Re: [PATCH v2 2/9] mm: move __phys_to_pfn and __pfn_to_phys to asm/generic/memory_model.h

[Nicolas Pitre]

On Tue, 29 Sep 2015, Tyler Baker wrote:

> On 29 September 2015 at 12:21, Nicolas Pitre <nicolas.pitre@xxxxxxxxxx> wrote:
> > On Tue, 25 Aug 2015, Dan Williams wrote:
> >
> >> From: Christoph Hellwig <hch@xxxxxx>
> >>
> >> Three architectures already define these, and we'll need them genericly
> >> soon.
> >>
> >> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> >> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> >> ---
> >>  arch/arm/include/asm/memory.h       |    6 ------
> >>  arch/arm64/include/asm/memory.h     |    6 ------
> >>  arch/unicore32/include/asm/memory.h |    6 ------
> >>  include/asm-generic/memory_model.h  |    6 ++++++
> >>  4 files changed, 6 insertions(+), 18 deletions(-)
> >>
> >> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> >> index b7f6fb462ea0..98d58bb04ac5 100644
> >> --- a/arch/arm/include/asm/memory.h
> >> +++ b/arch/arm/include/asm/memory.h
> >> @@ -119,12 +119,6 @@
> >>  #endif
> >>
> >>  /*
> >> - * Convert a physical address to a Page Frame Number and back
> >> - */
> >> -#define      __phys_to_pfn(paddr)    ((unsigned long)((paddr) >> PAGE_SHIFT))
> >> -#define      __pfn_to_phys(pfn)      ((phys_addr_t)(pfn) << PAGE_SHIFT)
> >> -
> >> -/*
> >>   * Convert a page to/from a physical address
> >>   */
> >>  #define page_to_phys(page)   (__pfn_to_phys(page_to_pfn(page)))
> >
> > [...]
> >
> >> diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
> >> index 14909b0b9cae..f20f407ce45d 100644
> >> --- a/include/asm-generic/memory_model.h
> >> +++ b/include/asm-generic/memory_model.h
> >> @@ -69,6 +69,12 @@
> >>  })
> >>  #endif /* CONFIG_FLATMEM/DISCONTIGMEM/SPARSEMEM */
> >>
> >> +/*
> >> + * Convert a physical address to a Page Frame Number and back
> >> + */
> >> +#define      __phys_to_pfn(paddr)    ((unsigned long)((paddr) >> PAGE_SHIFT))
> >> +#define      __pfn_to_phys(pfn)      ((pfn) << PAGE_SHIFT)
> >> +
> >
> > This patch, currently in mainline as commit 012dcef3f0, breaks LPAE on
> > ARM32 with more than 4GB of RAM. The phys_addr_t cast in the original
> > ARM definition is important when LPAE is enabled as phys_addr_t is 64
> > bits while longs are 32 bits.
> 
> Dan sent my fix above to Linus already, which is in mainline as commit
> ae4f97696889.

Excellent.  Somehow I was looking at v4.3-rc1 and not the latest.


Nicolas
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