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Commit 9ab9e4fc authored by Ard Biesheuvel's avatar Ard Biesheuvel
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ARM: memremap: implement arch_memremap_wb() 



The generic memremap() falls back to using ioremap_cache() to create
MEMREMAP_WB mappings if the requested region is not already covered
by the linear mapping, unless the architecture provides an implementation
of arch_memremap_wb().

Since ioremap_cache() is not appropriate on ARM to map memory with the
same attributes used for the linear mapping, implement arch_memremap_wb()
which does exactly that. Also, relax the WARN() check to allow MT_MEMORY_RW
mappings of pfn_valid() pages.

Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
parent c269cba3

arch/arm/include/asm/io.h

+6 −0
Original line number Diff line number Diff line
@@ -392,6 +392,9 @@ void __iomem *ioremap(resource_size_t res_cookie, size_t size); 
#define ioremap ioremap

#define ioremap_nocache ioremap



/*

 * Do not use ioremap_cache for mapping memory. Use memremap instead.

 */

void __iomem *ioremap_cache(resource_size_t res_cookie, size_t size);

#define ioremap_cache ioremap_cache
@@ -408,6 +411,9 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size); 
void iounmap(volatile void __iomem *iomem_cookie);

#define iounmap iounmap



void *arch_memremap_wb(phys_addr_t phys_addr, size_t size);

#define arch_memremap_wb arch_memremap_wb



/*

 * io{read,write}{16,32}be() macros

 */

arch/arm/mm/ioremap.c

+10 −2
Original line number Diff line number Diff line
@@ -297,9 +297,10 @@ static void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn, 
	}



	/*

	 * Don't allow RAM to be mapped - this causes problems with ARMv6+

	 * Don't allow RAM to be mapped with mismatched attributes - this

	 * causes problems with ARMv6+

	 */

	if (WARN_ON(pfn_valid(pfn)))

	if (WARN_ON(pfn_valid(pfn) && mtype != MT_MEMORY_RW))

		return NULL;



	area = get_vm_area_caller(size, VM_IOREMAP, caller);
@@ -418,6 +419,13 @@ __arm_ioremap_exec(phys_addr_t phys_addr, size_t size, bool cached) 
			__builtin_return_address(0));

}



void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)

{

	return (__force void *)arch_ioremap_caller(phys_addr, size,

						   MT_MEMORY_RW,

						   __builtin_return_address(0));

}



void __iounmap(volatile void __iomem *io_addr)

{

	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);

arch/arm/mm/nommu.c

+5 −0
Original line number Diff line number Diff line
@@ -384,6 +384,11 @@ void __iomem *ioremap_wc(resource_size_t res_cookie, size_t size) 
}

EXPORT_SYMBOL(ioremap_wc);



void *arch_memremap_wb(phys_addr_t phys_addr, size_t size)

{

	return (void *)phys_addr;

}



void __iounmap(volatile void __iomem *addr)

{

}