[U-Boot] [PATCH v5] arm: bugfix: save_boot_params_default accesses uninitalized stack when -O0

[Tetsuyuki Kobayashi]

save_boot_params_default() in cpu.c accesses uninitialized stack area
when it compiled with -O0 (not optimized).
This patch removes save_boot_params_default() and put the equivalent in start.S

Signed-off-by: Tetsuyuki Kobayashi <koba at kmckk.co.jp>
---
Hi Tom, Albert,

I rewrite it again.
I tested it quickly on my kzm9g board, and also build it for omap4_panda and
checked the generated code by objdump command.

Changes for v2:
 - include <linux/compiler.h> and use __naked instead of __attribute__((naked))

Changes for v3:
 - move __naked after void
 - reformat comments

Changes for v4:
 - v3 causes following warnings
  cpu.c: In function 'save_boot_params_default':
  cpu.c:48:1: warning: -fstack-usage not supported for this target [enabled by default]
 - move save_boot_params_default() and save_boot_params() from cpu.c to start.S
   and write them in asm language

Changes for v5
 - rename save_boot_parames_default() to save_boot_params() and drop aliasing
 - move the code after relocate_code (nearer to callee)
 - modify commit log

 arch/arm/cpu/armv7/cpu.c   |    7 -------
 arch/arm/cpu/armv7/start.S |   14 ++++++++++++++
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/arch/arm/cpu/armv7/cpu.c b/arch/arm/cpu/armv7/cpu.c
index c6fa8ef..b0677f4 100644
--- a/arch/arm/cpu/armv7/cpu.c
+++ b/arch/arm/cpu/armv7/cpu.c
@@ -37,13 +37,6 @@
 #include <asm/cache.h>
 #include <asm/armv7.h>
 
-void save_boot_params_default(u32 r0, u32 r1, u32 r2, u32 r3)
-{
-}
-
-void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3)
-	__attribute__((weak, alias("save_boot_params_default")));
-
 int cleanup_before_linux(void)
 {
 	/*
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index 261835b..bf734fb 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -293,6 +293,20 @@ ENDPROC(relocate_code)
 
 /*************************************************************************
  *
+ * void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3)
+ *	__attribute__((weak));
+ *
+ * Stack pointer is not yet initialized at this moment
+ * Don't save anything to stack even if compiled with -O0
+ *
+ *************************************************************************/
+ENTRY(save_boot_params)
+	bx	lr			@ back to my caller
+ENDPROC(save_boot_params)
+	.weak	save_boot_params
+
+/*************************************************************************
+ *
  * cpu_init_cp15
  *
  * Setup CP15 registers (cache, MMU, TLBs). The I-cache is turned on unless
-- 
1.7.9.5