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* io: Return EBAFD for negative file descriptor on fstat (BZ #27559)Adhemerval Zanella2021-03-112-0/+18
| | | | | | | | Now that fstat is implemented on top fstatat we need to handle negative inputs. The implementation now rejects AT_FDCWD, which would otherwise be accepted by the kernel. Checked on x86_64-linux-gnu and on i686-linux-gnu.
* Update kernel version to 5.11 in tst-mman-consts.py.Joseph Myers2021-03-101-1/+1
| | | | | | | | This patch updates the kernel version in the test tst-mman-consts.py to 5.11. (There are no new MAP_* constants covered by this test in 5.11 that need any other header changes.) Tested with build-many-glibcs.py.
* Linux: misc/tst-ofdlocks-compat can be a regular testFlorian Weimer2021-03-092-9/+7
| | | | | | | | Now that compat_symbol_reference works in non-internal tests. Also do not build and run the test at all on architectures which do not have the pre-2.28 symbol version of fcntl. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Linux: dirent/tst-readdir64-compat can be a regular testFlorian Weimer2021-03-092-6/+5
| | | | | | | | | | compat_symbol_reference works in non-internal tests now. Also avoid building the test for unsupported configurations at all. I verified by building with build-many-glibcs.py that GLIBC_2.1.3 works as the predecessor of GLIBC_2.2. (Symbol versions in the early days are complex.) Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* tst: Add test for ntp_adjtimeLukasz Majewski2021-03-082-1/+23
| | | | | | This test is a wrapper on tst-clock_adjtime test. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* tst: Add test for adjtimexLukasz Majewski2021-03-082-1/+23
| | | | | | This test is a wrapper on tst-clock_adjtime test. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* tst: Modify tst-clock_adjtime to allow reuse of its codeLukasz Majewski2021-03-081-1/+5
| | | | | | | The tst-clock_adjtime can be adjusted to be reused for also testing adjtimex. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* tst: Add test for clock_adjtimeLukasz Majewski2021-03-082-1/+59
| | | | | | | | | | | This code privides test to check if time on target machine is properly adjusted. The time is altered only when cross-test-ssh.sh is executed with --allow-time-setting flag. As the delta added to CLOCK_REALTIME is only 1 sec the original time is not restored and further tests are executed with this bias. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* linux: Fix __thrd_sleep64 hidden definitionAdhemerval Zanella2021-03-052-2/+2
| | | | The symbol is exported by libc.
* tst: Fix tst-timerfd testLukasz Majewski2021-03-021-11/+4
| | | | | | | | | | | | | | | | | | | There were following problems discovered for tst-timerfd test: 1. Do not set the struct itimerspec's it_interval tv_sec to 2 seconds. After this change the timerfd will trigger only once (the it_value is only set in this case). 2. The 'val1' variable (including the call to timerfd_gettime) is not needed anymore, as it is just enough to read the struct itimerspec after sleep. As a consequence the 'val2' has been renamed to 'val'. 3. After calling timerfd_gettime, the value of struct itimerspec time, when timer is running, is the remaining time. In the case of this test it would be less than 1 second. As a result the TEST_COMPARE macro logic had to be adjusted. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* ld.so: Implement the --list-diagnostics optionFlorian Weimer2021-03-021-0/+77
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* tst: Add test for utimesLukasz Majewski2021-03-022-1/+89
| | | | | | | | | | | This patch provides test for utimes. It uses wrapper to read access and modification times to compare them with ones written by utimes. Moreover, access and modification times beyond the Y2038 threshold date (i.e. 32 bit time_t overflow) are also checked. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* tst: Add test for utimeLukasz Majewski2021-03-022-1/+88
| | | | | | | | | | This patch provides test for utime. It uses wrapper to read access and modification times to compare them with ones written by utime. Moreover, access and modification times beyond the Y2038 threshold date (i.e. 32 bit time_t overflow) are also checked. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* tst: Add test for futimensLukasz Majewski2021-03-022-1/+85
| | | | | | | | | | | This patch provides test for futimens. It uses wrapper, which reads access and modification time to compare them with ones written by futimens. Moreover, access and modification times beyond the Y2038 threshold date (i.e. 32 bit time_t overflow) are also checked. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* nptl: Use <unwind-link.h> for accessing the libgcc_s unwinderFlorian Weimer2021-03-011-14/+2
| | | | Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Implement <unwind-link.h> for dynamically loading the libgcc_s unwinderFlorian Weimer2021-03-011-67/+0
| | | | | | | | | | This will be used to consolidate the libgcc_s access for backtrace and pthread_cancel. Unlike the existing backtrace implementations, it provides some hardening based on pointer mangling. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* Reduce the statically linked startup code [BZ #23323]Florian Weimer2021-02-2533-6/+39
| | | | | | | | | | | | | | | | | | | It turns out the startup code in csu/elf-init.c has a perfect pair of ROP gadgets (see Marco-Gisbert and Ripoll-Ripoll, "return-to-csu: A New Method to Bypass 64-bit Linux ASLR"). These functions are not needed in dynamically-linked binaries because DT_INIT/DT_INIT_ARRAY are already processed by the dynamic linker. However, the dynamic linker skipped the main program for some reason. For maximum backwards compatibility, this is not changed, and instead, the main map is consulted from __libc_start_main if the init function argument is a NULL pointer. For statically linked binaries, the old approach based on linker symbols is still used because there is nothing else available. A new symbol version __libc_start_main@@GLIBC_2.34 is introduced because new binaries running on an old libc would not run their ELF constructors, leading to difficult-to-debug issues.
* nptl: Move elision implementations into libcFlorian Weimer2021-02-2336-684/+24
| | | | | | | | | | | | | | | | | | The elision interfaces are closely aligned between the targets that implement them, so declare them in the generic <lowlevellock.h> file. Empty .c stubs are provided, so that fewer makefile updates under sysdeps are needed. Also simplify initialization via __libc_early_init. The symbols __lll_clocklock_elision, __lll_lock_elision, __lll_trylock_elision, __lll_unlock_elision, __pthread_force_elision move into libc. For the time being, non-hidden references are used from libpthread to access them, but once that part of libpthread is moved into libc, hidden symbols will be used again. (Hidden references seem desirable to reduce the likelihood of transactions aborts.)
* x86_64/clone.S: Upate commentsH.J. Lu2021-02-221-6/+8
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* i386/clone.S: Remove redundant EBX loadH.J. Lu2021-02-221-6/+0
| | | | | | | | | | | | | There is no neeed for call L(here) L(here): popl %ebx addl $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebx before movl %eax, %ebx
* aarch64: Remove the unused __read_tp symbolSzabolcs Nagy2021-02-223-51/+0
| | | | | | | | This was likely a mistake in the original aarch64 port copied over from arm: on aarch64 tpidr_el0 register is always available. The __read_tp symbol is visible with static linking, but it's not part of the public ABI so it should be safe to remove.
* Update syscall lists for Linux 5.11.Joseph Myers2021-02-1926-2/+28
| | | | | | | | Linux 5.11 has one new syscall, epoll_pwait2. Update syscall-names.list and regenerate the arch-syscall.h headers with build-many-glibcs.py update-syscalls. Tested with build-many-glibcs.py.
* Correct hppa EFD_NONBLOCK, IN_NONBLOCK, SFD_NONBLOCK and TFD_NONBLOCK defines.John David Anglin2021-02-194-4/+4
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* S390: Add new hwcap values.Stefan Liebler2021-02-161-0/+2
| | | | The new hwcap values indicate support for arch14 architecture.
* aarch64: Fix sys/ptrace.h if linux headers are includedSzabolcs Nagy2021-02-151-0/+34
| | | | | | If the linux asm/ptrace.h is included before sys/ptrace.h that breaks the newly added declarations there, so undef the names that may be defined as macros in the linux header.
* linux: Remove stat-check.cAdhemerval Zanella2021-02-113-30/+13
| | | | | | | The check is moved to LFS fstatat implementation (since it is the code that actually implements the syscall). Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Remove overflow.hAdhemerval Zanella2021-02-111-69/+0
| | | | | | The header is not used anywhere. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Consolidate internal_statvfsAdhemerval Zanella2021-02-119-37/+56
| | | | | | | | | | | Remove the internal_statvfs64.c and open code the implementation on internal_statvfs.c. The alpha is now unrequired, the generic implementation also handles it. Also, remove unused includes on internal_statvfs.c, and remove unused arguments on __internal_statvfs{64}. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Consolidate statvfs implementationsAdhemerval Zanella2021-02-116-46/+25
| | | | | | | | | There is no need to handle ENOSYS on fstatfs64 call, required only for alpha (where is already fallbacks to fstatfs). Checked on x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Consolidate fstatvfs implementationsAdhemerval Zanella2021-02-117-46/+25
| | | | | | | | | | | There is no need to handle ENOSYS on fstatfs64 call, required only for alpha (where is already fallbacks to fstatfs). The wordsize internal_statvfs64.c is removed, since how the LFS support is provided by fstatvfs64.c (used on 64-bit architectures as well). Checked on x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Consolidate statfs implementationsAdhemerval Zanella2021-02-119-81/+125
| | | | | | | | | | | | | | | | | | | | | | | | The __NR_statfs64 syscall is supported on all architectures but aarch64, mips64, riscv64, and x86_64. And newer ABIs also uses the new statfs64 interface (where the struct size is used as second argument). So the default implementation now uses: 1. __NR_statfs64 for non-LFS call and handle overflow directly There is no need to handle __NR_statfs since all architectures that only support are LFS only. 2. __NR_statfs if defined or __NR_statfs64 otherwise for LFS call. Alpha is the only outlier, since it is a 64-bit architecture which provides non-LFS interface and only provides __NR_statfs64 on newer kernels (v5.1+). Checked on x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Consolidate fstatfs implementationsAdhemerval Zanella2021-02-119-73/+126
| | | | | | | | | | | | | | | | | | | | | | | | The __NR_fstatfs64 syscall is supported on all architectures but aarch64, mips64, riscv64, and x86_64. And newer ABIs also uses the new fstatfs64 interface (where the struct size is used as first argument). So the default implementation now uses: 1. __NR_fstatfs64 for non-LFS call and handle overflow directly There is no need to handle __NR_fstatfs since all architectures that only support are LFS only. 2. __NR_fstatfs if defined or __NR_fstatfs64 otherwise for LFS call. Alpha is the only outlier, it is a 64-bit architecture which provides non-LFS interface and only provides __NR_fstatfs64 on newer kernels (5.1+). Checked on x86_64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Set LFS statfs as defaultAdhemerval Zanella2021-02-112-11/+75
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently glibc has three different struct statfs{64} definitions: 1. Non-LFS support where non-LFS and LFS struct have different size: alpha, arm, hppa, i686, m68k, microblaze, mips (all abis), powerpc32, s390, sh4, and sparc. 2. Non-LFS support where non-LFS and LFS struct have the same size: csky and nios2. 3. Only LFS support (where both struct have the same size): arc, ia64, powerpc64 (including LE), riscv (both 32 and 64 bits), s390x, sparc64, and x86 (including x32). The STATFS_IS_STATFS64/__STATFS_MATCHES_STATFS64 does not tell apart between 1. and 2. since for both the only difference is the struct size (for 2. both non-LFS and LFS uses the same syscall, where for 1. the old non-LFS is used for [f]statfs). This patch move the generic statfs.h for both csky and nios2, and make the default definitions for newer ABIs to assume that only LFS will be support (so there is no need to keep no-LFS and LFS struct statfs with the same size, it will be implicit). This patch does not change the code generation. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Set default kernel_stat.h to LFSAdhemerval Zanella2021-02-1115-200/+231
| | | | | | | | | | | | | | The XSTAT_IS_XSTAT64 and STAT_IS_KERNEL_STAT flags are now set to 1 and STATFS_IS_STATFS64 is set to __STATFS_MATCHES_STATFS64. This makes the default ABI for newer ports to provide only LFS calls. A copy of non-LFS support is provided to 32-bit ABIS with non-LFS support (arm, csky, i386, m68k, nios2, s390, and sh). Is also allows to remove the 64-bit ports, which already uses the default values. This patch does not change the code generation. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* linux: Fix STATFS_IS_STATFS64 definitionAdhemerval Zanella2021-02-118-8/+36
| | | | | | | | | | | | | | | aarch64, arc, ia64, mips64, powerpc64, riscv32, riscv64, s390x, sparc64, and x86_64 defines STATFS_IS_STATFS64 to 0, but all of them alias statfs to statfs64 and the struct statfs has the same and layout of struct statfs64. The correct definition will be used on the [f]statfs[64] consolidation. This patch does not change code generation since the symbols are implemented using the auto-generation syscall for all the aforementioned ABIs. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* tunables: Simplify TUNABLE_SET interfaceSiddhesh Poyarekar2021-02-101-1/+1
| | | | | | | | | | | | | | | The TUNABLE_SET interface took a primitive C type argument, which resulted in inconsistent type conversions internally due to incorrect dereferencing of types, especialy on 32-bit architectures. This change simplifies the TUNABLE setting logic along with the interfaces. Now all numeric tunable values are stored as signed numbers in tunable_num_t, which is intmax_t. All calls to set tunables cast the input value to its primitive type and then to tunable_num_t for storage. This relies on gcc-specific (although I suspect other compilers woul also do the same) unsigned to signed integer conversion semantics, i.e. the bit pattern is conserved. The reverse conversion is guaranteed by the standard.
* Add more ptrace constants for AArch64 and PowerPC.Joseph Myers2021-02-082-0/+26
| | | | | | | | | | | | Linux 5.10 adds PTRACE_PEEKMTETAGS and PTRACE_POKEMTETAGS for AArch64. Adding those shows up that glibc is also missing PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP, for AArch64 (where they were added to Linux in 5.3) and for PowerPC (where they were added in Linux 4.20); it already has those two defines for x86. Add all those defines to glibc's headers. Tested with build-many-glibcs.py for aarch64-linux-gnu and powerpc-linux-gnu.
* linux: Require /dev/shm as the shared memory file systemFlorian Weimer2021-02-081-147/+0
| | | | | | | | | | | | | | | | | | | | | Previously, glibc would pick an arbitrary tmpfs file system from /proc/mounts if /dev/shm was not available. This could lead to an unsuitable file system being picked for the backing storage for shm_open, sem_open, and related functions. This patch introduces a new function, __shm_get_name, which builds the file name under the appropriate (now hard-coded) directory. It is called from the various shm_* and sem_* function. Unlike the SHM_GET_NAME macro it replaces, the callers handle the return values and errno updates. shm-directory.c is moved directly into the posix subdirectory because it can be implemented directly using POSIX functionality. It resides in libc because it is needed by both librt and nptl/htl. In the sem_open implementation, tmpfname is initialized directly from a string constant. This happens to remove one alloca call. Checked on x86_64-linux-gnu.
* tst: Provide test for ppollLukasz Majewski2021-02-082-1/+57
| | | | | | | | | | | This change adds new test to assess ppoll()'s timeout related functionality (the struct pollfd does not provide valid fd to wait for - just wait for timeout). To be more specific - two use cases are checked: - if ppoll() times out immediately when passed struct timespec has zero values of tv_nsec and tv_sec. - if ppoll() times out after timeout specified in passed argument
* tst: Provide test for timerfd related functionsLukasz Majewski2021-02-082-1/+67
| | | | | | | This change adds new test to assess functionality of timerfd_* functions. It creates new timer (operates on its file descriptor) and checks if time before and after sleep is between expected values.
* linux: Remove shmmax check from tst-sysvshm-linuxAdhemerval Zanella2021-02-021-12/+14
| | | | | | | | | | | | | | | | | | | | The shmmax expected value is tricky to check because kernel clamps it to INT_MAX in two cases: 1. Compat symbols with IPC_64, i.e, 32-bit binaries running on 64-bit kernels. 2. Default symbol without IPC_64 (defined as IPC_OLD within Linux) and glibc always use IPC_64 for 32-bit ABIs (to support 64-bit time_t). It means that 32-bit binaries running on 32-bit kernels will not see shmmax being clamped. And finding out whether the compat symbol is used would require checking the underlying kernel against the current ABI. The shmall and shmmni already provided enough coverage. Checked on x86_64-linux-gnu and i686-linux-gnu. It should fix the tst-sysvshm-linux failures on 32-bit kernels.
* Add MS_NOSYMFOLLOW from Linux 5.10 to <sys/mount.h>.Joseph Myers2021-02-021-0/+2
| | | | | | | This patch adds the new constant MS_NOSYMFOLLOW from Linux 5.10 to <sys/mount.h>. Tested for x86_64.
* sysconf: Add _SC_MINSIGSTKSZ/_SC_SIGSTKSZ [BZ #20305]H.J. Lu2021-02-016-0/+195
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add _SC_MINSIGSTKSZ for the minimum signal stack size derived from AT_MINSIGSTKSZ, which is the minimum number of bytes of free stack space required in order to gurantee successful, non-nested handling of a single signal whose handler is an empty function, and _SC_SIGSTKSZ which is the suggested minimum number of bytes of stack space required for a signal stack. If AT_MINSIGSTKSZ isn't available, sysconf (_SC_MINSIGSTKSZ) returns MINSIGSTKSZ. On Linux/x86 with XSAVE, the signal frame used by kernel is composed of the following areas and laid out as: ------------------------------ | alignment padding | ------------------------------ | xsave buffer | ------------------------------ | fsave header (32-bit only) | ------------------------------ | siginfo + ucontext | ------------------------------ Compute AT_MINSIGSTKSZ value as size of xsave buffer + size of fsave header (32-bit only) + size of siginfo and ucontext + alignment padding. If _SC_SIGSTKSZ_SOURCE or _GNU_SOURCE are defined, MINSIGSTKSZ and SIGSTKSZ are redefined as /* Default stack size for a signal handler: sysconf (SC_SIGSTKSZ). */ # undef SIGSTKSZ # define SIGSTKSZ sysconf (_SC_SIGSTKSZ) /* Minimum stack size for a signal handler: SIGSTKSZ. */ # undef MINSIGSTKSZ # define MINSIGSTKSZ SIGSTKSZ Compilation will fail if the source assumes constant MINSIGSTKSZ or SIGSTKSZ. The reason for not simply increasing the kernel's MINSIGSTKSZ #define (apart from the fact that it is rarely used, due to glibc's shadowing definitions) was that userspace binaries will have baked in the old value of the constant and may be making assumptions about it. For example, the type (char [MINSIGSTKSZ]) changes if this #define changes. This could be a problem if an newly built library tries to memcpy() or dump such an object defined by and old binary. Bounds-checking and the stack sizes passed to things like sigaltstack() and makecontext() could similarly go wrong.
* ia64: Fix brk call on statupAdhemerval Zanella2021-01-281-0/+22
| | | | | | | | | brk used by statup before TCB is properly set, so we can't use IA64_USE_NEW_STUB. This patch fixes a regression introduced by 720480934ab910. Checked on ia64-linux-gnu.
* linux: mips: Fix getdents64 fallback on mips64-n32Adhemerval Zanella2021-01-222-24/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | GCC mainline shows the following error: ../sysdeps/unix/sysv/linux/mips/mips64/getdents64.c: In function '__getdents64': ../sysdeps/unix/sysv/linux/mips/mips64/getdents64.c:121:7: error: 'memcpy' forming offset [4, 7] is out of the bounds [0, 4] [-Werror=array-bounds] 121 | memcpy (((char *) dp + offsetof (struct dirent64, d_ino)), | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 122 | KDP_MEMBER (kdp, d_ino), sizeof ((struct dirent64){0}.d_ino)); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ../sysdeps/unix/sysv/linux/mips/mips64/getdents64.c:123:7: error: 'memcpy' forming offset [4, 7] is out of the bounds [0, 4] [-Werror=array-bounds] 123 | memcpy (((char *) dp + offsetof (struct dirent64, d_off)), | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 124 | KDP_MEMBER (kdp, d_off), sizeof ((struct dirent64){0}.d_off)); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The issue is due both d_ino and d_off fields for mips64-n32 kernel_dirent are 32-bits, while this is using memcpy to copy 64 bits from it into the glibc dirent64. The fix is to use a temporary buffer to read the correct type from kernel_dirent. Checked with a build-many-glibcs.py for mips64el-linux-gnu and I also checked the tst-getdents64 on mips64el 4.1.4 kernel with and without fallback enabled (by manually setting the getdents64_supported).
* x86-64: Update tst-glibc-hwcaps-2.c for x86-64 baselineH.J. Lu2021-01-221-1/+1
| | | | | Return EXIT_FAILURE only if the level 2 libx86-64-isa-level.so is used on x86-64 baseline machine.
* powerpc64: Select POWER9 machine for the scv instructionFlorian Weimer2021-01-222-1/+7
| | | | | | | | | It is not available with the baseline ISA. Fixes commit 68ab82f56690ada86ac1e0c46bad06ba189a10ef ("powerpc: Runtime selection between sc and scv for syscalls"). Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
* Revert "linux: Move {f}xstat{at} to compat symbols" for static buildAdhemerval Zanella2021-01-218-16/+17
| | | | | | | | | | | | | | This reverts commit 20b39d59467b0c1d858e89ded8b0cebe55e22f60 for static library. This avoids the need to rebuild the world for the case where libstdc++ (and potentially other libraries) are linked to a old glibc. To avoid requering to provide xstat symbols for newer ABIs (such as riscv32) a new LIB_COMPAT macro is added. It is similar to SHLIB_COMPAT but also works for static case (thus evaluating similar to SHLIB_COMPAT for both shared and static case). Checked with a check-abi on all affected ABIs. I also check if the static library does contains the xstat symbols.
* Use hidden visibility for early static PIE codeSzabolcs Nagy2021-01-211-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | Extern symbol access in position independent code usually involves GOT indirection which needs RELATIVE reloc in a static linked PIE. (On some targets this is avoided e.g. because the linker can relax a GOT access to a pc-relative access, but this is not generally true.) Code that runs before static PIE self relocation must avoid relying on dynamic relocations which can be ensured by using hidden visibility. However we cannot just make all symbols hidden: On i386, all calls to IFUNC functions must go through PLT and calls to hidden functions CANNOT go through PLT in PIE since EBX used in PIE PLT may not be set up for local calls to hidden IFUNC functions. This patch aims to make symbol references hidden in code that is used before and by _dl_relocate_static_pie when building a static PIE libc. Note: for an object that is used in the startup code, its references and definition may not have consistent visibility: it is only forced hidden in the startup code. This is needed for fixing bug 27072. Co-authored-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* <sys/platform/x86.h>: Remove the C preprocessor magicH.J. Lu2021-01-217-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In <sys/platform/x86.h>, define CPU features as enum instead of using the C preprocessor magic to make it easier to wrap this functionality in other languages. Move the C preprocessor magic to internal header for better GCC codegen when more than one features are checked in a single expression as in x86-64 dl-hwcaps-subdirs.c. 1. Rename COMMON_CPUID_INDEX_XXX to CPUID_INDEX_XXX. 2. Move CPUID_INDEX_MAX to sysdeps/x86/include/cpu-features.h. 3. Remove struct cpu_features and __x86_get_cpu_features from <sys/platform/x86.h>. 4. Add __x86_get_cpuid_feature_leaf to <sys/platform/x86.h> and put it in libc. 5. Make __get_cpu_features() private to glibc. 6. Replace __x86_get_cpu_features(N) with __get_cpu_features(). 7. Add _dl_x86_get_cpu_features to GLIBC_PRIVATE. 8. Use a single enum index for each CPU feature detection. 9. Pass the CPUID feature leaf to __x86_get_cpuid_feature_leaf. 10. Return zero struct cpuid_feature for the older glibc binary with a smaller CPUID_INDEX_MAX [BZ #27104]. 11. Inside glibc, use the C preprocessor magic so that cpu_features data can be loaded just once leading to more compact code for glibc. 256 bits are used for each CPUID leaf. Some leaves only contain a few features. We can add exceptions to such leaves. But it will increase code sizes and it is harder to provide backward/forward compatibilities when new features are added to such leaves in the future. When new leaves are added, _rtld_global_ro offsets will change which leads to race condition during in-place updates. We may avoid in-place updates by 1. Rename the old glibc. 2. Install the new glibc. 3. Remove the old glibc. NB: A function, __x86_get_cpuid_feature_leaf , is used to avoid the copy relocation issue with IFUNC resolver as shown in IFUNC resolver tests.
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