[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>
diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
index ac687d0..326595f 100644
--- a/arch/i386/kernel/syscall_table.S
+++ b/arch/i386/kernel/syscall_table.S
@@ -310,3 +310,5 @@
.long sys_pselect6
.long sys_ppoll
.long sys_unshare /* 310 */
+ .long sys_set_robust_list
+ .long sys_get_robust_list
diff --git a/include/asm-i386/futex.h b/include/asm-i386/futex.h
index 1f39ad9..41184a3 100644
--- a/include/asm-i386/futex.h
+++ b/include/asm-i386/futex.h
@@ -107,7 +107,28 @@
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 d8afd0e..014e356 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