From de26253715b91e7fd4a9854fe836baef86dbc7af Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Tue, 11 Apr 2000 17:03:03 +0000 Subject: Upadte. 2000-04-11 Ulrich Drepper * internals.h: Define MEMORY_BARRIER as empty if not defined already. * spinlock.c (__pthread_lock): Add memory barriers. (__pthread_unlock): Likewise. * sysdeps/alpha/pt-machine.h (MEMORY_BARRIER): Define using mb instruction. (RELEASE): Not needed anymore. (__compare_and_swap): Mark asm as modifying memory. * sysdeps/powerpc/pt-machine.h (sync): Remove. Replace with definition of MEMORY_BARRIER. (__compare_and_swap): Use MEMORY_BARRIER instead of sync. * sysdeps/sparc/sparc32/pt-machine.h (RELEASE): Not needed anymore. (MEMORY_BARRIER): Define using stbar. * sysdeps/sparc/sparc64/pt-machine.h (MEMORY_BARRIER): Define using stbar. (__compare_and_swap): Use MEMORY_BARRIER to ensure ordering. Patch by Xavier Leroy based on comments by Mike Burrows . --- linuxthreads/sysdeps/alpha/pt-machine.h | 12 ++++++------ linuxthreads/sysdeps/powerpc/pt-machine.h | 9 ++------- linuxthreads/sysdeps/sparc/sparc32/pt-machine.h | 5 ++--- linuxthreads/sysdeps/sparc/sparc64/pt-machine.h | 8 +++++++- 4 files changed, 17 insertions(+), 17 deletions(-) (limited to 'linuxthreads/sysdeps') diff --git a/linuxthreads/sysdeps/alpha/pt-machine.h b/linuxthreads/sysdeps/alpha/pt-machine.h index e59c690..25ba634 100644 --- a/linuxthreads/sysdeps/alpha/pt-machine.h +++ b/linuxthreads/sysdeps/alpha/pt-machine.h @@ -32,6 +32,10 @@ register char *stack_pointer __asm__("$30"); +/* Memory barrier; default is to do nothing */ +#define MEMORY_BARRIER() __asm__ __volatile__("mb" : : : "memory") + + /* Spinlock implementation; required. */ PT_EI long int testandset (int *spinlock) @@ -55,11 +59,6 @@ testandset (int *spinlock) return ret; } -/* Spinlock release; default is just set to zero. */ -#define RELEASE(spinlock) \ - __asm__ __volatile__("mb" : : : "memory"); \ - *spinlock = 0 - /* Begin allocating thread stacks at this address. Default is to allocate them just below the initial program stack. */ @@ -102,7 +101,8 @@ __compare_and_swap (long int *p, long int oldval, long int newval) "2:\tmb\n" "/* End compare & swap */" : "=&r"(ret), "=m"(*p) - : "r"(oldval), "r"(newval), "m"(*p)); + : "r"(oldval), "r"(newval), "m"(*p) + : "memory"); return ret; } diff --git a/linuxthreads/sysdeps/powerpc/pt-machine.h b/linuxthreads/sysdeps/powerpc/pt-machine.h index 578369a..c7d0670 100644 --- a/linuxthreads/sysdeps/powerpc/pt-machine.h +++ b/linuxthreads/sysdeps/powerpc/pt-machine.h @@ -27,12 +27,7 @@ /* For multiprocessor systems, we want to ensure all memory accesses are completed before we reset a lock. */ -#if 0 -/* on non multiprocessor systems, you can just: */ -#define sync() /* nothing */ -#else -#define sync() __asm__ __volatile__ ("sync") -#endif +#define MEMORY_BARRIER() __asm__ __volatile__ ("sync" : : : "memory") /* Get some notion of the current stack. Need not be exactly the top of the stack, just something somewhere in the current frame. */ @@ -64,6 +59,6 @@ __compare_and_swap (long int *p, long int oldval, long int newval) : "=&r"(ret) : "r"(p), "r"(newval), "r"(oldval) : "cr0", "memory"); - sync(); + MEMORY_BARRIER(); return ret == 0; } diff --git a/linuxthreads/sysdeps/sparc/sparc32/pt-machine.h b/linuxthreads/sysdeps/sparc/sparc32/pt-machine.h index 69af857..ddf4932 100644 --- a/linuxthreads/sysdeps/sparc/sparc32/pt-machine.h +++ b/linuxthreads/sysdeps/sparc/sparc32/pt-machine.h @@ -37,9 +37,8 @@ testandset (int *spinlock) } -/* Spinlock release; default is just set to zero. */ -#define RELEASE(spinlock) \ - __asm__ __volatile__("stbar; stb %1,%0" : "=m"(*(spinlock)) : "r"(0)); +/* Memory barrier; default is to do nothing */ +#define MEMORY_BARRIER() __asm__ __volatile__("stbar" : : : "memory") /* Get some notion of the current stack. Need not be exactly the top diff --git a/linuxthreads/sysdeps/sparc/sparc64/pt-machine.h b/linuxthreads/sysdeps/sparc/sparc64/pt-machine.h index 5560003..02167bd 100644 --- a/linuxthreads/sysdeps/sparc/sparc64/pt-machine.h +++ b/linuxthreads/sysdeps/sparc/sparc64/pt-machine.h @@ -37,6 +37,12 @@ testandset (int *spinlock) } +/* Memory barrier; default is to do nothing */ +/* FIXME: is stbar OK, or should we use the more general membar instruction? + If so, which mode to pass to membar? */ +#define MEMORY_BARRIER() __asm__ __volatile__("stbar" : : : "memory") + + /* Get some notion of the current stack. Need not be exactly the top of the stack, just something somewhere in the current frame. */ #define CURRENT_STACK_FRAME stack_pointer @@ -66,7 +72,7 @@ __compare_and_swap (long int *p, long int oldval, long int newval) __asm__ __volatile__ ("casx [%4], %2, %0" : "=r"(readval), "=m"(*p) : "r"(oldval), "m"(*p), "r"(p), "0"(newval)); - + MEMORY_BARRIER(); return readval == oldval; } -- cgit v1.1