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-rw-r--r--arch/x86/kernel/reboot.c72
-rw-r--r--include/linux/reboot.h14
2 files changed, 44 insertions, 42 deletions
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 654b46574b91..3399d3a99730 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -114,8 +114,8 @@ EXPORT_SYMBOL(machine_real_restart);
*/
static int __init set_pci_reboot(const struct dmi_system_id *d)
{
- if (reboot_type != BOOT_CF9) {
- reboot_type = BOOT_CF9;
+ if (reboot_type != BOOT_CF9_FORCE) {
+ reboot_type = BOOT_CF9_FORCE;
pr_info("%s series board detected. Selecting %s-method for reboots.\n",
d->ident, "PCI");
}
@@ -458,20 +458,23 @@ void __attribute__((weak)) mach_reboot_fixups(void)
}
/*
- * Windows compatible x86 hardware expects the following on reboot:
+ * To the best of our knowledge Windows compatible x86 hardware expects
+ * the following on reboot:
*
* 1) If the FADT has the ACPI reboot register flag set, try it
* 2) If still alive, write to the keyboard controller
* 3) If still alive, write to the ACPI reboot register again
* 4) If still alive, write to the keyboard controller again
* 5) If still alive, call the EFI runtime service to reboot
- * 6) If still alive, write to the PCI IO port 0xCF9 to reboot
- * 7) If still alive, inform BIOS to do a proper reboot
+ * 6) If no EFI runtime service, call the BIOS to do a reboot
*
- * If the machine is still alive at this stage, it gives up. We default to
- * following the same pattern, except that if we're still alive after (7) we'll
- * try to force a triple fault and then cycle between hitting the keyboard
- * controller and doing that
+ * We default to following the same pattern. We also have
+ * two other reboot methods: 'triple fault' and 'PCI', which
+ * can be triggered via the reboot= kernel boot option or
+ * via quirks.
+ *
+ * This means that this function can never return, it can misbehave
+ * by not rebooting properly and hanging.
*/
static void native_machine_emergency_restart(void)
{
@@ -492,6 +495,11 @@ static void native_machine_emergency_restart(void)
for (;;) {
/* Could also try the reset bit in the Hammer NB */
switch (reboot_type) {
+ case BOOT_ACPI:
+ acpi_reboot();
+ reboot_type = BOOT_KBD;
+ break;
+
case BOOT_KBD:
mach_reboot_fixups(); /* For board specific fixups */
@@ -509,43 +517,29 @@ static void native_machine_emergency_restart(void)
}
break;
- case BOOT_TRIPLE:
- load_idt(&no_idt);
- __asm__ __volatile__("int3");
-
- /* We're probably dead after this, but... */
- reboot_type = BOOT_KBD;
- break;
-
- case BOOT_BIOS:
- machine_real_restart(MRR_BIOS);
-
- /* We're probably dead after this, but... */
- reboot_type = BOOT_TRIPLE;
- break;
-
- case BOOT_ACPI:
- acpi_reboot();
- reboot_type = BOOT_KBD;
- break;
-
case BOOT_EFI:
if (efi_enabled(EFI_RUNTIME_SERVICES))
efi.reset_system(reboot_mode == REBOOT_WARM ?
EFI_RESET_WARM :
EFI_RESET_COLD,
EFI_SUCCESS, 0, NULL);
- reboot_type = BOOT_CF9_COND;
+ reboot_type = BOOT_BIOS;
+ break;
+
+ case BOOT_BIOS:
+ machine_real_restart(MRR_BIOS);
+
+ /* We're probably dead after this, but... */
+ reboot_type = BOOT_CF9_SAFE;
break;
- case BOOT_CF9:
+ case BOOT_CF9_FORCE:
port_cf9_safe = true;
/* Fall through */
- case BOOT_CF9_COND:
+ case BOOT_CF9_SAFE:
if (port_cf9_safe) {
- u8 reboot_code = reboot_mode == REBOOT_WARM ?
- 0x06 : 0x0E;
+ u8 reboot_code = reboot_mode == REBOOT_WARM ? 0x06 : 0x0E;
u8 cf9 = inb(0xcf9) & ~reboot_code;
outb(cf9|2, 0xcf9); /* Request hard reset */
udelay(50);
@@ -553,7 +547,15 @@ static void native_machine_emergency_restart(void)
outb(cf9|reboot_code, 0xcf9);
udelay(50);
}
- reboot_type = BOOT_BIOS;
+ reboot_type = BOOT_TRIPLE;
+ break;
+
+ case BOOT_TRIPLE:
+ load_idt(&no_idt);
+ __asm__ __volatile__("int3");
+
+ /* We're probably dead after this, but... */
+ reboot_type = BOOT_KBD;
break;
}
}
diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index 9e7db9e73cc1..48bf152761c7 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -20,13 +20,13 @@ enum reboot_mode {
extern enum reboot_mode reboot_mode;
enum reboot_type {
- BOOT_TRIPLE = 't',
- BOOT_KBD = 'k',
- BOOT_BIOS = 'b',
- BOOT_ACPI = 'a',
- BOOT_EFI = 'e',
- BOOT_CF9 = 'p',
- BOOT_CF9_COND = 'q',
+ BOOT_TRIPLE = 't',
+ BOOT_KBD = 'k',
+ BOOT_BIOS = 'b',
+ BOOT_ACPI = 'a',
+ BOOT_EFI = 'e',
+ BOOT_CF9_FORCE = 'p',
+ BOOT_CF9_SAFE = 'q',
};
extern enum reboot_type reboot_type;