[PATCH 1/4] msm: scm: Mark inline asm as volatile
From: Will Deacon <hidden>
Date: 2011-02-25 12:18:07
Also in:
linux-arm-msm, lkml
Hi Stephen, On Thu, 2011-02-24 at 18:44 +0000, Stephen Boyd wrote:
quoted hunk ↗ jump to hunk
We don't want the compiler to remove these asm statements or reorder them in any way. Mark them as volatile to be sure. Signed-off-by: Stephen Boyd <redacted> --- arch/arm/mach-msm/scm.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)diff --git a/arch/arm/mach-msm/scm.c b/arch/arm/mach-msm/scm.c index f4b9bc9..ba57b5a 100644 --- a/arch/arm/mach-msm/scm.c +++ b/arch/arm/mach-msm/scm.c@@ -174,7 +174,7 @@ static u32 smc(u32 cmd_addr) register u32 r0 asm("r0") = 1; register u32 r1 asm("r1") = (u32)&context_id; register u32 r2 asm("r2") = cmd_addr; - asm( + asm volatile( __asmeq("%0", "r0") __asmeq("%1", "r0") __asmeq("%2", "r1")@@ -271,7 +271,7 @@ u32 scm_get_version(void) return version; mutex_lock(&scm_lock); - asm( + asm volatile( __asmeq("%0", "r1") __asmeq("%1", "r0") __asmeq("%2", "r1")
These asm blocks all have sensible looking output constraints. Why do they need to be marked volatile? Will