[PATCH v2 0/3] Enable support IPI_CPU_CRASH_STOP to be pseudo-NMI

[Yuichi Ito]

This patchset enables IPI_CPU_CRASH_STOP IPI to be pseudo-NMI.
This allows kdump to collect system information even when the CPU is in
a HARDLOCKUP state.

Only IPI_CPU_CRASH_STOP uses NMI and the other IPIs remain normal IRQs.

The patch has been tested on FX1000.

It also uses some of Sumit's IPI patch set for NMI.[1]

[1] https://lore.kernel.org/lkml/1603983387-8738-3-git-send-email-sumit.garg@xxxxxxxxxx/

$ echo 1 > /proc/sys/kernel/panic_on_rcu_stal
$ echo HARDLOCKUP > /sys/kernel/debug/provoke-crash/DIRECT
   : kernel panics and crash kernel boot
   : makedumpfile saves the system state at HARDLOCKUP in vmcore.

crash utility:
 #7 [fffffe00290afd30] lkdtm_HARDLOCKUP at fffffe0010857ee8
 #8 [fffffe00290afd40] direct_entry at fffffe0010857c94
 #9 [fffffe00290afd90] full_proxy_write at fffffe001055dea0
#10 [fffffe00290afdd0] vfs_write at fffffe001047533c
#11 [fffffe00290afe10] ksys_write at fffffe001047563c
#12 [fffffe00290afe60] __arm64_sys_write at fffffe00104756e8
#13 [fffffe00290afe70] do_el0_svc at fffffe00101590cc
#14 [fffffe00290afea0] el0_svc at fffffe0010147a30
#15 [fffffe00290afeb0] el0_sync_handler at fffffe001014835c
#16 [fffffe00290afff0] el0_sync at fffffe0010142c14

Changes in v1:
- Rebased to head of upstream master.
- Rebased to Sumit's latest IPIs patch-set [1].

[1] https://lore.kernel.org/lkml/1603983387-8738-3-git-send-email-sumit.garg@xxxxxxxxxx/

- Add conditional branch of local_irq_disable(). 

Sumit Garg (1):
  irqchip/gic-v3: Enable support for SGIs to act as NMIs

Yuichi Ito (2):
  arch64: smp: Register IPI_CPU_CRASH_STOP IPI as pseudo-NMI
  arch64: smp: Disable priority masking when received NMI on PSR.I section

 arch/arm64/kernel/smp.c      | 44 +++++++++++++++++++++++++++++++++++---------
 drivers/irqchip/irq-gic-v3.c | 29 +++++++++++++++++++++--------
 2 files changed, 56 insertions(+), 17 deletions(-)

-- 
1.8.3.1