Le 13/03/2024 à 22:47, peterx@xxxxxxxxxx a écrit : > From: Peter Xu <peterx@xxxxxxxxxx> > > PowerPC book3s 4K mostly has the same definition on both, except pXd_huge() > constantly returns 0 for hash MMUs. As Michael Ellerman pointed out [1], > it is safe to check _PAGE_PTE on hash MMUs, as the bit will never be set so > it will keep returning false. > > As a reference, __p[mu]d_mkhuge() will trigger a BUG_ON trying to create > such huge mappings for 4K hash MMUs. Meanwhile, the major powerpc hugetlb > pgtable walker __find_linux_pte() already used pXd_leaf() to check hugetlb > mappings. > > The goal should be that we will have one API pXd_leaf() to detect all kinds > of huge mappings. AFAICT we need to use the pXd_leaf() impl (rather than > pXd_huge() ones) to make sure ie. THPs on hash MMU will also return true. All kinds of huge mappings ? pXd_leaf() will detect only leaf mappings (like pXd_huge() ). There are also huge mappings through hugepd. On powerpc 8xx we have 8M huge pages and 512k huge pages. A PGD entry covers 4M so pgd_leaf() won't report those huge pages. > > This helps to simplify a follow up patch to drop pXd_huge() treewide. > > NOTE: *_leaf() definition need to be moved before the inclusion of > asm/book3s/64/pgtable-4k.h, which defines pXd_huge() with it. > > [1] https://lore.kernel.org/r/87v85zo6w7.fsf@mail.lhotse > > Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> > Cc: Nicholas Piggin <npiggin@xxxxxxxxx> > Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx> > Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxx> > Cc: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxx> > Cc: linuxppc-dev@xxxxxxxxxxxxxxxx > Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> > --- > .../include/asm/book3s/64/pgtable-4k.h | 14 ++-------- > arch/powerpc/include/asm/book3s/64/pgtable.h | 27 +++++++++---------- > 2 files changed, 14 insertions(+), 27 deletions(-) > > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable-4k.h b/arch/powerpc/include/asm/book3s/64/pgtable-4k.h > index 48f21820afe2..92545981bb49 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable-4k.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable-4k.h > @@ -8,22 +8,12 @@ > #ifdef CONFIG_HUGETLB_PAGE > static inline int pmd_huge(pmd_t pmd) > { > - /* > - * leaf pte for huge page > - */ > - if (radix_enabled()) > - return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE)); > - return 0; > + return pmd_leaf(pmd); > } > > static inline int pud_huge(pud_t pud) > { > - /* > - * leaf pte for huge page > - */ > - if (radix_enabled()) > - return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE)); > - return 0; > + return pud_leaf(pud); > } > > /* > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h > index df66dce8306f..fd7180fded75 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > @@ -262,6 +262,18 @@ extern unsigned long __kernel_io_end; > > extern struct page *vmemmap; > extern unsigned long pci_io_base; > + > +#define pmd_leaf pmd_leaf > +static inline bool pmd_leaf(pmd_t pmd) > +{ > + return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE)); > +} > + > +#define pud_leaf pud_leaf > +static inline bool pud_leaf(pud_t pud) > +{ > + return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE)); > +} > #endif /* __ASSEMBLY__ */ > > #include <asm/book3s/64/hash.h> > @@ -1436,20 +1448,5 @@ static inline bool is_pte_rw_upgrade(unsigned long old_val, unsigned long new_va > return false; > } > > -/* > - * Like pmd_huge(), but works regardless of config options > - */ > -#define pmd_leaf pmd_leaf > -static inline bool pmd_leaf(pmd_t pmd) > -{ > - return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE)); > -} > - > -#define pud_leaf pud_leaf > -static inline bool pud_leaf(pud_t pud) > -{ > - return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE)); > -} > - > #endif /* __ASSEMBLY__ */ > #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */
