diff options
| author |   Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-10-22 14:41:15 +0530 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2020-11-19 14:50:13 +1100 |
| commit | 53f45ecc9cd04b4b963f3040f2a54c3baf03b229 (patch) | |
| tree | 074543d70a8da397546fcb96cab671dbefd0c4ef | |
| parent | powerpc/bitops: Fix possible undefined behaviour with fls() and fls64() (diff) | |
powerpc/mm: Move setting PTE specific flags to pfn_pmd()
powerpc used to set the PTE specific flags in set_pte_at(). That is
different from other architectures. To be consistent with other
architectures powerpc updated pfn_pte() to set _PAGE_PTE in commit
379c926d6334 ("powerpc/mm: move setting pte specific flags to
pfn_pte")
That commit didn't do the same for pfn_pmd() because we expect
pmd_mkhuge() to do that. But as per Linus that is a bad rule:
The rule that you must use "pmd_mkhuge()" seems _completely_ wrong.
The only valid use to ever make a pmd out of a pfn is to make a
huge-page.
Hence update pfn_pmd() to set _PAGE_PTE.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201022091115.39568-1-aneesh.kumar@linux.ibm.com
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/pgtable.h | 17 | ||||
| -rw-r--r-- | arch/powerpc/mm/book3s64/pgtable.c | 8 |
2 files changed, 23 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index cd3feeac6e87..a39886681629 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -1231,13 +1231,28 @@ static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b) return hash__pmd_same(pmd_a, pmd_b); } -static inline pmd_t pmd_mkhuge(pmd_t pmd) +static inline pmd_t __pmd_mkhuge(pmd_t pmd) { if (radix_enabled()) return radix__pmd_mkhuge(pmd); return hash__pmd_mkhuge(pmd); } +/* + * pfn_pmd return a pmd_t that can be used as pmd pte entry. + */ +static inline pmd_t pmd_mkhuge(pmd_t pmd) +{ +#ifdef CONFIG_DEBUG_VM + if (radix_enabled()) + WARN_ON((pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE)) == 0); + else + WARN_ON((pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE | H_PAGE_THP_HUGE)) != + cpu_to_be64(_PAGE_PTE | H_PAGE_THP_HUGE)); +#endif + return pmd; +} + #define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS extern int pmdp_set_access_flags(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp, diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c index e18ae50a275c..5b3a3bae21aa 100644 --- a/arch/powerpc/mm/book3s64/pgtable.c +++ b/arch/powerpc/mm/book3s64/pgtable.c @@ -136,12 +136,18 @@ static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot) return __pmd(pmd_val(pmd) | pgprot_val(pgprot)); } +/* + * At some point we should be able to get rid of + * pmd_mkhuge() and mk_huge_pmd() when we update all the + * other archs to mark the pmd huge in pfn_pmd() + */ pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot) { unsigned long pmdv; pmdv = (pfn << PAGE_SHIFT) & PTE_RPN_MASK; - return pmd_set_protbits(__pmd(pmdv), pgprot); + + return __pmd_mkhuge(pmd_set_protbits(__pmd(pmdv), pgprot)); } pmd_t mk_pmd(struct page *page, pgprot_t pgprot) |