[PATCH 0/5] arm: Early IRQ enabling in the Undef user handler

[Arun KS]

On Tue, Apr 1, 2014 at 9:11 PM, Catalin Marinas <catalin.marinas at arm.com> wrote:
> On Tue, Apr 01, 2014 at 01:03:04PM +0100, Arun KS wrote:
>> On Thu, Mar 13, 2014 at 11:45 PM, Catalin Marinas
>> <catalin.marinas at arm.com> wrote:
>> > 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
>> >
>> >  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(-)
>>
>> Tested-by: Arun KS<getarunks at gmail.com>
>
> Thanks. I assume it's tested only with VFP (not crunch nor iwmmxt).
Yes.

Thanks,
Arun
>
> --
> Catalin