Re: [U-Boot] [PATCH] arm: add 8-byte alignment for ABI compliance before board_init_f

12 Nov 2010


      Le 12/11/2010 07:53, Heiko Schocher a écrit :
...
suggested from Daniel Hobidaniel.hobi@schmid-telecom.ch
Tested on following boards:
arm1136: qong
armv7: omap3_beagle
arm926ejs: magnesium, tx25
Signed-off-by: Heiko Schocherhs@denx.de
cc: Daniel Hobidaniel.hobi@schmid-telecom.ch
cc: Albert ARIBAUDalbert.aribaud@free.fr
I'm a bit uneasy about having the symbol unaligned and the aligning done 
by the code (and in different places):
...
ldr	sp, =(CONFIG_SYS_INIT_SP_ADDR)

bic	sp, sp, #7 /* 8-byte alignment for ABI compliance */

...

gd = (gd_t *) (CONFIG_SYS_INIT_SP_ADDR);


gd = (gd_t *) ((CONFIG_SYS_INIT_SP_ADDR)&  ~0x07);

There is always a risk that overhauls of the code, or new uses elsewhere 
in the code, forget about the alignment constraint and use the symbol 
straight away, which could cause all sorts of hard to debug issues.
Could we not align the symbol value itself so that the code simply uses 
the symbol?
Amicalement,
-- 
Albert.