On 6 July 2012 20:26, Dave Martin <dave.mar...@linaro.org> wrote: > On Fri, Jul 06, 2012 at 07:07:35PM +0100, Peter Maydell wrote: >> On 6 July 2012 00:27, Rob Herring <robherri...@gmail.com> wrote: >> > I would just change arm_add_memory to use phys_addr_t for the size >> > param. This ultimately calls memblock functions which use phys_addr_t >> > for sizes. >> >> So I have a patch that does this which basically works. However >> there is a bit I'm not sure about. arm_add_memory() does this: >> bank->size = size & PAGE_MASK; >> >> in an attempt to clear the bottom bits of the size. However, >> since PAGE_MASK is defined as: >> #define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT) >> #define PAGE_MASK (~(PAGE_SIZE-1)) >> >> PAGE_MASK is a 32 bit unsigned constant and so this & will >> clear the top 32 bits of bank->size. >> >> I'm really not sure what the best way to fix this is; suggestions? > > Maybe something like > > ~(phys_addr_t)~PAGE_MASK > > or > > ~(phys_addr_t)(PAGE_SIZE - 1) > > would work.
Mmm. It feels a bit unsatisfactory that an "obviously correct" line of code like "size &= ~PAGE_MASK" could actually be subtly wrong (seems like the kind of thing that could easily slip through code review), so I was wondering if maybe redefining PAGE_MASK so it didn't do the wrong thing on 64 bit types would be better. (That's definitely way out of my depth though.) -- PMM _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
