[PATCH v3 7/9] mm/kasan: use hw_pte_t for the early shadow PTE table

[Muhammad Usama Anjum <usama.anjum@xxxxxxx>]

kasan_early_shadow_pte is a complete PTE table rather than a software
PTE value. Declare and define its elements as hw_pte_t so the object uses
the PTE table storage type.

Read the first element through ptep_get(), which returns the software PTE
value expected by note_page_pte(), instead of accessing hw_pte_t storage
directly. This also uses the accessor selected by the architecture.

No architecture selects ARCH_HAS_HW_PTE_T at this point, so the storage
representation remains unchanged.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@xxxxxxx>
---
Changes since v1:
- Use software PTE value terminology.

Changes since RFC v1:
- Update the description for the architecture opt-in model.
---
 include/linux/kasan.h | 2 +-
 mm/kasan/init.c       | 2 +-
 mm/ptdump.c           | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index bf233bde68c7e..ff41949c0ac08 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -51,7 +51,7 @@ typedef unsigned int __bitwise kasan_vmalloc_flags_t;
 #endif
 
 extern unsigned char kasan_early_shadow_page[PAGE_SIZE];
-extern pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS];
+extern hw_pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS];
 extern pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD];
 extern pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD];
 extern p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D];
diff --git a/mm/kasan/init.c b/mm/kasan/init.c
index 30c5266eaf37e..9bbc2a41d23f0 100644
--- a/mm/kasan/init.c
+++ b/mm/kasan/init.c
@@ -64,7 +64,7 @@ static inline bool kasan_pmd_table(pud_t pud)
        return false;
 }
 #endif
-pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS]
+hw_pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS]
        __bss_pgtbl;
 
 static inline bool kasan_pte_table(pmd_t pmd)
diff --git a/mm/ptdump.c b/mm/ptdump.c
index 376880071ca2a..8f19f20be3c44 100644
--- a/mm/ptdump.c
+++ b/mm/ptdump.c
@@ -19,7 +19,7 @@ static inline int note_kasan_page_table(struct mm_walk *walk,
 {
        struct ptdump_state *st = walk->private;
 
-       st->note_page_pte(st, addr, kasan_early_shadow_pte[0]);
+       st->note_page_pte(st, addr, ptep_get(kasan_early_shadow_pte));
 
        walk->action = ACTION_CONTINUE;
 

-- 
2.47.3