[PATCH v2 11/24] arm64: enable ARCH_HAS_PKEYS on arm64

[Joey Gouly <joey.gouly@arm.com>]

Enable the ARCH_HAS_PKEYS config, but provide dummy
functions for the entire interface.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
---
 arch/arm64/Kconfig             |  2 ++
 arch/arm64/include/asm/pkeys.h | 54 ++++++++++++++++++++++++++++++++++
 arch/arm64/mm/mmu.c            |  7 +++++
 3 files changed, 63 insertions(+)
 create mode 100644 arch/arm64/include/asm/pkeys.h

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1f1a12e28c3f..68cfcbd95c8e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2064,6 +2064,8 @@ menu "ARMv8.9 architectural features"
 config ARM64_POE
 	prompt "Permission Overlay Extension"
 	def_bool y
+	select ARCH_USES_HIGH_VMA_FLAGS
+	select ARCH_HAS_PKEYS
 	help
 	  The Permission Overlay Extension is used to implement Memory
 	  Protection Keys. Memory Protection Keys provides a mechanism for
diff --git a/arch/arm64/include/asm/pkeys.h b/arch/arm64/include/asm/pkeys.h
new file mode 100644
index 000000000000..5761fb48fd53
--- /dev/null
+++ b/arch/arm64/include/asm/pkeys.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 Arm Ltd.
+ *
+ * Based on arch/x86/include/asm/pkeys.h
+*/
+
+#ifndef _ASM_ARM64_PKEYS_H
+#define _ASM_ARM64_PKEYS_H
+
+#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2)
+
+#define arch_max_pkey() 0
+
+int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
+		unsigned long init_val);
+
+static inline bool arch_pkeys_enabled(void)
+{
+	return false;
+}
+
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+	return -1;
+}
+
+static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
+		int prot, int pkey)
+{
+	return -1;
+}
+
+static inline int execute_only_pkey(struct mm_struct *mm)
+{
+	return -1;
+}
+
+static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
+{
+	return false;
+}
+
+static inline int mm_pkey_alloc(struct mm_struct *mm)
+{
+	return -1;
+}
+
+static inline int mm_pkey_free(struct mm_struct *mm, int pkey)
+{
+	return -EINVAL;
+}
+
+#endif /* _ASM_ARM64_PKEYS_H */
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 47781bec6171..11765791b880 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1487,3 +1487,10 @@ void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte
 {
 	set_pte_at(vma->vm_mm, addr, ptep, pte);
 }
+
+#ifdef CONFIG_ARCH_HAS_PKEYS
+int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val)
+{
+	return -ENOSPC;
+}
+#endif
-- 
2.25.1