On 11 August 2017 at 21:06, Nicolas Pitre <nicolas.pitre@xxxxxxxxxx> wrote:
> On Fri, 11 Aug 2017, Ard Biesheuvel wrote:
>
>> On 11 August 2017 at 20:58, Nicolas Pitre <nicolas.pitre@xxxxxxxxxx> wrote:
>> > On Fri, 11 Aug 2017, Ard Biesheuvel wrote:
>> >
>> >> On 11 August 2017 at 16:13, Tony Lindgren <tony@xxxxxxxxxxx> wrote:
>> >> > * Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> [170805 13:54]:
>> >> >> Replace the open coded PC relative offset calculations with a pair
>> >> >> of adr_l invocations.
>> >> >>
>> >> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>> >> >> ---
>> >> >> arch/arm/kernel/head.S | 12 ++----------
>> >> >> 1 file changed, 2 insertions(+), 10 deletions(-)
>> >> >>
>> >> >> diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
>> >> >> index 6e9df3663a57..aed341e0f530 100644
>> >> >> --- a/arch/arm/kernel/head.S
>> >> >> +++ b/arch/arm/kernel/head.S
>> >> >> @@ -523,19 +523,11 @@ ARM_BE8(rev r0, r0) @ byteswap if big endian
>> >> >> retne lr
>> >> >>
>> >> >> __fixup_smp_on_up:
>> >> >> - adr r0, 1f
>> >> >> - ldmia r0, {r3 - r5}
>> >> >> - sub r3, r0, r3
>> >> >> - add r4, r4, r3
>> >> >> - add r5, r5, r3
>> >> >> + adr_l r4, __smpalt_begin
>> >> >> + adr_l r5, __smpalt_end
>> >> >> b __do_fixup_smp_on_up
>> >> >> ENDPROC(__fixup_smp)
>> >> >>
>> >> >> - .align
>> >> >> -1: .word .
>> >> >> - .word __smpalt_begin
>> >> >> - .word __smpalt_end
>> >> >> -
>> >> >> .pushsection .data
>> >> >> .globl smp_on_up
>> >> >> smp_on_up:
>> >> >
>> >> > Ard, it's this one that cause boot to fail on omap3.
>> >> > The rest of your set works for me with just this one
>> >> > left out.
>> >> >
>> >>
>> >> I'm completely puzzled.
>> >
>> > Found it.
>> >
>> > You replaced:
>> >
>> > - adr r0, 1f
>> > - ldmia r0, {r3 - r5}
>> > - sub r3, r0, r3
>> > - add r4, r4, r3
>> > - add r5, r5, r3
>> > + adr_l r4, __smpalt_begin
>> > + adr_l r5, __smpalt_end
>> > b __do_fixup_smp_on_up
>> >
>> > Notice that r3 is now uninitialized.
>> >
>> > Now have a look at the code for __do_fixup_smp_on_up.
>> >
>>
>> I still don't see it :-)
>>
>> __do_fixup_smp_on_up() mentions r3 in the comment block, but it does
>> not actually refer to it in the code, does it?
>
> __do_fixup_smp_on_up:
> cmp r4, r5
> reths lr
> ldmia r4!, {r0, r6}
> ARM( str r6, [r0, r3] ) <<============
> THUMB( add r0, r0, r3 ) <<============
> [...]
>
Aahhh
Looking at the wrong version of the file.
Thanks for spotting that.
