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* arm: Avoid UB in elf_machine_rel()Palmer Dabbelt2024-06-261-5/+4
| | | | | | | | | | This recently came up during a cleanup to remove misaligned accesses from the RISC-V port. Link: https://sourceware.org/pipermail/libc-alpha/2022-June/139961.html Suggested-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com> Reviewed-by: Fangrui Song <maskray@google.com>
* arm: Update ulpsAdhemerval Zanella2024-06-181-0/+48
| | | | For the exp10m1, exp2m1, and log10p1 implementations.
* Convert to autoconf 2.72 (vanilla release, no distribution patches)Andreas K. Hüttel2024-06-171-74/+72
| | | | | | | As discussed at the patch review meeting Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org> Reviewed-by: Simon Chopin <simon.chopin@canonical.com>
* Implement C23 logp1Joseph Myers2024-06-171-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | C23 adds various <math.h> function families originally defined in TS 18661-4. Add the logp1 functions (aliases for log1p functions - the name is intended to be more consistent with the new log2p1 and log10p1, where clearly it would have been very confusing to name those functions log21p and log101p). As aliases rather than new functions, the content of this patch is somewhat different from those actually adding new functions. Tests are shared with log1p, so this patch *does* mechanically update all affected libm-test-ulps files to expect the same errors for both functions. The vector versions of log1p on aarch64 and x86_64 are *not* updated to have logp1 aliases (and thus there are no corresponding header, tests, abilist or ulps changes for vector functions either). It would be reasonable for such vector aliases and corresponding changes to other files to be made separately. For now, the log1p tests instead avoid testing logp1 in the vector case (a Makefile change is needed to avoid problems with grep, used in generating the .c files for vector function tests, matching more than one ALL_RM_TEST line in a file testing multiple functions with the same inputs, when it assumes that the .inc file only has a single such line). Tested for x86_64 and x86, and with build-many-glibcs.py.
* arm: Update ulpsAdhemerval Zanella2024-05-201-0/+16
| | | | For the log2p1 implementation.
* login: structs utmp, utmpx, lastlog _TIME_BITS independence (bug 30701)Florian Weimer2024-04-191-0/+21
| | | | | | | | | These structs describe file formats under /var/log, and should not depend on the definition of _TIME_BITS. This is achieved by defining __WORDSIZE_TIME64_COMPAT32 to 1 on 32-bit ports that support 32-bit time_t values (where __time_t is 32 bits). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* login: Check default sizes of structs utmp, utmpx, lastlogFlorian Weimer2024-04-191-0/+2
| | | | | | | | The default <utmp-size.h> is for ports with a 64-bit time_t. Ports with a 32-bit time_t or with __WORDSIZE_TIME64_COMPAT32=1 need to override it. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* arm: Remove ld.so __tls_get_addr plt usageAdhemerval Zanella2024-04-041-1/+2
| | | | | | Use the hidden alias instead. Checked on arm-linux-gnueabihf.
* elf: Enable TLS descriptor tests on aarch64Adhemerval Zanella2024-03-191-4/+4
| | | | | | | | | | | | The aarch64 uses 'trad' for traditional tls and 'desc' for tls descriptors, but unlike other targets it defaults to 'desc'. The gnutls2 configure check does not set aarch64 as an ABI that uses TLS descriptors, which then disable somes stests. Also rename the internal machinery fron gnu2 to tls descriptors. Checked on aarch64-linux-gnu. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* arm: Update _dl_tlsdesc_dynamic to preserve caller-saved registers (BZ 31372)Adhemerval Zanella2024-03-194-8/+237
| | | | | | | | | | | | | | | | | | | | | | ARM _dl_tlsdesc_dynamic slow path has two issues: * The ip/r12 is defined by AAPCS as a scratch register, and gcc is used to save the stack pointer before on some function calls. So it should also be saved/restored as well. It fixes the tst-gnu2-tls2. * None of the possible VFP registers are saved/restored. ARM has the additional complexity to have different VFP bank sizes (depending of VFP support by the chip). The tst-gnu2-tls2 test is extended to check for VFP registers, although only for hardfp builds. Different than setcontext, _dl_tlsdesc_dynamic does not have HWCAP_ARM_IWMMXT (I don't have a way to properly test it and it is almost a decade since newer hardware was released). With this patch there is no need to mark tst-gnu2-tls2 as XFAIL. Checked on arm-linux-gnueabihf. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* arm: Use _dl_find_object on __gnu_Unwind_Find_exidx (BZ 31405)Adhemerval Zanella2024-02-231-53/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of __dl_iterate_phdr. On ARM dlfo_eh_frame/dlfo_eh_count maps to PT_ARM_EXIDX vaddr start / length. On a Neoverse N1 machine with 160 cores, the following program: $ cat test.c #include <stdlib.h> #include <pthread.h> #include <assert.h> enum { niter = 1024, ntimes = 128, }; static void * tf (void *arg) { int a = (int) arg; for (int i = 0; i < niter; i++) { void *p[ntimes]; for (int j = 0; j < ntimes; j++) p[j] = malloc (a * 128); for (int j = 0; j < ntimes; j++) free (p[j]); } return NULL; } int main (int argc, char *argv[]) { enum { nthreads = 16 }; pthread_t t[nthreads]; for (int i = 0; i < nthreads; i ++) assert (pthread_create (&t[i], NULL, tf, (void *) i) == 0); for (int i = 0; i < nthreads; i++) { void *r; assert (pthread_join (t[i], &r) == 0); assert (r == NULL); } return 0; } $ arm-linux-gnueabihf-gcc -fsanitize=address test.c -o test Improves from ~15s to 0.5s. Checked on arm-linux-gnueabihf.
* arm: Remove wrong ldr from _dl_start_user (BZ 31339)Adhemerval Zanella2024-02-051-1/+0
| | | | | | | | | | | | | | | | | | The commit 49d877a80b29d3002887b084eec6676d9f5fec18 (arm: Remove _dl_skip_args usage) removed the _SKIP_ARGS literal, which was previously loader to r4 on loader _start. However, the cleanup did not remove the following 'ldr r4, [sl, r4]' on _dl_start_user, used to check to skip the arguments after ld self-relocations. In my testing, the kernel initially set r4 to 0, which makes the ldr instruction just read the _GLOBAL_OFFSET_TABLE_. However, since r4 is a callee-saved register; a different runtime might not zero initialize it and thus trigger an invalid memory access. Checked on arm-linux-gnu. Reported-by: Adrian Ratiu <adrian.ratiu@collabora.com> Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* string: Use builtins for ffs and ffsllAdhemerval Zanella Netto2024-02-013-86/+2
| | | | | | | It allows to remove a lot of arch-specific implementations. Checked on x86_64, aarch64, powerpc64. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Refer to C23 in place of C2X in glibcJoseph Myers2024-02-011-1/+1
| | | | | | | | | | | | | | | WG14 decided to use the name C23 as the informal name of the next revision of the C standard (notwithstanding the publication date in 2024). Update references to C2X in glibc to use the C23 name. This is intended to update everything *except* where it involves renaming files (the changes involving renaming tests are intended to be done separately). In the case of the _ISOC2X_SOURCE feature test macro - the only user-visible interface involved - support for that macro is kept for backwards compatibility, while adding _ISOC23_SOURCE. Tested for x86_64.
* Update copyright dates with scripts/update-copyrightsPaul Eggert2024-01-01115-115/+115
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* elf: Remove LD_PROFILE for static binariesAdhemerval Zanella2023-11-212-2/+4
| | | | | | | | | | | The _dl_non_dynamic_init does not parse LD_PROFILE, which does not enable profile for dlopen objects. Since dlopen is deprecated for static objects, it is better to remove the support. It also allows to trim down libc.a of profile support. Checked on x86_64-linux-gnu. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* configure: Use autoconf 2.71Siddhesh Poyarekar2023-07-172-87/+118
| | | | | | | | | | | | | | Bump autoconf requirement to 2.71 to allow regenerating configure on more recent distributions. autoconf 2.71 has been in Fedora since F36 and is the current version in Debian stable (bookworm). It appears to be current in Gentoo as well. All sysdeps configure and preconfigure scripts have also been regenerated; all changes are trivial transformations that do not affect functionality. Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Fix misspellings in sysdeps/ -- BZ 25337Paul Pluzhnikov2023-05-3010-14/+14
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* Update arm libm-tests-ulpsAdhemerval Zanella2023-03-301-0/+1
| | | | For the next test from cf7ffdd8a5f6da55397e10b3860062944312824c.
* arm: Remove __builtin_arm_uqsub8 usage on string-fza.hAdhemerval Zanella Netto2023-03-021-4/+0
| | | | | | | | | | The __builtin_arm_uqsub8 is an internal GCC builtin which might change in future release (the correct way is to include "arm_acle.h" and use __uqsub8 ()). Since not all compilers support it, just use the inline assembler instead. Checked on armv7a-linux-gnueabihf. Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
* arm: Support gcc older than 10 for find_zero_allAdhemerval Zanella2023-02-201-0/+6
| | | | | | | | __builtin_arm_uqsub8 is only available on gcc newer or equal than 10. Checked on arm-linux-gnueabihf built with gcc 9. Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
* arm: Add string-fza.hRichard Henderson2023-02-061-0/+67
| | | | | | | | | | | While arm has the more important string functions in assembly, there are still a few generic routines used. Use the UQSUB8 insn for testing of zeros. Checked on armv7-linux-gnueabihf Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Update copyright dates with scripts/update-copyrightsJoseph Myers2023-01-06114-114/+114
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* configure: Use -Wno-ignored-attributes if compiler warns about multiple aliasesAdhemerval Zanella2022-11-011-0/+4
| | | | | | | | | clang emits an warning when a double alias redirection is used, to warn the the original symbol will be used even when weak definition is overridden. However, this is a common pattern for weak_alias, where multiple alias are set to same symbol. Reviewed-by: Fangrui Song <maskray@google.com>
* sysdeps: arm: Fix preconfigure script for ARMv8/v9 targets [BZ #29698]Felix Riemann2022-10-202-2/+2
| | | | | | | | | | | | | | | | | | | | The ARM preconfigure script tries to detect the capabilities of the target platform by checking the compiler's predefined architecture macros. However, if the compiler is tuning for AArch32 on ARMv8/v9 this step fails: checking for sysdeps preconfigure fragments... aarch64 alpha arc arm WARNING: arm/preconfigure: Did not find ARM architecture type; using default This is because preconfigure.ac doesn't escape the square brackets in the glob for matching compilers targeting ARMv8. Adding another pair of brackets to escape the first pair fixes this: checking for sysdeps preconfigure fragments... aarch64 alpha arc arm Found compiler is configured for something newer than v7 - using v7 Signed-off-by: Felix Riemann <felix.riemann@sma.de> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Use PTR_MANGLE and PTR_DEMANGLE unconditionally in C sourcesFlorian Weimer2022-10-181-2/+0
| | | | | | | | | | | | | | | | | In the future, this will result in a compilation failure if the macros are unexpectedly undefined (due to header inclusion ordering or header inclusion missing altogether). Assembler sources are more difficult to convert. In many cases, they are hand-optimized for the mangling and no-mangling variants, which is why they are not converted. sysdeps/s390/s390-32/__longjmp.c and sysdeps/s390/s390-64/__longjmp.c are special: These are C sources, but most of the implementation is in assembler, so the PTR_DEMANGLE macro has to be undefined in some cases, to match the assembler style. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Introduce <pointer_guard.h>, extracted from <sysdep.h>Florian Weimer2022-10-185-44/+70
| | | | | | | | | | | | | | This allows us to define a generic no-op version of PTR_MANGLE and PTR_DEMANGLE. In the future, we can use PTR_MANGLE and PTR_DEMANGLE unconditionally in C sources, avoiding an unintended loss of hardening due to missing include files or unlucky header inclusion ordering. In i386 and x86_64, we can avoid a <tls.h> dependency in the C code by using the computed constant from <tcb-offsets.h>. <sysdep.h> no longer includes these definitions, so there is no cyclic dependency anymore when computing the <tcb-offsets.h> constants. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* arm: Enable USE_ATOMIC_COMPILER_BUILTINS (BZ #24774)Adhemerval Zanella2022-10-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As per other architectures. I have checked on a armv8 hardware with the following configurations: arm-linux-gnueabihf (gcc built with --with-float=hard --with-cpu=arm926ej-s) armv5-linux-gnueabihf (-march=armv5te -mfpu=vfpv3) armv7-linux-gnueabihf (-march=armv7-a -mfpu=vfpv3) armv7-thumb-linux-gnueabihf (-march=armv7-a -mfpu=vfpv3 -mthumb) armv7-neon-linux-gnueabihf (-march=armv7-a -mfpu=neon) armv7-neonhard-linux-gnueabihf (-march=armv7-a -mfpu=neon -mfloat-abi=hard) Without any regression. I haven't dig into the code, but since Linux atomic-machine.h handle pre-ARMv6 and ARMv6 I expect the compiler might have some small room to optimize. The code size also improves is most of the configurations: * master text data bss dec hex filename 1727801 9720 37928 1775449 1b1759 arm-linux-gnueabihf/libc.so 1691729 9720 37928 1739377 1a8a71 arm-linux-gnueabihf-armv7-disable-multi-arch/libc.so 1725509 9720 37928 1773157 1b0e65 armv5-linux-gnueabihf/libc.so 1700757 9720 37928 1748405 1aadb5 armv6-linux-gnueabihf/libc.so 1698973 9720 37928 1746621 1aa6bd armv6t2-linux-gnueabihf/libc.so 1695481 9752 37928 1743161 1a9939 armv7-linux-gnueabihf/libc.so 1692917 9744 37928 1740589 1a8f2d armv7-neonhard-linux-gnueabihf/libc.so 1692917 9744 37928 1740589 1a8f2d armv7-neon-linux-gnueabihf/libc.so 1225353 9752 37928 1273033 136cc9 armv7-thumb-linux-gnueabihf/libc.so * patched text data bss dec hex filename 1726805 9720 37928 1774453 1b1375 arm-linux-gnueabihf/libc.so 1689321 9720 37928 1736969 1a8109 arm-linux-gnueabihf-armv7-disable-multi-arch/libc.so 1724433 9720 37928 1772081 1b0a31 armv5-linux-gnueabihf/libc.so 1698301 9720 37928 1745949 1aa41d armv6-linux-gnueabihf/libc.so 1696525 9720 37928 1744173 1a9d2d armv6t2-linux-gnueabihf/libc.so 1693009 9752 37928 1740689 1a8f91 armv7-linux-gnueabihf/libc.so 1690493 9744 37928 1738165 1a85b5 armv7-neonhard-linux-gnueabihf/libc.so 1690493 9744 37928 1738165 1a85b5 armv7-neon-linux-gnueabihf/libc.so 1223837 9752 37928 1271517 1366dd armv7-thumb-linux-gnueabihf/libc.so The idea is eventually move all architectures to use compiler builtins. Reviewed-by: Aurelien Jarno <aurelien@aurel32.net> Tested-by: Aurelien Jarno <aurelien@aurel32.net>
* Use atomic_exchange_release/acquireWilco Dijkstra2022-09-261-1/+1
| | | | | | | Rename atomic_exchange_rel/acq to use atomic_exchange_release/acquire since these map to the standard C11 atomic builtins. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* arm: Remove nested functionf rom relocate_pc24Adhemerval Zanella2022-08-121-10/+13
| | | | Checked on arm-linux-gnueabihf.
* arm: Remove RELA supportAdhemerval Zanella2022-08-042-106/+1
| | | | | Now that prelink is not support, there is no need to keep supporting rela for non bootstrap.
* Add bounds check to __libc_ifunc_impl_listWilco Dijkstra2022-06-101-2/+2
| | | | | | | | | | | | Add a proper bounds check to __libc_ifunc_impl_list. This makes MAX_IFUNC redundant and fixes several targets that will write outside the array. To avoid unnecessary large diffs, pass the maximum in the argument 'i' to IFUNC_IMPL_ADD - 'max' can be used in new ifunc definitions and existing ones can be updated if desired. Passes buildmanyglibc. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* grep: egrep -> grep -E, fgrep -> grep -FSam James2022-06-052-2/+2
| | | | | | | | | | | Newer versions of GNU grep (after grep 3.7, not inclusive) will warn on 'egrep' and 'fgrep' invocations. Convert usages within the tree to their expanded non-aliased counterparts to avoid irritating warnings during ./configure and the test suite. Signed-off-by: Sam James <sam@gentoo.org> Reviewed-by: Fangrui Song <maskray@google.com>
* arm: Remove _dl_skip_args usageAdhemerval Zanella2022-05-301-39/+0
| | | | | | | | | | | Since ad43cac44a the generic code already shuffles the argv/envp/auxv on the stack to remove the ld.so own arguments and thus _dl_skip_args is always 0. It makes the _fixup_stack branch ununsed. Checked with qemu-user that arguments are correctly passed on both constructors and main program. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Revert "[ARM][BZ #17711] Fix extern protected data handling"Fangrui Song2022-05-232-28/+3
| | | | | | | | This reverts commit 3bcea719ddd6ce399d7bccb492c40af77d216e42. Similar to commit e555954e026df1b85b8ef6c101d05f97b1520d7e for aarch64. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* rtld: Remove DL_ARGV_NOT_RELRO and make _dl_skip_args constSzabolcs Nagy2022-05-171-4/+0
| | | | | | | | | | | _dl_skip_args is always 0, so the target specific code that modifies argv after relro protection is applied is no longer used. After the patch relro protection is applied to _dl_argv consistently on all targets. Reviewed-by: Florian Weimer <fweimer@redhat.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Replace PI_STATIC_AND_HIDDEN with opposite HIDDEN_VAR_NEEDS_DYNAMIC_RELOCFangrui Song2022-04-262-8/+0
| | | | | | | | | | | | | | | | | | PI_STATIC_AND_HIDDEN indicates whether accesses to internal linkage variables and hidden visibility variables in a shared object (ld.so) need dynamic relocations (usually R_*_RELATIVE). PI (position independent) in the macro name is a misnomer: a code sequence using GOT is typically position-independent as well, but using dynamic relocations does not meet the requirement. Not defining PI_STATIC_AND_HIDDEN is legacy and we expect that all new ports will define PI_STATIC_AND_HIDDEN. Current ports defining PI_STATIC_AND_HIDDEN are more than the opposite. Change the configure default. No functional change. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Remove -z combreloc and HAVE_Z_COMBRELOCFangrui Song2022-04-041-16/+2
| | | | | | | | | | | | | -z combreloc has been the default regadless of the architecture since binutils commit f4d733664aabd7bd78c82895e030ec9779a92809 (2002). The configure check added in commit fdde83499a05 (2001) has long been unneeded. We can therefore treat HAVE_Z_COMBRELOC as always 1 and delete dead code paths in dl-machine.h files (many were copied from commit a711b01d34ca and ee0cb67ec238). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Remove prelink supportAdhemerval Zanella2022-02-101-4/+0
| | | | | | | | | | | | | Prelinked binaries and libraries still work, the dynamic tags DT_GNU_PRELINKED, DT_GNU_LIBLIST, DT_GNU_CONFLICT just ignored (meaning the process is reallocated as default). The loader environment variable TRACE_PRELINKING is also removed, since it used solely on prelink. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* Update copyright dates with scripts/update-copyrightsPaul Eggert2022-01-01114-114/+114
| | | | | | | | | | | | | | | | | | | | | | | I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
* elf: Add _dl_find_object functionFlorian Weimer2021-12-281-0/+25
| | | | | | | | | | | | | | | | | | | | | | | | | It can be used to speed up the libgcc unwinder, and the internal _dl_find_dso_for_object function (which is used for caller identification in dlopen and related functions, and in dladdr). _dl_find_object is in the internal namespace due to bug 28503. If libgcc switches to _dl_find_object, this namespace issue will be fixed. It is located in libc for two reasons: it is necessary to forward the call to the static libc after static dlopen, and there is a link ordering issue with -static-libgcc and libgcc_eh.a because libc.so is not a linker script that includes ld.so in the glibc build tree (so that GCC's internal -lc after libgcc_eh.a does not pick up ld.so). It is necessary to do the i386 customization in the sysdeps/x86/bits/dl_find_object.h header shared with x86-64 because otherwise, multilib installations are broken. The implementation uses software transactional memory, as suggested by Torvald Riegel. Two copies of the supporting data structures are used, also achieving full async-signal-safety. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* malloc: Remove memusage.hAdhemerval Zanella2021-12-281-20/+0
| | | | | | And use machine-sp.h instead. The Linux implementation is based on already provided CURRENT_STACK_FRAME (used on nptl code) and STACK_GROWS_UPWARD is replaced with _STACK_GROWS_UP.
* Remove atomic-machine.h atomic typedefsAdhemerval Zanella2021-12-281-17/+0
| | | | Now that memusage.c uses generic types we can remove them.
* elf: Add _dl_audit_pltexitAdhemerval Zanella2021-12-282-1/+3
| | | | | | | | | It consolidates the code required to call la_pltexit audit callback. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* Remove ununsed tcb-offsetAdhemerval Zanella2021-12-173-17/+0
| | | | Some architectures do not use the auto-generated tcb-offsets.h.
* Remove TLS_TCB_ALIGN and TLS_INIT_TCB_ALIGNFlorian Weimer2021-12-091-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | TLS_INIT_TCB_ALIGN is not actually used. TLS_TCB_ALIGN was likely introduced to support a configuration where the thread pointer has not the same alignment as THREAD_SELF. Only ia64 seems to use that, but for the stack/pointer guard, not for storing tcbhead_t. Some ports use TLS_TCB_OFFSET and TLS_PRE_TCB_SIZE to shift the thread pointer, potentially landing in a different residue class modulo the alignment, but the changes should not impact that. In general, given that TLS variables have their own alignment requirements, having different alignment for the (unshifted) thread pointer and struct pthread would potentially result in dynamic offsets, leading to more complexity. hppa had different values before: __alignof__ (tcbhead_t), which seems to be 4, and __alignof__ (struct pthread), which was 8 (old default) and is now 32. However, it defines THREAD_SELF as: /* Return the thread descriptor for the current thread. */ # define THREAD_SELF \ ({ struct pthread *__self; \ __self = __get_cr27(); \ __self - 1; \ }) So the thread pointer points after struct pthread (hence __self - 1), and they have to have the same alignment on hppa as well. Similarly, on ia64, the definitions were different. We have: # define TLS_PRE_TCB_SIZE \ (sizeof (struct pthread) \ + (PTHREAD_STRUCT_END_PADDING < 2 * sizeof (uintptr_t) \ ? ((2 * sizeof (uintptr_t) + __alignof__ (struct pthread) - 1) \ & ~(__alignof__ (struct pthread) - 1)) \ : 0)) # define THREAD_SELF \ ((struct pthread *) ((char *) __thread_self - TLS_PRE_TCB_SIZE)) And TLS_PRE_TCB_SIZE is a multiple of the struct pthread alignment (confirmed by the new _Static_assert in sysdeps/ia64/libc-tls.c). On m68k, we have a larger gap between tcbhead_t and struct pthread. But as far as I can tell, the port is fine with that. The definition of TCB_OFFSET is sufficient to handle the shifted TCB scenario. This fixes commit 23c77f60181eb549f11ec2f913b4270af29eee38 ("nptl: Increase default TCB alignment to 32"). Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* nptl: Introduce <tcb-access.h> for THREAD_* accessorsFlorian Weimer2021-12-091-9/+1
| | | | | | | These are common between most architectures. Only the x86 targets are outliers. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* nptl: Increase default TCB alignment to 32Florian Weimer2021-12-031-3/+0
| | | | | | | | | | rseq support will use a 32-byte aligned field in struct pthread, so the whole struct needs to have at least that alignment. nptl/tst-tls3mod.c uses TCB_ALIGNMENT, therefore include <descr.h> to obtain the fallback definition. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* arm: Use have-mtls-dialect-gnu2 to check for ARM TLS descriptors supportAdhemerval Zanella2021-11-011-6/+1
| | | | | | | The lld linker does not support TLSDESC for arm. The have-arm-tls-desc is a leftover of 56583289b1 to support NaCL. Reviewed-by: Fangrui Song <maskray@google.com>
* arm: Use internal symbol for _dl_argv on _dl_start_userAdhemerval Zanella2021-11-011-1/+1
| | | | | | | | | | | | The lld does not support R_ARM_GOTOFF32 to preemptible symbol (_dl_argv has default visibility). Use the internal alias instead (one option would to use HIDDEN_JUMPTARGET, bu the macro is not defined for !__ASSEMBLER__ and I made this patch arm-specific to avoid require to check extensivelly on other architecture it this might break something). Checked on arm-linux-gnueabihf. Reviewed-by: Fangrui Song <maskray@google.com>