diff mbox series

[v2,47/69] powerpc/mm: Map shared vmemmap tail pages read-only

Message ID 20260513132044.41690-1-songmuchun@bytedance.com (mailing list archive)
State Handled Elsewhere
Headers show
Series mm: Generalize HVO for HugeTLB and device DAX | expand

Commit Message

Muchun Song May 13, 2026, 1:20 p.m. UTC 
Shared vmemmap tail pages can also be installed through the powerpc
radix vmemmap populate path.

Map reused tail pages with PAGE_KERNEL_RO so writes to shared tail
vmemmap entries fault immediately instead of silently corrupting shared
metadata.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 arch/powerpc/mm/book3s64/radix_pgtable.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 18b24bb891b7..4c3d027c823c 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -1053,7 +1053,8 @@  static pte_t * __meminit radix__vmemmap_pte_populate(pmd_t *pmdp, unsigned long
 		}
 
 		VM_BUG_ON(!PAGE_ALIGNED(addr));
-		entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
+		entry = pfn_pte(__pa(p) >> PAGE_SHIFT,
+				reuse ? PAGE_KERNEL_RO : PAGE_KERNEL);
 		set_pte_at(&init_mm, addr, pte, entry);
 		asm volatile("ptesync": : :"memory");
 	}