[U-Boot] [PATCH 2/2] mpc85xx: Initial SP alignment is wrong.

[Joakim Tjernlund]

PowerPC mandates SP to be 16 bytes aligned.
Furthermore, a stack frame is added, pointing to the reset vector
which is just get in the way when gdb is walking the stack because
the reset vector may not accessible depending on emulator settings.
Also use a temp register so gdb doesn't pick up intermediate values.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund at transmode.se>
---
 arch/powerpc/cpu/mpc85xx/start.S |   16 +++++-----------
 1 files changed, 5 insertions(+), 11 deletions(-)

diff --git arch/powerpc/cpu/mpc85xx/start.S arch/powerpc/cpu/mpc85xx/start.S
index 8d66cf1..8c75af9 100644
--- arch/powerpc/cpu/mpc85xx/start.S
+++ arch/powerpc/cpu/mpc85xx/start.S
@@ -848,18 +848,12 @@ version_string:
 	.globl	_start_cont
 _start_cont:
 	/* Setup the stack in initial RAM,could be L2-as-SRAM or L1 dcache*/
-	lis	r1,CONFIG_SYS_INIT_RAM_ADDR at h
-	ori	r1,r1,CONFIG_SYS_INIT_SP_OFFSET at l
-
+	lis	r2,(CONFIG_SYS_INIT_RAM_ADDR)@h
+	ori	r2,r2,((CONFIG_SYS_INIT_SP_OFFSET-16)&~0xf)@l /* Align to 16 */
 	li	r0,0
-	stwu	r0,-4(r1)
-	stwu	r0,-4(r1)		/* Terminate call chain */
-
-	stwu	r1,-8(r1)		/* Save back chain and move SP */
-	lis	r0,RESET_VECTOR at h	/* Address of reset vector */
-	ori	r0,r0,RESET_VECTOR at l
-	stwu	r1,-8(r1)		/* Save back chain and move SP */
-	stw	r0,+12(r1)		/* Save return addr (underflow vect) */
+	stw	r0,-4(r2)	/* Store a NULL LR */
+	stw	r0,0(r2)	/* Store a NULL Back Chain */
+	mr	r1,r2		/* Transfer to SP(r1) */
 
 	GET_GOT
 	bl	cpu_init_early_f
-- 
1.7.3.4