From 8f76f9c46952659dd925c21c3f62a0d05a3f3e71 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Thu, 5 Aug 2021 12:14:08 -0700 Subject: [PATCH] bitops/non-atomic: make @nr unsigned to avoid any DIV signed math causes generation of costlier instructions such as DIV when they could be done by barrerl shifter. Worse part is this is not caught by things like bloat-o-meter since instruction length / symbols are typically same size. e.g. stock (signed math) __________________ 919b4614 : 919b4614: div r2,r0,0x20 ^^^ 919b4618: add2 r2,0x920f6050,r2 919b4620: ld_s r2,[r2,0] 919b4622: lsr r0,r2,r0 919b4626: j_s.d [blink] 919b4628: bmsk_s r0,r0,0 919b462a: nop_s (patched) unsigned math __________________ 919b4614 : 919b4614: lsr r2,r0,0x5 @nr/32 ^^^ 919b4618: add2 r2,0x920f6050,r2 919b4620: ld_s r2,[r2,0] 919b4622: lsr r0,r2,r0 #test_bit() 919b4626: j_s.d [blink] 919b4628: bmsk_s r0,r0,0 919b462a: nop_s Signed-off-by: Vineet Gupta Acked-by: Will Deacon Signed-off-by: Arnd Bergmann --- include/asm-generic/bitops/non-atomic.h | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/include/asm-generic/bitops/non-atomic.h b/include/asm-generic/bitops/non-atomic.h index 7e10c4b..c5a7d8e 100644 --- a/include/asm-generic/bitops/non-atomic.h +++ b/include/asm-generic/bitops/non-atomic.h @@ -13,7 +13,7 @@ * If it's called on the same region of memory simultaneously, the effect * may be that only one operation succeeds. */ -static inline void __set_bit(int nr, volatile unsigned long *addr) +static inline void __set_bit(unsigned int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); @@ -21,7 +21,7 @@ static inline void __set_bit(int nr, volatile unsigned long *addr) *p |= mask; } -static inline void __clear_bit(int nr, volatile unsigned long *addr) +static inline void __clear_bit(unsigned int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); @@ -38,7 +38,7 @@ static inline void __clear_bit(int nr, volatile unsigned long *addr) * If it's called on the same region of memory simultaneously, the effect * may be that only one operation succeeds. */ -static inline void __change_bit(int nr, volatile unsigned long *addr) +static inline void __change_bit(unsigned int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); @@ -55,7 +55,7 @@ static inline void __change_bit(int nr, volatile unsigned long *addr) * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. */ -static inline int __test_and_set_bit(int nr, volatile unsigned long *addr) +static inline int __test_and_set_bit(unsigned int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); @@ -74,7 +74,7 @@ static inline int __test_and_set_bit(int nr, volatile unsigned long *addr) * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. */ -static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) +static inline int __test_and_clear_bit(unsigned int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); @@ -85,7 +85,7 @@ static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) } /* WARNING: non atomic and it can be reordered! */ -static inline int __test_and_change_bit(int nr, +static inline int __test_and_change_bit(unsigned int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); @@ -101,7 +101,7 @@ static inline int __test_and_change_bit(int nr, * @nr: bit number to test * @addr: Address to start counting from */ -static inline int test_bit(int nr, const volatile unsigned long *addr) +static inline int test_bit(unsigned int nr, const volatile unsigned long *addr) { return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); } -- 2.7.4