[PATCH v8 0/3] Cortex-M3 series once more

[Jonathan Austin]

Hi Uwe,

On 17/01/13 08:59, Uwe Kleine-König wrote:
> Based on Jonny's comments I changed a few more details. The diff to v7
> can be found below after the diffstat. These are:
>
>   - describe why a #define for cr_alignment is OK in both the
>     commit log and a comment in the header file
>   - a work around for errata 752419 that newer gcc warns about
>   - add a few more comments for better readability
>   - a whitespace fix
>

Thanks for making these changes.

As you will see I've now reviewed the other to patches in the series and 
there are quite a few smaller things in there...

> I think the updates are minor enough to still allow the patches to go
> into v3.9-rc1. Russell, what do you think? You can pull them from
>

I think we should assess this once you've responded to the review of the 
other two patches.

As far as merging these patches go, as well as the review comments on 
each patch, I still have the same reservations that I raised around v6 
of these about the fact that NVIC support and a platform are missing. 
This means there's no way to actually *use* the V7M code. I understand 
that you're prepared to commit to getting this in shape and ready to be 
merged once the base support goes in - is that right?

What sort of time-frame do you expect to be able to do this in?

I'm happy to help review/work on NVIC support if you need more eyes (and 
perhaps even minds!) on the problem, as well as test on the efm32 board.

> 	git://git.pengutronix.de/git/ukl/linux.git for-next
>
> still based on v3.7-rc1 + your commit "ARM: fix oops on initial entry to
> userspace with Thumb2 kernels".

Does it trivially re-base to v3.8-rc4?

>
> Catalin Marinas (1):
>    Cortex-M3: Add base support for Cortex-M3
>
> Uwe Kleine-König (2):
>    ARM: make cr_alignment read-only #ifndef CONFIG_CPU_CP15
>    Cortex-M3: Add support for exception handling
>
>   arch/arm/include/asm/assembler.h   |   13 ++-
>   arch/arm/include/asm/cp15.h        |   16 +++-
>   arch/arm/include/asm/cputype.h     |    3 +
>   arch/arm/include/asm/glue-cache.h  |   25 ++++++
>   arch/arm/include/asm/glue-df.h     |    8 ++
>   arch/arm/include/asm/glue-proc.h   |    9 ++
>   arch/arm/include/asm/irqflags.h    |   22 +++--
>   arch/arm/include/asm/processor.h   |    7 ++
>   arch/arm/include/asm/ptrace.h      |    8 ++
>   arch/arm/include/asm/system_info.h |    1 +
>   arch/arm/include/uapi/asm/ptrace.h |   36 ++++++--
>   arch/arm/kernel/asm-offsets.c      |    3 +
>   arch/arm/kernel/entry-common.S     |    4 +
>   arch/arm/kernel/entry-header.S     |  148 +++++++++++++++++++++++++++++++++
>   arch/arm/kernel/entry-v7m.S        |  134 ++++++++++++++++++++++++++++++
>   arch/arm/kernel/head-common.S      |    9 +-
>   arch/arm/kernel/head-nommu.S       |    9 +-
>   arch/arm/kernel/process.c          |    4 +
>   arch/arm/kernel/ptrace.c           |    3 +
>   arch/arm/kernel/setup.c            |   13 ++-
>   arch/arm/kernel/traps.c            |    2 +
>   arch/arm/mm/alignment.c            |    2 +
>   arch/arm/mm/mmu.c                  |   17 ++++
>   arch/arm/mm/nommu.c                |    2 +
>   arch/arm/mm/proc-v7m.S             |  161 ++++++++++++++++++++++++++++++++++++
>   25 files changed, 637 insertions(+), 22 deletions(-)
>   create mode 100644 arch/arm/kernel/entry-v7m.S
>   create mode 100644 arch/arm/mm/proc-v7m.S
>
> The incremental changes since v7 are:
>
> diff --git a/arch/arm/include/asm/cp15.h b/arch/arm/include/asm/cp15.h
> index d814435..1f3262e 100644
> --- a/arch/arm/include/asm/cp15.h
> +++ b/arch/arm/include/asm/cp15.h
> @@ -86,6 +86,11 @@ static inline void set_copro_access(unsigned int val)
>
>   #else /* ifdef CONFIG_CPU_CP15 */
>
> +/*
> + * cr_alignment and cr_no_alignment are tightly coupled to cp15 (at least in the
> + * minds of the developers). Yielding 0 for machines without a cp15 (and making
> + * it read-only) is fine for most cases and saves quite some #ifdeffery.
> + */
>   #define cr_no_alignment	UL(0)
>   #define cr_alignment	UL(0)
>
> diff --git a/arch/arm/include/uapi/asm/ptrace.h b/arch/arm/include/uapi/asm/ptrace.h
> index 2ae7d1b..d3be66e 100644
> --- a/arch/arm/include/uapi/asm/ptrace.h
> +++ b/arch/arm/include/uapi/asm/ptrace.h
> @@ -144,7 +144,7 @@ struct pt_regs {
>   #define ARM_r1		uregs[1]
>   #define ARM_r0		uregs[0]
>   #define ARM_ORIG_r0	uregs[17]
> -#define ARM_EXC_RET    uregs[18]
> +#define ARM_EXC_RET	uregs[18]
>
>   /*
>    * The size of the user-visible VFP state as seen by PTRACE_GET/SETVFPREGS
> diff --git a/arch/arm/kernel/entry-v7m.S b/arch/arm/kernel/entry-v7m.S
> index a0991dc..842394c 100644
> --- a/arch/arm/kernel/entry-v7m.S
> +++ b/arch/arm/kernel/entry-v7m.S
> @@ -102,8 +102,8 @@ ENTRY(__switch_to)
>   	mov	ip, r4
>   	mov	r0, r5
>   	ldmia	ip!, {r4 - r11}		@ Load all regs saved previously
> -	ldr	sp, [ip], #4
> -	ldr	pc, [ip]
> +	ldr	sp, [ip]
> +	ldr	pc, [ip, #4]!
>   	.fnend
>   ENDPROC(__switch_to)
>
> diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S
> index 2f560c5..5b391a6 100644
> --- a/arch/arm/kernel/head-common.S
> +++ b/arch/arm/kernel/head-common.S
> @@ -117,7 +117,7 @@ __mmap_switched_data:
>   #ifdef CONFIG_CPU_CP15
>   	.long	cr_alignment			@ r7
>   #else
> -	.long	0
> +	.long	0				@ r7
>   #endif
>   	.long	init_thread_union + THREAD_START_SP @ sp
>   	.size	__mmap_switched_data, . - __mmap_switched_data
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index b675918..92abdb8 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -196,7 +196,7 @@ void adjust_cr(unsigned long mask, unsigned long set)
>   }
>   #endif
>
> -#else
> +#else /* ifdef CONFIG_CPU_CP15 */
>
>   static int __init early_cachepolicy(char *p)
>   {
> @@ -210,7 +210,7 @@ static int __init noalign_setup(char *__unused)
>   }
>   __setup("noalign", noalign_setup);
>
> -#endif
> +#endif /* ifdef CONFIG_CPU_CP15 / else */
>
>   #define PROT_PTE_DEVICE		L_PTE_PRESENT|L_PTE_YOUNG|L_PTE_DIRTY|L_PTE_XN
>   #define PROT_SECT_DEVICE	PMD_TYPE_SECT|PMD_SECT_AP_WRITE
>