From: Aurelien Jarno Date: Mon, 17 Jan 2022 18:41:40 +0000 (+0100) Subject: x86: use default cache size if it cannot be determined [BZ #28784] X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a51b76b71e8190a50b0e0c0b32f313888b930108;p=thirdparty%2Fglibc.git x86: use default cache size if it cannot be determined [BZ #28784] In some cases (e.g QEMU, non-Intel/AMD CPU) the cache information can not be retrieved and the corresponding values are set to 0. Commit 2d651eb9265d ("x86: Move x86 processor cache info to cpu_features") changed the behaviour in such case by defining the __x86_shared_cache_size and __x86_data_cache_size variables to 0 instead of using the default values. This cause an issue with the i686 SSE2 optimized bzero/routine which assumes that the cache size is at least 128 bytes, and otherwise tries to zero/set the whole address space minus 128 bytes. Fix that by restoring the original code to only update __x86_shared_cache_size and __x86_data_cache_size variables if the corresponding cache sizes are not zero. Fixes bug 28784 Fixes commit 2d651eb9265d Reviewed-by: H.J. Lu (cherry picked from commit c242fcce06e3102ca663b2f992611d0bda4f2668) --- diff --git a/NEWS b/NEWS index 6091d5bd82e..6e4221ca86e 100644 --- a/NEWS +++ b/NEWS @@ -271,6 +271,7 @@ The following bugs are resolved with this release: [27237] malloc: deadlock in malloc/tst-malloc-stats-cancellation [27256] locale: Assertion failure in ISO-2022-JP-3 gconv module related to combining characters (CVE-2021-3326) + [28784] x86: crash in 32bit memset-sse2.s when the cache size can not be determined Version 2.32 diff --git a/sysdeps/x86/cacheinfo.h b/sysdeps/x86/cacheinfo.h index 68c253542ff..0f850bdf120 100644 --- a/sysdeps/x86/cacheinfo.h +++ b/sysdeps/x86/cacheinfo.h @@ -63,16 +63,22 @@ init_cacheinfo (void) __x86_raw_data_cache_size = data; /* Round data cache size to multiple of 256 bytes. */ data = data & ~255L; - __x86_data_cache_size_half = data / 2; - __x86_data_cache_size = data; + if (data > 0) + { + __x86_data_cache_size_half = data / 2; + __x86_data_cache_size = data; + } long int shared = cpu_features->shared_cache_size; __x86_raw_shared_cache_size_half = shared / 2; __x86_raw_shared_cache_size = shared; /* Round shared cache size to multiple of 256 bytes. */ shared = shared & ~255L; - __x86_shared_cache_size_half = shared / 2; - __x86_shared_cache_size = shared; + if (shared > 0) + { + __x86_shared_cache_size_half = shared / 2; + __x86_shared_cache_size = shared; + } __x86_shared_non_temporal_threshold = cpu_features->non_temporal_threshold;