[v4,0/8] arm64: IRQ priority masking and Pseudo-NMI fixes

Message

Julien Thierry June 11, 2019, 9:38 a.m. UTC

Hi,

Version one[1] of this series attempted to fix the issue reported by
Zenghui[2] when using the function_graph tracer with IRQ priority
masking.

Since then, I realized that priority masking and the use of Pseudo-NMIs
was more broken than I thought.

* Patch 1-2 are just some cleanup
* Patch 3 fixes a potential issue with not clobbering condition flags
  in irqflags operations
* Patch 4 fixes an issue where calling C code in Pseudo-NMI before
  entering NMI enter could lead to potential races
* Patch 5 fixes the function_graph issue when using priority masking
* Patch 6 introduces some debug to hopefully avoid breaking things in
  the future
* Patch 7 is a rebased version of the patch sent by Wei Li[3] fixing
  an error that can happen during on some platform using the priority
  masking feature
* Patch 8 re-enables the Pseudo-NMI selection

Changes since V3 [4]:
- Rebase on v5.2-rc4
- Fix comments/typos/missed updates
- Use single condition evalution for nmi_enter and nmi_exit

Changes since V2 [5]:
- Rebase on v5.2-rc3
- clobber conditions flags for asm that needs it as pointed out by Marc Z.
  and Robin M.
- Fix the naming of the new PMR bit value
- Introduce some helper for the debug conditions
- use WARN_ONCE for debug that might be very noisy
- Reenable pseudo NMI.

Changes since V1 [1]:
- Fix possible race condition between NMI and trace irqflags
- Simplify the representation of PSR.I in the PMR value
- Include Wei Li's fix
- Rebase on v5.1-rc7

[1] https://marc.info/?l=linux-arm-kernel&m=155542458004480&w=2
[2] https://www.spinics.net/lists/arm-kernel/msg716956.html
[3] https://www.spinics.net/lists/arm-kernel/msg722171.html
[4] https://lkml.org/lkml/2019/6/6/280
[5] https://lkml.org/lkml/2019/4/29/643

Cheers,

Julien

-->

Julien Thierry (7):
  arm64: Do not enable IRQs for ct_user_exit
  arm64: irqflags: Pass flags as readonly operand to restore instruction
  arm64: irqflags: Add condition flags to inline asm clobber list
  arm64: Fix interrupt tracing in the presence of NMIs
  arm64: Fix incorrect irqflag restore for priority masking
  arm64: irqflags: Introduce explicit debugging for IRQ priorities
  arm64: Allow selecting Pseudo-NMI again

Wei Li (1):
  arm64: fix kernel stack overflow in kdump capture kernel

 arch/arm64/Kconfig                  | 12 +++++-
 arch/arm64/include/asm/arch_gicv3.h |  4 +-
 arch/arm64/include/asm/cpufeature.h |  6 +++
 arch/arm64/include/asm/daifflags.h  | 75 +++++++++++++++++++++------------
 arch/arm64/include/asm/irqflags.h   | 79 +++++++++++++++++-----------------
 arch/arm64/include/asm/kvm_host.h   |  7 ++--
 arch/arm64/include/asm/ptrace.h     | 10 ++++-
 arch/arm64/kernel/entry.S           | 84 +++++++++++++++++++++++++++++--------
 arch/arm64/kernel/irq.c             | 26 ++++++++++++
 arch/arm64/kernel/process.c         |  2 +-
 arch/arm64/kernel/smp.c             |  6 +--
 arch/arm64/kvm/hyp/switch.c         |  2 +-
 drivers/irqchip/irq-gic-v3.c        |  7 ++++
 kernel/irq/irqdesc.c                |  8 +++-
 14 files changed, 228 insertions(+), 100 deletions(-)

--
1.9.1

Comments

Marc Zyngier June 11, 2019, 1:28 p.m. UTC | #1

Hi Julien,

On 11/06/2019 10:38, Julien Thierry wrote:
> Hi,
> 
> Version one[1] of this series attempted to fix the issue reported by
> Zenghui[2] when using the function_graph tracer with IRQ priority
> masking.
> 
> Since then, I realized that priority masking and the use of Pseudo-NMIs
> was more broken than I thought.
> 
> * Patch 1-2 are just some cleanup
> * Patch 3 fixes a potential issue with not clobbering condition flags
>   in irqflags operations
> * Patch 4 fixes an issue where calling C code in Pseudo-NMI before
>   entering NMI enter could lead to potential races
> * Patch 5 fixes the function_graph issue when using priority masking
> * Patch 6 introduces some debug to hopefully avoid breaking things in
>   the future
> * Patch 7 is a rebased version of the patch sent by Wei Li[3] fixing
>   an error that can happen during on some platform using the priority
>   masking feature
> * Patch 8 re-enables the Pseudo-NMI selection
> 
> Changes since V3 [4]:
> - Rebase on v5.2-rc4
> - Fix comments/typos/missed updates
> - Use single condition evalution for nmi_enter and nmi_exit

Thanks for following up on this. For the whole series:

Reviewed-by: Marc Zyngier <[e-mail]>

	M.

Catalin Marinas June 21, 2019, 10:27 a.m. UTC | #2

On Tue, Jun 11, 2019 at 10:38:05AM +0100, Julien Thierry wrote:
> Julien Thierry (7):
>   arm64: Do not enable IRQs for ct_user_exit
>   arm64: irqflags: Pass flags as readonly operand to restore instruction
>   arm64: irqflags: Add condition flags to inline asm clobber list
>   arm64: Fix interrupt tracing in the presence of NMIs
>   arm64: Fix incorrect irqflag restore for priority masking
>   arm64: irqflags: Introduce explicit debugging for IRQ priorities
>   arm64: Allow selecting Pseudo-NMI again
> 
> Wei Li (1):
>   arm64: fix kernel stack overflow in kdump capture kernel

I queued these patches for 5.3 (and should appear in next soon). Thanks.