x86/mm: Add support to access boot related data in the clear

[mirror_ubuntu-bionic-kernel.git] / kernel / memremap.c

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 124bed776532d3d2e69f4079e3f2d23da193fd2e..9afdc434fb490a3384d847bc50647fa3dd3ab16a 100644 (file)
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -34,13 +34,24 @@ static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
 }
 #endif
 
-static void *try_ram_remap(resource_size_t offset, size_t size)
+#ifndef arch_memremap_can_ram_remap
+static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
+                                       unsigned long flags)
+{
+       return true;
+}
+#endif
+
+static void *try_ram_remap(resource_size_t offset, size_t size,
+                          unsigned long flags)
 {
        unsigned long pfn = PHYS_PFN(offset);
 
        /* In the simple case just return the existing linear address */
-       if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)))
+       if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&
+           arch_memremap_can_ram_remap(offset, size, flags))
                return __va(offset);
+
        return NULL; /* fallback to arch_memremap_wb */
 }
 
@@ -48,7 +59,8 @@ static void *try_ram_remap(resource_size_t offset, size_t size)
  * memremap() - remap an iomem_resource as cacheable memory
  * @offset: iomem resource start address
  * @size: size of remap
- * @flags: any of MEMREMAP_WB, MEMREMAP_WT and MEMREMAP_WC
+ * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
+ *               MEMREMAP_ENC, MEMREMAP_DEC
  *
  * memremap() is "ioremap" for cases where it is known that the resource
  * being mapped does not have i/o side effects and the __iomem
@@ -95,7 +107,7 @@ 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 = try_ram_remap(offset, size);
+                       addr = try_ram_remap(offset, size, flags);
                if (!addr)
                        addr = arch_memremap_wb(offset, size);
        }