diff mbox series

[RFC,v4,14/18] arm64: kpkeys: Support KPKEYS_LVL_PGTABLES

Message ID 20250411091631.954228-15-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 
Enable RW access to KPKEYS_PKEY_PGTABLES (used to map page table
pages) if switching to KPKEYS_LVL_PGTABLES, otherwise only grant RO
access.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 arch/arm64/include/asm/kpkeys.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
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Patch

diff --git a/arch/arm64/include/asm/kpkeys.h b/arch/arm64/include/asm/kpkeys.h
index 79ae33388088..64d6e22740ec 100644
--- a/arch/arm64/include/asm/kpkeys.h
+++ b/arch/arm64/include/asm/kpkeys.h
@@ -12,7 +12,8 @@ 
  * Equivalent to por_set_kpkeys_level(0, KPKEYS_LVL_DEFAULT), but can also be
  * used in assembly.
  */
-#define POR_EL1_INIT	POR_ELx_PERM_PREP(KPKEYS_PKEY_DEFAULT, POE_RWX)
+#define POR_EL1_INIT	(POR_ELx_PERM_PREP(KPKEYS_PKEY_DEFAULT, POE_RWX) | \
+			 POR_ELx_PERM_PREP(KPKEYS_PKEY_PGTABLES, POE_R))
 
 #ifndef __ASSEMBLY__
 
@@ -26,6 +27,8 @@  static inline bool arch_kpkeys_enabled(void)
 static inline u64 por_set_kpkeys_level(u64 por, int level)
 {
 	por = por_elx_set_pkey_perms(por, KPKEYS_PKEY_DEFAULT, POE_RWX);
+	por = por_elx_set_pkey_perms(por, KPKEYS_PKEY_PGTABLES,
+				     level == KPKEYS_LVL_PGTABLES ? POE_RW : POE_R);
 
 	return por;
 }