[PATCH AUTOSEL 4.4 20/26] x86/kexec: Don't setup EFI info if EFI runtime is not enabled

[Sasha Levin <sashal@xxxxxxxxxx>]

From: Kairui Song <kasong@xxxxxxxxxx>

[ Upstream commit 2aa958c99c7fd3162b089a1a56a34a0cdb778de1 ]

Kexec-ing a kernel with "efi=noruntime" on the first kernel's command
line causes the following null pointer dereference:

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

Just skip the EFI info setup if EFI runtime services are not enabled.

 [ bp: Massage commit message. ]

Suggested-by: Dave Young <dyoung@xxxxxxxxxx>
Signed-off-by: Kairui Song <kasong@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Acked-by: Dave Young <dyoung@xxxxxxxxxx>
Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: bhe@xxxxxxxxxx
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: erik.schmauss@xxxxxxxxx
Cc: fanc.fnst@xxxxxxxxxxxxxx
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: kexec@xxxxxxxxxxxxxxxxxxx
Cc: lenb@xxxxxxxxxx
Cc: linux-acpi@xxxxxxxxxxxxxxx
Cc: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx>
Cc: rafael.j.wysocki@xxxxxxxxx
Cc: robert.moore@xxxxxxxxx
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Cc: Yannik Sembritzki <yannik@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20190118111310.29589-2-kasong@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@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 0f8a6bbaaa443..0bf17576dd2af 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -168,6 +168,9 @@ 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;
 
-- 
2.19.1