[U-Boot] [PATCH v3] arm926ejs: 8-byte align stack to avoid LDRD/STRD problems
Simon Kagstrom
simon.kagstrom at netinsight.net
Tue Oct 6 08:44:22 CEST 2009
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).
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
v3: Update after Andrews and Måns comments
* Use bic instruction to clear low address bits (I'm a ARM asm newbie as
you can see)
* Update description to actually match the code
Thanks again for all the comments!
cpu/arm926ejs/start.S | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/cpu/arm926ejs/start.S b/cpu/arm926ejs/start.S
index 8043322..4421b6a 100644
--- a/cpu/arm926ejs/start.S
+++ b/cpu/arm926ejs/start.S
@@ -172,6 +172,7 @@ stack_setup:
sub r0, r0, #(CONFIG_STACKSIZE_IRQ+CONFIG_STACKSIZE_FIQ)
#endif
sub sp, r0, #12 /* leave 3 words for abort-stack */
+ bic sp, r0, #7 /* 8-byte align stack for ABI compliance */
clear_bss:
ldr r0, _bss_start /* find start of bss segment */
--
1.6.0.4
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