Author: jhibbits Date: Fri Mar 6 01:45:03 2020 New Revision: 358688 URL: https://svnweb.freebsd.org/changeset/base/358688
Log: powerpc/powerpc64: Enforce natural alignment in memcpy Summary: POWER architecture CPUs (Book-S) require natural alignment for cache-inhibited storage accesses. Since we can't know the caching model for a page ahead of time, always enforce natural alignment in memcpy. This fixes a SIGBUS in X with acceleration enabled on POWER9. As part of this, revert r358672, it's no longer necessary with this fix. Regression tested by alfredo. Reviewed by: alfredo Differential Revision: https://reviews.freebsd.org/D23969 Modified: head/lib/libc/powerpc64/string/bcopy_resolver.c head/lib/libc/powerpc64/string/memcpy.S head/lib/libc/powerpc64/string/memcpy_vsx.S Modified: head/lib/libc/powerpc64/string/bcopy_resolver.c ============================================================================== --- head/lib/libc/powerpc64/string/bcopy_resolver.c Thu Mar 5 22:45:16 2020 (r358687) +++ head/lib/libc/powerpc64/string/bcopy_resolver.c Fri Mar 6 01:45:03 2020 (r358688) @@ -66,7 +66,7 @@ DEFINE_UIFUNC(, FN_RET, FN_NAME, FN_PARAMS) * Since POWER ISA 2.07B this is solved transparently * by the hardware */ - if (cpu_features2 & PPC_FEATURE2_ARCH_2_07) + if (cpu_features2 & PPC_FEATURE_HAS_VSX) return (FN_NAME_VSX); else return (FN_NAME_NOVSX); Modified: head/lib/libc/powerpc64/string/memcpy.S ============================================================================== --- head/lib/libc/powerpc64/string/memcpy.S Thu Mar 5 22:45:16 2020 (r358687) +++ head/lib/libc/powerpc64/string/memcpy.S Fri Mar 6 01:45:03 2020 (r358688) @@ -39,6 +39,11 @@ WEAK_REFERENCE(__memcpy, memcpy); #define BLOCK_BYTES (1 << BLOCK_BITS) #define BLOCK_MASK (BLOCK_BYTES - 1) +/* Minimum 8 byte alignment, to avoid cache-inhibited alignment faults. */ +#ifndef ALIGN_MASK +#define ALIGN_MASK 0x7 +#endif + /* * r3: dst * r4: src @@ -48,6 +53,12 @@ ENTRY(FN_NAME) cmpdi %r5, 0 /* len == 0? nothing to do */ beqlr- + /* If src and dst are relatively misaligned, do byte copies. */ + andi. %r8, %r3, ALIGN_MASK + andi. %r7, %r4, ALIGN_MASK + cmpd %r8, %r7 + mr %r7, %r5 + bne+ .Lcopy_remaining_fix_index_byte mr %r8, %r3 /* save dst */ /* align src */ Modified: head/lib/libc/powerpc64/string/memcpy_vsx.S ============================================================================== --- head/lib/libc/powerpc64/string/memcpy_vsx.S Thu Mar 5 22:45:16 2020 (r358687) +++ head/lib/libc/powerpc64/string/memcpy_vsx.S Fri Mar 6 01:45:03 2020 (r358688) @@ -30,6 +30,7 @@ #define FN_NAME __memcpy_vsx #define BLOCK_BITS 6 +#define ALIGN_MASK 0xf /* * r5: bytes to copy (multiple of BLOCK_BYTES) _______________________________________________ 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"
