efi: x86: make efi_lookup_mapped_addr() a common function

[deliverable/linux.git] / drivers / firmware / efi / efi.c

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index e1010d450b659fd1e11570633394726b4525fc67..2e2fbdec0845414df2f32a8c0f862b4149ce3198 100644 (file)
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -150,6 +150,38 @@ err_put:
 subsys_initcall(efisubsys_init);
 
 
+/*
+ * We can't ioremap data in EFI boot services RAM, because we've already mapped
+ * it as RAM.  So, look it up in the existing EFI memory map instead.  Only
+ * callable after efi_enter_virtual_mode and before efi_free_boot_services.
+ */
+void __iomem *efi_lookup_mapped_addr(u64 phys_addr)
+{
+       struct efi_memory_map *map;
+       void *p;
+       map = efi.memmap;
+       if (!map)
+               return NULL;
+       if (WARN_ON(!map->map))
+               return NULL;
+       for (p = map->map; p < map->map_end; p += map->desc_size) {
+               efi_memory_desc_t *md = p;
+               u64 size = md->num_pages << EFI_PAGE_SHIFT;
+               u64 end = md->phys_addr + size;
+               if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
+                   md->type != EFI_BOOT_SERVICES_CODE &&
+                   md->type != EFI_BOOT_SERVICES_DATA)
+                       continue;
+               if (!md->virt_addr)
+                       continue;
+               if (phys_addr >= md->phys_addr && phys_addr < end) {
+                       phys_addr += md->virt_addr - md->phys_addr;
+                       return (__force void __iomem *)(unsigned long)phys_addr;
+               }
+       }
+       return NULL;
+}
+
 static __initdata efi_config_table_type_t common_tables[] = {
        {ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20},
        {ACPI_TABLE_GUID, "ACPI", &efi.acpi},