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authorJosh Triplett <josh@joshtriplett.org>2012-09-28 17:56:08 -0700
committerH. Peter Anvin <hpa@linux.intel.com>2012-09-29 12:21:02 -0700
commit7bc90e01c3f66c137e7e761f574bbf883087d590 (patch)
treeb8fbf8b842eabe17ff407fe7d2f13fc12d966bc2 /arch/x86/platform
parent785107923a83d8456bbd8564e288a24d84109a46 (diff)
efi: Add a function to look up existing IO memory mappings
The EFI initialization creates virtual mappings for EFI boot services memory, so if a driver wants to access EFI boot services memory, it cannot call ioremap itself; doing so will trip the WARN about mapping RAM twice. Thus, a driver accessing EFI boot services memory must do so via the existing mapping already created during EFI intiialization. Since the EFI code already maintains a memory map for that memory, add a function efi_lookup_mapped_addr to look up mappings in that memory map. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Link: http://lkml.kernel.org/r/0eb48ae012797912874919110660ad420b90268b.1348876882.git.josh@joshtriplett.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/platform')
-rw-r--r--arch/x86/platform/efi/efi.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index b3dbbdbd2a4..f7f928c315d 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -777,6 +777,34 @@ static void __init runtime_code_page_mkexec(void)
}
/*
+ * 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)
+{
+ void *p;
+ if (WARN_ON(!memmap.map))
+ return NULL;
+ for (p = memmap.map; p < memmap.map_end; p += memmap.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;
+}
+
+/*
* This function will switch the EFI runtime services to virtual mode.
* Essentially, look through the EFI memmap and map every region that
* has the runtime attribute bit set in its memory descriptor and update