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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-02-22 15:02:07 +0100
committerArd Biesheuvel <ard.biesheuvel@linaro.org>2016-04-04 10:26:41 +0200
commitc269cba35b061181bc23c470809c00e8f71e535a (patch)
tree5b34de143f15b6eb1b786394c45fa8012d4397a9 /kernel/memremap.c
parent7769aea2a27db8f12859dcecce37a3da44ab588b (diff)
downloadlinux-c269cba35b061181bc23c470809c00e8f71e535a.tar.bz2
memremap: add arch specific hook for MEMREMAP_WB mappings
Currently, the memremap code serves MEMREMAP_WB mappings directly from the kernel direct mapping, unless the region is in high memory, in which case it falls back to using ioremap_cache(). However, the semantics of ioremap_cache() are not unambiguously defined, and on ARM, it will actually result in a mapping type that differs from the attributes used for the linear mapping, and for this reason, the ioremap_cache() call fails if the region is part of the memory managed by the kernel. So instead, implement an optional hook 'arch_memremap_wb' whose default implementation calls ioremap_cache() as before, but which can be overridden by the architecture to do what is appropriate for it. Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Diffstat (limited to 'kernel/memremap.c')
-rw-r--r--kernel/memremap.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c
index a6d382312e6f..017532193fb1 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -27,6 +27,13 @@ __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
}
#endif
+#ifndef arch_memremap_wb
+static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
+{
+ return (__force void *)ioremap_cache(offset, size);
+}
+#endif
+
static void *try_ram_remap(resource_size_t offset, size_t size)
{
unsigned long pfn = PHYS_PFN(offset);
@@ -34,7 +41,7 @@ static void *try_ram_remap(resource_size_t offset, size_t size)
/* In the simple case just return the existing linear address */
if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)))
return __va(offset);
- return NULL; /* fallback to ioremap_cache */
+ return NULL; /* fallback to arch_memremap_wb */
}
/**
@@ -90,7 +97,7 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
if (is_ram == REGION_INTERSECTS)
addr = try_ram_remap(offset, size);
if (!addr)
- addr = ioremap_cache(offset, size);
+ addr = arch_memremap_wb(offset, size);
}
/*