| Message ID | 1360365467-25056-3-git-send-email-ben.dooks@codethink.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 8 Feb 2013, Ben Dooks wrote: > If we are booting in LE and compiled for BE8, then change the processor > state in the head code. Since the instruction stream is always LE, we > do not need to do anything special. > > Also ensure that the secondary processors are started in the same mode. > > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> > --- > arch/arm/boot/compressed/head.S | 3 +++ > arch/arm/kernel/head.S | 3 +++ > 2 files changed, 6 insertions(+) > > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index fe4d9c3..39940a7 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -134,6 +134,9 @@ start: > .word _edata @ zImage end address > THUMB( .thumb ) > 1: > +#ifdef CONFIG_CPU_BE8_BOOT_LE > + setend be @ go BE-8 if we booted LE / no-op if already BE-8 > +#endif > mrs r9, cpsr > #ifdef CONFIG_ARM_VIRT_EXT > bl __hyp_stub_install @ get into SVC mode, reversibly > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > index 486a15a..f1ab279 100644 > --- a/arch/arm/kernel/head.S > +++ b/arch/arm/kernel/head.S > @@ -333,6 +333,9 @@ ENTRY(secondary_startup) > * the processor type - there is no need to check the machine type > * as it has already been validated by the primary processor. > */ > +#ifdef CONFIG_CPU_BE8_BOOT_LE > + setend be @ if system starts LE, go to BE-8 > +#endif > #ifdef CONFIG_ARM_VIRT_EXT > bl __hyp_stub_install_secondary > #endif For consistency, you should add a setend on the primary CPU entry path in kernel/head.S and not rely on the decompressor. Some people don't use the compressed image. Nicolas
On 09/02/2013 03:33, Nicolas Pitre wrote: > On Fri, 8 Feb 2013, Ben Dooks wrote: > >> If we are booting in LE and compiled for BE8, then change the >> processor >> state in the head code. Since the instruction stream is always LE, >> we >> do not need to do anything special. >> >> Also ensure that the secondary processors are started in the same >> mode. >> >> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> >> --- >> arch/arm/boot/compressed/head.S | 3 +++ >> arch/arm/kernel/head.S | 3 +++ >> 2 files changed, 6 insertions(+) >> >> diff --git a/arch/arm/boot/compressed/head.S >> b/arch/arm/boot/compressed/head.S >> index fe4d9c3..39940a7 100644 >> --- a/arch/arm/boot/compressed/head.S >> +++ b/arch/arm/boot/compressed/head.S >> @@ -134,6 +134,9 @@ start: >> .word _edata @ zImage end address >> THUMB( .thumb ) >> 1: >> +#ifdef CONFIG_CPU_BE8_BOOT_LE >> + setend be @ go BE-8 if we booted LE / no-op if already BE-8 >> +#endif >> mrs r9, cpsr >> #ifdef CONFIG_ARM_VIRT_EXT >> bl __hyp_stub_install @ get into SVC mode, reversibly >> diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S >> index 486a15a..f1ab279 100644 >> --- a/arch/arm/kernel/head.S >> +++ b/arch/arm/kernel/head.S >> @@ -333,6 +333,9 @@ ENTRY(secondary_startup) >> * the processor type - there is no need to check the machine type >> * as it has already been validated by the primary processor. >> */ >> +#ifdef CONFIG_CPU_BE8_BOOT_LE >> + setend be @ if system starts LE, go to BE-8 >> +#endif >> #ifdef CONFIG_ARM_VIRT_EXT >> bl __hyp_stub_install_secondary >> #endif > > For consistency, you should add a setend on the primary CPU entry > path > in kernel/head.S and not rely on the decompressor. Some people don't > use the compressed image. Thank you for spotting this, will sort it out for the next round.
On 02/08/2013 05:17 PM, Ben Dooks wrote: > If we are booting in LE and compiled for BE8, then change the processor > state in the head code. Since the instruction stream is always LE, we > do not need to do anything special. > > Also ensure that the secondary processors are started in the same mode. > > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> > --- > arch/arm/boot/compressed/head.S | 3 +++ > arch/arm/kernel/head.S | 3 +++ > 2 files changed, 6 insertions(+) > > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index fe4d9c3..39940a7 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -134,6 +134,9 @@ start: > .word _edata @ zImage end address > THUMB( .thumb ) > 1: > +#ifdef CONFIG_CPU_BE8_BOOT_LE Can't you use CONFIG_CPU_BIG_ENDIAN here rather than a new config option? > + setend be @ go BE-8 if we booted LE / no-op if already BE-8 > +#endif > mrs r9, cpsr > #ifdef CONFIG_ARM_VIRT_EXT > bl __hyp_stub_install @ get into SVC mode, reversibly > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > index 486a15a..f1ab279 100644 > --- a/arch/arm/kernel/head.S > +++ b/arch/arm/kernel/head.S > @@ -333,6 +333,9 @@ ENTRY(secondary_startup) > * the processor type - there is no need to check the machine type > * as it has already been validated by the primary processor. > */ > +#ifdef CONFIG_CPU_BE8_BOOT_LE > + setend be @ if system starts LE, go to BE-8 > +#endif > #ifdef CONFIG_ARM_VIRT_EXT > bl __hyp_stub_install_secondary > #endif >
On 09/02/2013 21:38, Rob Herring wrote: > On 02/08/2013 05:17 PM, Ben Dooks wrote: >> If we are booting in LE and compiled for BE8, then change the >> processor >> state in the head code. Since the instruction stream is always LE, >> we >> do not need to do anything special. >> >> Also ensure that the secondary processors are started in the same >> mode. >> >> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> >> --- >> arch/arm/boot/compressed/head.S | 3 +++ >> arch/arm/kernel/head.S | 3 +++ >> 2 files changed, 6 insertions(+) >> >> diff --git a/arch/arm/boot/compressed/head.S >> b/arch/arm/boot/compressed/head.S >> index fe4d9c3..39940a7 100644 >> --- a/arch/arm/boot/compressed/head.S >> +++ b/arch/arm/boot/compressed/head.S >> @@ -134,6 +134,9 @@ start: >> .word _edata @ zImage end address >> THUMB( .thumb ) >> 1: >> +#ifdef CONFIG_CPU_BE8_BOOT_LE > > Can't you use CONFIG_CPU_BIG_ENDIAN here rather than a new config > option? For this, we can probably do this as it is a no-op, however other parts of the patch series do need this to allow it to boot from a little endian booting environment.
On 09/02/13 21:38, Rob Herring wrote: > On 02/08/2013 05:17 PM, Ben Dooks wrote: >> If we are booting in LE and compiled for BE8, then change the processor >> state in the head code. Since the instruction stream is always LE, we >> do not need to do anything special. >> >> Also ensure that the secondary processors are started in the same mode. >> >> Signed-off-by: Ben Dooks<ben.dooks@codethink.co.uk> >> --- >> arch/arm/boot/compressed/head.S | 3 +++ >> arch/arm/kernel/head.S | 3 +++ >> 2 files changed, 6 insertions(+) >> >> diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S >> index fe4d9c3..39940a7 100644 >> --- a/arch/arm/boot/compressed/head.S >> +++ b/arch/arm/boot/compressed/head.S >> @@ -134,6 +134,9 @@ start: >> .word _edata @ zImage end address >> THUMB( .thumb ) >> 1: >> +#ifdef CONFIG_CPU_BE8_BOOT_LE > > Can't you use CONFIG_CPU_BIG_ENDIAN here rather than a new config option? Actually, no as not all big endian CPUs will be BE8 (which should guarnatee us the 'setend be' to be available) as we could still build for BE32 systems where we would not want this. I was considering doing the following: ARM_BE8( setend be ) What do people think? It is a waste of 16 bytes if our system is already in BE8 mode, but is going to look cleaner than ARM_BE8_LEBOOT( setend be ) Any thoughts?
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index fe4d9c3..39940a7 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -134,6 +134,9 @@ start: .word _edata @ zImage end address THUMB( .thumb ) 1: +#ifdef CONFIG_CPU_BE8_BOOT_LE + setend be @ go BE-8 if we booted LE / no-op if already BE-8 +#endif mrs r9, cpsr #ifdef CONFIG_ARM_VIRT_EXT bl __hyp_stub_install @ get into SVC mode, reversibly diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 486a15a..f1ab279 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -333,6 +333,9 @@ ENTRY(secondary_startup) * the processor type - there is no need to check the machine type * as it has already been validated by the primary processor. */ +#ifdef CONFIG_CPU_BE8_BOOT_LE + setend be @ if system starts LE, go to BE-8 +#endif #ifdef CONFIG_ARM_VIRT_EXT bl __hyp_stub_install_secondary #endif
If we are booting in LE and compiled for BE8, then change the processor state in the head code. Since the instruction stream is always LE, we do not need to do anything special. Also ensure that the secondary processors are started in the same mode. Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> --- arch/arm/boot/compressed/head.S | 3 +++ arch/arm/kernel/head.S | 3 +++ 2 files changed, 6 insertions(+)