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arm: Early IRQ enabling in the Undef user handler

Catalin Marinas linux-arm-kernel 1 version New

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  1. v1 Latest0 of 5 patches 0 repliesNew

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Cover letter [PATCH 0/5] arm: Early IRQ enabling in the Undef user handler
Quoted 33 lines · Arun KS
Quoted 22 lines · Catalin Marinas

I've had this series in my repo for a long time with some follow-ups on the list but without any conclusive ACK or NAK. If there are no objections, I plan to send it to the patch system.

The only change is rebasing to 3.14-rc6 and adding some Cc for the crunch bits.

The __und_usr handler accesses the user space to read the opcode of the faulting instruction. This is currently done with interrupts disabled but it could potentially cause a data abort of the page table was modified from another CPU. The data abort with interrupts disabled triggers a might_sleep() warning in do_page_fault() or, worse, deadlock on the pte lock when TLB ops broadcasting is enabled (ARM11MPCore or A15 together with workaround for erratum 798181).

Catalin Marinas (5):
arm: Move asm macro get_thread_info to asm/assembler.h
arm: Add {inc,dec}_preempt_count asm macros
arm: Disable preemption in iwmmxt_task_enable()
arm: Disable preemption in crunch_task_enable()
arm: Enable IRQs before attempting to read user space in __und_usr

Quoted 8 lines
 arch/arm/include/asm/assembler.h   | 42 ++++++++++++++++++++++++++++++++++++++
 arch/arm/kernel/entry-armv.S       | 11 ++++++----
 arch/arm/kernel/entry-header.S     | 11 ----------
 arch/arm/kernel/iwmmxt.S           | 15 ++++++++++----
 arch/arm/mach-ep93xx/crunch-bits.S | 13 +++++++++---
 arch/arm/vfp/entry.S               | 28 ++++++++-----------------
 arch/arm/vfp/vfphw.S               | 19 ++++++-----------
 7 files changed, 84 insertions(+), 55 deletions(-)
Quoted 1 line
Tested-by Arun KS<[email protected]>

Thanks. I assume it's tested only with VFP (not crunch nor iwmmxt).

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