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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2018-07-11 11:40:39 +0200
committerIngo Molnar <mingo@kernel.org>2018-07-16 00:43:12 +0200
commit7e1550b8f2081cccdfa9f1cf1e54cbc4d720af7f (patch)
tree26db3da4456dc0517d0206ae0baca29071229f88 /drivers/firmware/efi
parent3d7ee348aa4127a7893c11261da9b76371a970e6 (diff)
download96b-common-7e1550b8f2081cccdfa9f1cf1e54cbc4d720af7f.tar.gz
efi: Drop type and attribute checks in efi_mem_desc_lookup()
The current implementation of efi_mem_desc_lookup() includes the following check on the memory descriptor it returns: if (!(md->attribute & EFI_MEMORY_RUNTIME) && md->type != EFI_BOOT_SERVICES_DATA && md->type != EFI_RUNTIME_SERVICES_DATA) { continue; } This means that only EfiBootServicesData or EfiRuntimeServicesData regions are considered, or any other region type provided that it has the EFI_MEMORY_RUNTIME attribute set. Given what the name of the function implies, and the fact that any physical address can be described in the UEFI memory map only a single time, it does not make sense to impose this condition in the body of the loop, but instead, should be imposed by the caller depending on the value that is returned to it. Two such callers exist at the moment: - The BGRT code when running on x86, via efi_mem_reserve() and efi_arch_mem_reserve(). In this case, the region is already known to be EfiBootServicesData, and so the check is redundant. - The ESRT handling code which introduced this function, which calls it both directly from efi_esrt_init() and again via efi_mem_reserve() and efi_arch_mem_reserve() [on x86]. So let's move this check into the callers instead. This preserves the current behavior both for BGRT and ESRT handling, and allows the lookup routine to be reused by other [upcoming] users that don't have this limitation. In the ESRT case, keep the entire condition, so that platforms that deviate from the UEFI spec and use something other than EfiBootServicesData for the ESRT table will keep working as before. For x86's efi_arch_mem_reserve() implementation, limit the type to EfiBootServicesData, since it is the only type the reservation code expects to operate on in the first place. While we're at it, drop the __init annotation so that drivers can use it as well. Tested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Jones <pjones@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20180711094040.12506-8-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/firmware/efi')
-rw-r--r--drivers/firmware/efi/efi.c8
-rw-r--r--drivers/firmware/efi/esrt.c5
2 files changed, 5 insertions, 8 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 1379a375dfa8..d8a33a781a57 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -402,7 +402,7 @@ subsys_initcall(efisubsys_init);
* and if so, populate the supplied memory descriptor with the appropriate
* data.
*/
-int __init efi_mem_desc_lookup(u64 phys_addr, efi_memory_desc_t *out_md)
+int efi_mem_desc_lookup(u64 phys_addr, efi_memory_desc_t *out_md)
{
efi_memory_desc_t *md;
@@ -420,12 +420,6 @@ int __init efi_mem_desc_lookup(u64 phys_addr, efi_memory_desc_t *out_md)
u64 size;
u64 end;
- if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
- md->type != EFI_BOOT_SERVICES_DATA &&
- md->type != EFI_RUNTIME_SERVICES_DATA) {
- continue;
- }
-
size = md->num_pages << EFI_PAGE_SHIFT;
end = md->phys_addr + size;
if (phys_addr >= md->phys_addr && phys_addr < end) {
diff --git a/drivers/firmware/efi/esrt.c b/drivers/firmware/efi/esrt.c
index 1ab80e06e7c5..375a77c1c6e5 100644
--- a/drivers/firmware/efi/esrt.c
+++ b/drivers/firmware/efi/esrt.c
@@ -250,7 +250,10 @@ void __init efi_esrt_init(void)
return;
rc = efi_mem_desc_lookup(efi.esrt, &md);
- if (rc < 0) {
+ if (rc < 0 ||
+ (!(md.attribute & EFI_MEMORY_RUNTIME) &&
+ md.type != EFI_BOOT_SERVICES_DATA &&
+ md.type != EFI_RUNTIME_SERVICES_DATA)) {
pr_warn("ESRT header is not in the memory map.\n");
return;
}