1 files changed, 172 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
new file mode 100644
index 000000000..59a2c7dbc
--- /dev/null
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -0,0 +1,172 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * PowerPC Memory Protection Keys management
+ *
+ * Copyright 2017, Ram Pai, IBM Corporation.
+ */
+
+#ifndef _ASM_POWERPC_KEYS_H
+#define _ASM_POWERPC_KEYS_H
+
+#include <linux/jump_label.h>
+#include <asm/firmware.h>
+
+extern int num_pkey;
+extern u32 reserved_allocation_mask; /* bits set for reserved keys */
+
+#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
+			    VM_PKEY_BIT3 | VM_PKEY_BIT4)
+
+/* Override any generic PKEY permission defines */
+#define PKEY_DISABLE_EXECUTE   0x4
+#define PKEY_ACCESS_MASK       (PKEY_DISABLE_ACCESS | \
+				PKEY_DISABLE_WRITE  | \
+				PKEY_DISABLE_EXECUTE)
+
+#ifdef CONFIG_PPC_BOOK3S_64
+#include <asm/book3s/64/pkeys.h>
+#else
+#error "Not supported"
+#endif
+
+
+static inline u64 pkey_to_vmflag_bits(u16 pkey)
+{
+	return (((u64)pkey << VM_PKEY_SHIFT) & ARCH_VM_PKEY_FLAGS);
+}
+
+static inline int vma_pkey(struct vm_area_struct *vma)
+{
+	if (!mmu_has_feature(MMU_FTR_PKEY))
+		return 0;
+	return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT;
+}
+
+static inline int arch_max_pkey(void)
+{
+	return num_pkey;
+}
+
+#define pkey_alloc_mask(pkey) (0x1 << pkey)
+
+#define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map)
+
+#define __mm_pkey_allocated(mm, pkey) {	\
+	mm_pkey_allocation_map(mm) |= pkey_alloc_mask(pkey); \
+}
+
+#define __mm_pkey_free(mm, pkey) {	\
+	mm_pkey_allocation_map(mm) &= ~pkey_alloc_mask(pkey);	\
+}
+
+#define __mm_pkey_is_allocated(mm, pkey)	\
+	(mm_pkey_allocation_map(mm) & pkey_alloc_mask(pkey))
+
+#define __mm_pkey_is_reserved(pkey) (reserved_allocation_mask & \
+				       pkey_alloc_mask(pkey))
+
+static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
+{
+	if (pkey < 0 || pkey >= arch_max_pkey())
+		return false;
+
+	/* Reserved keys are never allocated. */
+	if (__mm_pkey_is_reserved(pkey))
+		return false;
+
+	return __mm_pkey_is_allocated(mm, pkey);
+}
+
+/*
+ * Returns a positive, 5-bit key on success, or -1 on failure.
+ * Relies on the mmap_lock to protect against concurrency in mm_pkey_alloc() and
+ * mm_pkey_free().
+ */
+static inline int mm_pkey_alloc(struct mm_struct *mm)
+{
+	/*
+	 * Note: this is the one and only place we make sure that the pkey is
+	 * valid as far as the hardware is concerned. The rest of the kernel
+	 * trusts that only good, valid pkeys come out of here.
+	 */
+	u32 all_pkeys_mask = (u32)(~(0x0));
+	int ret;
+
+	if (!mmu_has_feature(MMU_FTR_PKEY))
+		return -1;
+	/*
+	 * Are we out of pkeys? We must handle this specially because ffz()
+	 * behavior is undefined if there are no zeros.
+	 */
+	if (mm_pkey_allocation_map(mm) == all_pkeys_mask)
+		return -1;
+
+	ret = ffz((u32)mm_pkey_allocation_map(mm));
+	__mm_pkey_allocated(mm, ret);
+
+	return ret;
+}
+
+static inline int mm_pkey_free(struct mm_struct *mm, int pkey)
+{
+	if (!mmu_has_feature(MMU_FTR_PKEY))
+		return -1;
+
+	if (!mm_pkey_is_allocated(mm, pkey))
+		return -EINVAL;
+
+	__mm_pkey_free(mm, pkey);
+
+	return 0;
+}
+
+/*
+ * Try to dedicate one of the protection keys to be used as an
+ * execute-only protection key.
+ */
+extern int execute_only_pkey(struct mm_struct *mm);
+extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma,
+					 int prot, int pkey);
+static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
+					      int prot, int pkey)
+{
+	if (!mmu_has_feature(MMU_FTR_PKEY))
+		return 0;
+
+	/*
+	 * Is this an mprotect_pkey() call? If so, never override the value that
+	 * came from the user.
+	 */
+	if (pkey != -1)
+		return pkey;
+
+	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);
+static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
+					    unsigned long init_val)
+{
+	if (!mmu_has_feature(MMU_FTR_PKEY))
+		return -EINVAL;
+
+	/*
+	 * userspace should not change pkey-0 permissions.
+	 * pkey-0 is associated with every page in the kernel.
+	 * If userspace denies any permission on pkey-0, the
+	 * kernel cannot operate.
+	 */
+	if (pkey == 0)
+		return init_val ? -EINVAL : 0;
+
+	return __arch_set_user_pkey_access(tsk, pkey, init_val);
+}
+
+static inline bool arch_pkeys_enabled(void)
+{
+	return mmu_has_feature(MMU_FTR_PKEY);
+}
+
+extern void pkey_mm_init(struct mm_struct *mm);
+#endif /*_ASM_POWERPC_KEYS_H */