| Message ID | 1341498915-19127-1-git-send-email-bocui107@gmail.com |
|---|---|
| State | Superseded |
| Delegated to: | Albert ARIBAUD |
| Headers | show |
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
On 05.07.2012 17:38, Andreas Bießmann wrote: <snip> >> -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. Well, I just realized you do check for less ;)
Hi Zhong, On Thu, 5 Jul 2012 22:35:15 +0800, Zhong Hongbo <bocui107@gmail.com> 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. > > 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: > > /* > * We are done. Do not return, instead branch to second part of board Just checking: that's the same as your 'infinite' patch, right? Amicalement,
On 07/05/2012 11:52 PM, Andreas Bießmann wrote: > On 05.07.2012 17:38, Andreas Bießmann wrote: > > <snip> > >>> -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. > > Well, I just realized you do check for less ;) > Yes, Thanks, hongbo
On 07/06/2012 01:44 PM, Albert ARIBAUD wrote: > Hi Zhong, > > On Thu, 5 Jul 2012 22:35:15 +0800, Zhong Hongbo <bocui107@gmail.com> 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. >> >> 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: >> >> /* >> * We are done. Do not return, instead branch to second part of board > > Just checking: that's the same as your 'infinite' patch, right? You are right. I think the description(V1 patch) have not very clear, So I modify it. Thanks, hongbo > > Amicalement, >
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: /* * We are done. Do not return, instead branch to second part of board