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-rw-r--r--arch/x86/include/asm/pkeys.h126
1 files changed, 126 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
new file mode 100644
index 000000000..2e6c04d8a
--- /dev/null
+++ b/arch/x86/include/asm/pkeys.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_PKEYS_H
+#define _ASM_X86_PKEYS_H
+
+/*
+ * 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.
+ */
+extern int __execute_only_pkey(struct mm_struct *mm);
+static inline int execute_only_pkey(struct mm_struct *mm)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
+ return ARCH_DEFAULT_PKEY;
+
+ return __execute_only_pkey(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 (!cpu_feature_enabled(X86_FEATURE_OSPKE))
+ return 0;
+
+ return __arch_override_mprotect_pkey(vma, prot, pkey);
+}
+
+#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)
+#define mm_set_pkey_allocated(mm, pkey) do { \
+ mm_pkey_allocation_map(mm) |= (1U << pkey); \
+} while (0)
+#define mm_set_pkey_free(mm, pkey) do { \
+ mm_pkey_allocation_map(mm) &= ~(1U << pkey); \
+} while (0)
+
+static inline
+bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
+{
+ /*
+ * "Allocated" pkeys are those that have been returned
+ * from pkey_alloc() or pkey 0 which is allocated
+ * implicitly when the mm is created.
+ */
+ 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);
+}
+
+/*
+ * Returns a positive, 4-bit key on success, or -1 on failure.
+ */
+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.
+ */
+ u16 all_pkeys_mask = ((1U << arch_max_pkey()) - 1);
+ int ret;
+
+ /*
+ * 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(mm_pkey_allocation_map(mm));
+
+ mm_set_pkey_allocated(mm, ret);
+
+ return ret;
+}
+
+static inline
+int mm_pkey_free(struct mm_struct *mm, int pkey)
+{
+ if (!mm_pkey_is_allocated(mm, pkey))
+ return -EINVAL;
+
+ mm_set_pkey_free(mm, pkey);
+
+ return 0;
+}
+
+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 */