From: Ard Biesheuvel ardb@kernel.org
[ Upstream commit dd09fad9d2caad2325a39b766ce9e79cfc690184 ]
Commit:
3a6b6c6fb23667fa ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE initialization common across all architectures")
moved the call to efi_memattr_init() from ARM specific to the generic EFI init code, in order to be able to apply the restricted permissions described in that table on x86 as well.
We never enabled this feature fully on i386, and so mapping and reserving this table is pointless. However, due to the early call to memblock_reserve(), the memory bookkeeping gets confused to the point where it produces the splat below when we try to map the memory later on:
------------[ cut here ]------------ ioremap on RAM at 0x3f251000 - 0x3fa1afff WARNING: CPU: 0 PID: 0 at arch/x86/mm/ioremap.c:166 __ioremap_caller ... Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.20.0 #48 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015 EIP: __ioremap_caller.constprop.0+0x249/0x260 Code: 90 0f b7 05 4e 38 40 de 09 45 e0 e9 09 ff ff ff 90 8d 45 ec c6 05 ... EAX: 00000029 EBX: 00000000 ECX: de59c228 EDX: 00000001 ESI: 3f250fff EDI: 00000000 EBP: de3edf20 ESP: de3edee0 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00200296 CR0: 80050033 CR2: ffd17000 CR3: 1e58c000 CR4: 00040690 Call Trace: ioremap_cache+0xd/0x10 ? old_map_region+0x72/0x9d old_map_region+0x72/0x9d efi_map_region+0x8/0xa efi_enter_virtual_mode+0x260/0x43b start_kernel+0x329/0x3aa i386_start_kernel+0xa7/0xab startup_32_smp+0x164/0x168 ---[ end trace e15ccf6b9f356833 ]---
Let's work around this by disregarding the memory attributes table altogether on i386, which does not result in a loss of functionality or protection, given that we never consumed the contents.
Fixes: 3a6b6c6fb23667fa ("efi: Make EFI_MEMORY_ATTRIBUTES_TABLE ... ") Tested-by: Arvind Sankar nivedita@alum.mit.edu Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Ingo Molnar mingo@kernel.org Link: https://lore.kernel.org/r/20200304165917.5893-1-ardb@kernel.org Link: https://lore.kernel.org/r/20200308080859.21568-21-ardb@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/efi/efi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index f50072b51aefb..b39b7e6d4e4dc 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -550,7 +550,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, } }
- if (efi_enabled(EFI_MEMMAP)) + if (!IS_ENABLED(CONFIG_X86_32) && efi_enabled(EFI_MEMMAP)) efi_memattr_init();
/* Parse the EFI Properties table if it exists */