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3603a2512f
linux_dsm_epyc7002/arch/x86/kernel
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Don Zickus 3603a2512f x86, reboot: Use NMI instead of REBOOT_VECTOR to stop cpus 
A recent discussion started talking about the locking on the
pstore fs and how it relates to the kmsg infrastructure.  We
noticed it was possible for userspace to r/w to the pstore fs
(grabbing the locks in the process) and block the panic path
from r/w to the same fs.

The reason was the cpu with the lock could be doing work while
the crashing cpu is panic'ing.  Busting those spinlocks might
cause those cpus to step on each other's data.  Fine, fair
enough.

It was suggested it would be nice to serialize the panic path
(ie stop the other cpus) and have only one cpu running.  This
would allow us to bust the spinlocks and not worry about another
cpu stepping on the data.

Of course, smp_send_stop() does this in the panic case.
kmsg_dump() would have to be moved to be called after it.  Easy
enough.

The only problem is on x86 the smp_send_stop() function calls
the REBOOT_VECTOR.  Any cpu with irqs disabled (which pstore and
its backend ERST would do), block this IPI and thus do not stop.
 This makes it difficult to reliably log data to the pstore fs.

The patch below switches from the REBOOT_VECTOR to NMI (and
mimics what kdump does).  Switching to NMI allows us to deliver
the IPI when irqs are disabled, increasing the reliability of
this function.

However, Andi carefully noted that on some machines this
approach does not work because of broken BIOSes or whatever.

To help accomodate this, the next couple of patches will run a
selftest and provide a knob to disable.

V2:
  uses atomic ops to serialize the cpu that shuts everyone down
V3:
  comment cleanup

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>
Cc: seiji.aguchi@hds.com
Cc: vgoyal@redhat.com
Cc: mjg@redhat.com
Cc: tony.luck@intel.com
Cc: gong.chen@intel.com
Cc: satoru.moriya@hds.com
Cc: avi@redhat.com
Cc: Andi Kleen <andi@firstfloor.org>
Link: http://lkml.kernel.org/r/1318533267-18880-2-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-12-05 12:00:14 +01:00
..
acpi x86 idle: move mwait_idle_with_hints() to where it is used 2011-08-03 19:06:36 -04:00
apic x86, ioapic: Only print ioapic debug information for IRQs belonging to an ioapic chip 2011-11-10 18:31:23 +01:00
cpu x86: Fix boot failures on older AMD CPU's 2011-12-04 11:57:09 -08:00
.gitignore
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 x86, amd-nb: Rename CPU PCI id define for F4 2011-03-31 08:51:38 +02:00
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 x86, gart: Don't enforce GART aperture lower-bound by alignment 2011-04-18 10:31:38 -07:00
apm_32.c doc: fix broken references 2011-09-27 18:08:04 +02:00
asm-offsets_32.c lguest: use a special 1:1 linear pagetable mode until first switch. 2011-07-22 14:39:48 +09:30
asm-offsets_64.c x86: Partly unify asm-offsets_{32,64}.c 2011-02-10 13:31:37 +01:00
asm-offsets.c x86, asm: Cleanup unnecssary macros in asm-offsets.c 2011-02-25 16:37:32 -08:00
audit_64.c
bootflag.c
check.c x86: Don't check for BIOS corruption in first 64K when there's no need to 2011-03-09 16:36:41 +01:00
cpuid.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
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
crash.c x86, nmi: Wire up NMI handlers to new routines 2011-10-10 06:56:57 +02:00
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
dumpstack_32.c x86, dumpstack: Correct stack dump info when frame pointer is available 2011-03-18 10:51:42 +01:00
dumpstack_64.c x86: Don't use frame pointer to save old stack on irq entry 2011-07-02 18:06:36 +02:00
dumpstack.c Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2011-05-19 18:24:11 -07:00
e820.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
early_printk.c x86, earlyprintk: Move mrst early console to platform/ and fix a typo 2010-12-06 20:52:04 +01:00
early-quirks.c x86, quirk: Fix SB600 revision check 2011-03-16 14:03:32 +01:00
entry_32.S x86-32: Fix boot with CONFIG_X86_INVD_BUG 2011-08-25 13:27:14 -07:00
entry_64.S x86-64: Fix CFI data for interrupt frames 2011-09-28 19:04:52 +02:00
ftrace.c x86/ftrace: Fix compiler warning in ftrace.c 2011-05-25 19:56:26 -04:00
head32.c Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-05-19 18:08:06 -07:00
head64.c x86: Cleanup highmap after brk is concluded 2011-03-19 11:58:19 -07:00
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, trampoline: Common infrastructure for low memory trampolines 2011-02-17 21:02:43 -08:00
head.c
hpet.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
hw_breakpoint.c x86: Use this_cpu_ops to optimize code 2010-12-30 12:20:28 +01:00
i386_ksyms_32.c
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
io_delay.c
ioport.c x86: Use bitmap library functions 2011-02-17 14:59:22 +01:00
irq_32.c x86: Panic on detection of stack overflow 2011-12-05 11:37:47 +01:00
irq_64.c x86: Clean up the range of stack overflow checking 2011-12-05 11:37:48 +01:00
irq_work.c irq_work: Add generic hardirq context callbacks 2010-10-18 19:58:50 +02:00
irq.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
irqinit.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
jump_label.c x86/jump_label: add arch_jump_label_transform_static() 2011-10-25 11:54:42 -07:00
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: KVM Steal time registration 2011-07-24 11:49:36 +03:00
kvmclock.c KVM guest: prevent tracing recursion with kvmclock 2011-11-20 10:53:48 +02:00
ldt.c
machine_kexec_32.c
machine_kexec_64.c
Makefile x86, nmi: Split out nmi from traps.c 2011-10-10 06:56:47 +02:00
mca_32.c x86: Fix common misspellings 2011-03-18 10:39:30 +01:00
microcode_amd.c x86, microcode, AMD: Add microcode revision to /proc/cpuinfo 2011-10-19 16:07:30 +02:00
microcode_core.c x86, microcode: Don't request microcode from userspace unnecessarily 2011-10-13 16:20:35 +02:00
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 x86, ioapic: Consolidate mp_ioapics[] into 'struct ioapic' 2011-05-20 13:40:59 +02:00
msr.c BKL: remove extraneous #include <smp_lock.h> 2010-11-17 08:59:32 -08:00
nmi.c x86, ioapic: Only print ioapic debug information for IRQs belonging to an ioapic chip 2011-11-10 18:31:23 +01:00
paravirt_patch_32.c
paravirt_patch_64.c
paravirt-spinlocks.c
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
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 x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
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
pci-swiotlb.c
pcspeaker.c
probe_roms.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
process_32.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
process_64.c x86, nmi: Add in logic to handle multiple events and unknown NMIs 2011-10-10 06:57:01 +02:00
process.c xen/pm_idle: Make pm_idle be default_idle under Xen. 2011-12-03 10:49:58 -08:00
ptrace.c perf: Add context field to perf_event 2011-07-01 11:06:38 +02:00
pvclock.c x86/pvclock: Zero last_value on resume 2010-11-28 09:33:20 +01:00
quirks.c x86, quirks: Use pci_dev->revision 2011-07-21 10:26:00 +02:00
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
reboot.c x86, nmi: Wire up NMI handlers to new routines 2011-10-10 06:56:57 +02:00
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: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
setup_percpu.c x86: Unify CPU -> NUMA node mapping between 32 and 64bit 2011-01-28 14:54:09 +01:00
setup.c x86/platform: Add a wallclock_init func to x86_platforms ops 2011-11-10 16:20:53 +01:00
signal.c x86: Kill handle_signal()->set_fs() 2011-07-14 21:46:20 -07:00
smp.c x86, reboot: Use NMI instead of REBOOT_VECTOR to stop cpus 2011-12-05 12:00:14 +01:00
smpboot.c Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-07-22 17:02:38 -07:00
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
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_64.c
syscall_table_32.S Cross Memory Attach 2011-10-31 17:30:44 -07:00
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
test_nx.c x86: Eliminate various 'set but not used' warnings 2011-05-21 19:10:33 +02:00
test_rodata.c
time.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
tls.c
tls.h
topology.c x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
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
trampoline.c x86, trampoline: Common infrastructure for low memory trampolines 2011-02-17 21:02:43 -08:00
traps.c x86, nmi: Split out nmi from traps.c 2011-10-10 06:56:47 +02:00
tsc_sync.c
tsc.c Merge branches 'x86-detect-hyper-for-linus', 'x86-fpu-for-linus', 'x86-kexec-for-linus', 'x86-platform-for-linus', 'x86-quirks-for-linus', 'x86-tsc-for-linus' and 'x86-smpboot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2011-07-23 10:38:21 -07:00
verify_cpu.S x86: Fix common misspellings 2011-03-18 10:39:30 +01:00
vm86_32.c thp: split_huge_page_mm/vma 2011-01-13 17:32:41 -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
vsyscall_64.c x86: fix implicit include of <linux/topology.h> in vsyscall_64 2011-10-31 19:30:34 -04:00
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 x86/mrst: Avoid reporting wrong nmi status 2011-11-10 16:21:01 +01:00
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