[tip:efi/core] x86/efi: Force EFI reboot to process pending capsules

[tip-bot for Matt Fleming]

Commit-ID:  87615a34d561ef59bd0cffc73256a21220dfdffd
Gitweb:     http://git.kernel.org/tip/87615a34d561ef59bd0cffc73256a21220dfdffd
Author:     Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
AuthorDate: Mon, 25 Apr 2016 21:07:00 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 28 Apr 2016 11:34:04 +0200

x86/efi: Force EFI reboot to process pending capsules

If an EFI capsule has been sent to the firmware we must match the type
of EFI reset against that required by the capsule to ensure it is
processed correctly.

Force an EFI reboot if a capsule is pending for the next reset.

Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Kweh Hock Leong <hock.leong.kweh@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: joeyli <jlee@xxxxxxxx>
Cc: linux-efi@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1461614832-17633-29-git-send-email-matt@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/kernel/reboot.c | 9 +++++++++
 include/linux/efi.h      | 6 ++++++
 2 files changed, 15 insertions(+)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index ab0adc0..a9b31eb 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -535,6 +535,15 @@ static void native_machine_emergency_restart(void)
 	mode = reboot_mode == REBOOT_WARM ? 0x1234 : 0;
 	*((unsigned short *)__va(0x472)) = mode;
 
+	/*
+	 * If an EFI capsule has been registered with the firmware then
+	 * override the reboot= parameter.
+	 */
+	if (efi_capsule_pending(NULL)) {
+		pr_info("EFI capsule is pending, forcing EFI reboot.\n");
+		reboot_type = BOOT_EFI;
+	}
+
 	for (;;) {
 		/* Could also try the reset bit in the Hammer NB */
 		switch (reboot_type) {
diff --git a/include/linux/efi.h b/include/linux/efi.h
index a3b4c1e..aa36fb8 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1085,6 +1085,12 @@ static inline bool efi_enabled(int feature)
 }
 static inline void
 efi_reboot(enum reboot_mode reboot_mode, const char *__unused) {}
+
+static inline bool
+efi_capsule_pending(int *reset_type)
+{
+	return false;
+}
 #endif
 
 extern int efi_status_to_err(efi_status_t status);