[PATCH] ARM: tlb: __flush_tlb_mm need to use int asid var for BE correct operation

[will.deacon@arm.com (Will Deacon)]

On Mon, Oct 07, 2013 at 11:45:24AM +0100, Russell King - ARM Linux wrote:
> On Sun, Oct 06, 2013 at 11:47:38PM -0700, Victor Kamensky wrote:
> > __flush_tlb_mm function need to use intermediate 'int' type 'asid'
> > variable int tlb_op macro call. Direct use of ASID macro produces
> > 64 bit unsigned long long type passed to inline assembler statement
> > as 'r' operand (32bit), and resulting behavior is not well specified.
> > It works in little endian case, but is broken in big endian case. In
> > big endian case gcc generate such code that 0 is passed to
> > 'mcr	15, 0, r4, cr8, cr3, {2}' operation.
> > 
> > Note other functions like __local_flush_tlb_mm, and local_flush_tlb_mm
> > already use intermediate 'asid' variable in similar code.
> 
> A much better solution would be to ensure that ASID() only returns
> the 'unsigned' type, not a long long type.
> 
> #define ASID(mm)        ((unsigned)(mm)->context.id.counter & ~ASID_MASK)

Yup, that looks good to me. This is similar to the problem Ben already fixed
in the mmid macro, so I think this should be included as part of his BE
series.

Speaking of which -- it's probably a good time to refresh and repost that if
we're aiming for 3.13...

Will