linux/arch/x86/kernel
Ingo Molnar 5be44a6fb1 x86: Remove the PCI reboot method from the default chain
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>
2014-04-16 08:56:09 +02:00
..
acpi Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux into pm-cpuidle 2014-04-08 13:25:25 +02:00
apic Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-11 11:58:33 -07:00
cpu Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-11 11:58:33 -07:00
kprobes Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-09-04 08:42:44 -07:00
.gitignore
alternative.c lockdep, x86/alternatives: Drop ancient lockdep fixup message 2013-09-28 10:09:41 +02:00
amd_gart_64.c x86, mm: use pfn_range_is_mapped() with gart 2012-11-17 11:59:10 -08:00
amd_nb.c A bunch of EDAC updates all over the place: 2014-04-01 13:54:00 -07:00
apb_timer.c intel_mid: Renamed *mrst* to *intel_mid* 2013-10-17 16:40:47 -07:00
aperture_64.c Revert "[PATCH] Insert GART region into resource map" 2014-03-18 14:26:12 -06:00
apm_32.c x86, asmlinkage, apm: Make APM data structure used from assembler visible 2013-08-06 14:20:20 -07:00
asm-offsets_32.c x86: Get rid of ->hard_math and all the FPU asm fu 2013-06-06 14:32:04 -07:00
asm-offsets_64.c x86, gdt, hibernate: Store/load GDT for hibernate path. 2013-05-02 11:27:35 -07:00
asm-offsets.c sched, x86: Provide a per-cpu preempt_count implementation 2013-09-25 14:07:57 +02:00
audit_64.c
bootflag.c
check.c x86/mm: memblock: switch to use NUMA_NO_NODE 2014-01-21 16:19:47 -08:00
cpuid.c x86, cpuid: Fix CPU hotplug callback registration 2014-03-20 13:43:42 +01:00
crash_dump_32.c
crash_dump_64.c
crash.c x86, crash: Unify ifdef 2014-03-13 15:32:44 -07:00
devicetree.c Merge remote-tracking branch 'grant/devicetree/next' into for-next 2013-11-07 10:34:46 -06:00
doublefault.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
dumpstack_32.c Merge branch 'x86-threadinfo-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-01 10:17:18 -07:00
dumpstack_64.c x86: Fix dumpstack_64 irq stack handling 2014-04-02 11:46:50 -07:00
dumpstack.c x86/dumpstack: Fix printk_address for direct addresses 2013-11-12 21:06:06 +01:00
e820.c x86/mm: memblock: switch to use NUMA_NO_NODE 2014-01-21 16:19:47 -08:00
early_printk.c Merge branch 'x86-intel-mid-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-11-12 11:12:22 +09:00
early-quirks.c x86/gpu: Fix sign extension issue in Intel graphics stolen memory quirks 2014-04-14 08:50:56 +02:00
entry_32.S ftrace/x86: Load ftrace_ops in parameter not the variable holding it 2014-01-09 13:24:29 -08:00
entry_64.S ftrace/x86: Load ftrace_ops in parameter not the variable holding it 2014-01-09 13:24:29 -08:00
ftrace.c ftrace/x86: BUG when ftrace recovery fails 2014-03-07 10:06:16 -05:00
head_32.S x86: fix compile error due to X86_TRAP_NMI use in asm files 2014-03-07 18:58:40 -08:00
head_64.S x86: fix compile error due to X86_TRAP_NMI use in asm files 2014-03-07 18:58:40 -08:00
head.c x86: Make sure we can boot in the case the BDA contains pure garbage 2013-02-27 13:38:57 -08:00
head32.c intel_mid: Renamed *mrst* to *intel_mid* 2013-10-17 16:40:47 -07:00
head64.c x86, trace: Register exception handler to trace IDT 2013-11-08 14:15:45 -08:00
hpet.c CPU hotplug notifiers registration fixes for 3.15-rc1 2014-04-07 14:55:46 -07:00
hw_breakpoint.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
i386_ksyms_32.c sched, x86: Optimize the preempt_schedule() call 2013-09-25 14:23:07 +02:00
i387.c x86, fpu: Check tsk_used_math() in kernel_fpu_end() for eager FPU 2014-03-11 12:32:52 -07:00
i8237.c
i8253.c
i8259.c x86/irq: Correct comment about i8259 initialization 2013-09-04 07:46:04 +02:00
io_delay.c
ioport.c x86: get rid of pt_regs argument of iopl(2) 2013-02-03 18:16:24 -05:00
iosf_mbi.c arch: x86: New MailBox support driver for Intel SOC's 2014-01-08 14:36:29 -08:00
irq_32.c x86, threadinfo: Redo "x86: Use inline assembler to get sp" 2014-03-10 17:32:01 -07:00
irq_64.c irq: Consolidate do_softirq() arch overriden implementations 2013-10-01 12:53:25 +02:00
irq_work.c x86, asmlinkage: Make all interrupt handlers asmlinkage / __visible 2013-08-06 14:18:23 -07:00
irq.c x86/platform/hyperv: Handle VMBUS driver being a module 2014-04-02 09:49:47 +02:00
irqinit.c x86/irq: Fix do_IRQ() interrupt warning for cpu hotplug retriggered irqs 2014-01-12 13:13:02 +01:00
jump_label.c x86/jump_label: expect default_nop if static_key gets enabled on boot-up 2013-10-19 19:45:35 -04:00
kdebugfs.c
kgdb.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
ksysfs.c x86: ksysfs.c build fix 2014-01-03 14:37:13 +00:00
kvm.c kvm: remove redundant registration of BSP's hv_clock area 2014-02-22 15:53:32 +01:00
kvmclock.c kvm: remove redundant registration of BSP's hv_clock area 2014-02-22 15:53:32 +01:00
ldt.c x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels 2014-04-11 10:10:09 -07:00
machine_kexec_32.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
machine_kexec_64.c x86, kaslr: export offset in VMCOREINFO ELF notes 2014-02-25 16:57:47 -08:00
Makefile x86, vdso: Make vsyscall_gtod_data handling x86 generic 2014-03-18 12:51:52 -07:00
mmconf-fam10h_64.c x86: delete __cpuinit usage from all x86 files 2013-07-14 19:36:56 -04:00
module.c x86, kaslr: fix module lock ordering problem 2014-03-24 10:18:26 -07:00
mpparse.c
msr.c x86, msr: Fix CPU hotplug callback registration 2014-03-20 13:43:42 +01:00
nmi_selftest.c
nmi.c x86/nmi: Push duration printk() to irq context 2014-02-09 13:17:22 +01:00
paravirt_patch_32.c
paravirt_patch_64.c
paravirt-spinlocks.c x86, ticketlock: Add slowpath logic 2013-08-09 07:54:00 -07:00
paravirt.c x86, paravirt: Remove duplicate definition for DEF_NATIVE 2013-09-04 09:46:43 -07:00
pci-calgary_64.c x86, calgary: Use 8M TCE table size by default 2014-04-10 19:51:32 -07:00
pci-dma.c x86: dma-mapping: fix GFP_ATOMIC macro usage 2014-02-11 09:40:15 +01:00
pci-iommu_table.c
pci-nommu.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
pci-swiotlb.c
pcspeaker.c
perf_regs.c
preempt.S sched, x86: Optimize the preempt_schedule() call 2013-09-25 14:23:07 +02:00
probe_roms.c
process_32.c x86: Keep thread_info on thread stack in x86_32 2014-03-06 16:56:55 -08:00
process_64.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-11-14 16:55:56 +09:00
process.c sched/idle, x86: Remove redundant cpuidle_idle_call() 2014-02-11 09:58:28 +01:00
ptrace.c x86: Keep thread_info on thread stack in x86_32 2014-03-06 16:56:55 -08:00
pvclock.c hung_task: add method to reset detector 2013-11-06 09:49:02 +02:00
quirks.c x86/amd/numa: Fix northbridge quirk to assign correct NUMA node 2014-03-14 11:05:36 +01:00
reboot_fixups_32.c
reboot.c x86: Remove the PCI reboot method from the default chain 2014-04-16 08:56:09 +02:00
relocate_kernel_32.S x86, asm, cleanup: Replace open-coded control register values with symbolic 2013-06-25 16:26:06 -07:00
relocate_kernel_64.S x86, reloc: Use xorl instead of xorq in relocate_kernel_64.S 2013-06-20 21:30:04 -07:00
resource.c
rtc.c Merge branch 'x86-intel-mid-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-11-12 11:12:22 +09:00
setup_percpu.c
setup.c Merge branch 'x86-nuke-platforms-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-02 13:15:58 -07:00
signal.c Merge branch 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-09-04 11:08:32 -07:00
smp.c x86, asmlinkage: Make all interrupt handlers asmlinkage / __visible 2013-08-06 14:18:23 -07:00
smpboot.c Merge branch 'x86-threadinfo-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-01 10:17:18 -07:00
stacktrace.c
step.c ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL 2013-01-22 10:08:00 -08:00
sys_x86_64.c x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member 2013-08-22 10:19:35 -07:00
syscall_32.c x86, asmlinkage: Make syscall tables visible 2013-08-06 14:20:18 -07:00
syscall_64.c x86, asmlinkage: Make syscall tables visible 2013-08-06 14:20:18 -07:00
sysfb_efi.c x86: sysfb: move EFI quirks from efifb to sysfb 2013-08-02 16:17:47 -07:00
sysfb_simplefb.c x86/simplefb: Mark framebuffer mem-resources as IORESOURCE_BUSY to avoid bootup warning 2013-10-03 07:51:11 +02:00
sysfb.c x86: sysfb: move EFI quirks from efifb to sysfb 2013-08-02 16:17:47 -07:00
tboot.c x86 / tboot / ACPI: Fail extended mode reduced hardware sleep 2013-07-31 14:25:51 +02:00
tce_64.c
test_nx.c
test_rodata.c
time.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-01 11:22:57 -07:00
tls.c make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect 2013-03-03 22:58:33 -05:00
tls.h
topology.c hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock() 2013-09-30 19:55:51 +02:00
trace_clock.c tracing,x86: Add a TSC trace_clock 2012-11-13 15:48:27 -05:00
tracepoint.c x86: Make sure IDT is page aligned 2013-07-16 15:14:48 -07:00
traps.c x86/traps: Clean up error exception handler definitions 2013-12-12 14:46:42 +01:00
tsc_msr.c x86: tsc: Add missing Baytrail frequency to the table 2014-02-19 17:12:24 +01:00
tsc_sync.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
tsc.c Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-04-02 12:26:43 -07:00
uprobes.c uretprobes/x86: Hijack return address 2013-04-13 15:31:55 +02:00
verify_cpu.S
vm86_32.c x86, vm86: fix VM86 syscalls: use SYSCALL_DEFINEx(...) 2013-05-02 20:36:32 -04:00
vmlinux.lds.S x86, vdso: Zero-pad the VVAR page 2014-03-18 12:52:44 -07:00
vsmp_64.c x86, asmlinkage, paravirt: Make paravirt thunks global 2014-01-29 22:17:17 -08:00
vsyscall_64.c CPU hotplug notifiers registration fixes for 3.15-rc1 2014-04-07 14:55:46 -07:00
vsyscall_emu_64.S
vsyscall_gtod.c x86, vdso: Add 32 bit VDSO time support for 64 bit kernel 2014-03-18 12:52:41 -07:00
vsyscall_trace.h
x86_init.c PCI: Drop "irq" param from *_restore_msi_irqs() 2013-12-13 08:44:30 -07:00
x8664_ksyms_64.c sched, x86: Optimize the preempt_schedule() call 2013-09-25 14:23:07 +02:00
xsave.c x86, xsave: Support eager-only xsave features, add MPX support 2013-12-06 17:17:42 -08:00