From e87fc0ec070554e34812be68267a9450271868d6 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 18 Apr 2016 01:16:08 +0200 Subject: [PATCH] locking/atomic, arch/blackfin: Implement atomic_fetch_{add,sub,and,or,xor}() 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) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Steven Miao Cc: Thomas Gleixner Cc: adi-buildroot-devel@lists.sourceforge.net Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- 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(-) diff --git a/arch/blackfin/include/asm/atomic.h b/arch/blackfin/include/asm/atomic.h index 1c1c42330c99..63c7deceeeb6 100644 --- 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(const volatile int *ptr, int value); #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 diff --git a/arch/blackfin/kernel/bfin_ksyms.c b/arch/blackfin/kernel/bfin_ksyms.c index a401c27b69b4..68096e8f787f 100644 --- 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); diff --git a/arch/blackfin/mach-bf561/atomic.S b/arch/blackfin/mach-bf561/atomic.S index 26fccb5568b9..1e2989c5d6b2 100644 --- a/arch/blackfin/mach-bf561/atomic.S +++ b/arch/blackfin/mach-bf561/atomic.S @@ -605,6 +605,28 @@ ENTRY(___raw_atomic_add_asm) rts; 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 @@ -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;