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[POWERPC] Implement PowerPC futex_atomic_cmpxchg_inatomic(). 

The sys_[gs]et_robust_list() syscalls were wired up on PowerPC but
didn't work correctly because futex_atomic_cmpxchg_inatomic() wasn't
implemented.  Implement it, based on __cmpxchg_u32().

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
David Woodhouse 2006-09-04 21:53:14 -07:00 committed by Paul Mackerras
parent 20fb96e2aa
commit 6958829818
1 changed files with 27 additions and 1 deletions
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28
include/asm-powerpc/futex.h
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@ -84,7 +84,33 @@ static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
static inline int
futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
{
return -ENOSYS;
int prev;
if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
return -EFAULT;
__asm__ __volatile__ (
LWSYNC_ON_SMP
"1: lwarx %0,0,%2 # futex_atomic_cmpxchg_inatomic\n\
cmpw 0,%0,%3\n\
bne- 3f\n"
PPC405_ERR77(0,%2)
"2: stwcx. %4,0,%2\n\
bne- 1b\n"
ISYNC_ON_SMP
"3: .section .fixup,\"ax\"\n\
4: li %0,%5\n\
b 3b\n\
.previous\n\
.section __ex_table,\"a\"\n\
.align 3\n\
" PPC_LONG "1b,4b,2b,4b\n\
.previous" \
: "=&r" (prev), "+m" (*uaddr)
: "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
: "cc", "memory");
return prev;
}
#endif /* __KERNEL__ */