From 2eec5dedf770dc85c1fdf6b86873165e61bb1fff Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 17 Feb 2016 12:36:00 +0000 Subject: [PATCH] efi/arm-init: Use read-only early mappings The early mappings of the EFI system table contents and the UEFI memory map are read-only from the OS point of view. So map them read-only to protect them from inadvertent modification. Tested-by: Mark Rutland Signed-off-by: Ard Biesheuvel Signed-off-by: Matt Fleming Acked-by: Mark Rutland Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/1455712566-16727-8-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar --- drivers/firmware/efi/arm-init.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c index 9e15d571b53c..aa1f743152a2 100644 --- a/drivers/firmware/efi/arm-init.c +++ b/drivers/firmware/efi/arm-init.c @@ -61,8 +61,8 @@ static int __init uefi_init(void) char vendor[100] = "unknown"; int i, retval; - efi.systab = early_memremap(efi_system_table, - sizeof(efi_system_table_t)); + efi.systab = early_memremap_ro(efi_system_table, + sizeof(efi_system_table_t)); if (efi.systab == NULL) { pr_warn("Unable to map EFI system table.\n"); return -ENOMEM; @@ -86,8 +86,8 @@ static int __init uefi_init(void) efi.systab->hdr.revision & 0xffff); /* Show what we know for posterity */ - c16 = early_memremap(efi_to_phys(efi.systab->fw_vendor), - sizeof(vendor) * sizeof(efi_char16_t)); + c16 = early_memremap_ro(efi_to_phys(efi.systab->fw_vendor), + sizeof(vendor) * sizeof(efi_char16_t)); if (c16) { for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i) vendor[i] = c16[i]; @@ -100,8 +100,8 @@ static int __init uefi_init(void) efi.systab->hdr.revision & 0xffff, vendor); table_size = sizeof(efi_config_table_64_t) * efi.systab->nr_tables; - config_tables = early_memremap(efi_to_phys(efi.systab->tables), - table_size); + config_tables = early_memremap_ro(efi_to_phys(efi.systab->tables), + table_size); if (config_tables == NULL) { pr_warn("Unable to map EFI config table array.\n"); retval = -ENOMEM; @@ -185,7 +185,7 @@ void __init efi_init(void) efi_system_table = params.system_table; memmap.phys_map = params.mmap; - memmap.map = early_memremap(params.mmap, params.mmap_size); + memmap.map = early_memremap_ro(params.mmap, params.mmap_size); if (memmap.map == NULL) { /* * If we are booting via UEFI, the UEFI memory map is the only -- 2.20.1