glibc/sysdeps/generic, branch master

elf: Support recursive use of dynamic TLS in interposed malloc

2024-07-01T17:02:11Z

It turns out that quite a few applications use bundled mallocs that have been built to use global-dynamic TLS (instead of the recommended initial-exec TLS). The previous workaround from commit afe42e935b3ee97bac9a7064157587777259c60e ("elf: Avoid some free (NULL) calls in _dl_update_slotinfo") does not fix all encountered cases unfortunatelly. This change avoids the TLS generation update for recursive use of TLS from a malloc that was called during a TLS update. This is possible because an interposed malloc has a fixed module ID and TLS slot. (It cannot be unloaded.) If an initially-loaded module ID is encountered in __tls_get_addr and the dynamic linker is already in the middle of a TLS update, use the outdated DTV, thus avoiding another call into malloc. It's still necessary to update the DTV to the most recent generation, to get out of the slow path, which is why the check for recursion is needed. The bookkeeping is done using a global counter instead of per-thread flag because TLS access in the dynamic linker is tricky. All this will go away once the dynamic linker stops using malloc for TLS, likely as part of a change that pre-allocates all TLS during pthread_create/dlopen. Fixes commit d2123d68275acc0f061e73d5f86ca504e0d5a344 ("elf: Fix slow tls access after dlopen [BZ #19924]"). Reviewed-by: Szabolcs Nagy

elf: Remove HWCAP_IMPORTANT

2024-06-18T08:45:36Z

Remove the definitions of HWCAP_IMPORTANT after removal of LD_HWCAP_MASK / tunable glibc.cpu.hwcap_mask. There HWCAP_IMPORTANT was used as default value. Reviewed-by: Adhemerval Zanella

elf: Remove LD_HWCAP_MASK / tunable glibc.cpu.hwcap_mask

2024-06-18T08:45:36Z

Remove the environment variable LD_HWCAP_MASK and the tunable glibc.cpu.hwcap_mask as those are not used anymore in common-code after removal in elf/dl-cache.c:search_cache(). The only remaining user is sparc32 where it is used in elf_machine_matches_host(). If sparc32 does not need it anymore, we can get rid of it at all. Otherwise we could also move LD_HWCAP_MASK / tunable glibc.cpu.hwcap_mask to be sparc32 specific. Reviewed-by: Adhemerval Zanella

elf: Remove _DL_HWCAP_PLATFORM

2024-06-18T08:45:36Z

Remove the definitions of _DL_HWCAP_PLATFORM as those are not used anymore after removal in elf/dl-cache.c:search_cache(). Reviewed-by: Adhemerval Zanella

elf: Remove _dl_string_platform

2024-06-18T08:45:36Z

Despite of powerpc where the returned integer is stored in tcb, and the diagnostics output, there is no user anymore. Thus this patch removes the diagnostics output and _dl_string_platform for all other platforms. Reviewed-by: Adhemerval Zanella

login: Check default sizes of structs utmp, utmpx, lastlog

2024-04-19T12:38:17Z

The default 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

elf: Add CPU iteration support for future use in ld.so diagnostics

2024-04-08T14:48:55Z

Reviewed-by: Szabolcs Nagy

Reinstate generic features-time64.h

2024-04-05T12:02:36Z

The a4ed0471d7 removed the generic version which is included by features.h and used by Hurd. Checked by building i686-gnu and x86_64-gnu with build-many-glibc.py.

Always define __USE_TIME_BITS64 when 64 bit time_t is used

2024-04-02T18:28:36Z

It was raised on libc-help [1] that some Linux kernel interfaces expect the libc to define __USE_TIME_BITS64 to indicate the time_t size for the kABI. Different than defined by the initial y2038 design document [2], the __USE_TIME_BITS64 is only defined for ABIs that support more than one time_t size (by defining the _TIME_BITS for each module). The 64 bit time_t redirects are now enabled using a different internal define (__USE_TIME64_REDIRECTS). There is no expected change in semantic or code generation. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and arm-linux-gnueabi [1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html [2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign Reviewed-by: DJ Delorie

powerpc: Add HWCAP3/HWCAP4 data to TCB for Power Architecture.

2024-03-19T22:19:27Z

This patch adds a new feature for powerpc. In order to get faster access to the HWCAP3/HWCAP4 masks, similar to HWCAP/HWCAP2 (i.e. for implementing __builtin_cpu_supports() in GCC) without the overhead of reading them from the auxiliary vector, we now reserve space for them in the TCB. This is an ABI change for GLIBC 2.39. Suggested-by: Peter Bergner Reviewed-by: Peter Bergner

glibc/sysdeps/generic, branch master

elf: Support recursive use of dynamic TLS in interposed malloc

elf: Remove HWCAP_IMPORTANT

elf: Remove LD_HWCAP_MASK / tunable glibc.cpu.hwcap_mask

elf: Remove _DL_HWCAP_PLATFORM

elf: Remove _dl_string_platform

login: Check default sizes of structs utmp, utmpx, lastlog

elf: Add CPU iteration support for future use in ld.so diagnostics

Reinstate generic features-time64.h

Always define __USE_TIME_BITS64 when 64 bit time_t is used

﻿powerpc: Add HWCAP3/HWCAP4 data to TCB for Power Architecture.

powerpc: Add HWCAP3/HWCAP4 data to TCB for Power Architecture.