Implement FETCH-OP atomic primitives, these are very similar to the existing OP-RETURN primitives we already have, except they return the value of the atomic variable _before_ modification. This is especially useful for irreversible operations -- such as bitops (because it becomes impossible to reconstruct the state prior to modification). Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> --- arch/blackfin/include/asm/atomic.h | 8 ++++++ arch/blackfin/kernel/bfin_ksyms.c | 1 arch/blackfin/mach-bf561/atomic.S | 43 ++++++++++++++++++++++++++----------- 3 files changed, 40 insertions(+), 12 deletions(-) --- a/arch/blackfin/include/asm/atomic.h +++ b/arch/blackfin/include/asm/atomic.h @@ -17,6 +17,7 @@ asmlinkage int __raw_uncached_fetch_asm(const volatile int *ptr); asmlinkage int __raw_atomic_add_asm(volatile int *ptr, int value); +asmlinkage int __raw_atomic_xadd_asm(volatile int *ptr, int value); asmlinkage int __raw_atomic_and_asm(volatile int *ptr, int value); asmlinkage int __raw_atomic_or_asm(volatile int *ptr, int value); @@ -28,10 +29,17 @@ asmlinkage int __raw_atomic_test_asm(con #define atomic_add_return(i, v) __raw_atomic_add_asm(&(v)->counter, i) #define atomic_sub_return(i, v) __raw_atomic_add_asm(&(v)->counter, -(i)) +#define atomic_fetch_add(i, v) __raw_atomic_xadd_asm(&(v)->counter, i) +#define atomic_fetch_sub(i, v) __raw_atomic_xadd_asm(&(v)->counter, -(i)) + #define atomic_or(i, v) (void)__raw_atomic_or_asm(&(v)->counter, i) #define atomic_and(i, v) (void)__raw_atomic_and_asm(&(v)->counter, i) #define atomic_xor(i, v) (void)__raw_atomic_xor_asm(&(v)->counter, i) +#define atomic_fetch_or(i, v) __raw_atomic_or_asm(&(v)->counter, i) +#define atomic_fetch_and(i, v) __raw_atomic_and_asm(&(v)->counter, i) +#define atomic_fetch_xor(i, v) __raw_atomic_xor_asm(&(v)->counter, i) + #endif #include <asm-generic/atomic.h> --- a/arch/blackfin/kernel/bfin_ksyms.c +++ b/arch/blackfin/kernel/bfin_ksyms.c @@ -84,6 +84,7 @@ EXPORT_SYMBOL(insl_16); #ifdef CONFIG_SMP EXPORT_SYMBOL(__raw_atomic_add_asm); +EXPORT_SYMBOL(__raw_atomic_xadd_asm); EXPORT_SYMBOL(__raw_atomic_and_asm); EXPORT_SYMBOL(__raw_atomic_or_asm); EXPORT_SYMBOL(__raw_atomic_xor_asm); --- a/arch/blackfin/mach-bf561/atomic.S +++ b/arch/blackfin/mach-bf561/atomic.S @@ -607,6 +607,28 @@ ENDPROC(___raw_atomic_add_asm) /* * r0 = ptr + * r1 = value + * + * ADD a signed value to a 32bit word and return the old value atomically. + * Clobbers: r3:0, p1:0 + */ +ENTRY(___raw_atomic_xadd_asm) + p1 = r0; + r3 = r1; + [--sp] = rets; + call _get_core_lock; + r3 = [p1]; + r2 = r3 + r2; + [p1] = r2; + r1 = p1; + call _put_core_lock; + r0 = r3; + rets = [sp++]; + rts; +ENDPROC(___raw_atomic_add_asm) + +/* + * r0 = ptr * r1 = mask * * AND the mask bits from a 32bit word and return the old 32bit value @@ -618,10 +640,9 @@ ENTRY(___raw_atomic_and_asm) r3 = r1; [--sp] = rets; call _get_core_lock; - r2 = [p1]; - r3 = r2 & r3; - [p1] = r3; - r3 = r2; + r3 = [p1]; + r2 = r2 & r3; + [p1] = r2; r1 = p1; call _put_core_lock; r0 = r3; @@ -642,10 +663,9 @@ ENTRY(___raw_atomic_or_asm) r3 = r1; [--sp] = rets; call _get_core_lock; - r2 = [p1]; - r3 = r2 | r3; - [p1] = r3; - r3 = r2; + r3 = [p1]; + r2 = r2 | r3; + [p1] = r2; r1 = p1; call _put_core_lock; r0 = r3; @@ -666,10 +686,9 @@ ENTRY(___raw_atomic_xor_asm) r3 = r1; [--sp] = rets; call _get_core_lock; - r2 = [p1]; - r3 = r2 ^ r3; - [p1] = r3; - r3 = r2; + r3 = [p1]; + r2 = r2 ^ r3; + [p1] = r2; r1 = p1; call _put_core_lock; r0 = r3; -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
