From da7196e1f986c846ffa8b2ec385223fad38e8518 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 3 Mar 2010 11:47:58 +0000 Subject: [PATCH] perf, ARM: Modify kuser rmb() call to compile for Thumb-2 The Thumb-2 instruction set does not provide an encoding for sub pc, r0, #95 as present in the rmb() definition used by perf. This results in compilation failure when using a compiler targetting an instruction set other than ARM. This patch redefines rmb() for ARM by casting the address of the kuser helper to a function pointer, therefore getting the compiler to take care of making the call. Patch taken against tip/master. Signed-off-by: Will Deacon Cc: Russell King - ARM Linux Cc: Jamie Iles Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: <1267616878-2154-1-git-send-email-will.deacon@arm.com> Signed-off-by: Ingo Molnar --- tools/perf/perf.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/tools/perf/perf.h b/tools/perf/perf.h index 75f941bfba9e..6fb379bc1d1f 100644 --- a/tools/perf/perf.h +++ b/tools/perf/perf.h @@ -65,9 +65,7 @@ * Use the __kuser_memory_barrier helper in the CPU helper page. See * arch/arm/kernel/entry-armv.S in the kernel source for details. */ -#define rmb() asm volatile("mov r0, #0xffff0fff; mov lr, pc;" \ - "sub pc, r0, #95" ::: "r0", "lr", "cc", \ - "memory") +#define rmb() ((void(*)(void))0xffff0fa0)() #define cpu_relax() asm volatile("":::"memory") #endif