From 7bc90e01c3f66c137e7e761f574bbf883087d590 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Fri, 28 Sep 2012 17:56:08 -0700 Subject: 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 Link: http://lkml.kernel.org/r/0eb48ae012797912874919110660ad420b90268b.1348876882.git.josh@joshtriplett.org Signed-off-by: H. Peter Anvin --- arch/x86/platform/efi/efi.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'arch/x86') diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index b3dbbdbd2a42..f7f928c315da 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -776,6 +776,34 @@ 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 -- cgit v1.2.3-58-ga151