Hi Andreas, On 07/05/2012 11:38 PM, Andreas Bießmann wrote: > Dear Zhong Hongbo, > > this is arm related and should therefore apply to all the different > arch/arm/cpu/*/start.S (as long as they have SPL support). Ok, I will do it. Thanks for your advise.
> > On 05.07.2012 16:35, Zhong Hongbo wrote: >> From: Zhong Hongbo <[email protected]> >> >> In currently, when __bss_start is equal to __bss_end__, >> The bss loop will clear all the things in memory space. > > I ask myself why there is no bss at all. Have you just initialized data > in your spl code? Yes > >> >> But just only when __bss_end__ greater than __bss_start__, >> we do the clear bss section operation. >> >> Signed-off-by: Hongbo Zhong <[email protected]> >> --- >> arch/arm/cpu/armv7/start.S | 9 ++++++--- >> 1 files changed, 6 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S >> index 22a3ced..2e583ee 100644 >> --- a/arch/arm/cpu/armv7/start.S >> +++ b/arch/arm/cpu/armv7/start.S >> @@ -259,10 +259,13 @@ clear_bss: >> #endif >> mov r2, #0x00000000 /* clear */ >> >> -clbss_l:str r2, [r0] /* clear loop... */ >> +clbss_l: >> + cmp r1, r0 >> + bls clbss_end >> + str r2, [r0] /* clear loop... */ >> add r0, r0, #4 >> - cmp r0, r1 >> - bne clbss_l >> + b clbss_l >> +clbss_end: > > Looks sane, I maybe had checked before clbss_l, jumped over clear loop > if r0 and r1 equal (to emphasize the fact that this is a check for entry > correctness) and wouldn't change the loop at all. To be more precise we > could also check if end is after start. I check the starts of arm92ejs, I found the issue display in other arm platform. As following: commit 8f1da53508c78789ebeea98a92a3f55c3f84dc5d Author: Christian Riesch <[email protected]> Date: Wed Nov 30 22:27:37 2011 +0000 arm, arm926ejs: Fix clear bss loop for zero length bss This patch fixes the clear bss loop for bss sections that have zero length, i.e., where __bss_start == __bss_end__. Signed-off-by: Christian Riesch <[email protected]> Cc: Albert Aribaud <[email protected]> diff --git a/arch/arm/cpu/arm926ejs/start.S b/arch/arm/cpu/arm926ejs/start.S index 339c5ed..bb4d00b 100644 --- a/arch/arm/cpu/arm926ejs/start.S +++ b/arch/arm/cpu/arm926ejs/start.S @@ -301,10 +301,12 @@ clear_bss: #endif mov r2, #0x00000000 /* clear */ -clbss_l:str r2, [r0] /* clear loop... */ +clbss_l:cmp r0, r1 /* clear loop... */ + bhs clbss_e /* if reached end of bss, exit */ + str r2, [r0] add r0, r0, #4 - cmp r0, r1 - bne clbss_l + b clbss_l +clbss_e: Thanks, hongbo > >> >> /* >> * We are done. Do not return, instead branch to second part of board >> > > Best regards > > Andreas Bießmann > _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
