From 6f6266a561306e206e0e31a5038f029b6a7b1d89 Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Wed, 12 Apr 2017 16:27:19 +0100 Subject: [PATCH] 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 Signed-off-by: Matt Fleming Cc: # v4.9+ Cc: Ard Biesheuvel Cc: Dave Young Cc: Linus Torvalds Cc: Peter Jones Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Fixes: 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()") Link: http://lkml.kernel.org/r/20170412152719.9779-2-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar --- 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 30031d5293c4..cdfe8c628959 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); -- 2.20.1