linux-kernel - [PATCH 3/4] msm: scm: Check for interruption immediately

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Date:	Thu, 24 Feb 2011 10:44:44 -0800
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	David Brown <davidb@...eaurora.org>
Cc:	linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: [PATCH 3/4] msm: scm: Check for interruption immediately

When we're interrupted on the secure side, we should just issue
another smc instruction again instead of replaying the arguments
to smc. Fix it.

Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
---
 arch/arm/mach-msm/scm.c |   51 ++++++++++++++++++++++++----------------------
 1 files changed, 27 insertions(+), 24 deletions(-)

diff --git a/arch/arm/mach-msm/scm.c b/arch/arm/mach-msm/scm.c
index 5eddf54..cfa808d 100644
--- a/arch/arm/mach-msm/scm.c
+++ b/arch/arm/mach-msm/scm.c
@@ -174,15 +174,18 @@ 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 volatile(
-		__asmeq("%0", "r0")
-		__asmeq("%1", "r0")
-		__asmeq("%2", "r1")
-		__asmeq("%3", "r2")
-		"smc	#0	@ switch to secure world\n"
-		: "=r" (r0)
-		: "r" (r0), "r" (r1), "r" (r2)
-		: "r3");
+	do {
+		asm volatile(
+			__asmeq("%0", "r0")
+			__asmeq("%1", "r0")
+			__asmeq("%2", "r1")
+			__asmeq("%3", "r2")
+			"smc	#0	@ switch to secure world\n"
+			: "=r" (r0)
+			: "r" (r0), "r" (r1), "r" (r2)
+			: "r3");
+	} while (r0 == SCM_INTERRUPTED);
+
 	return r0;
 }
 
@@ -197,13 +200,9 @@ static int __scm_call(const struct scm_command *cmd)
 	 * side in the buffer.
 	 */
 	flush_cache_all();
-	do {
-		ret = smc(cmd_addr);
-		if (ret < 0) {
-			ret = scm_remap_error(ret);
-			break;
-		}
-	} while (ret == SCM_INTERRUPTED);
+	ret = smc(cmd_addr);
+	if (ret < 0)
+		ret = scm_remap_error(ret);
 
 	return ret;
 }
@@ -274,14 +273,18 @@ u32 scm_get_version(void)
 
 	r0 = 0x1 << 8;
 	r1 = (u32)&context_id;
-	asm volatile(
-		__asmeq("%0", "r1")
-		__asmeq("%1", "r0")
-		__asmeq("%2", "r1")
-		"smc	#0	@ switch to secure world\n"
-		: "=r" (r1)
-		: "r" (r0), "r" (r1)
-		: "r2", "r3");
+	do {
+		asm volatile(
+			__asmeq("%0", "r0")
+			__asmeq("%1", "r1")
+			__asmeq("%2", "r0")
+			__asmeq("%3", "r1")
+			"smc	#0	@ switch to secure world\n"
+			: "=r" (r0), "=r" (r1)
+			: "r" (r0), "r" (r1)
+			: "r2", "r3");
+	} while (r0 == SCM_INTERRUPTED);
+
 	version = r1;
 	mutex_unlock(&scm_lock);
 
-- 
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

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