* [PATCH] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL
@ 2016-01-29 22:11 Chris Brandt
2016-01-31 23:20 ` Arnd Bergmann
2016-02-01 14:08 ` [PATCH v2] " Chris Brandt
0 siblings, 2 replies; 8+ messages in thread
From: Chris Brandt @ 2016-01-29 22:11 UTC (permalink / raw)
To: linux-arm-kernel
When XIP_KERNEL is enabled, the virt to phys address translation for RAM
is not the same as the virt to phys address translation for .text.
The only way to know where physical RAM is located is to use
PLAT_PHYS_OFFSET.
The MACRO will be useful for other places where there is a similar problem.
Written by Nicolas Pitre
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
---
arch/arm/include/asm/memory.h | 8 ++++++++
arch/arm/mm/proc-v7.S | 2 +-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index c79b57b..7dd2ab5 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -134,6 +134,14 @@
*/
#define PLAT_PHYS_OFFSET UL(CONFIG_PHYS_OFFSET)
+#ifdef CONFIG_XIP_KERNEL
+#define PHYS_OFFSET_FIXUP \
+ ( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
+ PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
+#else
+#define PHYS_OFFSET_FIXUP 0
+#endif
+
#ifndef __ASSEMBLY__
/*
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 0f92d57..1595fb2 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -487,7 +487,7 @@ __errata_finish:
.align 2
__v7_setup_stack_ptr:
- .word __v7_setup_stack - .
+ .word __v7_setup_stack - . + PHYS_OFFSET_FIXUP
ENDPROC(__v7_setup)
.bss
--
1.9.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL
2016-01-29 22:11 [PATCH] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL Chris Brandt
@ 2016-01-31 23:20 ` Arnd Bergmann
2016-02-01 14:08 ` Chris Brandt
2016-02-01 14:08 ` [PATCH v2] " Chris Brandt
1 sibling, 1 reply; 8+ messages in thread
From: Arnd Bergmann @ 2016-01-31 23:20 UTC (permalink / raw)
To: linux-arm-kernel
On Friday 29 January 2016 17:11:14 Chris Brandt wrote:
> When XIP_KERNEL is enabled, the virt to phys address translation for RAM
> is not the same as the virt to phys address translation for .text.
> The only way to know where physical RAM is located is to use
> PLAT_PHYS_OFFSET.
> The MACRO will be useful for other places where there is a similar problem.
>
> Written by Nicolas Pitre
>
> Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
> Signed-off-by: Nicolas Pitre <nico@linaro.org>
>
I have not verified the contents of the patch, but have two comments on the
submission form:
- replace the 'Written by Nicolas Pitre' sentence with a 'From: Nicolas
Pitre <nico@linaro.org>' line as the first line of the changelog text,
followed by an empty line, so that 'git am' can set the correct author
field.
- put your Signed-off-by: line after Nico's for correct documentation
of who sent what.
Arnd
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL
2016-01-31 23:20 ` Arnd Bergmann
@ 2016-02-01 14:08 ` Chris Brandt
0 siblings, 0 replies; 8+ messages in thread
From: Chris Brandt @ 2016-02-01 14:08 UTC (permalink / raw)
To: linux-arm-kernel
> I have not verified the contents of the patch, but have two comments on the submission form:
>
> - replace the 'Written by Nicolas Pitre' sentence with a 'From: Nicolas
> Pitre <nico@linaro.org>' line as the first line of the changelog text,
> followed by an empty line, so that 'git am' can set the correct author
> field.
>
> - put your Signed-off-by: line after Nico's for correct documentation
> of who sent what.
>
> Arnd
OK, thank you. That makes more sense.
Chris
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL
2016-01-29 22:11 [PATCH] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL Chris Brandt
2016-01-31 23:20 ` Arnd Bergmann
@ 2016-02-01 14:08 ` Chris Brandt
2016-02-01 21:15 ` Nicolas Pitre
1 sibling, 1 reply; 8+ messages in thread
From: Chris Brandt @ 2016-02-01 14:08 UTC (permalink / raw)
To: linux-arm-kernel
From: Nicolas Pitre <nico@linaro.org>
When XIP_KERNEL is enabled, the virt to phys address translation for RAM
is not the same as the virt to phys address translation for .text.
The only way to know where physical RAM is located is to use
PLAT_PHYS_OFFSET.
The MACRO will be useful for other places where there is a similar problem.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
---
v2:
* Fixed Signed-off to show correct author
---
arch/arm/include/asm/memory.h | 8 ++++++++
arch/arm/mm/proc-v7.S | 2 +-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index c79b57b..7dd2ab5 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -134,6 +134,14 @@
*/
#define PLAT_PHYS_OFFSET UL(CONFIG_PHYS_OFFSET)
+#ifdef CONFIG_XIP_KERNEL
+#define PHYS_OFFSET_FIXUP \
+ ( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
+ PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
+#else
+#define PHYS_OFFSET_FIXUP 0
+#endif
+
#ifndef __ASSEMBLY__
/*
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 0f92d57..1595fb2 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -487,7 +487,7 @@ __errata_finish:
.align 2
__v7_setup_stack_ptr:
- .word __v7_setup_stack - .
+ .word __v7_setup_stack - . + PHYS_OFFSET_FIXUP
ENDPROC(__v7_setup)
.bss
--
1.9.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL
2016-02-01 14:08 ` [PATCH v2] " Chris Brandt
@ 2016-02-01 21:15 ` Nicolas Pitre
2016-02-16 17:32 ` Russell King - ARM Linux
0 siblings, 1 reply; 8+ messages in thread
From: Nicolas Pitre @ 2016-02-01 21:15 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, 1 Feb 2016, Chris Brandt wrote:
> From: Nicolas Pitre <nico@linaro.org>
>
> When XIP_KERNEL is enabled, the virt to phys address translation for RAM
> is not the same as the virt to phys address translation for .text.
> The only way to know where physical RAM is located is to use
> PLAT_PHYS_OFFSET.
> The MACRO will be useful for other places where there is a similar problem.
>
> Signed-off-by: Nicolas Pitre <nico@linaro.org>
> Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Looks fine. You may submit it here:
http://www.arm.linux.org.uk/developer/patches/
> ---
> v2:
> * Fixed Signed-off to show correct author
> ---
> arch/arm/include/asm/memory.h | 8 ++++++++
> arch/arm/mm/proc-v7.S | 2 +-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index c79b57b..7dd2ab5 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -134,6 +134,14 @@
> */
> #define PLAT_PHYS_OFFSET UL(CONFIG_PHYS_OFFSET)
>
> +#ifdef CONFIG_XIP_KERNEL
> +#define PHYS_OFFSET_FIXUP \
> + ( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
> + PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
> +#else
> +#define PHYS_OFFSET_FIXUP 0
> +#endif
> +
> #ifndef __ASSEMBLY__
>
> /*
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> index 0f92d57..1595fb2 100644
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -487,7 +487,7 @@ __errata_finish:
>
> .align 2
> __v7_setup_stack_ptr:
> - .word __v7_setup_stack - .
> + .word __v7_setup_stack - . + PHYS_OFFSET_FIXUP
> ENDPROC(__v7_setup)
>
> .bss
> --
> 1.9.1
>
>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL
2016-02-01 21:15 ` Nicolas Pitre
@ 2016-02-16 17:32 ` Russell King - ARM Linux
2016-02-16 18:53 ` Chris Brandt
2016-02-16 20:16 ` Nicolas Pitre
0 siblings, 2 replies; 8+ messages in thread
From: Russell King - ARM Linux @ 2016-02-16 17:32 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Feb 01, 2016 at 04:15:38PM -0500, Nicolas Pitre wrote:
> On Mon, 1 Feb 2016, Chris Brandt wrote:
>
> > From: Nicolas Pitre <nico@linaro.org>
> >
> > When XIP_KERNEL is enabled, the virt to phys address translation for RAM
> > is not the same as the virt to phys address translation for .text.
> > The only way to know where physical RAM is located is to use
> > PLAT_PHYS_OFFSET.
> > The MACRO will be useful for other places where there is a similar problem.
> >
> > Signed-off-by: Nicolas Pitre <nico@linaro.org>
> > Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
>
> Looks fine. You may submit it here:
...
> > +#ifdef CONFIG_XIP_KERNEL
> > +#define PHYS_OFFSET_FIXUP \
> > + ( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
> > + PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
> > +#else
> > +#define PHYS_OFFSET_FIXUP 0
> > +#endif
> > +
> > #ifndef __ASSEMBLY__
> >
> > /*
> > diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> > index 0f92d57..1595fb2 100644
> > --- a/arch/arm/mm/proc-v7.S
> > +++ b/arch/arm/mm/proc-v7.S
> > @@ -487,7 +487,7 @@ __errata_finish:
> >
> > .align 2
> > __v7_setup_stack_ptr:
> > - .word __v7_setup_stack - .
> > + .word __v7_setup_stack - . + PHYS_OFFSET_FIXUP
I keep looking at this patch, and I really find that I detest this
PHYS_OFFSET_FIXUP thing - it's really not obvious what's going on
here. It's taken a _long_ time to work this out, which _really_
isn't good going forward.
Let's instead change things to make it much more obvious - see the
patch below.
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index ebdaaf7dd19f..593e5613184d 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -135,11 +135,18 @@
#define PLAT_PHYS_OFFSET UL(CONFIG_PHYS_OFFSET)
#ifdef CONFIG_XIP_KERNEL
-#define PHYS_OFFSET_FIXUP \
- ( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
- PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
+/*
+ * When referencing data in RAM from the XIP region in a relative manner
+ * with the MMU off, we need the relative offset between the two physical
+ * addresses. The macro below achieves this, which is:
+ * __pa(v_data) - __xip_pa(v_text)
+ */
+#define PHYS_RELATIVE(v_data, v_text) \
+ (((v_data) - PAGE_OFFSET + PLAT_PHYS_OFFSET) - \
+ ((v_text) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) + \
+ CONFIG_XIP_PHYS_ADDR))
#else
-#define PHYS_OFFSET_FIXUP 0
+#define PHYS_RELATIVE(v_data, v_text) (v_data) - (v_text)
#endif
#ifndef __ASSEMBLY__
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 1595fb29ec12..0f8963a7e7d9 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -487,7 +487,7 @@ __errata_finish:
.align 2
__v7_setup_stack_ptr:
- .word __v7_setup_stack - . + PHYS_OFFSET_FIXUP
+ .word PHYS_RELATIVE(__v7_setup_stack, .)
ENDPROC(__v7_setup)
.bss
--
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL
2016-02-16 17:32 ` Russell King - ARM Linux
@ 2016-02-16 18:53 ` Chris Brandt
2016-02-16 20:16 ` Nicolas Pitre
1 sibling, 0 replies; 8+ messages in thread
From: Chris Brandt @ 2016-02-16 18:53 UTC (permalink / raw)
To: linux-arm-kernel
On 16 Feb 2016, Russell King - ARM Linux wrote:
> I keep looking at this patch, and I really find that I detest this
> PHYS_OFFSET_FIXUP thing - it's really not obvious what's going on here.
> It's taken a _long_ time to work this out, which _really_ isn't good
> going forward.
>
> Let's instead change things to make it much more obvious - see the
> patch below.
>
>
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index ebdaaf7dd19f..593e5613184d 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -135,11 +135,18 @@
> #define PLAT_PHYS_OFFSET UL(CONFIG_PHYS_OFFSET)
>
> #ifdef CONFIG_XIP_KERNEL
> -#define PHYS_OFFSET_FIXUP \
> - ( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
> - PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
> +/*
> + * When referencing data in RAM from the XIP region in a relative
> +manner
> + * with the MMU off, we need the relative offset between the two
> +physical
> + * addresses. The macro below achieves this, which is:
> + * __pa(v_data) - __xip_pa(v_text)
> + */
> +#define PHYS_RELATIVE(v_data, v_text) \
> + (((v_data) - PAGE_OFFSET + PLAT_PHYS_OFFSET) - \
> + ((v_text) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) + \
> + CONFIG_XIP_PHYS_ADDR))
> #else
> -#define PHYS_OFFSET_FIXUP 0
> +#define PHYS_RELATIVE(v_data, v_text) (v_data) - (v_text)
> #endif
>
> #ifndef __ASSEMBLY__
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S index
> 1595fb29ec12..0f8963a7e7d9 100644
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -487,7 +487,7 @@ __errata_finish:
>
> .align 2
> __v7_setup_stack_ptr:
> - .word __v7_setup_stack - . + PHYS_OFFSET_FIXUP
> + .word PHYS_RELATIVE(__v7_setup_stack, .)
> ENDPROC(__v7_setup)
>
> .bss
>
This works fine for me (comes up with the same number either way).
Just tested it with my XIP_KERNEL ARMv7 system.
Chris
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL
2016-02-16 17:32 ` Russell King - ARM Linux
2016-02-16 18:53 ` Chris Brandt
@ 2016-02-16 20:16 ` Nicolas Pitre
1 sibling, 0 replies; 8+ messages in thread
From: Nicolas Pitre @ 2016-02-16 20:16 UTC (permalink / raw)
To: linux-arm-kernel
On Tue, 16 Feb 2016, Russell King - ARM Linux wrote:
> > > index 0f92d57..1595fb2 100644
> > > --- a/arch/arm/mm/proc-v7.S
> > > +++ b/arch/arm/mm/proc-v7.S
> > > @@ -487,7 +487,7 @@ __errata_finish:
> > >
> > > .align 2
> > > __v7_setup_stack_ptr:
> > > - .word __v7_setup_stack - .
> > > + .word __v7_setup_stack - . + PHYS_OFFSET_FIXUP
>
> I keep looking at this patch, and I really find that I detest this
> PHYS_OFFSET_FIXUP thing - it's really not obvious what's going on
> here. It's taken a _long_ time to work this out, which _really_
> isn't good going forward.
>
> Let's instead change things to make it much more obvious - see the
> patch below.
>
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index ebdaaf7dd19f..593e5613184d 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -135,11 +135,18 @@
> #define PLAT_PHYS_OFFSET UL(CONFIG_PHYS_OFFSET)
>
> #ifdef CONFIG_XIP_KERNEL
> -#define PHYS_OFFSET_FIXUP \
> - ( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
> - PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
> +/*
> + * When referencing data in RAM from the XIP region in a relative manner
> + * with the MMU off, we need the relative offset between the two physical
> + * addresses. The macro below achieves this, which is:
> + * __pa(v_data) - __xip_pa(v_text)
> + */
> +#define PHYS_RELATIVE(v_data, v_text) \
> + (((v_data) - PAGE_OFFSET + PLAT_PHYS_OFFSET) - \
> + ((v_text) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) + \
> + CONFIG_XIP_PHYS_ADDR))
Sure, this is less opaque.
> #else
> -#define PHYS_OFFSET_FIXUP 0
> +#define PHYS_RELATIVE(v_data, v_text) (v_data) - (v_text)
You should probably surround the whole thing with parents in case this
gets used in some other computations.
Nicolas
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2016-02-16 20:16 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-01-29 22:11 [PATCH] ARM: proc-v7.S: Adjust stack address when XIP_KERNEL Chris Brandt
2016-01-31 23:20 ` Arnd Bergmann
2016-02-01 14:08 ` Chris Brandt
2016-02-01 14:08 ` [PATCH v2] " Chris Brandt
2016-02-01 21:15 ` Nicolas Pitre
2016-02-16 17:32 ` Russell King - ARM Linux
2016-02-16 18:53 ` Chris Brandt
2016-02-16 20:16 ` Nicolas Pitre
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