[U-Boot] [PATCH v2] arm926ejs: 16-byte align stack to avoid LDRD/STRD problems

[Simon Kagstrom]

U-boot for Marvell Kirkwood boards no longer work after the EABI changes
introduced in commit f772acf8a584067033eff1e231fcd1fb3a00d3d9. This
turns out to be caused by a stack alignment issue. The armv5te
instructions ldrd/strd instructions require 8-byte alignment to work
properly (otherwise undefined behavior), and start.S gave the stack a
12-byte alignment.

Tested on an OpenRD base board, where both printouts and ubifs stuff now
works.

Signed-off-by: Simon Kagstrom <simon.kagstrom at netinsight.net>
---
ChangeLog:
 v2: Update after Andrews comments
   * Mask away the low address bits to get 16-byte alignment

 cpu/arm926ejs/start.S |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/cpu/arm926ejs/start.S b/cpu/arm926ejs/start.S
index 8043322..cd3a6bd 100644
--- a/cpu/arm926ejs/start.S
+++ b/cpu/arm926ejs/start.S
@@ -171,7 +171,10 @@ stack_setup:
 #ifdef CONFIG_USE_IRQ
 	sub	r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
 #endif
-	sub	sp, r0, #12		/* leave 3 words for abort-stack    */
+	sub	r0, r0, #12		/* leave 3 words for abort-stack and */
+	mov	r1, #7			/* 8-byte align stack for ldrd/strd */
+	and	r1, r0
+	sub	sp, r0, r1
 
 clear_bss:
 	ldr	r0, _bss_start		/* find start of bss segment        */
-- 
1.6.0.4