Author: alfredo Date: Thu Mar 5 14:13:22 2020 New Revision: 358672 URL: https://svnweb.freebsd.org/changeset/base/358672
Log: [PowerPC64] restrict memcpy/bcopy optimization to POWER ISA >=V2.07 VSX instructions were added in POWER ISA V2.06 (POWER7), but it requires data to be word-aligned. Such requirement was removed in ISA V2.07B (POWER8). Since current memcpy/bcopy optimization relies on VSX instructions handling misalignment transparently, and kernel doesn't currently implement an alignment error handler, this optimzation should be restrict to ISA V2.07 onwards. SIGBUS on stxvd2x instruction was reproduced in POWER7+ CPU. Reviewed by: luporl, jhibbits, bdragon Approved by: jhibbits (mentor) Differential Revision: https://reviews.freebsd.org/D23958 Modified: head/lib/libc/powerpc64/string/bcopy_resolver.c Modified: head/lib/libc/powerpc64/string/bcopy_resolver.c ============================================================================== --- head/lib/libc/powerpc64/string/bcopy_resolver.c Thu Mar 5 14:05:22 2020 (r358671) +++ head/lib/libc/powerpc64/string/bcopy_resolver.c Thu Mar 5 14:13:22 2020 (r358672) @@ -61,7 +61,12 @@ FN_RET FN_NAME_VSX FN_PARAMS; DEFINE_UIFUNC(, FN_RET, FN_NAME, FN_PARAMS) { - if (cpu_features & PPC_FEATURE_HAS_VSX) + /* VSX instructions were added in POWER ISA 2.06, + * however it requires data to be word-aligned. + * Since POWER ISA 2.07B this is solved transparently + * by the hardware + */ + if (cpu_features2 & PPC_FEATURE2_ARCH_2_07) return (FN_NAME_VSX); else return (FN_NAME_NOVSX); _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
