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efi/arm-init: Use read-only early mappings

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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 <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
This commit is contained in:
Ard Biesheuvel 2016-02-17 12:36:00 +00:00 committed by Ingo Molnar
parent 07e83dbb75
commit 2eec5dedf7
1 changed files with 7 additions and 7 deletions
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14
drivers/firmware/efi/arm-init.c
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@ -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