On 03/05/2020 16:29, Catalin Marinas wrote:
On Wed, Apr 22, 2020 at 03:25:29PM +0100, Steven Price wrote:
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 39a372bf8afc..a4ad1b75a1a7 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -80,6 +80,8 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#define pte_user_exec(pte) (!(pte_val(pte) & PTE_UXN))
#define pte_cont(pte) (!!(pte_val(pte) & PTE_CONT))
#define pte_devmap(pte) (!!(pte_val(pte) & PTE_DEVMAP))
+#define pte_tagged(pte) (!!((pte_val(pte) & PTE_ATTRINDX_MASK) == \
+ PTE_ATTRINDX(MT_NORMAL_TAGGED)))
#define pte_cont_addr_end(addr, end) \
({ unsigned long __boundary = ((addr) + CONT_PTE_SIZE) & CONT_PTE_MASK; \
@@ -268,12 +270,17 @@ static inline void __check_racy_pte_update(struct mm_struct *mm, pte_t *ptep,
__func__, pte_val(old_pte), pte_val(pte));
}
+void mte_sync_tags(pte_t *ptep, pte_t pte);
+
static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, pte_t pte)
{
if (pte_present(pte) && pte_user_exec(pte) && !pte_special(pte))
__sync_icache_dcache(pte);
+ if (system_supports_mte() && pte_tagged(pte))
+ mte_sync_tags(ptep, pte);
I think this needs a pte_present() check as well, otherwise pte_tagged()
could match some random swap entry.
Good spot - mte_sync_tags() bails out fairly early in this case (which
explains why I didn't see any problems). But it's *after* PG_mte_tagged
is set which will lead to incorrectly flagging pages.
Thanks,
Steve
