[RFC PATCH 2/2] arm: mm: Double logical invert for LPAE pte_write(), pte_dirty()

[Russell King - ARM Linux]

On Fri, Feb 14, 2014 at 04:55:13PM +0000, Steve Capper wrote:
> On LPAE, L_PTE_WRITE and L_PTE_DIRTY are in the upper 32-bits.
> Unfortunately, results from pte_write() and pte_dirty() are downcast
> to 32-bits by core code:
>   o gather_stats
>   o huge_pte_dirty
>   o huge_pte_write
>   o make_migration_entry
> 
> This patch adds a double logical invert to pte_write() and pte_dirty()
> for LPAE to ensure that the lower 32-bits are set if true.

We should ensure all those functions return something which is compatible
with "int" correctly.  It didn't matter for non-LPAE as the PTEs fit in
32-bit, but with LPAE, that really needs fixing independently of your
other patch.

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