The patch titled
x86: attempt rebooting via port CF9 if it seems to be available
has been added to the -mm tree. Its filename is
x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available.patch
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------------------------------------------------------
Subject: x86: attempt rebooting via port CF9 if it seems to be available
From: "H. Peter Anvin" <hpa@xxxxxxxxx>
Impact: Changes reboot behavior.
If port CF9 seems to be safe to touch, attempt it before trying the
keyboard controller. Port CF9 is not available on all chipsets (a
significant but decreasing number of modern chipsets don't implement it),
but port CF9 itself should in general be safe to poke (no ill effects if
unimplemented) on any system which has PCI Configuration Method #1 or #2,
as it falls inside the PCI configuration port range in both cases. No
chipset without PCI is known to have port CF9, either, although an
explicit "pci=bios" would mean we miss this and therefore don't use port
CF9. An explicit "reboot=pci" can be used to force the use of port CF9.
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Matthew Garrett <mjg@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxx>
Cc: Andrey Borzenkov <arvidjaar@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Eduardo Habkost <ehabkost@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/emergency-restart.h | 4 +-
arch/x86/kernel/reboot.c | 34 ++++++++++++++++-----
arch/x86/pci/direct.c | 4 +-
arch/x86/pci/pci.h | 1
4 files changed, 34 insertions(+), 9 deletions(-)
diff -puN arch/x86/include/asm/emergency-restart.h~x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available arch/x86/include/asm/emergency-restart.h
--- a/arch/x86/include/asm/emergency-restart.h~x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available
+++ a/arch/x86/include/asm/emergency-restart.h
@@ -8,7 +8,9 @@ enum reboot_type {
BOOT_BIOS = 'b',
#endif
BOOT_ACPI = 'a',
- BOOT_EFI = 'e'
+ BOOT_EFI = 'e',
+ BOOT_CF9 = 'p',
+ BOOT_CF9_COND = 'q',
};
extern enum reboot_type reboot_type;
diff -puN arch/x86/kernel/reboot.c~x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available arch/x86/kernel/reboot.c
--- a/arch/x86/kernel/reboot.c~x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available
+++ a/arch/x86/kernel/reboot.c
@@ -29,14 +29,17 @@ EXPORT_SYMBOL(pm_power_off);
static const struct desc_ptr no_idt = {};
static int reboot_mode;
-enum reboot_type reboot_type = BOOT_ACPI;
+enum reboot_type reboot_type = BOOT_CF9_COND;
int reboot_force;
#if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
static int reboot_cpu = -1;
#endif
-/* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old]
+/* This is set by the PCI code if either type 1 or type 2 PCI is detected */
+bool port_cf9_safe = false;
+
+/* reboot=b[ios] | s[mp] | t[riple] | k[bd] | e[fi] [, [w]arm | [c]old] | p[ci]
warm Don't set the cold reboot flag
cold Set the cold reboot flag
bios Reboot by jumping through the BIOS (only for X86_32)
@@ -45,6 +48,7 @@ static int reboot_cpu = -1;
kbd Use the keyboard controller. cold reset (default)
acpi Use the RESET_REG in the FADT
efi Use efi reset_system runtime service
+ pci Use the so-called "PCI reset register", CF9
force Avoid anything that could hang.
*/
static int __init reboot_setup(char *str)
@@ -79,6 +83,7 @@ static int __init reboot_setup(char *str
case 'k':
case 't':
case 'e':
+ case 'p':
reboot_type = *str;
break;
@@ -387,28 +392,43 @@ static void native_machine_emergency_res
load_idt(&no_idt);
__asm__ __volatile__("int3");
- reboot_type = BOOT_KBD;
+ reboot_type = BOOT_CF9_COND;
break;
#ifdef CONFIG_X86_32
case BOOT_BIOS:
machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
- reboot_type = BOOT_KBD;
+ reboot_type = BOOT_CF9_COND;
break;
#endif
case BOOT_ACPI:
acpi_reboot();
- reboot_type = BOOT_KBD;
+ reboot_type = BOOT_CF9_COND;
break;
-
case BOOT_EFI:
if (efi_enabled)
- efi.reset_system(reboot_mode ? EFI_RESET_WARM : EFI_RESET_COLD,
+ efi.reset_system(reboot_mode ?
+ EFI_RESET_WARM :
+ EFI_RESET_COLD,
EFI_SUCCESS, 0, NULL);
+ reboot_type = BOOT_CF9_COND;
+ break;
+
+ case BOOT_CF9:
+ port_cf9_safe = true;
+ /* fall through */
+ case BOOT_CF9_COND:
+ if (port_cf9_safe) {
+ u8 cf9 = inb(0xcf9) & ~6;
+ outb(cf9|2, 0xcf9); /* Request hard reset */
+ udelay(50);
+ outb(cf9|6, 0xcf9); /* Actually do the reset */
+ udelay(50);
+ }
reboot_type = BOOT_KBD;
break;
}
diff -puN arch/x86/pci/direct.c~x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available arch/x86/pci/direct.c
--- a/arch/x86/pci/direct.c~x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available
+++ a/arch/x86/pci/direct.c
@@ -173,7 +173,7 @@ static int pci_conf2_write(unsigned int
#undef PCI_CONF2_ADDRESS
-static struct pci_raw_ops pci_direct_conf2 = {
+struct pci_raw_ops pci_direct_conf2 = {
.read = pci_conf2_read,
.write = pci_conf2_write,
};
@@ -289,6 +289,7 @@ int __init pci_direct_probe(void)
if (pci_check_type1()) {
raw_pci_ops = &pci_direct_conf1;
+ port_cf9_safe = true;
return 1;
}
release_resource(region);
@@ -305,6 +306,7 @@ int __init pci_direct_probe(void)
if (pci_check_type2()) {
raw_pci_ops = &pci_direct_conf2;
+ port_cf9_safe = true;
return 2;
}
diff -puN arch/x86/pci/pci.h~x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available arch/x86/pci/pci.h
--- a/arch/x86/pci/pci.h~x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available
+++ a/arch/x86/pci/pci.h
@@ -96,6 +96,7 @@ extern struct pci_raw_ops *raw_pci_ops;
extern struct pci_raw_ops *raw_pci_ext_ops;
extern struct pci_raw_ops pci_direct_conf1;
+extern bool port_cf9_safe;
/* arch_initcall level */
extern int pci_direct_probe(void);
_
Patches currently in -mm which might be from hpa@xxxxxxxxx are
linux-next.patch
x86-attempt-rebooting-via-port-cf9-if-it-seems-to-be-available.patch
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