[PATCH] Handle instruction cache maintenance fault properly
Kirill A. Shutemov
kirill at shutemov.name
Mon May 10 09:34:57 EDT 2010
On Mon, May 10, 2010 at 4:15 PM, Russell King - ARM Linux
<linux at arm.linux.org.uk> wrote:
> On Mon, May 10, 2010 at 04:07:57PM +0300, Kirill A. Shutemov wrote:
>> Between "clean D line..." and "invalidate I line" operations in
>> v7_coherent_user_range(), the memory page may get swapped out.
>> And the fault on "invalidate I line" could not be properly handled
>> causing the oops.
>
> You have to be very careful when doing this kind of change - you need to
> review the behaviour of previous ARMs to ensure that you don't throw the
> CPU into an infinite loop when an "external abort on linefetch" occurs.
>
> With older CPUs, an "external abort on linefetch" is most probably fatal
> to the process and can never be recovered.
It looks like cache maintenance fault was introduced in ARMv6.
So, what is the right way to fix it? Something like:
#if __LINUX_ARM_ARCH__ < 6
{ do_bad, SIGBUS, 0, "external
abort on linefetch" },
#else
{ do_translation_fault, SIGSEGV, SEGV_MAPERR, "I-cache
maintenance fault" },
#endif
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