[RFC 2/3] arm: mm: Define set_memory_* functions for ARM

[Will Deacon]

On Wed, Jun 12, 2013 at 06:23:29PM +0100, Laura Abbott wrote:
> Other architectures define various set_memory functions to allow
> attributes to be changed (e.g. set_memory_x, set_memory_rw, etc.)
> Currently, these functions are missing on ARM. Define these in an
> appropriate manner for ARM.
> 
> Signed-off-by: Laura Abbott <lauraa at codeaurora.org>
> ---
>  arch/arm/include/asm/cacheflush.h |    5 ++
>  arch/arm/mm/mmu.c                 |   86 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 91 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/include/asm/cacheflush.h b/arch/arm/include/asm/cacheflush.h
> index bff7138..55ed26b 100644
> --- a/arch/arm/include/asm/cacheflush.h
> +++ b/arch/arm/include/asm/cacheflush.h
> @@ -438,4 +438,9 @@ static inline void __sync_cache_range_r(volatile void *p, size_t size)
>  #define sync_cache_w(ptr) __sync_cache_range_w(ptr, sizeof *(ptr))
>  #define sync_cache_r(ptr) __sync_cache_range_r(ptr, sizeof *(ptr))
>  
> +int set_memory_ro(unsigned long addr, int numpages);
> +int set_memory_rw(unsigned long addr, int numpages);
> +int set_memory_x(unsigned long addr, int numpages);
> +int set_memory_nx(unsigned long addr, int numpages);

This seems like a pretty clunky interface with a horribly generic name, but
that seems to be what x86 and s390 are using. I wonder if there would be any
interest in tidying it up a bit? It really looks like something that is
x86-specific but has started to grow users in core code (set_memory_4k?!).

Will