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@xxxxxxxxxxxxx>
---
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);
}
--
2.26.2
