From: Graf Yang Date: Thu, 7 Jan 2010 06:57:30 +0000 (+0000) Subject: Blackfin: SMP: make all barriers handle cache issues X-Git-Tag: firefly_0821_release~7613^2~1615^2~3 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=943aee0c685d0563228d5a2ad9c8394ad0300fb5;p=firefly-linux-kernel-4.4.55.git Blackfin: SMP: make all barriers handle cache issues When suspending/resuming, the common task freezing code will run in parallel and freeze processes on each core. This is because the code uses the non-smp version of memory barriers (as well it should). The Blackfin smp barrier logic at the moment contains the cache sync logic, but the non-smp barriers do not. This is incorrect as Rafel summarized: > ... > The existing memory barriers are SMP barriers too, but they are more > than _just_ SMP barriers. At least that's how it is _supposed_ to be > (eg. rmb() is supposed to be stronger than smp_rmb()). > ... > However, looking at the blackfin's definitions of SMP barriers I see > that it uses extra stuff that should _also_ be used in the definitions > of the mandatory barriers. > ... URL: http://lkml.org/lkml/2011/4/13/11 LKML-Reference: Signed-off-by: Graf Yang Signed-off-by: Mike Frysinger --- diff --git a/arch/blackfin/include/asm/system.h b/arch/blackfin/include/asm/system.h index 19e2c7c3e63a..44bd0cced725 100644 --- a/arch/blackfin/include/asm/system.h +++ b/arch/blackfin/include/asm/system.h @@ -19,11 +19,11 @@ * Force strict CPU ordering. */ #define nop() __asm__ __volatile__ ("nop;\n\t" : : ) -#define mb() __asm__ __volatile__ ("" : : : "memory") -#define rmb() __asm__ __volatile__ ("" : : : "memory") -#define wmb() __asm__ __volatile__ ("" : : : "memory") -#define set_mb(var, value) do { (void) xchg(&var, value); } while (0) -#define read_barrier_depends() do { } while(0) +#define smp_mb() mb() +#define smp_rmb() rmb() +#define smp_wmb() wmb() +#define set_mb(var, value) do { var = value; mb(); } while (0) +#define smp_read_barrier_depends() read_barrier_depends() #ifdef CONFIG_SMP asmlinkage unsigned long __raw_xchg_1_asm(volatile void *ptr, unsigned long value); @@ -37,16 +37,16 @@ asmlinkage unsigned long __raw_cmpxchg_4_asm(volatile void *ptr, unsigned long new, unsigned long old); #ifdef __ARCH_SYNC_CORE_DCACHE -# define smp_mb() do { barrier(); smp_check_barrier(); smp_mark_barrier(); } while (0) -# define smp_rmb() do { barrier(); smp_check_barrier(); } while (0) -# define smp_wmb() do { barrier(); smp_mark_barrier(); } while (0) -#define smp_read_barrier_depends() do { barrier(); smp_check_barrier(); } while (0) - +/* Force Core data cache coherence */ +# define mb() do { barrier(); smp_check_barrier(); smp_mark_barrier(); } while (0) +# define rmb() do { barrier(); smp_check_barrier(); } while (0) +# define wmb() do { barrier(); smp_mark_barrier(); } while (0) +# define read_barrier_depends() do { barrier(); smp_check_barrier(); } while (0) #else -# define smp_mb() barrier() -# define smp_rmb() barrier() -# define smp_wmb() barrier() -#define smp_read_barrier_depends() barrier() +# define mb() barrier() +# define rmb() barrier() +# define wmb() barrier() +# define read_barrier_depends() do { } while (0) #endif static inline unsigned long __xchg(unsigned long x, volatile void *ptr, @@ -99,10 +99,10 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, #else /* !CONFIG_SMP */ -#define smp_mb() barrier() -#define smp_rmb() barrier() -#define smp_wmb() barrier() -#define smp_read_barrier_depends() do { } while(0) +#define mb() barrier() +#define rmb() barrier() +#define wmb() barrier() +#define read_barrier_depends() do { } while (0) struct __xchg_dummy { unsigned long a[100];