ARM: Use a definition for the userspace cmpxchg emulation syscall

Use a definition for the cmpxchg SWI instead of hard-coding the number.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Nicolas Pitre <nico@fluxnic.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 7020217fc49f..4e506d09e5f9 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -403,6 +403,15 @@
 #define __ARM_NR_set_tls                (__ARM_NR_BASE+5)
 
 /*
+ * *NOTE*: This is a ghost syscall private to the kernel.  Only the
+ * __kuser_cmpxchg code in entry-armv.S should be aware of its
+ * existence.  Don't ever use this from user code.
+ */
+#ifdef __KERNEL__
+#define __ARM_NR_cmpxchg                (__ARM_NR_BASE+0x00fff0)
+#endif
+
+/*
  * The following syscalls are obsolete and no longer available for EABI.
  */
 #if defined(__ARM_EABI__) && !defined(__KERNEL__)