From ef80617d1e17e0878a909baad62a75ba265c0e00 Mon Sep 17 00:00:00 2001 From: Nikos Mavrogiannopoulos Date: Fri, 2 Aug 2019 21:57:40 +0200 Subject: [PATCH] read_cpuid_vals: use __get_cpuid_count() only when available This makes the functionality available on gcc 4.8. Resolves: #812 Signed-off-by: Nikos Mavrogiannopoulos [Retrieved from: https://github.com/gnutls/gnutls/commit/ef80617d1e17e0878a909baad62a75ba265c0e00] Signed-off-by: Fabrice Fontaine --- configure.ac | 11 +++++++++++ lib/accelerated/x86/x86-common.c | 24 ++++++++++++++++++++---- 2 files changed, 31 insertions(+), 4 deletions(-) diff --git a/configure.ac b/configure.ac index 6a1d3dbc5c..1bf9bce95e 100644 --- a/configure.ac +++ b/configure.ac @@ -182,6 +182,17 @@ case $host_cpu in ;; esac +# check for gcc's __get_cpuid_count functionality +AC_MSG_CHECKING([for __get_cpuid_count]) +AC_LINK_IFELSE( + [AC_LANG_SOURCE([ + #include + int main(void) { unsigned t1; return __get_cpuid_count(7, 0, &t1, &t1, &t1, &t1); } + ])], + [AC_DEFINE([HAVE_GET_CPUID_COUNT], [1], [use __get_cpuid_count]) AC_MSG_RESULT([yes])], + [AC_MSG_RESULT([no])] +) + fi AC_ARG_ENABLE(tls13-interop, diff --git a/lib/accelerated/x86/x86-common.c b/lib/accelerated/x86/x86-common.c index fb3ff90919..516d6776c5 100644 --- a/lib/accelerated/x86/x86-common.c +++ b/lib/accelerated/x86/x86-common.c @@ -106,17 +106,33 @@ unsigned int _gnutls_x86_cpuid_s[4]; #define VIA_PADLOCK_PHE (1<<21) #define VIA_PADLOCK_PHE_SHA512 (1<<22) +#ifndef HAVE_GET_CPUID_COUNT +static inline void +get_cpuid_level7(unsigned int *eax, unsigned int *ebx, + unsigned int *ecx, unsigned int *edx) +{ + /* we avoid using __get_cpuid_count, because it is not available with gcc 4.8 */ + if (__get_cpuid_max(7, 0) < 7) + return; + + __cpuid_count(7, 0, *eax, *ebx, *ecx, *edx); + return; +} +#else +# define get_cpuid_level7(a,b,c,d) __get_cpuid_count(7, 0, a, b, c, d) +#endif + static unsigned read_cpuid_vals(unsigned int vals[4]) { unsigned t1, t2, t3; - if (!__get_cpuid(1, &t1, &vals[0], - &vals[1], &t2)) + vals[0] = vals[1] = vals[2] = vals[3] = 0; + + if (!__get_cpuid(1, &t1, &vals[0], &vals[1], &t2)) return 0; /* suppress AVX512; it works conditionally on certain CPUs on the original code */ vals[1] &= 0xfffff7ff; - if (!__get_cpuid_count(7, 0, &t1, &vals[2], &t2, &t3)) - return 0; + get_cpuid_level7(&t1, &vals[2], &t2, &t3); return 1; }