diff options
| author | Ingo Molnar <mingo@elte.hu> | 2006-03-27 01:16:25 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-27 08:44:49 -0800 |
| commit | dfd4e3ec246355274c9cf62c6b04a1ee6fa3caba (patch) | |
| tree | 9b745a5f4b5134c2a101280f6bbd1947c15800d8 /include/asm-i386/futex.h | |
| parent | 34f192c6527f20c47ccec239e7d51a27691b93fc (diff) | |
[PATCH] lightweight robust futexes: i386
i386: add the futex_atomic_cmpxchg_inuser() assembly implementation, and wire
up the new syscalls.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Acked-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-i386/futex.h')
| -rw-r--r-- | include/asm-i386/futex.h | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/include/asm-i386/futex.h b/include/asm-i386/futex.h index 1f39ad9d52a1..41184a31885c 100644 --- a/include/asm-i386/futex.h +++ b/include/asm-i386/futex.h @@ -107,7 +107,28 @@ futex_atomic_op_inuser (int encoded_op, int __user *uaddr) static inline int futex_atomic_cmpxchg_inuser(int __user *uaddr, int oldval, int newval) { - return -ENOSYS; + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) + return -EFAULT; + + __asm__ __volatile__( + "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n" + + "2: .section .fixup, \"ax\" \n" + "3: mov %2, %0 \n" + " jmp 2b \n" + " .previous \n" + + " .section __ex_table, \"a\" \n" + " .align 8 \n" + " .long 1b,3b \n" + " .previous \n" + + : "=a" (oldval), "=m" (*uaddr) + : "i" (-EFAULT), "r" (newval), "0" (oldval) + : "memory" + ); + + return oldval; } #endif |