[PATCH 1/2] x86, kexec_file_load: Don't setup EFI info if EFI runtime is not enabled

From: Kairui Song
Date: Wed Jan 09 2019 - 01:45:14 EST


Currenly with "efi=noruntime" in kernel command line, calling
kexec_file_load will raise below problem:

[ 97.967067] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[ 97.967894] #PF error: [normal kernel read fault]
...
[ 97.980456] Call Trace:
[ 97.980724] efi_runtime_map_copy+0x28/0x30
[ 97.981267] bzImage64_load+0x688/0x872
[ 97.981794] arch_kexec_kernel_image_load+0x6d/0x70
[ 97.982441] kimage_file_alloc_init+0x13e/0x220
[ 97.983035] __x64_sys_kexec_file_load+0x144/0x290
[ 97.983586] do_syscall_64+0x55/0x1a0
[ 97.983962] entry_SYSCALL_64_after_hwframe+0x44/0xa9

When efi runtime is not enabled, efi memmap is not mapped, so just skip
EFI info setup.

Suggested-by: Dave Young <dyoung@xxxxxxxxxx>
Signed-off-by: Kairui Song <kasong@xxxxxxxxxx>
---
arch/x86/kernel/kexec-bzimage64.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index 0d5efa34f359..53917a3ebf94 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -167,6 +167,9 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
struct efi_info *current_ei = &boot_params.efi_info;
struct efi_info *ei = &params->efi_info;

+ if (!efi_enabled(EFI_RUNTIME_SERVICES))
+ return 0;
+
if (!current_ei->efi_memmap_size)
return 0;

--
2.20.1