[PATCH 1/2] arm64: mm: dump: fix shift warning

[Mark Rutland]

On Fri, Dec 05, 2014 at 01:39:56PM +0000, Steve Capper wrote:
> On 5 December 2014 at 12:34, Mark Rutland <mark.rutland at arm.com> wrote:
> > When building with 48-bit VAs, it's possible to get the following
> > warning when building the arm64 page table dumping code:
> >
> > arch/arm64/mm/dump.c: In function ‘walk_pgd’:
> > arch/arm64/mm/dump.c:266:2: warning: right shift count >= width of type
> >   pgd_t *pgd = pgd_offset(mm, 0);
> >   ^
> >
> > As pgd_offset is a macro and the second argument is not cast to any
> > particular type, the zero will be given integer type by the compiler.
> > As pgd_offset passes the pargument to pgd_index, we then try to shift
> > the 32-bit integer by at least 39 bits (for 4k pages).
> >
> > Elsewhere the pgd_offset is passed a second argument of unsigned long
> > type, so let's do the same here by passing '0UL' rather than '0'.
> >
> 
> Hi Mark,
> Thanks, I must not have spotted that warning earlier.

Me neither, I'd tested on this configuration but somehow missed the
build warning.

> Acked-by: Steve Capper <steve.capper at linaro.org>

Cheers!

Mark.