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Don Zickus 7d007d21e5 x86/reboot: Use NMI to assist in shutting down if IRQ fails 
For v3.3, I added code to use the NMI to stop other cpus in the
panic case.  The idea was to make sure all cpus on the system
were definitely halted to help serialize the panic path to
execute the rest of the code on a single cpu.

The main problem it was trying to solve was how to stop a cpu
that was spinning with its irqs disabled.  A IPI irq would be
stuck and couldn't get in there, but an NMI could.

Things were great until we had another conversation about some
pstore changes.  Because some of the backend pstore still uses
spinlocks to protect the device access, things could get ugly if
a panic happened and we were stuck spinning on a lock.

Now with the NMI shutting down cpus, we could assume no other
cpus were running and just bust the spin lock and proceed.

The counter argument was, well if you do that the backend could
be in a screwed up state and you might not be able to save
anything as a result. If we could have just given the cpu a
little more time to finish things, we could have grabbed the
spin lock cleanly and everything would have been fine.

Well, how do give a cpu a 'little more time' in the panic case?
For the most part you can't without spinning on the lock and
even in that case, how long do you spin for?

So instead of making it ugly in the pstore code, just mimic the
idea that stop_machine had, which is block on an IRQ IPI until
the remote cpu has re-enabled interrupts and left the critical
region.  Which is what happens now using REBOOT_IRQ.

Then leave the NMI case for those cpus that are truly stuck
after a short time.  This leaves the current behaviour alone and
just handle a corner case.  Most systems should never have to
enter the NMI code and if they do, print out a message in case
the NMI itself causes another issue.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1336761675-24296-3-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 		2012-05-14 11:49:37 +02:00
..
acpi x86, acpi: Skip acpi x2apic entries if the x2apic feature is not present 2011-12-23 11:00:50 -08:00
apic x86, UV: Update Boot messages for SGI UV2 platform 2012-01-08 12:35:44 +01:00
cpu mce: fix warning messages about static struct mce_device 2012-01-16 17:08:42 -08:00
.gitignore
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Makefile Merge branch 'x86-syscall-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-16 18:19:19 -08:00
alternative.c x86: Call stop_machine_text_poke() on all CPUs 2011-11-14 13:05:15 +01:00
amd_gart_64.c doc: fix broken references 2011-09-27 18:08:04 +02:00
amd_nb.c Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
apb_timer.c Merge branch 'timers-clocksource-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-07-23 10:34:47 -07:00
aperture_64.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
apm_32.c module_param: make bool parameters really bool (arch) 2012-01-13 09:32:18 +10:30
asm-offsets.c x86, efi: EFI boot stub support 2011-12-12 14:26:10 -08:00
asm-offsets_32.c x86: Generate system call tables and unistd_*.h from tables 2011-11-17 13:35:37 -08:00
asm-offsets_64.c x86: Generate system call tables and unistd_*.h from tables 2011-11-17 13:35:37 -08:00
audit_64.c
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bootflag.c
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check.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
cpuid.c switch device_get_devnode() and ->devnode() to umode_t * 2012-01-03 22:54:55 -05:00
crash.c x86, nmi: Wire up NMI handlers to new routines 2011-10-10 06:56:57 +02:00
crash_dump_32.c crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn 2011-03-23 19:47:19 -07:00
crash_dump_64.c crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn 2011-03-23 19:47:19 -07:00
devicetree.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
doublefault_32.c
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dumpstack.c bugs, x86: Fix printk levels for panic, softlockups and stack dumps 2012-01-26 21:28:45 +01:00
dumpstack_32.c x86, dumpstack: Fix code bytes breakage due to missing KERN_CONT 2011-12-19 13:09:56 -08:00
dumpstack_64.c Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', 'sched-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-02-02 11:11:13 -08:00
e820.c Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-01-18 15:51:48 -08:00
early-quirks.c x86, quirk: Fix SB600 revision check 2011-03-16 14:03:32 +01:00
early_printk.c Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-11 19:13:40 -08:00
entry_32.S Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit 2012-01-17 16:41:31 -08:00
entry_64.S Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit 2012-01-17 16:41:31 -08:00
ftrace.c x86/ftrace: Fix compiler warning in ftrace.c 2011-05-25 19:56:26 -04:00
head.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
head32.c memblock: Kill memblock_init() 2011-12-08 10:22:07 -08:00
head64.c memblock: Kill memblock_init() 2011-12-08 10:22:07 -08:00
head_32.S Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-03-15 20:01:36 -07:00
head_64.S x86: Keep current stack in NMI breakpoints 2011-12-21 15:38:55 -05:00
hpet.c Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 2012-01-07 12:03:30 -08:00
hw_breakpoint.c x86: Use this_cpu_ops to optimize code 2010-12-30 12:20:28 +01:00
i386_ksyms_32.c
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i387.c treewide: fix potentially dangerous trailing ';' in #defined values/expressions 2011-07-21 14:10:00 +02:00
i8237.c x86: Use syscore_ops instead of sysdev classes and sysdevs 2011-03-23 22:15:54 +01:00
i8253.c x86: Use common i8253 clockevent 2011-07-01 10:37:14 +02:00
i8259.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
init_task.c
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io_delay.c
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ioport.c x86: Use bitmap library functions 2011-02-17 14:59:22 +01:00
irq.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-06 13:58:21 -08:00
irq_32.c x86: Fix the 32-bit stackoverflow-debug build 2011-12-05 12:25:44 +01:00
irq_64.c x86: Add stack top margin for stack overflow checking 2011-12-07 09:27:11 +01:00
irq_work.c irq_work: Add generic hardirq context callbacks 2010-10-18 19:58:50 +02:00
irqinit.c driver-core: remove sysdev.h usage. 2011-12-21 16:26:03 -08:00
jump_label.c jump_label, x86: Fix section mismatch 2011-12-06 20:41:02 +01:00
kdebugfs.c llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
kgdb.c x86, nmi: Wire up NMI handlers to new routines 2011-10-10 06:56:57 +02:00
kprobes.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2011-10-26 17:03:38 +02:00
kvm.c KVM guest: remove KVM guest pv mmu support 2011-12-27 11:17:08 +02:00
kvmclock.c KVM guest: prevent tracing recursion with kvmclock 2011-11-20 10:53:48 +02:00
ldt.c
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machine_kexec_32.c
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machine_kexec_64.c x86, cleanups: Use clear_page/copy_page rather than memset/memcpy 2010-09-22 15:36:49 -07:00
mca_32.c x86: Fix common misspellings 2011-03-18 10:39:30 +01:00
microcode_amd.c x86/microcode_amd: Add support for CPU family specific container files 2012-01-26 12:06:39 +01:00
microcode_core.c Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 2012-01-07 12:03:30 -08:00
microcode_intel.c x86, intel: Output microcode revision in /proc/cpuinfo 2011-10-14 13:16:35 +02:00
mmconf-fam10h_64.c x86-64: Fix and clean up AMD Fam10 MMCONF enabling 2010-11-18 13:41:35 +01:00
module.c modules: make arch's use default loader hooks 2011-07-24 22:06:04 +09:30
mpparse.c Merge branch 'memblock-kill-early_node_map' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/memblock 2011-12-20 12:14:26 +01:00
msr.c switch device_get_devnode() and ->devnode() to umode_t * 2012-01-03 22:54:55 -05:00
nmi.c x86: Allow NMIs to hit breakpoints in i386 2011-12-21 15:38:55 -05:00
nmi_selftest.c x86, NMI: Add to_cpumask() to silence compile warning 2011-12-07 23:26:57 +01:00
paravirt-spinlocks.c
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paravirt.c Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-tip 2011-08-12 20:46:24 -07:00
paravirt_patch_32.c
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paravirt_patch_64.c
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pci-calgary_64.c treewide: Convert uses of struct resource to resource_size(ptr) 2011-06-10 14:55:36 +02:00
pci-dma.c iommu: Add option to group multi-function devices 2011-11-15 12:22:31 +01:00
pci-iommu_table.c arch/x86/kernel/pci-iommu_table.c: Convert sprintf_symbol to %pS 2011-05-10 10:21:35 +02:00
pci-nommu.c
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pci-swiotlb.c x86, swiotlb: Make SWIOTLB use IOMMU_INIT_* macros. 2010-08-26 15:13:37 -07:00
pcspeaker.c
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probe_roms.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
process.c x86: Fix rflags in FAKE_STACK_FRAME 2011-12-06 10:02:38 +01:00
process_32.c nohz: Remove tick_nohz_idle_enter_norcu() / tick_nohz_idle_exit_norcu() 2011-12-11 10:31:57 -08:00
process_64.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-06 14:00:12 -08:00
ptrace.c audit: inline audit_syscall_entry to reduce burden on archs 2012-01-17 16:16:56 -05:00
pvclock.c x86/pvclock: Zero last_value on resume 2010-11-28 09:33:20 +01:00
quirks.c x86, amd: Fix up numa_node information for AMD CPU family 15h model 0-0fh northbridge functions 2011-12-05 18:13:11 +01:00
reboot.c x86/reboot: Clean up coding style 2012-02-07 11:34:12 +01:00
reboot_32.S x86, reboot: Fix relocations in reboot_32.S 2011-05-02 14:44:46 -07:00
reboot_fixups_32.c x86: Ce4100: Add reboot_fixup() for CE4100 2010-11-12 00:45:41 +01:00
relocate_kernel_32.S kexec, x86: Fix incorrect jump back address if not preserving context 2011-07-21 11:19:28 +02:00
relocate_kernel_64.S kexec, x86: Fix incorrect jump back address if not preserving context 2011-07-21 11:19:28 +02:00
resource.c x86: avoid high BIOS area when allocating address space 2010-12-17 10:01:30 -08:00
rtc.c x86/rtc, mrst: Don't register a platform RTC device for for Intel MID platforms 2011-12-05 17:09:21 +01:00
setup.c Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-11 19:12:33 -08:00
setup_percpu.c x86: Unify CPU -> NUMA node mapping between 32 and 64bit 2011-01-28 14:54:09 +01:00
signal.c signal: add block_sigmask() for adding sigmask to current->blocked 2012-01-10 16:30:54 -08:00
smp.c x86/reboot: Use NMI to assist in shutting down if IRQ fails 2012-05-14 11:49:37 +02:00
smpboot.c Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-11 19:13:40 -08:00
stacktrace.c x86: Swap save_stack_trace_regs parameters 2011-06-14 22:48:51 -04:00
step.c x86-64: Add user_64bit_mode paravirt op 2011-08-04 16:13:49 -07:00
sys_i386_32.c i386: Make kernel_execve() suitable for stack unwinding 2010-09-03 08:16:02 +02:00
sys_x86_64.c x86, amd: Include linux/elf.h since we use stuff from asm/elf.h 2011-09-28 10:34:31 +02:00
syscall_32.c x86, syscall: Re-fix typo in comment 2011-11-18 16:25:07 -08:00
syscall_64.c x86: Generate system call tables and unistd_*.h from tables 2011-11-17 13:35:37 -08:00
tboot.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
tce_64.c
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test_nx.c x86: Eliminate various 'set but not used' warnings 2011-05-21 19:10:33 +02:00
test_rodata.c
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time.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
tls.c
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tls.h
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topology.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
trampoline.c memblock, x86: Replace memblock_x86_reserve/free_range() with generic ones 2011-07-14 11:47:53 -07:00
trampoline_32.S x86, trampoline: Common infrastructure for low memory trampolines 2011-02-17 21:02:43 -08:00
trampoline_64.S x86-64, trampoline: Remove unused variable 2011-02-18 15:50:36 -08:00
traps.c Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-15 11:26:35 -08:00
tsc.c Merge remote-tracking branch 'linus/master' into x86/urgent 2012-01-19 12:56:50 -08:00
tsc_sync.c x86, tsc: Skip TSC synchronization checks for tsc=reliable 2011-12-05 18:00:31 +01:00
verify_cpu.S x86: Fix common misspellings 2011-03-18 10:39:30 +01:00
vm86_32.c x86-32: Fix build failure with AUDIT=y, AUDITSYSCALL=n 2012-01-17 18:10:11 -08:00
vmlinux.lds.S x86-64: Rework vsyscall emulation and add vsyscall= parameter 2011-08-10 19:26:46 -05:00
vsmp_64.c
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vsyscall_64.c x86: Default to vsyscall=emulate 2011-12-05 12:17:29 +01:00
vsyscall_emu_64.S x86-64: Rework vsyscall emulation and add vsyscall= parameter 2011-08-10 19:26:46 -05:00
vsyscall_trace.h x86-64: Add vsyscall:emulate_vsyscall trace event 2011-08-04 16:13:53 -07:00
x86_init.c Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
x8664_ksyms_64.c x86-64, mem: Convert memmove() to assembly file and fix return value bug 2011-01-25 16:58:39 -08:00
xsave.c x86: Fix common misspellings 2011-03-18 10:39:30 +01:00