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

From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: catalin.marinas@arm.com, james.morse@arm.com, joey.gouly@arm.com,
	mark.rutland@arm.com, peterz@infradead.org, will@kernel.org
Subject: [PATCH v2 0/9] arm64: rework UNDEFINED instruction traps
Date: Wed, 19 Oct 2022 15:41:14 +0100	[thread overview]
Message-ID: <20221019144123.612388-1-mark.rutland@arm.com> (raw)

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(-)

-- 
2.30.2

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