[tip:efi/urgent] x86/efi: Don't try to reserve runtime regions
From: tip-bot for Omar Sandoval
Date: Thu Apr 13 2017 - 02:19:10 EST
Commit-ID: 6f6266a561306e206e0e31a5038f029b6a7b1d89
Gitweb: http://git.kernel.org/tip/6f6266a561306e206e0e31a5038f029b6a7b1d89
Author: Omar Sandoval <osandov@xxxxxx>
AuthorDate: Wed, 12 Apr 2017 16:27:19 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 13 Apr 2017 08:09:27 +0200
x86/efi: Don't try to reserve runtime regions
Reserving a runtime region results in splitting the EFI memory
descriptors for the runtime region. This results in runtime region
descriptors with bogus memory mappings, leading to interesting crashes
like the following during a kexec:
general protection fault: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc1 #53
Hardware name: Wiwynn Leopard-Orv2/Leopard-DDR BW, BIOS LBM05 09/30/2016
RIP: 0010:virt_efi_set_variable()
...
Call Trace:
efi_delete_dummy_variable()
efi_enter_virtual_mode()
start_kernel()
? set_init_arg()
x86_64_start_reservations()
x86_64_start_kernel()
start_cpu()
...
Kernel panic - not syncing: Fatal exception
Runtime regions will not be freed and do not need to be reserved, so
skip the memmap modification in this case.
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.9+
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Dave Young <dyoung@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Jones <pjones@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-efi@xxxxxxxxxxxxxxx
Fixes: 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()")
Link: http://lkml.kernel.org/r/20170412152719.9779-2-matt@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/platform/efi/quirks.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 30031d5..cdfe8c6 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -201,6 +201,10 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size)
return;
}
+ /* No need to reserve regions that will never be freed. */
+ if (md.attribute & EFI_MEMORY_RUNTIME)
+ return;
+
size += addr % EFI_PAGE_SIZE;
size = round_up(size, EFI_PAGE_SIZE);
addr = round_down(addr, EFI_PAGE_SIZE);