efi: Get and store the secure boot status
Get the firmware's secure-boot status in the kernel boot wrapper and stash
it somewhere that the main kernel image can find.
The efi_get_secureboot() function is extracted from the ARM stub and (a)
generalised so that it can be called from x86 and (b) made to use
efi_call_runtime() so that it can be run in mixed-mode.
For x86, it is stored in boot_params and can be overridden by the boot
loader or kexec. This allows secure-boot mode to be passed on to a new
kernel.
Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1486380166-31868-5-git-send-email-ard.biesheuvel@linaro.org
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index f99978d..801c7a15 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -988,6 +988,13 @@ struct boot_params *efi_main(struct efi_config *c,
else
setup_boot_services32(efi_early);
+ /*
+ * If the boot loader gave us a value for secure_boot then we use that,
+ * otherwise we ask the BIOS.
+ */
+ if (boot_params->secure_boot == efi_secureboot_mode_unset)
+ boot_params->secure_boot = efi_get_secureboot(sys_table);
+
setup_graphics(boot_params);
setup_efi_pci(boot_params);