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authorIngo Molnar <mingo@elte.hu>2006-03-27 01:16:25 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-27 08:44:49 -0800
commitdfd4e3ec246355274c9cf62c6b04a1ee6fa3caba (patch)
tree9b745a5f4b5134c2a101280f6bbd1947c15800d8 /include/asm-i386
parent34f192c6527f20c47ccec239e7d51a27691b93fc (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')
-rw-r--r--include/asm-i386/futex.h23
-rw-r--r--include/asm-i386/unistd.h4
2 files changed, 25 insertions, 2 deletions
diff --git a/include/asm-i386/futex.h b/include/asm-i386/futex.h
index 1f39ad9d52a..41184a31885 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
diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index d8afd0e3b81..014e3562895 100644
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -316,8 +316,10 @@
#define __NR_pselect6 308
#define __NR_ppoll 309
#define __NR_unshare 310
+#define __NR_set_robust_list 311
+#define __NR_get_robust_list 312
-#define NR_syscalls 311
+#define NR_syscalls 313
/*
* user-visible error numbers are in the range -1 - -128: see