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: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
This commit is contained in:
Ard Biesheuvel 2016-02-22 15:02:08 +01:00
parent c269cba35b
commit 9ab9e4fce4
3 changed files with 21 additions and 2 deletions

View File

@ -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
*/

View File

@ -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);

View File

@ -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)
{
}