On Tue, Nov 10, 2015 at 01:34:29PM +0100, Borislav Petkov wrote:
> On Tue, Nov 10, 2015 at 01:18:10AM +0200, Kirill A. Shutemov wrote:
> > diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
> > index dd5b0aa9dd2f..c1e797266ce9 100644
> > --- a/arch/x86/include/asm/pgtable_types.h
> > +++ b/arch/x86/include/asm/pgtable_types.h
> > @@ -279,17 +279,14 @@ static inline pmdval_t native_pmd_val(pmd_t pmd)
> > static inline pudval_t pud_pfn_mask(pud_t pud)
> > {
> > if (native_pud_val(pud) & _PAGE_PSE)
> > - return PUD_PAGE_MASK & PHYSICAL_PAGE_MASK;
> > + return ~((1ULL << PUD_SHIFT) - 1) & PHYSICAL_PAGE_MASK;
>
> In file included from ./arch/x86/include/asm/boot.h:5:0,
> from ./arch/x86/boot/boot.h:26,
> from arch/x86/realmode/rm/wakemain.c:2:
> ./arch/x86/include/asm/pgtable_types.h: In function ‘pud_pfn_mask’:
> ./arch/x86/include/asm/pgtable_types.h:282:10: warning: large integer implicitly truncated to unsigned type [-Woverflow]
> return ~((1ULL << PUD_SHIFT) - 1) & PHYSICAL_PAGE_MASK;
> ^
> ./arch/x86/include/asm/pgtable_types.h: In function ‘pmd_pfn_mask’:
> ./arch/x86/include/asm/pgtable_types.h:300:10: warning: large integer implicitly truncated to unsigned type [-Woverflow]
> return ~((1ULL << PMD_SHIFT) - 1) & PHYSICAL_PAGE_MASK;
> ^
> In file included from ./arch/x86/include/asm/boot.h:5:0,
> from arch/x86/realmode/rm/../../boot/boot.h:26,
> from arch/x86/realmode/rm/../../boot/video-mode.c:18,
> from arch/x86/realmode/rm/video-mode.c:1:
> ./arch/x86/include/asm/pgtable_types.h: In function ‘pud_pfn_mask’:
> ./arch/x86/include/asm/pgtable_types.h:282:10: warning: large integer implicitly truncated to unsigned type [-Woverflow]
> return ~((1ULL << PUD_SHIFT) - 1) & PHYSICAL_PAGE_MASK;
> ^
> ...
>
> That's a 64-bit config.
Oh.. pmdval_t/pudval_t is 'unsinged long' on 64 bit. But realmode code
uses -m16 which makes 'unsigned long' 32-bit therefore truncation warning.
These helpers not really used in realmode code. I see few ways out:
- convert helpers to macros to avoid their translation;
- wrap the code into not-for-realmode ifdef. (Do we have any?);
- convert pudval_t/pmdval_t to u64 for 64-bit. I'm not sure what side
effects would it have.
Any opinions?
--
Kirill A. Shutemov
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