| Message ID | 1454335736-10084-1-git-send-email-chris.brandt@renesas.com |
|---|---|
| State | New |
| Headers | show |
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 > > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/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. -- 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. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kerneldiff --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
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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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