From 434836c4802e11bddfc98b2addbd4bea952a6fc9 Mon Sep 17 00:00:00 2001 From: "A. Wilcox" Date: Sun, 4 May 2025 15:01:25 -0500 Subject: [PATCH] cpuinfo: Use auxv for AltiVec on Linux if possible The SIGILL handler is not very reliable and can cause crashes. Linux provides the CPU's AltiVec support status in getauxval. (cherry picked from commit 7490471796f287cb284b21ec2643af98e9982b53) --- src/cpuinfo/SDL_cpuinfo.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/cpuinfo/SDL_cpuinfo.c b/src/cpuinfo/SDL_cpuinfo.c index 81d1e914ce..a8feec846f 100644 --- a/src/cpuinfo/SDL_cpuinfo.c +++ b/src/cpuinfo/SDL_cpuinfo.c @@ -115,7 +115,7 @@ #define CPU_CFG2_LSX (1 << 6) #define CPU_CFG2_LASX (1 << 7) -#if defined(SDL_ALTIVEC_BLITTERS) && defined(HAVE_SETJMP) && !defined(SDL_PLATFORM_MACOS) && !defined(SDL_PLATFORM_OPENBSD) && !defined(SDL_PLATFORM_FREEBSD) +#if defined(SDL_ALTIVEC_BLITTERS) && defined(HAVE_SETJMP) && !defined(SDL_PLATFORM_MACOS) && !defined(SDL_PLATFORM_OPENBSD) && !defined(SDL_PLATFORM_FREEBSD) && (defined(SDL_PLATFORM_LINUX) && !defined(HAVE_GETAUXVAL)) /* This is the brute force way of detecting instruction sets... the idea is borrowed from the libmpeg2 library - thanks! */ @@ -344,6 +344,8 @@ static int CPU_haveAltiVec(void) elf_aux_info(AT_HWCAP, &cpufeatures, sizeof(cpufeatures)); altivec = cpufeatures & PPC_FEATURE_HAS_ALTIVEC; return altivec; +#elif defined(SDL_PLATFORM_LINUX) && defined(__powerpc__) && defined(HAVE_GETAUXVAL) + altivec = getauxval(AT_HWCAP) & PPC_FEATURE_HAS_ALTIVEC; #elif defined(SDL_ALTIVEC_BLITTERS) && defined(HAVE_SETJMP) void (*handler)(int sig); handler = signal(SIGILL, illegal_instruction);