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-rw-r--r--kernel/memremap.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/kernel/memremap.c b/kernel/memremap.c
index 72b0c66628b6..9d6b55587eaa 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -24,6 +24,16 @@ __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
}
#endif
+static void *try_ram_remap(resource_size_t offset, size_t size)
+{
+ struct page *page = pfn_to_page(offset >> PAGE_SHIFT);
+
+ /* In the simple case just return the existing linear address */
+ if (!PageHighMem(page))
+ return __va(offset);
+ return NULL; /* fallback to ioremap_cache */
+}
+
/**
* memremap() - remap an iomem_resource as cacheable memory
* @offset: iomem resource start address
@@ -66,8 +76,8 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
* the requested range is potentially in "System RAM"
*/
if (is_ram == REGION_INTERSECTS)
- addr = __va(offset);
- else
+ addr = try_ram_remap(offset, size);
+ if (!addr)
addr = ioremap_cache(offset, size);
}