When running the ll/sc version of the mutex code (for MULTIPROCESSOR kernels),

correctly handle sc failures. All other ll/sc constructs were doing this
correctly but apparently noone had noticed mutex did not.

diff --git a/sys/arch/octeon/octeon/mutex.c b/sys/arch/octeon/octeon/mutex.c
index 2026a60..8876a5e 100644 (file)
--- a/sys/arch/octeon/octeon/mutex.c
+++ b/sys/arch/octeon/octeon/mutex.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: mutex.c,v 1.5 2011/04/21 04:34:12 miod Exp $  */
+/*     $OpenBSD: mutex.c,v 1.6 2013/12/26 21:02:37 miod Exp $  */
 
 /*
  * Copyright (c) 2004 Artur Grabowski <art@openbsd.org>
@@ -39,12 +39,15 @@ try_lock(struct mutex *mtx)
 
         asm volatile (
                ".set noreorder\n"
-               "ll     %0, %2\n"
-               "bnez   %0, 1f\n"
-               "nop\n"
-               "li     %1, 1\n"
-               "sc     %1, %2\n"
                "1:\n"
+               "ll     %0, %2\n"               /* tmp = mtx->mtx_lock */
+               "bnez   %0, 2f\n"
+               " li    %1, 0\n"                /* ret = 0 */
+               "li     %1, 1\n"                /* ret = 1 */
+               "sc     %1, %2\n"               /* mtx->mtx_lock = 1 */
+               "beqz   %1, 1b\n"               /* update failed */
+               " nop\n"
+               "2:\n"
                ".set reorder\n"
                : "+r"(tmp), "+r"(ret)
                : "m"(mtx->mtx_lock));

diff --git a/sys/arch/sgi/sgi/mutex.c b/sys/arch/sgi/sgi/mutex.c
index 2c85fa8..3fa43da 100644 (file)
--- a/sys/arch/sgi/sgi/mutex.c
+++ b/sys/arch/sgi/sgi/mutex.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: mutex.c,v 1.12 2011/04/21 04:34:12 miod Exp $ */
+/*     $OpenBSD: mutex.c,v 1.13 2013/12/26 21:02:37 miod Exp $ */
 
 /*
  * Copyright (c) 2004 Artur Grabowski <art@openbsd.org>
@@ -39,12 +39,15 @@ try_lock(struct mutex *mtx)
 
         asm volatile (
                ".set noreorder\n"
-               "ll     %0, %2\n"
-               "bnez   %0, 1f\n"
-               "nop\n"
-               "li     %1, 1\n"
-               "sc     %1, %2\n"
                "1:\n"
+               "ll     %0, %2\n"               /* tmp = mtx->mtx_lock */
+               "bnez   %0, 2f\n"
+               " li    %1, 0\n"                /* ret = 0 */
+               "li     %1, 1\n"                /* ret = 1 */
+               "sc     %1, %2\n"               /* mtx->mtx_lock = 1 */
+               "beqz   %1, 1b\n"               /* update failed */
+               " nop\n"
+               "2:\n"
                ".set reorder\n"
                : "+r"(tmp), "+r"(ret)
                : "m"(mtx->mtx_lock));