Date: Tue, 31 Jan 2017 03:40:13 +0000 (UTC) From: Justin Hibbits <jhibbits@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r313007 - head/sys/powerpc/include Message-ID: <201701310340.v0V3eDcj028799@repo.freebsd.org>
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Author: jhibbits Date: Tue Jan 31 03:40:13 2017 New Revision: 313007 URL: https://svnweb.freebsd.org/changeset/base/313007 Log: Don't retry a lost reservation in atomic_fcmpset() The desired behavior of atomic_fcmpset_() is to always exit on error. Instead of retrying on lost reservation, leave the retry to the caller, and return error. Reported by: kib Modified: head/sys/powerpc/include/atomic.h Modified: head/sys/powerpc/include/atomic.h ============================================================================== --- head/sys/powerpc/include/atomic.h Tue Jan 31 03:26:32 2017 (r313006) +++ head/sys/powerpc/include/atomic.h Tue Jan 31 03:40:13 2017 (r313007) @@ -678,18 +678,18 @@ atomic_fcmpset_int(volatile u_int *p, u_ int ret; __asm __volatile ( - "1:\tlwarx %0, 0, %3\n\t" /* load old value */ + "lwarx %0, 0, %3\n\t" /* load old value */ "cmplw %4, %0\n\t" /* compare */ - "bne 2f\n\t" /* exit if not equal */ + "bne 1f\n\t" /* exit if not equal */ "stwcx. %5, 0, %3\n\t" /* attempt to store */ - "bne- 1b\n\t" /* spin if failed */ + "bne- 1f\n\t" /* exit if failed */ "li %0, 1\n\t" /* success - retval = 1 */ - "b 3f\n\t" /* we've succeeded */ - "2:\n\t" + "b 2f\n\t" /* we've succeeded */ + "1:\n\t" "stwcx. %0, 0, %3\n\t" /* clear reservation (74xx) */ "stwx %0, 0, %7\n\t" "li %0, 0\n\t" /* failure - retval = 0 */ - "3:\n\t" + "2:\n\t" : "=&r" (ret), "=m" (*p), "=m" (*cmpval) : "r" (p), "r" (*cmpval), "r" (newval), "m" (*p), "r"(cmpval) : "cr0", "memory"); @@ -703,20 +703,20 @@ atomic_fcmpset_long(volatile u_long *p, __asm __volatile ( #ifdef __powerpc64__ - "1:\tldarx %0, 0, %3\n\t" /* load old value */ + "ldarx %0, 0, %3\n\t" /* load old value */ "cmpld %4, %0\n\t" /* compare */ - "bne 2f\n\t" /* exit if not equal */ + "bne 1f\n\t" /* exit if not equal */ "stdcx. %5, 0, %3\n\t" /* attempt to store */ #else - "1:\tlwarx %0, 0, %3\n\t" /* load old value */ + "lwarx %0, 0, %3\n\t" /* load old value */ "cmplw %4, %0\n\t" /* compare */ - "bne 2f\n\t" /* exit if not equal */ + "bne 1f\n\t" /* exit if not equal */ "stwcx. %5, 0, %3\n\t" /* attempt to store */ #endif - "bne- 1b\n\t" /* spin if failed */ + "bne- 1f\n\t" /* exit if failed */ "li %0, 1\n\t" /* success - retval = 1 */ - "b 3f\n\t" /* we've succeeded */ - "2:\n\t" + "b 2f\n\t" /* we've succeeded */ + "1:\n\t" #ifdef __powerpc64__ "stdcx. %0, 0, %3\n\t" /* clear reservation (74xx) */ "stdx %0, 0, %7\n\t" @@ -725,7 +725,7 @@ atomic_fcmpset_long(volatile u_long *p, "stwx %0, 0, %7\n\t" #endif "li %0, 0\n\t" /* failure - retval = 0 */ - "3:\n\t" + "2:\n\t" : "=&r" (ret), "=m" (*p), "=m" (*cmpval) : "r" (p), "r" (*cmpval), "r" (newval), "m" (*p), "r"(cmpval) : "cr0", "memory");
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