On Sun, 11 Jun 2006 23:25:43 +0900 (JST), Atsushi Nemoto <anemo@xxxxxxxxxxxxx> wrote:
> I found that NPTL's pthread_cond_signal() does not work properly on
> kernels compiled by gcc 4.1.x. I suppose inline asm for
> __futex_atomic_op() was wrong. I suppose:
>
> 1. "=&r" constraint should be used for oldval.
> 2. Instead of "r" (uaddr), "=R" (*uaddr) for output and "R" (*uaddr)
> for input should be used.
> 3. "memory" should be added to the clobber list.
>
> This patch solved the problem.
And here is a patch for 2.6.16-stable tree.
Signed-off-by: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
diff --git a/include/asm-mips/futex.h b/include/asm-mips/futex.h
index 2454c44..e1f960d 100644
--- a/include/asm-mips/futex.h
+++ b/include/asm-mips/futex.h
@@ -20,26 +20,27 @@
" .set push \n" \
" .set noat \n" \
" .set mips3 \n" \
- "1: ll %1, (%3) # __futex_atomic_op1 \n" \
+ "1: ll %1, %4 # __futex_atomic_op1 \n" \
" .set mips0 \n" \
" " insn " \n" \
" .set mips3 \n" \
- "2: sc $1, (%3) \n" \
+ "2: sc $1, %2 \n" \
" beqzl $1, 1b \n" \
__FUTEX_SMP_SYNC \
"3: \n" \
" .set pop \n" \
" .set mips0 \n" \
" .section .fixup,\"ax\" \n" \
- "4: li %0, %5 \n" \
+ "4: li %0, %6 \n" \
" j 2b \n" \
" .previous \n" \
" .section __ex_table,\"a\" \n" \
" "__UA_ADDR "\t1b, 4b \n" \
" "__UA_ADDR "\t2b, 4b \n" \
" .previous \n" \
- : "=r" (ret), "=r" (oldval) \
- : "0" (0), "r" (uaddr), "Jr" (oparg), "i" (-EFAULT)); \
+ : "=r" (ret), "=&r" (oldval), "=R" (*uaddr) \
+ : "0" (0), "R" (*uaddr), "Jr" (oparg), "i" (-EFAULT) \
+ : "memory"); \
}
static inline int
@@ -60,23 +61,23 @@ futex_atomic_op_inuser (int encoded_op,
switch (op) {
case FUTEX_OP_SET:
- __futex_atomic_op("move $1, %z4", ret, oldval, uaddr, oparg);
+ __futex_atomic_op("move $1, %z5", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
- __futex_atomic_op("addu $1, %1, %z4",
+ __futex_atomic_op("addu $1, %1, %z5",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
- __futex_atomic_op("or $1, %1, %z4",
+ __futex_atomic_op("or $1, %1, %z5",
ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ANDN:
- __futex_atomic_op("and $1, %1, %z4",
+ __futex_atomic_op("and $1, %1, %z5",
ret, oldval, uaddr, ~oparg);
break;
case FUTEX_OP_XOR:
- __futex_atomic_op("xor $1, %1, %z4",
+ __futex_atomic_op("xor $1, %1, %z5",
ret, oldval, uaddr, oparg);
break;
default:
