diff options
Diffstat (limited to 'arch/m32r')
| -rw-r--r-- | arch/m32r/Kconfig | 8 | ||||
| -rw-r--r-- | arch/m32r/include/asm/barrier.h | 80 |
2 files changed, 5 insertions, 83 deletions
diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig index 09ef94a8a7c..ca4504424da 100644 --- a/arch/m32r/Kconfig +++ b/arch/m32r/Kconfig @@ -277,13 +277,13 @@ config SMP bool "Symmetric multi-processing support" ---help--- This enables support for systems with more than one CPU. If you have - a system with only one CPU, like most personal computers, say N. If - you have a system with more than one CPU, say Y. + a system with only one CPU, say N. If you have a system with more + than one CPU, say Y. - If you say N here, the kernel will run on single and multiprocessor + If you say N here, the kernel will run on uni- and multiprocessor machines, but will use only one CPU of a multiprocessor machine. If you say Y here, the kernel will run on many, but not all, - singleprocessor machines. On a singleprocessor machine, the kernel + uniprocessor machines. On a uniprocessor machine, the kernel will run faster if you say N here. People using multiprocessor machines who say Y here should also say diff --git a/arch/m32r/include/asm/barrier.h b/arch/m32r/include/asm/barrier.h index 6976621efd3..1a40265e8d8 100644 --- a/arch/m32r/include/asm/barrier.h +++ b/arch/m32r/include/asm/barrier.h @@ -11,84 +11,6 @@ #define nop() __asm__ __volatile__ ("nop" : : ) -/* - * Memory barrier. - * - * mb() prevents loads and stores being reordered across this point. - * rmb() prevents loads being reordered across this point. - * wmb() prevents stores being reordered across this point. - */ -#define mb() barrier() -#define rmb() mb() -#define wmb() mb() - -/** - * read_barrier_depends - Flush all pending reads that subsequents reads - * depend on. - * - * No data-dependent reads from memory-like regions are ever reordered - * over this barrier. All reads preceding this primitive are guaranteed - * to access memory (but not necessarily other CPUs' caches) before any - * reads following this primitive that depend on the data return by - * any of the preceding reads. This primitive is much lighter weight than - * rmb() on most CPUs, and is never heavier weight than is - * rmb(). - * - * These ordering constraints are respected by both the local CPU - * and the compiler. - * - * Ordering is not guaranteed by anything other than these primitives, - * not even by data dependencies. See the documentation for - * memory_barrier() for examples and URLs to more information. - * - * For example, the following code would force ordering (the initial - * value of "a" is zero, "b" is one, and "p" is "&a"): - * - * <programlisting> - * CPU 0 CPU 1 - * - * b = 2; - * memory_barrier(); - * p = &b; q = p; - * read_barrier_depends(); - * d = *q; - * </programlisting> - * - * - * because the read of "*q" depends on the read of "p" and these - * two reads are separated by a read_barrier_depends(). However, - * the following code, with the same initial values for "a" and "b": - * - * <programlisting> - * CPU 0 CPU 1 - * - * a = 2; - * memory_barrier(); - * b = 3; y = b; - * read_barrier_depends(); - * x = a; - * </programlisting> - * - * does not enforce ordering, since there is no data dependency between - * the read of "a" and the read of "b". Therefore, on some CPUs, such - * as Alpha, "y" could be set to 3 and "x" to 0. Use rmb() - * in cases like this where there are no data dependencies. - **/ - -#define read_barrier_depends() do { } while (0) - -#ifdef CONFIG_SMP -#define smp_mb() mb() -#define smp_rmb() rmb() -#define smp_wmb() wmb() -#define smp_read_barrier_depends() read_barrier_depends() -#define set_mb(var, value) do { (void) xchg(&var, value); } while (0) -#else -#define smp_mb() barrier() -#define smp_rmb() barrier() -#define smp_wmb() barrier() -#define smp_read_barrier_depends() do { } while (0) -#define set_mb(var, value) do { var = value; barrier(); } while (0) -#endif +#include <asm-generic/barrier.h> #endif /* _ASM_M32R_BARRIER_H */ |