1 files changed, 33 insertions, 15 deletions

diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index b3b09b98896d..2e6c04d8a45b 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -1,11 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _ASM_X86_PKEYS_H
 #define _ASM_X86_PKEYS_H
 
-#define arch_max_pkey() (boot_cpu_has(X86_FEATURE_OSPKE) ? 16 : 1)
+/*
+ * If more than 16 keys are ever supported, a thorough audit
+ * will be necessary to ensure that the types that store key
+ * numbers and masks have sufficient capacity.
+ */
+#define arch_max_pkey() (cpu_feature_enabled(X86_FEATURE_OSPKE) ? 16 : 1)
 
 extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 		unsigned long init_val);
 
+static inline bool arch_pkeys_enabled(void)
+{
+	return cpu_feature_enabled(X86_FEATURE_OSPKE);
+}
+
 /*
  * Try to dedicate one of the protection keys to be used as an
  * execute-only protection key.
@@ -13,8 +24,8 @@ extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 extern int __execute_only_pkey(struct mm_struct *mm);
 static inline int execute_only_pkey(struct mm_struct *mm)
 {
-	if (!boot_cpu_has(X86_FEATURE_OSPKE))
-		return 0;
+	if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
+		return ARCH_DEFAULT_PKEY;
 
 	return __execute_only_pkey(mm);
 }
@@ -24,15 +35,12 @@ extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma,
 static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
 		int prot, int pkey)
 {
-	if (!boot_cpu_has(X86_FEATURE_OSPKE))
+	if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
 		return 0;
 
 	return __arch_override_mprotect_pkey(vma, prot, pkey);
 }
 
-extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
-		unsigned long init_val);
-
 #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | VM_PKEY_BIT3)
 
 #define mm_pkey_allocation_map(mm)	(mm->context.pkey_allocation_map)
@@ -48,13 +56,21 @@ bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
 {
 	/*
 	 * "Allocated" pkeys are those that have been returned
-	 * from pkey_alloc().  pkey 0 is special, and never
-	 * returned from pkey_alloc().
+	 * from pkey_alloc() or pkey 0 which is allocated
+	 * implicitly when the mm is created.
 	 */
-	if (pkey <= 0)
+	if (pkey < 0)
 		return false;
 	if (pkey >= arch_max_pkey())
 		return false;
+	/*
+	 * The exec-only pkey is set in the allocation map, but
+	 * is not available to any of the user interfaces like
+	 * mprotect_pkey().
+	 */
+	if (pkey == mm->context.execute_only_pkey)
+		return false;
+
 	return mm_pkey_allocation_map(mm) & (1U << pkey);
 }
 
@@ -99,10 +115,12 @@ int mm_pkey_free(struct mm_struct *mm, int pkey)
 	return 0;
 }
 
-extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
-		unsigned long init_val);
-extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
-		unsigned long init_val);
-extern void copy_init_pkru_to_fpregs(void);
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+	unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 |
+				      VM_PKEY_BIT2 | VM_PKEY_BIT3;
+
+	return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
+}
 
 #endif /*_ASM_X86_PKEYS_H */