arm64: pgtable: Warn unexpected pmdp_test_and_clear_young()

Yicong Yang · ctmarinas · commit b349a5a2b6e2 · 2024-11-05T13:21:14.000Z
Young bit operation on PMD table entry is only supported if FEAT_HAFT enabled system wide. Add a warning for notifying the misbehaviour. Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20241102104235.62560-6-yangyicong@huawei.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
@@ -1265,6 +1265,8 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
 					    unsigned long address,
 					    pmd_t *pmdp)
 {
+	/* Operation applies to PMD table entry only if FEAT_HAFT is enabled */
+	VM_WARN_ON(pmd_table(READ_ONCE(*pmdp)) && !system_supports_haft());
 	return __ptep_test_and_clear_young(vma, address, (pte_t *)pmdp);
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG */

Original file line number	Diff line number	Diff line change
`@@ -1265,6 +1265,8 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,`
`1265`	`1265`	`unsigned long address,`
`1266`	`1266`	`pmd_t *pmdp)`
`1267`	`1267`	`{`
	`1268`	`+ /* Operation applies to PMD table entry only if FEAT_HAFT is enabled */`
	`1269`	`+ VM_WARN_ON(pmd_table(READ_ONCE(*pmdp)) && !system_supports_haft());`
`1268`	`1270`	`return __ptep_test_and_clear_young(vma, address, (pte_t *)pmdp);`
`1269`	`1271`	`}`
`1270`	`1272`	`#endif /* CONFIG_TRANSPARENT_HUGEPAGE \|\| CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG */`