Subject: [PATCH] ARM: keystone: remove hand-coded smc instruction

From: [email-masked] (Santosh Shilimkar)
Date: Fri, 21 Jun 2013 18:54:47 -0400

On Friday 21 June 2013 05:41 PM, Arnd Bergmann wrote:
> On Friday 21 June 2013, Santosh Shilimkar wrote:
>>>
>> I was curious how you will fix that for a c file.
>> Just to be clear, I was planning to do that in 3.11-rcx/3.12
>> time. Let me know if it needs to be done earlier than that.
> 
> It breaks randconfig builds on arm-soc at the moment, so I'd
> like the fix as early as possible for 3.11.
> 
Ok, fix is at end of the email. Let me know if it makes
to pass both the builds now. I have build and boot tested
both ARM and THUMB2 builds on Keystone board.

Regards,
Santosh

>>From 05d6a5b6cad624fb3791e8c1f8eb7c774f0790d9 Mon Sep 17 00:00:00 2001
From: Santosh Shilimkar <[email-masked]>
Date: Fri, 21 Jun 2013 18:35:32 -0400
Subject: [PATCH] ARM: keystone: Move CPU bringup code to dedicated asm file

Because of inline asm usage in platsmp.c, smc instruction
creates build failure for ARM V6+V7 build where as using instruction
encoding for smc breaks the thumb2 build.

So move the code snippet to separate asm file and mark
it with 'armv7-a$(plus_sec)' to avoid any build issues.

Cc: Arnd Bergmann <[email-masked]>

Signed-off-by: Santosh Shilimkar <[email-masked]>
---
 arch/arm/mach-keystone/Makefile   |    6 +++++-
 arch/arm/mach-keystone/keystone.h |    6 ++++++
 arch/arm/mach-keystone/platsmp.c  |   15 +++------------
 arch/arm/mach-keystone/smc.S      |   29 +++++++++++++++++++++++++++++
 4 files changed, 43 insertions(+), 13 deletions(-)
 create mode 100644 arch/arm/mach-keystone/smc.S

diff --git a/arch/arm/mach-keystone/Makefile b/arch/arm/mach-keystone/Makefile
index 3f6b8ab..ddc52b0 100644
--- a/arch/arm/mach-keystone/Makefile
+++ b/arch/arm/mach-keystone/Makefile
@@ -1,2 +1,6 @@
-obj-y					:= keystone.o
+obj-y					:= keystone.o smc.o
+
+plus_sec := $(call as-instr,.arch_extension sec,+sec)
+AFLAGS_smc.o				:=-Wa,-march=armv7-a$(plus_sec)
+
 obj-$(CONFIG_SMP)			+= platsmp.o
diff --git a/arch/arm/mach-keystone/keystone.h b/arch/arm/mach-keystone/keystone.h
index 43a1b47..60bef9d 100644
--- a/arch/arm/mach-keystone/keystone.h
+++ b/arch/arm/mach-keystone/keystone.h
@@ -11,7 +11,13 @@
 #ifndef __KEYSTONE_H__
 #define __KEYSTONE_H__
 
+#define KEYSTONE_MON_CPU_UP_IDX		0x00
+
+#ifndef __ASSEMBLER__
+
 extern struct smp_operations keystone_smp_ops;
 extern void secondary_startup(void);
+extern u32 keystone_cpu_smc(u32 command, u32 cpu, u32 addr);
 
+#endif /* __ASSEMBLER__ */
 #endif /* __KEYSTONE_H__ */
diff --git a/arch/arm/mach-keystone/platsmp.c b/arch/arm/mach-keystone/platsmp.c
index 630ab3b..1d4181e 100644
--- a/arch/arm/mach-keystone/platsmp.c
+++ b/arch/arm/mach-keystone/platsmp.c
@@ -30,18 +30,9 @@ static int __cpuinit keystone_smp_boot_secondary(unsigned int cpu,
 	pr_debug("keystone-smp: booting cpu %d, vector %08lx\n",
 		 cpu, start);
 
-	asm volatile (
-		"mov    r0, #0\n"	/* power on cmd	*/
-		"mov    r1, %1\n"	/* cpu		*/
-		"mov    r2, %2\n"	/* start	*/
-		".inst  0xe1600070\n"	/* smc #0	*/
-		"mov    %0, r0\n"
-		: "=r" (error)
-		: "r"(cpu), "r"(start)
-		: "cc", "r0", "r1", "r2", "memory"
-	);
-
-	pr_debug("keystone-smp: monitor returned %d\n", error);
+	error = keystone_cpu_smc(KEYSTONE_MON_CPU_UP_IDX, cpu, start);
+	if (error)
+		pr_err("CPU %d bringup failed with %d\n", cpu, error);
 
 	return error;
 }
diff --git a/arch/arm/mach-keystone/smc.S b/arch/arm/mach-keystone/smc.S
new file mode 100644
index 0000000..9b9e4f7
--- /dev/null
+++ b/arch/arm/mach-keystone/smc.S
@@ -0,0 +1,29 @@
+/*
+ * Keystone Secure APIs
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ * 	Santosh Shilimkar <[email-masked]>
+ *
+ * This program is free software,you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+
+/**
+ * u32 keystone_cpu_smc(u32 command, u32 cpu, u32 addr)
+ *
+ * Low level CPU monitor API
+ * @command:	Monitor command.
+ * @cpu:	CPU Number
+ * @addr:	Kernel jump address for boot CPU
+ *
+ * Return: Non zero value on failure
+ */
+ENTRY(keystone_cpu_smc)
+	stmfd   sp!, {r4-r12, lr}
+	smc	#0
+	dsb
+	ldmfd   sp!, {r4-r12, pc}
+ENDPROC(keystone_cpu_smc)
-- 
1.7.9.5