From 511c5a1087991108118c6e9c9546e83e992bf39c Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Tue, 23 May 2017 00:59:16 +0530 Subject: Make LD_HWCAP_MASK usable for static binaries The LD_HWCAP_MASK environment variable was ignored in static binaries, which is inconsistent with the behaviour of dynamically linked binaries. This seems to have been because of the inability of ld_hwcap_mask being read early enough to influence anything but now that it is in tunables, the mask is usable in static binaries as well. This feature is important for aarch64, which relies on HWCAP_CPUID being masked out to disable multiarch. A sanity test on x86_64 shows that there are no failures. Likewise for aarch64. * elf/dl-hwcaps.h [HAVE_TUNABLES]: Always read hwcap_mask. * sysdeps/sparc/sparc32/dl-machine.h [HAVE_TUNABLES]: Likewise. * sysdeps/x86/cpu-features.c (init_cpu_features): Always set up hwcap and hwcap_mask. --- sysdeps/sparc/sparc32/dl-machine.h | 2 +- sysdeps/x86/cpu-features.c | 8 +++----- 2 files changed, 4 insertions(+), 6 deletions(-) (limited to 'sysdeps') diff --git a/sysdeps/sparc/sparc32/dl-machine.h b/sysdeps/sparc/sparc32/dl-machine.h index f9ae133..95f6732 100644 --- a/sysdeps/sparc/sparc32/dl-machine.h +++ b/sysdeps/sparc/sparc32/dl-machine.h @@ -37,7 +37,7 @@ elf_machine_matches_host (const Elf32_Ehdr *ehdr) return 1; else if (ehdr->e_machine == EM_SPARC32PLUS) { -#ifdef SHARED +#if HAVE_TUNABLES || defined SHARED uint64_t hwcap_mask = GET_HWCAP_MASK(); return GLRO(dl_hwcap) & hwcap_mask & HWCAP_SPARC_V9; #else diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c index 4fe58bf..4288001 100644 --- a/sysdeps/x86/cpu-features.c +++ b/sysdeps/x86/cpu-features.c @@ -312,17 +312,16 @@ no_cpuid: cpu_features->model = model; cpu_features->kind = kind; -#if IS_IN (rtld) /* Reuse dl_platform, dl_hwcap and dl_hwcap_mask for x86. */ GLRO(dl_platform) = NULL; GLRO(dl_hwcap) = 0; -#if !HAVE_TUNABLES +#if !HAVE_TUNABLES && defined SHARED /* The glibc.tune.hwcap_mask tunable is initialized already, so no need to do this. */ GLRO(dl_hwcap_mask) = HWCAP_IMPORTANT; #endif -# ifdef __x86_64__ +#ifdef __x86_64__ if (cpu_features->kind == arch_kind_intel) { if (CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable) @@ -352,7 +351,7 @@ no_cpuid: && CPU_FEATURES_CPU_P (cpu_features, POPCNT)) GLRO(dl_platform) = "haswell"; } -# else +#else if (CPU_FEATURES_CPU_P (cpu_features, SSE2)) GLRO(dl_hwcap) |= HWCAP_X86_SSE2; @@ -360,6 +359,5 @@ no_cpuid: GLRO(dl_platform) = "i686"; else if (CPU_FEATURES_ARCH_P (cpu_features, I586)) GLRO(dl_platform) = "i586"; -# endif #endif } -- cgit v1.1