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5be44a6fb1
Steve reported a reboot hang and bisected it back to this commit:
a4f1987e4c x86, reboot: Add EFI and CF9 reboot methods into the default list
He heroically tested all reboot methods and found the following:
reboot=t # triple fault ok
reboot=k # keyboard ctrl FAIL
reboot=b # BIOS ok
reboot=a # ACPI FAIL
reboot=e # EFI FAIL [system has no EFI]
reboot=p # PCI 0xcf9 FAIL
And I think it's pretty obvious that we should only try PCI 0xcf9 as a
last resort - if at all.
The other observation is that (on this box) we should never try
the PCI reboot method, but close with either the 'triple fault'
or the 'BIOS' (terminal!) reboot methods.
Thirdly, CF9_COND is a total misnomer - it should be something like
CF9_SAFE or CF9_CAREFUL, and 'CF9' should be 'CF9_FORCE' ...
So this patch fixes the worst problems:
- it orders the actual reboot logic to follow the reboot ordering
pattern - it was in a pretty random order before for no good
reason.
- it fixes the CF9 misnomers and uses BOOT_CF9_FORCE and
BOOT_CF9_SAFE flags to make the code more obvious.
- it tries the BIOS reboot method before the PCI reboot method.
(Since 'BIOS' is a terminal reboot method resulting in a hang
if it does not work, this is essentially equivalent to removing
the PCI reboot method from the default reboot chain.)
- just for the miraculous possibility of terminal (resulting
in hang) reboot methods of triple fault or BIOS returning
without having done their job, there's an ordering between
them as well.
Reported-and-bisected-and-tested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Aubrey <aubrey.li@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Link: http://lkml.kernel.org/r/20140404064120.GB11877@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
80 lines
1.7 KiB
C
80 lines
1.7 KiB
C
#ifndef _LINUX_REBOOT_H
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#define _LINUX_REBOOT_H
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#include <linux/notifier.h>
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#include <uapi/linux/reboot.h>
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#define SYS_DOWN 0x0001 /* Notify of system down */
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#define SYS_RESTART SYS_DOWN
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#define SYS_HALT 0x0002 /* Notify of system halt */
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#define SYS_POWER_OFF 0x0003 /* Notify of system power off */
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enum reboot_mode {
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REBOOT_COLD = 0,
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REBOOT_WARM,
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REBOOT_HARD,
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REBOOT_SOFT,
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REBOOT_GPIO,
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};
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extern enum reboot_mode reboot_mode;
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enum reboot_type {
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BOOT_TRIPLE = 't',
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BOOT_KBD = 'k',
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BOOT_BIOS = 'b',
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BOOT_ACPI = 'a',
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BOOT_EFI = 'e',
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BOOT_CF9_FORCE = 'p',
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BOOT_CF9_SAFE = 'q',
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};
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extern enum reboot_type reboot_type;
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extern int reboot_default;
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extern int reboot_cpu;
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extern int reboot_force;
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extern int register_reboot_notifier(struct notifier_block *);
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extern int unregister_reboot_notifier(struct notifier_block *);
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/*
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* Architecture-specific implementations of sys_reboot commands.
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*/
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extern void migrate_to_reboot_cpu(void);
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extern void machine_restart(char *cmd);
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extern void machine_halt(void);
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extern void machine_power_off(void);
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extern void machine_shutdown(void);
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struct pt_regs;
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extern void machine_crash_shutdown(struct pt_regs *);
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/*
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* Architecture independent implemenations of sys_reboot commands.
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*/
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extern void kernel_restart_prepare(char *cmd);
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extern void kernel_restart(char *cmd);
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extern void kernel_halt(void);
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extern void kernel_power_off(void);
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extern int C_A_D; /* for sysctl */
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void ctrl_alt_del(void);
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#define POWEROFF_CMD_PATH_LEN 256
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extern char poweroff_cmd[POWEROFF_CMD_PATH_LEN];
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extern int orderly_poweroff(bool force);
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/*
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* Emergency restart, callable from an interrupt handler.
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*/
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extern void emergency_restart(void);
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#include <asm/emergency-restart.h>
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#endif /* _LINUX_REBOOT_H */
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