mbox series

[v2,0/9] arm64: rework UNDEFINED instruction traps

Message ID 20221019144123.612388-1-mark.rutland@arm.com (mailing list archive)
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Series arm64: rework UNDEFINED instruction traps | expand

Message

Mark Rutland Oct. 19, 2022, 2:41 p.m. UTC 
This series reworks the way UNDEFINED instruction traps are handled,
removing some dynamic data structure manipulation and related locking.
This makes the code a bit simpler and removes some unnecessary
bottlenecks when traps are handled.

My original aim for this series was to get rid of the RCU_NONIDLE() call
in cpu_suspend(), requiring the removal of the undef_hook list
manipulation. In the process of looking at that I figured we had a set
of related problems with UNDEF handling and deprecated instruction
handling, which this series addresses. This series does not remove the
RCU_NONIDLE() call from cpu_suspend() as removing that will require
further rework of the suspend code (e.g. for noinstr safety).

I've tested this series in VMs on ThunderX2 (for the ID reg emulation
changes) and a Raspberry Pi 4 (for the armv8_deprecated changes), as
described in the relevant commits.

Since v1 [1]:
* Rebase atop v6.1-rc1
* Fix typos

[1] https://lore.kernel.org/linux-arm-kernel/20220928102659.247510-1-mark.rutland@arm.com/

Thanks,
Mark.

Mark Rutland (9):
  arm64: allow kprobes on EL0 handlers
  arm64: split EL0/EL1 UNDEF handlers
  arm64: factor out EL1 SSBS emulation hook
  arm64: factor insn read out of call_undef_hook()
  arm64: rework EL0 MRS emulation
  arm64: armv8_deprecated: fold ops into insn_emulation
  arm64: armv8_deprecated move emulation functions
  arm64: armv8_deprecated: move aarch32 helper earlier
  arm64: armv8_deprecated: rework deprected instruction handling

 arch/arm64/include/asm/cpufeature.h  |   3 +-
 arch/arm64/include/asm/exception.h   |   7 +-
 arch/arm64/include/asm/spectre.h     |   2 +
 arch/arm64/include/asm/traps.h       |  19 +-
 arch/arm64/kernel/armv8_deprecated.c | 567 +++++++++++++--------------
 arch/arm64/kernel/cpufeature.c       |  23 +-
 arch/arm64/kernel/entry-common.c     |   8 +-
 arch/arm64/kernel/proton-pack.c      |  26 +-
 arch/arm64/kernel/traps.c            |  93 ++---
 9 files changed, 345 insertions(+), 403 deletions(-)

Comments

Will Deacon Nov. 14, 2022, 2:20 p.m. UTC | #1 
On Wed, 19 Oct 2022 15:41:14 +0100, Mark Rutland wrote:
> This series reworks the way UNDEFINED instruction traps are handled,
> removing some dynamic data structure manipulation and related locking.
> This makes the code a bit simpler and removes some unnecessary
> bottlenecks when traps are handled.
> 
> My original aim for this series was to get rid of the RCU_NONIDLE() call
> in cpu_suspend(), requiring the removal of the undef_hook list
> manipulation. In the process of looking at that I figured we had a set
> of related problems with UNDEF handling and deprecated instruction
> handling, which this series addresses. This series does not remove the
> RCU_NONIDLE() call from cpu_suspend() as removing that will require
> further rework of the suspend code (e.g. for noinstr safety).
> 
> [...]

Applied to arm64 (for-next/undef-traps), thanks!

[1/9] arm64: allow kprobes on EL0 handlers
      https://git.kernel.org/arm64/c/5111047c6c82
[2/9] arm64: split EL0/EL1 UNDEF handlers
      https://git.kernel.org/arm64/c/59a75653d8f9
[3/9] arm64: factor out EL1 SSBS emulation hook
      https://git.kernel.org/arm64/c/e3bee62254e1
[4/9] arm64: factor insn read out of call_undef_hook()
      https://git.kernel.org/arm64/c/2bef997bb4d4
[5/9] arm64: rework EL0 MRS emulation
      https://git.kernel.org/arm64/c/796ab8bb33c5
[6/9] arm64: armv8_deprecated: fold ops into insn_emulation
      https://git.kernel.org/arm64/c/e86cf2e60826
[7/9] arm64: armv8_deprecated move emulation functions
      https://git.kernel.org/arm64/c/270af901e2c2
[8/9] arm64: armv8_deprecated: move aarch32 helper earlier
      https://git.kernel.org/arm64/c/37402c31aa9c
[9/9] arm64: armv8_deprecated: rework deprected instruction handling
      https://git.kernel.org/arm64/c/b6d6c0923f59

Cheers,