diff mbox series

[RFC,v4,13/18] mm: Map page tables with privileged pkey

Message ID 20250411091631.954228-14-kevin.brodsky@arm.com (mailing list archive)
State New
Headers show
Series pkeys-based page table hardening | expand

Commit Message

Kevin Brodsky April 11, 2025, 9:16 a.m. UTC 
If CONFIG_KPKEYS_HARDENED_PGTABLES is enabled, map allocated page
table pages using a privileged pkey (KPKEYS_PKEY_PGTABLES), so that
page tables can only be written under guard(kpkeys_hardened_pgtables).

This patch is a no-op if CONFIG_KPKEYS_HARDENED_PGTABLES is disabled
(default).

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 include/linux/mm.h | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 43e35d41b850..411707dabe65 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -33,6 +33,7 @@ 
 #include <linux/slab.h>
 #include <linux/cacheinfo.h>
 #include <linux/rcuwait.h>
+#include <linux/kpkeys.h>
 
 struct mempolicy;
 struct anon_vma;
@@ -3083,6 +3084,8 @@  static inline bool __pagetable_ctor(struct ptdesc *ptdesc)
 
 	__folio_set_pgtable(folio);
 	lruvec_stat_add_folio(folio, NR_PAGETABLE);
+	if (kpkeys_protect_pgtable_memory(folio))
+		return false;
 	return true;
 }
 
@@ -3093,6 +3096,7 @@  static inline void pagetable_dtor(struct ptdesc *ptdesc)
 	ptlock_free(ptdesc);
 	__folio_clear_pgtable(folio);
 	lruvec_stat_sub_folio(folio, NR_PAGETABLE);
+	kpkeys_unprotect_pgtable_memory(folio);
 }
 
 static inline void pagetable_dtor_free(struct ptdesc *ptdesc)