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4ef702c10b
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Andi Kleen 4ef702c10b x86: fix panic with interrupts off (needed for MCE) 
For some time each panic() called with interrupts disabled
triggered the !irqs_disabled() WARN_ON in smp_call_function(),
producing ugly backtraces and confusing users.

This is a common situation with machine checks for example which
tend to call panic with interrupts disabled, but will also hit
in other situations e.g. panic during early boot.  In fact it
means that panic cannot be called in many circumstances, which
would be bad.

This all started with the new fancy queued smp_call_function,
which is then used by the shutdown path to shut down the other
CPUs.

On closer examination it turned out that the fancy RCU
smp_call_function() does lots of things not suitable in a panic
situation anyways, like allocating memory and relying on complex
system state.

I originally tried to patch this over by checking for panic
there, but it was quite complicated and the original patch
was also not very popular.  This also didn't fix some of the
underlying complexity problems.

The new code in post 2.6.29 tries to patch around this by
checking for oops_in_progress, but that is not enough to make
this fully safe and I don't think that's a real solution
because panic has to be reliable.

So instead use an own vector to reboot.  This makes the reboot
code extremly straight forward, which is definitely a big plus
in a panic situation where it is important to avoid relying on
too much kernel state.  The new simple code is also safe to be
called from interupts off region because it is very very simple.

There can be situations where it is important that panic
is reliable.  For example on a fatal machine check the panic
is needed to get the system up again and running as quickly
as possible.  So it's important that panic is reliable and
all function it calls simple.

This is why I came up with this simple vector scheme.
It's very hard to beat in simplicity.  Vectors are not
particularly precious anymore since all big systems are
using per CPU vectors.

Another possibility would have been to use an NMI similar
to kdump, but there is still the problem that NMIs don't
work reliably on some systems due to BIOS issues.  NMIs
would have been able to stop CPUs running with interrupts
off too.  In the sake of universal reliability I opted for
using a non NMI vector for now.

I put the reboot vector into the highest priority bucket of
the APIC vectors and moved the 64bit UV_BAU message down
instead into the next lower priority.

[ Impact: bug fix, fixes an old regression ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-03 14:45:35 -07:00
..
acpi x86, irq: don't call mp_config_acpi_gsi() if update_mptable is not enabled 2009-05-18 09:33:29 +02:00
apic Merge branch 'irq/numa' into x86/mce3 2009-06-01 15:25:31 -07:00
cpu x86, mce: export MCE severities coverage via debugfs 2009-06-03 14:45:34 -07:00
.gitignore
alternative.c x86: expand irq-off region in text_poke() 2009-03-10 16:24:23 +01:00
amd_iommu_init.c amd-iommu: fix iommu flag masks 2009-05-04 15:05:24 +02:00
amd_iommu.c Merge git://git.infradead.org/iommu-2.6 2009-04-03 10:36:57 -07:00
aperture_64.c aperture_64.c: clarify that too small aperture is valid reason for this code 2008-11-28 15:24:39 +01:00
apm_32.c Merge branch 'cpumask-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-03-31 13:33:50 +10:30
asm-offsets_32.c pm: rework includes, remove arch ifdefs 2009-04-01 08:59:16 -07:00
asm-offsets_64.c pm: rework includes, remove arch ifdefs 2009-04-01 08:59:16 -07:00
asm-offsets.c
audit_64.c
bios_uv.c x86, UV: system table in bios accessed after unmap 2009-04-03 19:25:57 +02:00
bootflag.c
check.c x86: fix 64k corruption-check 2009-03-15 07:03:15 +01:00
cpuid.c Merge branch 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-03 12:04:39 -08:00
crash_dump_32.c
crash_dump_64.c
crash.c x86, apic: remove duplicate asm/apic.h inclusions 2009-02-17 17:52:44 +01:00
doublefault_32.c
ds.c x86, pebs: correct qualifier passed to ds_write_config() from ds_request_pebs() 2009-03-06 16:13:15 +01:00
dumpstack_32.c ftrace: print real return in dumpstack for function graph 2008-12-03 08:56:25 +01:00
dumpstack_64.c x86-64: Move current task from PDA to per-cpu and consolidate with 32-bit. 2009-01-19 00:38:58 +09:00
dumpstack.c Merge commit 'origin/master' into next 2009-03-30 14:04:53 +11:00
dumpstack.h ftrace: print real return in dumpstack for function graph 2008-12-03 08:56:25 +01:00
e820.c x86: fix boot hang in early_reserve_e820() 2009-05-07 21:42:39 -07:00
early_printk.c x86: properly __init-annotate recent early_printk additions 2009-03-13 02:37:18 +01:00
early-quirks.c x86: only scan the root bus in early PCI quirks 2009-01-09 12:46:22 -08:00
efi_32.c
efi_64.c Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2 2009-03-27 17:28:43 +01:00
efi_stub_32.S Merge branch 'x86/asm' into x86/mm 2009-02-25 08:27:46 +01:00
efi_stub_64.S x86: efi_stub_32,64 - add missing ENDPROCs 2009-02-24 18:08:40 +01:00
efi.c Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2 2009-03-27 17:28:43 +01:00
entry_32.S x86: entry_32.S fix compile warnings - fix work mask bit width 2009-03-14 09:42:51 +01:00
entry_64.S x86: fix panic with interrupts off (needed for MCE) 2009-06-03 14:45:35 -07:00
ftrace.c x86/function-graph: fix constraint for recording old return value 2009-05-13 13:52:19 -04:00
geode_32.c
head32.c x86-32: use brk segment for allocating initial kernel pagetable 2009-03-14 17:23:47 -07:00
head64.c x86: add brk allocation for very, very early allocations 2009-03-14 15:37:14 -07:00
head_32.S x86-32: tighten the bound on additional memory to map 2009-03-17 11:52:10 -07:00
head_64.S x86: head_64.S - use IDT_ENTRIES instead of hardcoded number 2009-02-24 18:08:38 +01:00
head.c x86, debug: remove EBDA debug printk 2008-12-12 11:08:42 +01:00
hpet.c x86: hpet: fix periodic mode programming on AMD 81xx 2009-04-22 15:53:40 +02:00
i386_ksyms_32.c
i387.c x86, math-emu: fix init_fpu for task != current 2009-03-04 20:33:16 +01:00
i8237.c i8327: fix outb() parameter order 2009-02-10 13:13:23 +01:00
i8253.c clocksource: pass clocksource to read() callback 2009-04-21 13:41:47 -07:00
i8259.c x86: refactor x86_quirks support 2009-02-23 00:08:11 +01:00
init_task.c take init_fs to saner place 2008-12-31 18:07:42 -05:00
io_delay.c x86: io_delay.c cleanup 2009-03-21 16:57:04 +05:30
ioport.c x86-32: use non-lazy io bitmap context switching 2009-03-02 12:07:48 +01:00
irq_32.c Merge branch 'tj-percpu' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/percpu 2009-02-24 21:52:45 +01:00
irq_64.c x86: unify do_IRQ() 2009-02-09 12:16:05 +01:00
irq.c x86, mce: add MCE poll count to /proc/interrupts 2009-06-03 14:40:38 -07:00
irqinit.c x86: fix panic with interrupts off (needed for MCE) 2009-06-03 14:45:35 -07:00
k8.c x86, gart: fix gart detection for Fam11h CPUs 2008-10-28 17:10:27 +01:00
kdebugfs.c x86: kdebugfs.c cleanup 2009-03-21 16:55:45 +05:30
kgdb.c kgdb,i386: use address that SP register points to in the exception frame 2009-05-15 07:56:25 -05:00
kprobes.c Merge branch 'tracing/core-v2' into tracing-for-linus 2009-04-02 00:49:02 +02:00
kvm.c x86: with the last user gone, remove set_pte_present 2009-03-19 14:04:19 +01:00
kvmclock.c clocksource: pass clocksource to read() callback 2009-04-21 13:41:47 -07:00
ldt.c x86: ldt.c fix style problems 2009-01-02 17:46:24 +01:00
machine_kexec_32.c x86, kexec: fix crashdump panic with CONFIG_KEXEC_JUMP 2009-05-07 22:01:05 -07:00
machine_kexec_64.c x86, kexec: fix crashdump panic with CONFIG_KEXEC_JUMP 2009-05-07 22:01:05 -07:00
Makefile Merge branch 'linus' into irq/numa 2009-06-01 21:06:21 +02:00
mca_32.c x86: refactor x86_quirks support 2009-02-23 00:08:11 +01:00
mfgpt_32.c cpumask: remove references to struct irqaction's mask field. 2009-03-30 22:05:14 +10:30
microcode_amd.c x86: microcode: cleanup 2009-03-18 13:51:17 +01:00
microcode_core.c Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-17 09:56:11 -07:00
microcode_intel.c x86: microcode: cleanup 2009-03-18 13:51:17 +01:00
mmconf-fam10h_64.c x86: move various CPU initialization objects into .cpuinit.rodata 2009-03-12 13:13:07 +01:00
module_32.c x86: module_32.c fix style problems 2009-01-12 11:22:55 +01:00
module_64.c x86: module_64.c fix style problems 2009-01-12 11:23:01 +01:00
mpparse.c x86, irq: don't call mp_config_acpi_gsi() if update_mptable is not enabled 2009-05-18 09:33:29 +02:00
msr.c x86: msr.c fix style problems 2009-01-12 11:22:50 +01:00
olpc.c x86, olpc: fix model detection without OFW 2009-02-14 23:05:25 +01:00
paravirt_patch_32.c x86/pvops: add a paravirt_ident functions to allow special patching 2009-01-30 14:51:44 -08:00
paravirt_patch_64.c x86/pvops: add a paravirt_ident functions to allow special patching 2009-01-30 14:51:44 -08:00
paravirt-spinlocks.c x86: remove byte locks 2009-01-20 17:14:28 +01:00
paravirt.c x86: Fix performance regression caused by paravirt_ops on native kernels 2009-05-15 20:07:42 +02:00
pci-calgary_64.c x86, ia64: convert to use generic dma_map_ops struct 2009-01-06 14:06:57 +01:00
pci-dma.c dma-mapping: replace all DMA_24BIT_MASK macro with DMA_BIT_MASK(24) 2009-04-07 08:31:12 -07:00
pci-gart_64.c Merge branch 'linus' into core/iommu 2009-03-05 12:47:28 +01:00
pci-nommu.c dma-mapping: replace all DMA_32BIT_MASK macro with DMA_BIT_MASK(32) 2009-04-07 08:31:11 -07:00
pci-swiotlb.c x86: pci-swiotlb.c swiotlb_dma_ops should be static 2009-04-14 02:51:04 +02:00
pcspeaker.c
pmtimer_64.c
probe_roms_32.c x86: move mach-default/*.h files to asm/ 2009-01-29 14:16:51 +01:00
process_32.c Simplify copy_thread() 2009-04-02 19:04:51 -07:00
process_64.c Simplify copy_thread() 2009-04-02 19:04:51 -07:00
process.c Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-05 11:04:19 -07:00
ptrace.c tracing/syscalls: use a dedicated file header 2009-04-09 05:43:32 +02:00
pvclock.c
quirks.c x86, hpet: Stop soliciting hpet=force users on ICH4M 2009-04-24 08:41:39 +02:00
reboot_fixups_32.c
reboot.c x86: DMI match for the Sony VGN-Z540N as it needs BIOS reboot 2009-05-22 09:11:30 +02:00
relocate_kernel_32.S x86, kexec: fix kexec x86 coding style 2009-03-10 18:13:25 -07:00
relocate_kernel_64.S x86, kexec: x86_64: add kexec jump support for x86_64 2009-03-10 18:13:25 -07:00
rtc.c x86: rtc.c cleanup 2009-03-21 16:56:37 +05:30
scx200_32.c
setup_percpu.c x86: Remove remap percpu allocator for the time being 2009-05-25 05:37:55 +02:00
setup.c x86: move x86_quirk_pre_intr_init() to irqinit_32.c 2009-04-10 14:35:53 +02:00
signal.c x86, mce: use 64bit machine check code on 32bit 2009-05-28 09:24:13 -07:00
smp.c x86: fix panic with interrupts off (needed for MCE) 2009-06-03 14:45:35 -07:00
smpboot.c x86: smpboot - wakeup_secondary should be done via __cpuinit section 2009-04-19 10:22:14 +02:00
stacktrace.c x86: update copyrights 2009-01-31 04:21:18 +01:00
step.c
sys_i386_32.c
sys_x86_64.c
syscall_64.c x86: Fix ASM_X86__ header guards 2008-10-22 22:55:23 -07:00
syscall_table_32.S preadv/pwritev: Add preadv and pwritev system calls. 2009-04-02 19:05:08 -07:00
tce_64.c
test_nx.c
test_rodata.c
time_32.c x86: refactor x86_quirks support 2009-02-23 00:08:11 +01:00
time_64.c cpumask: remove references to struct irqaction's mask field. 2009-03-30 22:05:14 +10:30
tlb_uv.c Merge branch 'x86/uv' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-04-16 16:43:20 -07:00
tls.c
tls.h
topology.c x86: topology.c cleanup 2009-03-21 16:55:24 +05:30
trampoline_32.S x86: use _types.h headers in asm where available 2009-02-13 11:35:01 -08:00
trampoline_64.S x86: use _types.h headers in asm where available 2009-02-13 11:35:01 -08:00
trampoline.c x86: change static allocation of trampoline area 2008-12-08 13:49:45 +01:00
traps.c Merge branch 'irq/numa' into x86/mce3 2009-06-01 15:25:31 -07:00
tsc_sync.c Merge branches 'x86/apic', 'x86/cleanups', 'x86/cpufeature', 'x86/crashdump', 'x86/debug', 'x86/defconfig', 'x86/detect-hyper', 'x86/doc', 'x86/dumpstack', 'x86/early-printk', 'x86/fpu', 'x86/idle', 'x86/io', 'x86/memory-corruption-check', 'x86/microcode', 'x86/mm', 'x86/mtrr', 'x86/nmi-watchdog', 'x86/pat2', 'x86/pci-ioapic-boot-irq-quirks', 'x86/ptrace', 'x86/quirks', 'x86/reboot', 'x86/setup-memory', 'x86/signal', 'x86/sparse-fixes', 'x86/time', 'x86/uv' and 'x86/xen' into x86/core 2008-12-23 16:27:23 +01:00
tsc.c clocksource: pass clocksource to read() callback 2009-04-21 13:41:47 -07:00
uv_irq.c x86, apic: remove genapic.h 2009-02-17 17:52:44 +01:00
uv_sysfs.c x86: prevent /sys/firmware/sgi_uv from being created on non-uv systems 2009-04-08 14:58:10 +02:00
uv_time.c uv_time: add parameter to uv_read_rtc() 2009-04-22 17:41:25 +02:00
verify_cpu_64.S
visws_quirks.c x86: convert obsolete irq_desc_t typedef to struct irq_desc 2009-03-11 09:49:01 +01:00
vm86_32.c x86: use regparm(3) for passed-in pt_regs pointer 2009-02-11 14:00:56 -08:00
vmi_32.c x86: with the last user gone, remove set_pte_present 2009-03-19 14:04:19 +01:00
vmiclock_32.c clocksource: pass clocksource to read() callback 2009-04-21 13:41:47 -07:00
vmlinux_32.lds.S x86-32: move _end to a dummy section 2009-03-17 14:16:02 -07:00
vmlinux_64.lds.S x86/brk: put the brk reservations in their own section 2009-03-17 12:58:15 -07:00
vmlinux.lds.S
vsmp_64.c Revert "x86: don't compile vsmp_64 for 32bit" 2009-03-25 21:34:28 +01:00
vsyscall_64.c Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-28 12:21:10 -08:00
x8664_ksyms_64.c x86: convert pda ops to wrappers around x86 percpu accessors 2009-01-16 14:20:22 +01:00
xsave.c x86-64: fix FPU corruption with signals and preemption 2009-04-20 14:33:00 -07:00