| Message ID | 20200827080438.315345-2-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/debug_vm_pgtable fixes | expand |
On 08/27/2020 01:34 PM, Aneesh Kumar K.V wrote: > With the hash page table, the kernel should not use pmd_clear for clearing > huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage. > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > --- > arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h > index 6de56c3b33c4..079211968987 100644 > --- a/arch/powerpc/include/asm/book3s/64/pgtable.h > +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h > @@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte) > > static inline void pmd_clear(pmd_t *pmdp) > { > + if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) { > + /* > + * Don't use this if we can possibly have a hash page table > + * entry mapping this. > + */ > + WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); > + } > *pmdp = __pmd(0); > } > > @@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd) > > static inline void pud_clear(pud_t *pudp) > { > + if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) { > + /* > + * Don't use this if we can possibly have a hash page table > + * entry mapping this. > + */ > + WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); > + } > *pudp = __pud(0); > } There are two checkpatch.pl warnings for this patch. WARNING: line length of 105 exceeds 100 columns #27: FILE: arch/powerpc/include/asm/book3s/64/pgtable.h:876: + WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); WARNING: line length of 105 exceeds 100 columns #41: FILE: arch/powerpc/include/asm/book3s/64/pgtable.h:931: + WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); total: 0 errors, 2 warnings, 26 lines checked
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 6de56c3b33c4..079211968987 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -868,6 +868,13 @@ static inline bool pte_ci(pte_t pte) static inline void pmd_clear(pmd_t *pmdp) { + if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) { + /* + * Don't use this if we can possibly have a hash page table + * entry mapping this. + */ + WARN_ON((pmd_val(*pmdp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); + } *pmdp = __pmd(0); } @@ -916,6 +923,13 @@ static inline int pmd_bad(pmd_t pmd) static inline void pud_clear(pud_t *pudp) { + if (IS_ENABLED(CONFIG_DEBUG_VM) && !radix_enabled()) { + /* + * Don't use this if we can possibly have a hash page table + * entry mapping this. + */ + WARN_ON((pud_val(*pudp) & (H_PAGE_HASHPTE | _PAGE_PTE)) == (H_PAGE_HASHPTE | _PAGE_PTE)); + } *pudp = __pud(0); }
With the hash page table, the kernel should not use pmd_clear for clearing huge pte entries. Add a DEBUG_VM WARN to catch the wrong usage. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- arch/powerpc/include/asm/book3s/64/pgtable.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+)