I've maintained this patch, originally from Thiemo Seufer in 2004, for a really long time, but I think it's time for it to get a look at for possible inclusion. I have had no problems with it across various SGI systems over the years. To quote the post here: http://www.linux-mips.org/archives/linux-mips/2004-12/msg00000.html "the atomic functions use so far memory references for the inline assembler to access the semaphore. This can lead to additional instructions in the ll/sc loop, because newer compilers don't expand the memory reference any more but leave it to the assembler. The appended patch uses registers instead, and makes the ll/sc arguments more explicit. In some cases it will lead also to better register scheduling because the register isn't bound to an output any more." Signed-off-by: Joshua Kinard <kumba@xxxxxxxxxx> --- atomic.h | 64 ++++++++++++++++++++++++++++----------------------------------- 1 file changed, 29 insertions(+), 35 deletions(-) diff -Naurp a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h --- a/arch/mips/include/asm/atomic.h +++ b/arch/mips/include/asm/atomic.h @@ -59,8 +59,8 @@ static __inline__ void atomic_add(int i, " sc %0, %1 \n" " beqzl %0, 1b \n" " .set mips0 \n" - : "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter)); + : "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } else if (kernel_uses_llsc) { int temp; @@ -71,8 +71,8 @@ static __inline__ void atomic_add(int i, " addu %0, %2 \n" " sc %0, %1 \n" " .set mips0 \n" - : "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter)); + : "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } while (unlikely(!temp)); } else { unsigned long flags; @@ -102,8 +102,8 @@ static __inline__ void atomic_sub(int i, " sc %0, %1 \n" " beqzl %0, 1b \n" " .set mips0 \n" - : "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter)); + : "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } else if (kernel_uses_llsc) { int temp; @@ -114,8 +114,8 @@ static __inline__ void atomic_sub(int i, " subu %0, %2 \n" " sc %0, %1 \n" " .set mips0 \n" - : "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter)); + : "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } while (unlikely(!temp)); } else { unsigned long flags; @@ -146,9 +146,8 @@ static __inline__ int atomic_add_return( " beqzl %0, 1b \n" " addu %0, %1, %3 \n" " .set mips0 \n" - : "=&r" (result), "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter) - : "memory"); + : "=&r" (result), "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } else if (kernel_uses_llsc) { int temp; @@ -159,9 +158,8 @@ static __inline__ int atomic_add_return( " addu %0, %1, %3 \n" " sc %0, %2 \n" " .set mips0 \n" - : "=&r" (result), "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter) - : "memory"); + : "=&r" (result), "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } while (unlikely(!result)); result = temp + i; @@ -212,9 +210,8 @@ static __inline__ int atomic_sub_return( " subu %0, %1, %3 \n" " sc %0, %2 \n" " .set mips0 \n" - : "=&r" (result), "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter) - : "memory"); + : "=&r" (result), "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } while (unlikely(!result)); result = temp - i; @@ -262,7 +259,7 @@ static __inline__ int atomic_sub_if_posi " .set reorder \n" "1: \n" " .set mips0 \n" - : "=&r" (result), "=&r" (temp), "=m" (v->counter) + : "=&r" (result), "=&r" (temp), "+m" (v->counter) : "Ir" (i), "m" (v->counter) : "memory"); } else if (kernel_uses_llsc) { @@ -280,9 +277,8 @@ static __inline__ int atomic_sub_if_posi " .set reorder \n" "1: \n" " .set mips0 \n" - : "=&r" (result), "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter) - : "memory"); + : "=&r" (result), "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } else { unsigned long flags; @@ -430,8 +426,8 @@ static __inline__ void atomic64_add(long " scd %0, %1 \n" " beqzl %0, 1b \n" " .set mips0 \n" - : "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter)); + : "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } else if (kernel_uses_llsc) { long temp; @@ -442,8 +438,8 @@ static __inline__ void atomic64_add(long " daddu %0, %2 \n" " scd %0, %1 \n" " .set mips0 \n" - : "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter)); + : "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } while (unlikely(!temp)); } else { unsigned long flags; @@ -473,8 +469,8 @@ static __inline__ void atomic64_sub(long " scd %0, %1 \n" " beqzl %0, 1b \n" " .set mips0 \n" - : "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter)); + : "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } else if (kernel_uses_llsc) { long temp; @@ -485,8 +481,8 @@ static __inline__ void atomic64_sub(long " dsubu %0, %2 \n" " scd %0, %1 \n" " .set mips0 \n" - : "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter)); + : "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } while (unlikely(!temp)); } else { unsigned long flags; @@ -517,9 +513,8 @@ static __inline__ long atomic64_add_retu " beqzl %0, 1b \n" " daddu %0, %1, %3 \n" " .set mips0 \n" - : "=&r" (result), "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter) - : "memory"); + : "=&r" (result), "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } else if (kernel_uses_llsc) { long temp; @@ -649,9 +644,8 @@ static __inline__ long atomic64_sub_if_p " .set reorder \n" "1: \n" " .set mips0 \n" - : "=&r" (result), "=&r" (temp), "=m" (v->counter) - : "Ir" (i), "m" (v->counter) - : "memory"); + : "=&r" (result), "=&r" (temp), "+m" (v->counter) + : "Ir" (i)); } else { unsigned long flags;
