diff mbox

[v3] ARM: xip: Use correct symbol for end of ROM marker

Message ID alpine.LFD.2.20.1511172255410.22569@knanqh.ubzr (mailing list archive)
State Changes Requested
Delegated to: Simon Horman
Headers show

Commit Message

Nicolas Pitre Nov. 18, 2015, 3:58 a.m. UTC 
On Tue, 17 Nov 2015, Chris Brandt wrote:

> I think this one is more of a coding issue.
> These were the attempts to fix the temporary stack issue:
> 
> My first patch:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-July/357106.html
> 
> Magnus's try:
> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-November/383394.html

Here's my proposal:

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Comments

Magnus Damm Nov. 18, 2015, 5:12 a.m. UTC | #1 
Hi Nicolas,

On Wed, Nov 18, 2015 at 12:58 PM, Nicolas Pitre <nico@fluxnic.net> wrote:
> On Tue, 17 Nov 2015, Chris Brandt wrote:
>
>> I think this one is more of a coding issue.
>> These were the attempts to fix the temporary stack issue:
>>
>> My first patch:
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-July/357106.html
>>
>> Magnus's try:
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-November/383394.html
>
> Here's my proposal:
>
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> index de2b246fed..2d0ac32320 100644
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -274,10 +274,12 @@ __v7_ca15mp_setup:
>  __v7_b15mp_setup:
>  __v7_ca17mp_setup:
>         mov     r10, #0
> -1:     adr     r12, __v7_setup_stack           @ the local stack
> -       stmia   r12, {r0-r5, lr}                @ v7_invalidate_l1 touches r0-r6
> +1:     adr     r0, __v7_setup_stack_ptr
> +       ldr     r12, [r0]
> +       add     r12, r12, r0                    @ the local stack
> +       stmia   r12, {r1-r6, lr}                @ v7_invalidate_l1 touches r0-r6
>         bl      v7_invalidate_l1
> -       ldmia   r12, {r0-r5, lr}
> +       ldmia   r12, {r1-r6, lr}
>  #ifdef CONFIG_SMP
>         ALT_SMP(mrc     p15, 0, r0, c1, c0, 1)
>         ALT_UP(mov      r0, #(1 << 6))          @ fake it for UP

[snip]

> @@ -480,11 +484,16 @@ __errata_finish:
>         orr     r0, r0, r6                      @ set them
>   THUMB(        orr     r0, r0, #1 << 30        )       @ Thumb exceptions
>         ret     lr                              @ return to head.S:__ret
> +
> +       .align  2
> +__v7_setup_stack_ptr:
> +       .word   __v7_setup_stack - .
>  ENDPROC(__v7_setup)

Thanks for your take on this. I did a couple of local implementations
before submitting, and one of the issues I ran into was the need to
get rid of PAGE_OFFSET due to the code running without MMU enabled. I
suppose that is taken care of the "__v7_setup_stack - ." calculation
above?

Cheers,

/ magnus
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Nicolas Pitre Nov. 18, 2015, 1:45 p.m. UTC | #2 
On Wed, 18 Nov 2015, Magnus Damm wrote:

> Hi Nicolas,
> 
> On Wed, Nov 18, 2015 at 12:58 PM, Nicolas Pitre <nico@fluxnic.net> wrote:
> > On Tue, 17 Nov 2015, Chris Brandt wrote:
> >
> >> I think this one is more of a coding issue.
> >> These were the attempts to fix the temporary stack issue:
> >>
> >> My first patch:
> >> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-July/357106.html
> >>
> >> Magnus's try:
> >> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-November/383394.html
> >
> > Here's my proposal:
> >
> > diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> > index de2b246fed..2d0ac32320 100644
> > --- a/arch/arm/mm/proc-v7.S
> > +++ b/arch/arm/mm/proc-v7.S
> > @@ -274,10 +274,12 @@ __v7_ca15mp_setup:
> >  __v7_b15mp_setup:
> >  __v7_ca17mp_setup:
> >         mov     r10, #0
> > -1:     adr     r12, __v7_setup_stack           @ the local stack
> > -       stmia   r12, {r0-r5, lr}                @ v7_invalidate_l1 touches r0-r6
> > +1:     adr     r0, __v7_setup_stack_ptr
> > +       ldr     r12, [r0]
> > +       add     r12, r12, r0                    @ the local stack
> > +       stmia   r12, {r1-r6, lr}                @ v7_invalidate_l1 touches r0-r6
> >         bl      v7_invalidate_l1
> > -       ldmia   r12, {r0-r5, lr}
> > +       ldmia   r12, {r1-r6, lr}
> >  #ifdef CONFIG_SMP
> >         ALT_SMP(mrc     p15, 0, r0, c1, c0, 1)
> >         ALT_UP(mov      r0, #(1 << 6))          @ fake it for UP
> 
> [snip]
> 
> > @@ -480,11 +484,16 @@ __errata_finish:
> >         orr     r0, r0, r6                      @ set them
> >   THUMB(        orr     r0, r0, #1 << 30        )       @ Thumb exceptions
> >         ret     lr                              @ return to head.S:__ret
> > +
> > +       .align  2
> > +__v7_setup_stack_ptr:
> > +       .word   __v7_setup_stack - .
> >  ENDPROC(__v7_setup)
> 
> Thanks for your take on this. I did a couple of local implementations
> before submitting, and one of the issues I ran into was the need to
> get rid of PAGE_OFFSET due to the code running without MMU enabled. I
> suppose that is taken care of the "__v7_setup_stack - ." calculation
> above?

Yes.  That provides the offset from __v7_setup_stack_ptr to reach 
__v7_setup_stack. And __v7_setup_stack_ptr is obtained with adr which is 
relative to the current pc. So this works whether or not the MMU is 
enabled.


Nicolas
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diff mbox

Patch

diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index de2b246fed..2d0ac32320 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -274,10 +274,12 @@  __v7_ca15mp_setup:
 __v7_b15mp_setup:
 __v7_ca17mp_setup:
 	mov	r10, #0
-1:	adr	r12, __v7_setup_stack		@ the local stack
-	stmia	r12, {r0-r5, lr}		@ v7_invalidate_l1 touches r0-r6
+1:	adr	r0, __v7_setup_stack_ptr
+	ldr	r12, [r0]
+	add	r12, r12, r0			@ the local stack
+	stmia	r12, {r1-r6, lr}		@ v7_invalidate_l1 touches r0-r6
 	bl      v7_invalidate_l1
-	ldmia	r12, {r0-r5, lr}
+	ldmia	r12, {r1-r6, lr}
 #ifdef CONFIG_SMP
 	ALT_SMP(mrc	p15, 0, r0, c1, c0, 1)
 	ALT_UP(mov	r0, #(1 << 6))		@ fake it for UP
@@ -415,10 +417,12 @@  __v7_pj4b_setup:
 #endif /* CONFIG_CPU_PJ4B */
 
 __v7_setup:
-	adr	r12, __v7_setup_stack		@ the local stack
-	stmia	r12, {r0-r5, lr}		@ v7_invalidate_l1 touches r0-r6
+	adr	r0, __v7_setup_stack_ptr
+	ldr	r12, [r0]
+	add	r12, r12, r0			@ the local stack
+	stmia	r12, {r1-r6, lr}		@ v7_invalidate_l1 touches r0-r6
 	bl      v7_invalidate_l1
-	ldmia	r12, {r0-r5, lr}
+	ldmia	r12, {r1-r6, lr}
 
 __v7_setup_cont:
 	and	r0, r9, #0xff000000		@ ARM?
@@ -480,11 +484,16 @@  __errata_finish:
 	orr	r0, r0, r6			@ set them
  THUMB(	orr	r0, r0, #1 << 30	)	@ Thumb exceptions
 	ret	lr				@ return to head.S:__ret
+
+	.align	2
+__v7_setup_stack_ptr:
+	.word	__v7_setup_stack - .
 ENDPROC(__v7_setup)
 
+	.bss
 	.align	2
 __v7_setup_stack:
-	.space	4 * 7				@ 12 registers
+	.space	4 * 7				@ 7 registers
 
 	__INITDATA
 
diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S
index 67d9209077..8cd465927a 100644
--- a/arch/arm/mm/proc-v7m.S
+++ b/arch/arm/mm/proc-v7m.S
@@ -123,10 +123,12 @@  __v7m_setup:
 	ret	lr
 ENDPROC(__v7m_setup)
 
+	.pushsection .bss
 	.align 2
 __v7m_setup_stack:
 	.space	4 * 8				@ 8 registers
 __v7m_setup_stack_top:
+	.previous
 
 	define_processor_functions v7m, dabort=nommu_early_abort, pabort=legacy_pabort, nommu=1