On Sat, Mar 23, 2024 at 11:16:43AM -0400, peterx@xxxxxxxxxx wrote: > From: Peter Xu <peterx@xxxxxxxxxx> > > The comment in the code explains the reasons. We took a different approach > comparing to pmd_pfn() by providing a fallback function. > > Another option is to provide some lower level config options (compare to > HUGETLB_PAGE or THP) to identify which layer an arch can support for such > huge mappings. However that can be an overkill. > > Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Closes: https://lore.kernel.org/oe-kbuild-all/202403231529.HRev1zcD-lkp@xxxxxxxxx/ Also: Closes: https://lore.kernel.org/oe-kbuild-all/202403240112.kHKVSfCL-lkp@xxxxxxxxx/ > Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> > --- > > Andrew, > > If we care about per-commit build errors (and if it is ever feasible to > reorder), we can move this patch to be before the patch "mm/gup: handle > huge pud for follow_pud_mask()" in mm-unstable to unbreak build on that > commit. > > Thanks, > --- > arch/riscv/include/asm/pgtable.h | 1 + > arch/s390/include/asm/pgtable.h | 1 + > arch/sparc/include/asm/pgtable_64.h | 1 + > arch/x86/include/asm/pgtable.h | 1 + > include/linux/pgtable.h | 10 ++++++++++ > 5 files changed, 14 insertions(+) > > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index 20242402fc11..0ca28cc8e3fa 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -646,6 +646,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd) > > #define __pud_to_phys(pud) (__page_val_to_pfn(pud_val(pud)) << PAGE_SHIFT) > > +#define pud_pfn pud_pfn > static inline unsigned long pud_pfn(pud_t pud) > { > return ((__pud_to_phys(pud) & PUD_MASK) >> PAGE_SHIFT); > diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h > index 1a71cb19c089..6cbbe473f680 100644 > --- a/arch/s390/include/asm/pgtable.h > +++ b/arch/s390/include/asm/pgtable.h > @@ -1414,6 +1414,7 @@ static inline unsigned long pud_deref(pud_t pud) > return (unsigned long)__va(pud_val(pud) & origin_mask); > } > > +#define pud_pfn pud_pfn > static inline unsigned long pud_pfn(pud_t pud) > { > return __pa(pud_deref(pud)) >> PAGE_SHIFT; > diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h > index 4d1bafaba942..26efc9bb644a 100644 > --- a/arch/sparc/include/asm/pgtable_64.h > +++ b/arch/sparc/include/asm/pgtable_64.h > @@ -875,6 +875,7 @@ static inline bool pud_leaf(pud_t pud) > return pte_val(pte) & _PAGE_PMD_HUGE; > } > > +#define pud_pfn pud_pfn > static inline unsigned long pud_pfn(pud_t pud) > { > pte_t pte = __pte(pud_val(pud)); > diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h > index cefc7a84f7a4..273f7557218c 100644 > --- a/arch/x86/include/asm/pgtable.h > +++ b/arch/x86/include/asm/pgtable.h > @@ -234,6 +234,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd) > return (pfn & pmd_pfn_mask(pmd)) >> PAGE_SHIFT; > } > > +#define pud_pfn pud_pfn > static inline unsigned long pud_pfn(pud_t pud) > { > phys_addr_t pfn = pud_val(pud); > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h > index 2a1c044ae467..deae9e50f1a8 100644 > --- a/include/linux/pgtable.h > +++ b/include/linux/pgtable.h > @@ -1817,6 +1817,16 @@ typedef unsigned int pgtbl_mod_mask; > #define pte_leaf_size(x) PAGE_SIZE > #endif > > +/* > + * We always define pmd_pfn for all archs as it's used in lots of generic > + * code. Now it happens too for pud_pfn (and can happen for larger > + * mappings too in the future; we're not there yet). Instead of defining > + * it for all archs (like pmd_pfn), provide a fallback. > + */ > +#ifndef pud_pfn > +#define pud_pfn(x) ({ BUILD_BUG(); 0; }) > +#endif > + > /* > * Some architectures have MMUs that are configurable or selectable at boot > * time. These lead to variable PTRS_PER_x. For statically allocated arrays it > -- > 2.44.0 > -- Peter Xu
