first word of the descriptor is the physical address of theA function,
otherwise, the first word of the descriptor points to a trampoline in the
PLT.
This patch also adds a workaround on tests because on hppa (and it seems
to be the only ABI I have see it), some shared library adds a dynamic PLT
relocation to am empty symbol name:
$ readelf -r elf/tst-audit25mod1.so
[...]
Relocation section '.rela.plt' at offset 0x464 contains 6 entries:
Offset Info Type Sym.Value Sym. Name + Addend 0000200800000081 R_PARISC_IPLT 508
[...]
It breaks some assumptions on the test, where a symbol with an empty
name ("") is passed on la_symbind.
Ben Woodard [Mon, 24 Jan 2022 13:46:18 +0000 (10:46 -0300)]
elf: Fix runtime linker auditing on aarch64 (BZ #26643)
The rtld audit support show two problems on aarch64:
1. _dl_runtime_resolve does not preserve x8, the indirect result
location register, which might generate wrong result calls
depending of the function signature.
2. The NEON Q registers pushed onto the stack by _dl_runtime_resolve
were twice the size of D registers extracted from the stack frame by
_dl_runtime_profile.
While 2. might result in wrong information passed on the PLT tracing,
1. generates wrong runtime behaviour.
The aarch64 rtld audit support is changed to:
* Both La_aarch64_regs and La_aarch64_retval are expanded to include
both x8 and the full sized NEON V registers, as defined by the
ABI.
* dl_runtime_profile needed to extract registers saved by
_dl_runtime_resolve and put them into the new correctly sized
La_aarch64_regs structure.
* The LAV_CURRENT check is change to only accept new audit modules
to avoid the undefined behavior of not save/restore x8.
* Different than other architectures, audit modules older than
LAV_CURRENT are rejected (both La_aarch64_regs and La_aarch64_retval
changed their layout and there are no requirements to support multiple
audit interface with the inherent aarch64 issues).
* A new field is also reserved on both La_aarch64_regs and
La_aarch64_retval to support variant pcs symbols.
Similar to x86, a new La_aarch64_vector type to represent the NEON
register is added on the La_aarch64_regs (so each type can be accessed
directly).
Since LAV_CURRENT was already bumped to support bind-now, there is
no need to increase it again.
Checked on aarch64-linux-gnu.
Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit ce9a68c57c260c8417afc93972849ac9ad243ec4)
The audit symbind callback is not called for binaries built with
-Wl,-z,now or when LD_BIND_NOW=1 is used, nor the PLT tracking callbacks
(plt_enter and plt_exit) since this would change the expected
program semantics (where no PLT is expected) and would have performance
implications (such as for BZ#15533).
LAV_CURRENT is also bumped to indicate the audit ABI change (where
la_symbind flags are set by the loader to indicate no possible PLT
trace).
To handle powerpc64 ELFv1 function descriptor, _dl_audit_symbind
requires to know whether bind-now is used so the symbol value is
updated to function text segment instead of the OPD (for lazy binding
this is done by PPC64_LOAD_FUNCPTR on _dl_runtime_resolve).
Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
powerpc64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 32612615c58b394c3eb09f020f31310797ad3854)
elf: Fix initial-exec TLS access on audit modules (BZ #28096)
For audit modules and dependencies with initial-exec TLS, we can not
set the initial TLS image on default loader initialization because it
would already be set by the audit setup. However, subsequent thread
creation would need to follow the default behaviour.
This patch fixes it by setting l_auditing link_map field not only
for the audit modules, but also for all its dependencies. This is
used on _dl_allocate_tls_init to avoid the static TLS initialization
at load time.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 254d3d5aef2fd8430c469e1938209ac100ebf132)
la_activity is not called during application exit, even though
la_objclose is.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit 5fa11a2bc94c912c3b25860065086902674537ba)
elf: Do not fail for failed dlmopen on audit modules (BZ #28061)
The dl_main sets the LM_ID_BASE to RT_ADD just before starting to
add load new shared objects. The state is set to RT_CONSISTENT just
after all objects are loaded.
However if a audit modules tries to dlmopen an inexistent module,
the _dl_open will assert that the namespace is in an inconsistent
state.
This is different than dlopen, since first it will not use
LM_ID_BASE and second _dl_map_object_from_fd is the sole responsible
to set and reset the r_state value.
So the assert on _dl_open can not really be seen if the state is
consistent, since _dt_main resets it. This patch removes the assert.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
The vDSO is is listed in the link_map chain, but is never the subject of
an la_objopen call. A new internal flag __RTLD_VDSO is added that
acts as __RTLD_OPENEXEC to allocate the required 'struct auditstate'
extra space for the 'struct link_map'.
The return value from the callback is currently ignored, since there
is no PLT call involved by glibc when using the vDSO, neither the vDSO
are exported directly.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
elf: Avoid unnecessary slowdown from profiling with audit (BZ#15533)
The rtld-audit interfaces introduces a slowdown due to enabling
profiling instrumentation (as if LD_AUDIT implied LD_PROFILE).
However, instrumenting is only necessary if one of audit libraries
provides PLT callbacks (la_pltenter or la_pltexit symbols). Otherwise,
the slowdown can be avoided.
The following patch adjusts the logic that enables profiling to iterate
over all audit modules and check if any of those provides a PLT hook.
To keep la_symbind to work even without PLT callbacks, _dl_fixup now
calls the audit callback if the modules implements it.
Co-authored-by: Alexander Monakov <amonakov@ispras.ru>
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
elf: Add _dl_audit_activity_map and _dl_audit_activity_nsid
It consolidates the code required to call la_activity audit
callback.
Also for a new Lmid_t the namespace link_map list are empty, so it
requires to check if before using it. This can happen for when audit
module is used along with dlmopen.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
THe d6d89608ac8c broke powerpc for --enable-bind-now because it turned
out that different than patch assumption rtld elf_get_dynamic_info()
does require to handle RTLD_BOOTSTRAP to avoid DT_FLAGS and
DT_RUNPATH (more specially the GLRO usage which is not reallocate
yet).
This patch fixes by passing two arguments to elf_get_dynamic_info()
to inform that by rtld (bootstrap) or static pie initialization
(static_pie_bootstrap). I think using explicit argument is way more
clear and burried C preprocessor, and compiler should remove the
dead code.
I checked on x86_64 and i686 with default options, --enable-bind-now,
and --enable-bind-now and --enable--static-pie. I also check on
aarch64, armhf, powerpc64, and powerpc with default and
--enable-bind-now.
The 4af6982e4c fix does not fully handle RTLD_BOOTSTRAP usage on
rtld.c due two issues:
1. RTLD_BOOTSTRAP is also used on dl-machine.h on various
architectures and it changes the semantics of various machine
relocation functions.
2. The elf_get_dynamic_info() change was done sideways, previously
to 490e6c62aa get-dynamic-info.h was included by the first
dynamic-link.h include *without* RTLD_BOOTSTRAP being defined.
It means that the code within elf_get_dynamic_info() that uses
RTLD_BOOTSTRAP is in fact unused.
To fix 1. this patch now includes dynamic-link.h only once with
RTLD_BOOTSTRAP defined. The ELF_DYNAMIC_RELOCATE call will now have
the relocation fnctions with the expected semantics for the loader.
And to fix 2. part of 4af6982e4c is reverted (the check argument
elf_get_dynamic_info() is not required) and the RTLD_BOOTSTRAP
pieces are removed.
To reorganize the includes the static TLS definition is moved to
its own header to avoid a circular dependency (it is defined on
dynamic-link.h and dl-machine.h requires it at same time other
dynamic-link.h definition requires dl-machine.h defitions).
Also ELF_MACHINE_NO_REL, ELF_MACHINE_NO_RELA, and ELF_MACHINE_PLT_REL
are moved to its own header. Only ancient ABIs need special values
(arm, i386, and mips), so a generic one is used as default.
The powerpc Elf64_FuncDesc is also moved to its own header, since
csu code required its definition (which would require either include
elf/ folder or add a full path with elf/).
Checked on x86_64, i686, aarch64, armhf, powerpc64, powerpc32,
and powerpc64le.
Before to 490e6c62aa31a8a ('elf: Avoid nested functions in the loader
[BZ #27220]'), elf_get_dynamic_info() was defined twice on rtld.c: on
the first dynamic-link.h include and later within _dl_start(). The
former definition did not define DONT_USE_BOOTSTRAP_MAP and it is used
on setup_vdso() (since it is a global definition), while the former does
define DONT_USE_BOOTSTRAP_MAP and it is used on loader self-relocation.
With the commit change, the function is now included and defined once
instead of defined as a nested function. So rtld.c defines without
defining RTLD_BOOTSTRAP and it brokes at least powerpc32.
This patch fixes by moving the get-dynamic-info.h include out of
dynamic-link.h, which then the caller can corirectly set the expected
semantic by defining STATIC_PIE_BOOTSTRAP, RTLD_BOOTSTRAP, and/or
RESOLVE_MAP.
It also required to enable some asserts only for the loader bootstrap
to avoid issues when called from setup_vdso().
As a side note, this is another issues with nested functions: it is
not clear from pre-processed output (-E -dD) how the function will
be build and its semantic (since nested function will be local and
extra C defines may change it).
I checked on x86_64-linux-gnu (w/o --enable-static-pie),
i686-linux-gnu, powerpc64-linux-gnu, powerpc-linux-gnu-power4,
aarch64-linux-gnu, arm-linux-gnu, sparc64-linux-gnu, and
s390x-linux-gnu.
Fangrui Song [Thu, 7 Oct 2021 18:55:02 +0000 (11:55 -0700)]
elf: Avoid nested functions in the loader [BZ #27220]
dynamic-link.h is included more than once in some elf/ files (rtld.c,
dl-conflict.c, dl-reloc.c, dl-reloc-static-pie.c) and uses GCC nested
functions. This harms readability and the nested functions usage
is the biggest obstacle prevents Clang build (Clang doesn't support GCC
nested functions).
The key idea for unnesting is to add extra parameters (struct link_map
*and struct r_scope_elm *[]) to RESOLVE_MAP,
ELF_MACHINE_BEFORE_RTLD_RELOC, ELF_DYNAMIC_RELOCATE, elf_machine_rel[a],
elf_machine_lazy_rel, and elf_machine_runtime_setup. (This is inspired
by Stan Shebs' ppc64/x86-64 implementation in the
google/grte/v5-2.27/master which uses mixed extra parameters and static
variables.)
Future simplification:
* If mips elf_machine_runtime_setup no longer needs RESOLVE_GOTSYM,
elf_machine_runtime_setup can drop the `scope` parameter.
* If TLSDESC no longer need to be in elf_machine_lazy_rel,
elf_machine_lazy_rel can drop the `scope` parameter.
Tested on aarch64, i386, x86-64, powerpc64le, powerpc64, powerpc32,
sparc64, sparcv9, s390x, s390, hppa, ia64, armhf, alpha, and mips64.
In addition, tested build-many-glibcs.py with {arc,csky,microblaze,nios2}-linux-gnu
and riscv64-linux-gnu-rv64imafdc-lp64d.
debug: Synchronize feature guards in fortified functions [BZ #28746]
Some functions (e.g. stpcpy, pread64, etc.) had moved to POSIX in the
main headers as they got incorporated into the standard, but their
fortified variants remained under __USE_GNU. As a result, these
functions did not get fortified when _GNU_SOURCE was not defined.
Add test wrappers that check all functions tested in tst-chk0 at all
levels with _GNU_SOURCE undefined and then use the failures to (1)
exclude checks for _GNU_SOURCE functions in these tests and (2) Fix
feature macro guards in the fortified function headers so that they're
the same as the ones in the main headers.
Rename debug/tst-chk1.c to debug/tst-fortify.c and add make hackery to
autogenerate tests with different macros enabled to build and run the
same test with different configurations as well as different
fortification levels.
The change also ends up expanding the -lfs tests to include
_FORTIFY_SOURCE=3.
Make sure that the fortified function conditionals are constant
In _FORTIFY_SOURCE=3, the size expression may be non-constant,
resulting in branches in the inline functions remaining intact and
causing a tiny overhead. Clang (and in future, gcc) make sure that
the -1 case is always safe, i.e. any comparison of the generated
expression with (size_t)-1 is always false so that bit is taken care
of. The rest is avoidable since we want the _chk variant whenever we
have a size expression and it's not -1.
Rework the conditionals in a uniform way to clearly indicate two
conditions at compile time:
- Either the size is unknown (-1) or we know at compile time that the
operation length is less than the object size. We can call the
original function in this case. It could be that either the length,
object size or both are non-constant, but the compiler, through
range analysis, is able to fold the *comparison* to a constant.
- The size and length are known and the compiler can see at compile
time that operation length > object size. This is valid grounds for
a warning at compile time, followed by emitting the _chk variant.
For everything else, emit the _chk variant.
This simplifies most of the fortified function implementations and at
the same time, ensures that only one call from _chk or the regular
function is emitted.
Don't add access size hints to fortifiable functions
In the context of a function definition, the size hints imply that the
size of an object pointed to by one parameter is another parameter.
This doesn't make sense for the fortified versions of the functions
since that's the bit it's trying to validate.
This is harmless with __builtin_object_size since it has fairly simple
semantics when it comes to objects passed as function parameters.
With __builtin_dynamic_object_size we could (as my patchset for gcc[1]
already does) use the access attribute to determine the object size in
the general case but it misleads the fortified functions.
Basically the problem occurs when access attributes are present on
regular functions that have inline fortified definitions to generate
_chk variants; the attributes get inherited by these definitions,
causing problems when analyzing them. For example with poll(fds, nfds,
timeout), nfds is hinted using the __attr_access as being the size of
fds.
Now, when analyzing the inline function definition in bits/poll2.h, the
compiler sees that nfds is the size of fds and tries to use that
information in the function body. In _FORTIFY_SOURCE=3 case, where the
object size could be a non-constant expression, this information results
in the conclusion that nfds is the size of fds, which defeats the
purpose of the implementation because we're trying to check here if nfds
does indeed represent the size of fds. Hence for this case, it is best
to not have the access attribute.
With the attributes gone, the expression evaluation should get delayed
until the function is actually inlined into its destinations.
Disable the access attribute for fortified function inline functions
when building at _FORTIFY_SOURCE=3 to make this work better. The
access attributes remain for the _chk variants since they can be used
by the compiler to warn when the caller is passing invalid arguments.
Florian Weimer [Fri, 11 Mar 2022 07:23:56 +0000 (08:23 +0100)]
nss: Protect against errno changes in function lookup (bug 28953)
dlopen may clobber errno. The nss_test_errno module uses an ELF
constructor to achieve that, but there could be internal errors
during dlopen that cause this, too. Therefore, the NSS framework
has to guard against such errno clobbers.
__nss_module_get_function is currently the only function that calls
__nss_module_load, so it is sufficient to save and restore errno
around this call.
Florian Weimer [Fri, 11 Mar 2022 07:23:56 +0000 (08:23 +0100)]
nss: Do not mention NSS test modules in <gnu/lib-names.h>
They are not actually installed. Use the nss_files version instead
in nss/Makefile, similar to how __nss_shlib_revision is derived
from LIBNSS_FILES_SO.
This change fixes two warnings from _dl_lookup_address.
The first warning comes from dropping the volatile keyword from
desc in the call to _dl_read_access_allowed. We now have a full
atomic barrier between loading desc[0] and the access check, so
desc no longer needs to be declared as volatile.
The second warning comes from the implicit declaration of
_dl_fix_reloc_arg. This is fixed by including dl-runtime.h and
declaring _dl_fix_reloc_arg in dl-runtime.h.
_STACK_GROWS_DOWN is defined to 0 when the stack grows up. The
code in unwind.c used `#ifdef _STACK_GROWS_DOWN' to selct the
stack grows down define for FRAME_LEFT. As a result, the
_STACK_GROWS_DOWN define was always selected and cleanups were
incorrectly sequenced when the stack grows up.
The current getcontext return trampoline is overly complex and it
unnecessarily clobbers several registers. By saving the context
pointer (r26) in the context, __getcontext_ret can restore any
registers not restored by setcontext. This allows getcontext to
save and restore the entire register context present when getcontext
is entered. We use the unused oR0 context slot for the return
from __getcontext_ret.
While this is not directly useful in C, it can be exploited in
assembly code. Registers r20, r23, r24 and r25 are not clobbered
in the call path to getcontext. This allows a small simplification
of swapcontext.
It also allows saving and restoring the 6-bit SAR register in the
LSB of the oSAR context slot. The getcontext flag value can be
stored in the MSB of the oSAR slot.
This change fixes the failure of stdlib/tst-setcontext2 and
stdlib/tst-setcontext7 on hppa. The implementation of swapcontext
in C is broken. C saves the return pointer (rp) and any non
call-clobbered registers (in this case r3, r4 and r5) on the
stack. However, the setcontext call in swapcontext pops the
stack and subsequent calls clobber the saved registers. When
the context in oucp is restored, both tests fault.
Here we rewrite swapcontext in assembly code to avoid using
the stack for register values that need to be used after
restoration. The getcontext and setcontext routines are
revised to save and restore register ret1 for normal returns.
We copy the oucp pointer to ret1. This allows access to
the old context after calling getcontext and setcontext.
The test elf/tst-audit2 fails on hppa with a segmentation fault in the
long branch stub used to call malloc from calloc. This occurs because
the test is not a PIC executable and calloc is called from the dynamic
linker before the dp register is initialized in _dl_start_user.
The fix is to move the dp register initialization into
elf_machine_runtime_setup. Since the address of $global$ can't be
loaded directly, we continue to use the DT_PLTGOT value from the
the main_map to initialize dp. Since l_main_map is not available
in v2.34 and earlier, we use a new function, elf_machine_main_map,
to find the main map.
Arjun Shankar [Thu, 24 Feb 2022 20:43:09 +0000 (21:43 +0100)]
localedef: Handle symbolic links when generating locale-archive
Whenever locale data for any locale included symbolic links, localedef
would throw the error "incomplete set of locale files" and exclude it
from the generated locale archive. This commit fixes that.
Co-authored-by: Florian Weimer <fweimer@redhat.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
(cherry picked from commit ea89d5bbd9e5e514b606045d909e6ab87d851c88)
Noah Goldstein [Fri, 18 Feb 2022 23:00:25 +0000 (17:00 -0600)]
x86: Fix TEST_NAME to make it a string in tst-strncmp-rtm.c
Previously TEST_NAME was passing a function pointer. This didn't fail
because of the -Wno-error flag (to allow for overflow sizes passed
to strncmp/wcsncmp)
Noah Goldstein [Fri, 18 Feb 2022 20:19:15 +0000 (14:19 -0600)]
x86: Test wcscmp RTM in the wcsncmp overflow case [BZ #28896]
In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would
call strcmp-avx2 and wcscmp-avx2 respectively. This would have
not checks around vzeroupper and would trigger spurious
aborts. This commit fixes that.
test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass on
AVX2 machines with and without RTM. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
(cherry picked from commit 7835d611af0854e69a0c71e3806f8fe379282d6f)
Noah Goldstein [Tue, 15 Feb 2022 14:18:15 +0000 (08:18 -0600)]
x86: Fallback {str|wcs}cmp RTM in the ncmp overflow case [BZ #28896]
In the overflow fallback strncmp-avx2-rtm and wcsncmp-avx2-rtm would
call strcmp-avx2 and wcscmp-avx2 respectively. This would have
not checks around vzeroupper and would trigger spurious
aborts. This commit fixes that.
test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass on
AVX2 machines with and without RTM.
Dmitry V. Levin [Sat, 5 Feb 2022 08:00:00 +0000 (08:00 +0000)]
linux: fix accuracy of get_nprocs and get_nprocs_conf [BZ #28865]
get_nprocs() and get_nprocs_conf() use various methods to obtain an
accurate number of processors. Re-introduce __get_nprocs_sched() as
a source of information, and fix the order in which these methods are
used to return the most accurate information. The primary source of
information used in both functions remains unchanged.
This also changes __get_nprocs_sched() error return value from 2 to 0,
but all its users are already prepared to handle that.
Fixes: 342298278e ("linux: Revert the use of sched_getaffinity on get_nproc") Closes: BZ #28865 Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit e1d32b836410767270a3adf1f82b1a47e6e4cd51)
Commit 948ce73b31 made recvmsg/recvmmsg to always call
__convert_scm_timestamps for 64 bit time_t symbol, so adjust it to
always build it for __TIMESIZE != 64.
It fixes build for architecture with 32 bit time_t support when
configured with minimum kernel of 5.1.
Samuel Thibault [Sun, 17 Oct 2021 23:39:02 +0000 (01:39 +0200)]
hurd if_index: Explicitly use AF_INET for if index discovery
5bf07e1b3a74 ("Linux: Simplify __opensock and fix race condition [BZ #28353]")
made __opensock try NETLINK then UNIX then INET. On the Hurd, only INET
knows about network interfaces, so better actually specify that in
if_index.
Linux: Simplify __opensock and fix race condition [BZ #28353]
AF_NETLINK support is not quite optional on modern Linux systems
anymore, so it is likely that the first attempt will always succeed.
Consequently, there is no need to cache the result. Keep AF_UNIX
and the Internet address families as a fallback, for the rare case
that AF_NETLINK is missing. The other address families previously
probed are totally obsolete be now, so remove them.
Use this simplified version as the generic implementation, disabling
Netlink support as needed.
Linux: Only generate 64 bit timestamps for 64 bit time_t recvmsg/recvmmsg
The timestamps created by __convert_scm_timestamps only make sense for
64 bit time_t programs, 32 bit time_t programs will ignore 64 bit time_t
timestamps since SO_TIMESTAMP will be defined to old values (either by
glibc or kernel headers).
Worse, if the buffer is not suffice MSG_CTRUNC is set to indicate it
(which breaks some programs [1]).
This patch makes only 64 bit time_t recvmsg and recvmmsg to call
__convert_scm_timestamps. Also, the assumption to called it is changed
from __ASSUME_TIME64_SYSCALLS to __TIMESIZE != 64 since the setsockopt
might be called by libraries built without __TIME_BITS=64. The
MSG_CTRUNC is only set for the 64 bit symbols, it should happen only
if 64 bit time_t programs run older kernels.
linux: Fix ancillary 64-bit time timestamp conversion (BZ #28349, BZ#28350)
The __convert_scm_timestamps only updates the control message last
pointer for SOL_SOCKET type, so if the message control buffer contains
multiple ancillary message types the converted timestamp one might
overwrite a valid message.
The test checks if the extra ancillary space is correctly handled
by recvmsg/recvmmsg, where if there is no extra space for the 64-bit
time_t converted message the control buffer should be marked with
MSG_TRUNC. It also check if recvmsg/recvmmsg handle correctly multiple
ancillary data.
Checked on x86_64-linux and on i686-linux-gnu on both 5.11 and
4.15 kernel.
Check if the socket support 64-bit network packages timestamps
(SO_TIMESTAMP and SO_TIMESTAMPNS). This will be used on recvmsg
and recvmmsg tests to check if the timestamp should be generated.
Florian Weimer [Thu, 27 Jan 2022 15:03:58 +0000 (16:03 +0100)]
Fix glibc 2.34 ABI omission (missing GLIBC_2.34 in dynamic loader)
The glibc 2.34 release really should have added a GLIBC_2.34
symbol to the dynamic loader. With it, we could move functions such
as dlopen or pthread_key_create that work on process-global state
into the dynamic loader (once we have fixed a longstanding issue
with static linking). Without the GLIBC_2.34 symbol, yet another
new symbol version would be needed because old glibc will fail to
load binaries due to the missing symbol version in ld.so that newly
linked programs will require.
projects / thirdparty / glibc.git / log
