Commit-ID: d325209b6000dcd13404ee946d2292e15a56718c Gitweb: http://git.kernel.org/tip/d325209b6000dcd13404ee946d2292e15a56718c Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Wed, 9 Apr 2014 21:51:29 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 14 Aug 2014 12:48:05 +0200
locking,arch,avr32: Fold atomic_ops Many of the atomic op implementations are the same except for one instruction; fold the lot into a few CPP macros and reduce LoC. This also prepares for easy addition of new ops. Requires the asm_op because of eor. AVR32 is a bit special in that its ADD/SUB instructions are not symmetric. Its SUB instruction allows for an 21bit immediate. Signed-off-by: Peter Zijlstra <pet...@infradead.org> Cc: Hans-Christian Egtvedt <egtv...@samfundet.no> Cc: Haavard Skinnemoen <hskinnem...@gmail.com> Cc: Hans-Christian Egtvedt <egtv...@samfundet.no> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/20140531141445.gd16...@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/avr32/include/asm/atomic.h | 123 ++++++++++++++++++++-------------------- 1 file changed, 62 insertions(+), 61 deletions(-) diff --git a/arch/avr32/include/asm/atomic.h b/arch/avr32/include/asm/atomic.h index 0780f3f..83e980a 100644 --- a/arch/avr32/include/asm/atomic.h +++ b/arch/avr32/include/asm/atomic.h @@ -22,30 +22,43 @@ #define atomic_read(v) (*(volatile int *)&(v)->counter) #define atomic_set(v, i) (((v)->counter) = i) +#define ATOMIC_OP_RETURN(op, asm_op, asm_con) \ +static inline int __atomic_##op##_return(int i, atomic_t *v) \ +{ \ + int result; \ + \ + asm volatile( \ + "/* atomic_" #op "_return */\n" \ + "1: ssrf 5\n" \ + " ld.w %0, %2\n" \ + " " #asm_op " %0, %3\n" \ + " stcond %1, %0\n" \ + " brne 1b" \ + : "=&r" (result), "=o" (v->counter) \ + : "m" (v->counter), #asm_con (i) \ + : "cc"); \ + \ + return result; \ +} + +ATOMIC_OP_RETURN(sub, sub, rKs21) +ATOMIC_OP_RETURN(add, add, r) + +#undef ATOMIC_OP_RETURN + /* - * atomic_sub_return - subtract the atomic variable - * @i: integer value to subtract - * @v: pointer of type atomic_t + * Probably found the reason why we want to use sub with the signed 21-bit + * limit, it uses one less register than the add instruction that can add up to + * 32-bit values. * - * Atomically subtracts @i from @v. Returns the resulting value. + * Both instructions are 32-bit, to use a 16-bit instruction the immediate is + * very small; 4 bit. + * + * sub 32-bit, type IV, takes a register and subtracts a 21-bit immediate. + * add 32-bit, type II, adds two register values together. */ -static inline int atomic_sub_return(int i, atomic_t *v) -{ - int result; - - asm volatile( - "/* atomic_sub_return */\n" - "1: ssrf 5\n" - " ld.w %0, %2\n" - " sub %0, %3\n" - " stcond %1, %0\n" - " brne 1b" - : "=&r"(result), "=o"(v->counter) - : "m"(v->counter), "rKs21"(i) - : "cc"); - - return result; -} +#define IS_21BIT_CONST(i) \ + (__builtin_constant_p(i) && ((i) >= -1048575) && ((i) <= 1048576)) /* * atomic_add_return - add integer to atomic variable @@ -56,51 +69,25 @@ static inline int atomic_sub_return(int i, atomic_t *v) */ static inline int atomic_add_return(int i, atomic_t *v) { - int result; - - if (__builtin_constant_p(i) && (i >= -1048575) && (i <= 1048576)) - result = atomic_sub_return(-i, v); - else - asm volatile( - "/* atomic_add_return */\n" - "1: ssrf 5\n" - " ld.w %0, %1\n" - " add %0, %3\n" - " stcond %2, %0\n" - " brne 1b" - : "=&r"(result), "=o"(v->counter) - : "m"(v->counter), "r"(i) - : "cc", "memory"); + if (IS_21BIT_CONST(i)) + return __atomic_sub_return(-i, v); - return result; + return __atomic_add_return(i, v); } /* - * atomic_sub_unless - sub unless the number is a given value + * atomic_sub_return - subtract the atomic variable + * @i: integer value to subtract * @v: pointer of type atomic_t - * @a: the amount to subtract from v... - * @u: ...unless v is equal to u. * - * Atomically subtract @a from @v, so long as it was not @u. - * Returns the old value of @v. -*/ -static inline void atomic_sub_unless(atomic_t *v, int a, int u) + * Atomically subtracts @i from @v. Returns the resulting value. + */ +static inline int atomic_sub_return(int i, atomic_t *v) { - int tmp; + if (IS_21BIT_CONST(i)) + return __atomic_sub_return(i, v); - asm volatile( - "/* atomic_sub_unless */\n" - "1: ssrf 5\n" - " ld.w %0, %2\n" - " cp.w %0, %4\n" - " breq 1f\n" - " sub %0, %3\n" - " stcond %1, %0\n" - " brne 1b\n" - "1:" - : "=&r"(tmp), "=o"(v->counter) - : "m"(v->counter), "rKs21"(a), "rKs21"(u) - : "cc", "memory"); + return __atomic_add_return(-i, v); } /* @@ -116,9 +103,21 @@ static inline int __atomic_add_unless(atomic_t *v, int a, int u) { int tmp, old = atomic_read(v); - if (__builtin_constant_p(a) && (a >= -1048575) && (a <= 1048576)) - atomic_sub_unless(v, -a, u); - else { + if (IS_21BIT_CONST(a)) { + asm volatile( + "/* __atomic_sub_unless */\n" + "1: ssrf 5\n" + " ld.w %0, %2\n" + " cp.w %0, %4\n" + " breq 1f\n" + " sub %0, %3\n" + " stcond %1, %0\n" + " brne 1b\n" + "1:" + : "=&r"(tmp), "=o"(v->counter) + : "m"(v->counter), "rKs21"(-a), "rKs21"(u) + : "cc", "memory"); + } else { asm volatile( "/* __atomic_add_unless */\n" "1: ssrf 5\n" @@ -137,6 +136,8 @@ static inline int __atomic_add_unless(atomic_t *v, int a, int u) return old; } +#undef IS_21BIT_CONST + /* * atomic_sub_if_positive - conditionally subtract integer from atomic variable * @i: integer value to subtract -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
