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).
On 05.07.2012 16:35, Zhong Hongbo wrote:
From: Zhong Hongbo bocui107@gmail.com
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?
But just only when __bss_end__ greater than __bss_start__, we do the clear bss section operation.
Signed-off-by: Hongbo Zhong bocui107@gmail.com
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.
/*
- We are done. Do not return, instead branch to second part of board
Best regards
Andreas Bießmann