From 3a4730256a96ac1a229a7fe1f6171f669fb1d000 Mon Sep 17 00:00:00 2001 From: Attilio Rao Date: Tue, 9 Oct 2012 14:32:30 +0000 Subject: Add an unified macro to deny ability from the compiler to reorder instruction loads/stores at its will. The macro __compiler_membar() is currently supported for both gcc and clang, but kernel compilation will fail otherwise. Reviewed by: bde, kib Discussed with: dim, theraven MFC after: 2 weeks --- sys/amd64/include/atomic.h | 4 ++-- sys/gnu/fs/xfs/FreeBSD/xfs_compat.h | 4 ---- sys/gnu/fs/xfs/FreeBSD/xfs_freebsd.h | 2 +- sys/i386/include/atomic.h | 4 ++-- sys/kern/kern_rmlock.c | 8 ++------ sys/mips/include/cpufunc.h | 2 +- sys/pc98/include/bus.h | 2 +- sys/sparc64/include/atomic.h | 6 +++--- sys/sys/cdefs.h | 7 +++++++ sys/x86/include/bus.h | 2 +- 10 files changed, 20 insertions(+), 21 deletions(-) diff --git a/sys/amd64/include/atomic.h b/sys/amd64/include/atomic.h index 99a94b77bb15..91c33e6f61e9 100644 --- a/sys/amd64/include/atomic.h +++ b/sys/amd64/include/atomic.h @@ -226,7 +226,7 @@ atomic_fetchadd_long(volatile u_long *p, u_long v) static __inline void \ atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ { \ - __asm __volatile("" : : : "memory"); \ + __compiler_membar(); \ *p = v; \ } \ struct __hack @@ -240,7 +240,7 @@ atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ u_##TYPE tmp; \ \ tmp = *p; \ - __asm __volatile("" : : : "memory"); \ + __compiler_membar(); \ return (tmp); \ } \ struct __hack diff --git a/sys/gnu/fs/xfs/FreeBSD/xfs_compat.h b/sys/gnu/fs/xfs/FreeBSD/xfs_compat.h index 7229f277f13d..55a03c96bdad 100644 --- a/sys/gnu/fs/xfs/FreeBSD/xfs_compat.h +++ b/sys/gnu/fs/xfs/FreeBSD/xfs_compat.h @@ -129,10 +129,6 @@ typedef dev_t os_dev_t; #define copy_from_user(dst, src, len) copyin((src), (dst), (len)) #endif -#ifndef barrier -#define barrier() __asm__ __volatile__("": : :"memory") -#endif - /* * Map simple global vairables to FreeBSD kernel equivalents */ diff --git a/sys/gnu/fs/xfs/FreeBSD/xfs_freebsd.h b/sys/gnu/fs/xfs/FreeBSD/xfs_freebsd.h index a47c413cb0d2..cc1d8df0adc6 100644 --- a/sys/gnu/fs/xfs/FreeBSD/xfs_freebsd.h +++ b/sys/gnu/fs/xfs/FreeBSD/xfs_freebsd.h @@ -162,7 +162,7 @@ */ #define EFSCORRUPTED 990 /* Filesystem is corrupted */ -#define SYNCHRONIZE() barrier() +#define SYNCHRONIZE() __compiler_membar() #define __return_address __builtin_return_address(0) /* diff --git a/sys/i386/include/atomic.h b/sys/i386/include/atomic.h index 6ef59622649f..3b9d00194426 100644 --- a/sys/i386/include/atomic.h +++ b/sys/i386/include/atomic.h @@ -296,7 +296,7 @@ atomic_fetchadd_int(volatile u_int *p, u_int v) static __inline void \ atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\ { \ - __asm __volatile("" : : : "memory"); \ + __compiler_membar(); \ *p = v; \ } \ struct __hack @@ -310,7 +310,7 @@ atomic_load_acq_##TYPE(volatile u_##TYPE *p) \ u_##TYPE tmp; \ \ tmp = *p; \ - __asm __volatile("" : : : "memory"); \ + __compiler_membar(); \ return (tmp); \ } \ struct __hack diff --git a/sys/kern/kern_rmlock.c b/sys/kern/kern_rmlock.c index ef1920b490e9..30400b178217 100644 --- a/sys/kern/kern_rmlock.c +++ b/sys/kern/kern_rmlock.c @@ -65,10 +65,6 @@ __FBSDID("$FreeBSD$"); * does not seem very useful */ -static __inline void compiler_memory_barrier(void) { - __asm __volatile("":::"memory"); -} - static void assert_rm(const struct lock_object *lock, int what); static void lock_rm(struct lock_object *lock, int how); #ifdef KDTRACE_HOOKS @@ -353,7 +349,7 @@ _rm_rlock(struct rmlock *rm, struct rm_priotracker *tracker, int trylock) td->td_critnest++; /* critical_enter(); */ - compiler_memory_barrier(); + __compiler_membar(); pc = cpuid_to_pcpu[td->td_oncpu]; /* pcpu_find(td->td_oncpu); */ @@ -361,7 +357,7 @@ _rm_rlock(struct rmlock *rm, struct rm_priotracker *tracker, int trylock) sched_pin(); - compiler_memory_barrier(); + __compiler_membar(); td->td_critnest--; diff --git a/sys/mips/include/cpufunc.h b/sys/mips/include/cpufunc.h index 513237f9e37a..3611d6e11604 100644 --- a/sys/mips/include/cpufunc.h +++ b/sys/mips/include/cpufunc.h @@ -70,7 +70,7 @@ static __inline void mips_barrier(void) { #if defined(CPU_CNMIPS) || defined(CPU_RMI) || defined(CPU_NLM) - __asm __volatile("" : : : "memory"); + __compiler_membar(); #else __asm __volatile (".set noreorder\n\t" "nop\n\t" diff --git a/sys/pc98/include/bus.h b/sys/pc98/include/bus.h index 69e80f040a78..46d1a1bfbd36 100644 --- a/sys/pc98/include/bus.h +++ b/sys/pc98/include/bus.h @@ -593,7 +593,7 @@ bus_space_barrier(bus_space_tag_t tag, bus_space_handle_t bsh, if (flags & BUS_SPACE_BARRIER_READ) __asm __volatile("lock; addl $0,0(%%esp)" : : : "memory"); else - __asm __volatile("" : : : "memory"); + __compiler_membar(); } #ifdef BUS_SPACE_NO_LEGACY diff --git a/sys/sparc64/include/atomic.h b/sys/sparc64/include/atomic.h index 06a19846ccbc..447880a4fa9d 100644 --- a/sys/sparc64/include/atomic.h +++ b/sys/sparc64/include/atomic.h @@ -97,7 +97,7 @@ #define atomic_cas_acq(p, e, s, sz) ({ \ itype(sz) v; \ v = atomic_cas((p), (e), (s), sz); \ - __asm __volatile("" : : : "memory"); \ + __compiler_membar(); \ v; \ }) @@ -122,7 +122,7 @@ #define atomic_op_acq(p, op, v, sz) ({ \ itype(sz) t; \ t = atomic_op((p), op, (v), sz); \ - __asm __volatile("" : : : "memory"); \ + __compiler_membar(); \ t; \ }) @@ -139,7 +139,7 @@ #define atomic_load_acq(p, sz) ({ \ itype(sz) v; \ v = atomic_load((p), sz); \ - __asm __volatile("" : : : "memory"); \ + __compiler_membar(); \ v; \ }) diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h index d4c78a91699f..ad6aefc27a8b 100644 --- a/sys/sys/cdefs.h +++ b/sys/sys/cdefs.h @@ -82,6 +82,13 @@ # define __GNUC_VA_LIST_COMPATIBILITY 1 #endif +/* + * Compiler memory barriers, specific to gcc and clang. + */ +#if defined(__GNUC__) +#define __compiler_membar() __asm __volatile(" " : : : "memory") +#endif + #ifndef __INTEL_COMPILER # define __GNUCLIKE_BUILTIN_NEXT_ARG 1 # define __GNUCLIKE_MATH_BUILTIN_RELOPS diff --git a/sys/x86/include/bus.h b/sys/x86/include/bus.h index 3b4342a40345..fb5babf43268 100644 --- a/sys/x86/include/bus.h +++ b/sys/x86/include/bus.h @@ -1014,7 +1014,7 @@ bus_space_barrier(bus_space_tag_t tag __unused, bus_space_handle_t bsh __unused, __asm __volatile("lock; addl $0,0(%%esp)" : : : "memory"); #endif else - __asm __volatile("" : : : "memory"); + __compiler_membar(); #endif } -- cgit v1.2.3