[PATCH v3 15/20] ARM: LPAE: use phys_addr_t instead of unsigned long for physical addresses

On 17 November 2010 11:18, Arnd Bergmann [off-list ref] wrote:

On Wednesday 17 November 2010, Catalin Marinas wrote:

quoted

quoted

It may make sense to mark it const volatile, as that's the most
permissive set of attributes possible (iow, it'll accept any pointer
without warning.) ?However, might be an idea to check what other
arches do.

The majority of architectures use volatile and a few add both const
and volatile.

I usually use the generic headers as reference for function prototypes
and that's just using volatile without a const (cc'ing Arnd for any
view on this).

const volatile sounds right here, I can also change the generic header
if we agree to do the same in arm.

That's what I plan to add, though it may be better to push as a
separate patch to fix compiler warnings now. I don't know when the
LPAE patches would go in.

--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h

@@ -189,7 +189,7 @@
  * translation for translating DMA addresses.  Use the driver
  * DMA support - see dma-mapping.h.
  */
-static inline phys_addr_t virt_to_phys(void *x)
+static inline phys_addr_t virt_to_phys(const volatile void *x)
 {
 	return __virt_to_phys((unsigned long)(x));
 }

-- 
Catalin