[PATCH] lightweight robust futexes: x86_64
x86_64: 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>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
index 7549a43..35b2fac 100644
--- a/arch/x86_64/ia32/ia32entry.S
+++ b/arch/x86_64/ia32/ia32entry.S
@@ -688,6 +688,8 @@
.quad sys_ni_syscall /* pselect6 for now */
.quad sys_ni_syscall /* ppoll for now */
.quad sys_unshare /* 310 */
+ .quad compat_sys_set_robust_list
+ .quad compat_sys_get_robust_list
ia32_syscall_end:
.rept IA32_NR_syscalls-(ia32_syscall_end-ia32_sys_call_table)/8
.quad ni_syscall
diff --git a/include/asm-x86_64/futex.h b/include/asm-x86_64/futex.h
index 4f4cb34..7d9eb1a 100644
--- a/include/asm-x86_64/futex.h
+++ b/include/asm-x86_64/futex.h
@@ -97,7 +97,28 @@
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"
+ " .quad 1b,3b \n"
+ " .previous \n"
+
+ : "=a" (oldval), "=m" (*uaddr)
+ : "i" (-EFAULT), "r" (newval), "0" (oldval)
+ : "memory"
+ );
+
+ return oldval;
}
#endif
diff --git a/include/asm-x86_64/unistd.h b/include/asm-x86_64/unistd.h
index da0341c..fcc5163 100644
--- a/include/asm-x86_64/unistd.h
+++ b/include/asm-x86_64/unistd.h
@@ -605,8 +605,12 @@
__SYSCALL(__NR_ppoll, sys_ni_syscall) /* for now */
#define __NR_unshare 272
__SYSCALL(__NR_unshare, sys_unshare)
+#define __NR_set_robust_list 273
+__SYSCALL(__NR_set_robust_list, sys_set_robust_list)
+#define __NR_get_robust_list 274
+__SYSCALL(__NR_get_robust_list, sys_get_robust_list)
-#define __NR_syscall_max __NR_unshare
+#define __NR_syscall_max __NR_get_robust_list
#ifndef __NO_STUBS