1 files changed, 110 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/nohash/kup-booke.h b/arch/powerpc/include/asm/nohash/kup-booke.h
new file mode 100644
index 000000000000..49bb41ed0816
--- /dev/null
+++ b/arch/powerpc/include/asm/nohash/kup-booke.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_KUP_BOOKE_H_
+#define _ASM_POWERPC_KUP_BOOKE_H_
+
+#include <asm/bug.h>
+
+#ifdef CONFIG_PPC_KUAP
+
+#ifdef __ASSEMBLY__
+
+.macro kuap_check_amr	gpr1, gpr2
+.endm
+
+#else
+
+#include <linux/jump_label.h>
+#include <linux/sched.h>
+
+#include <asm/reg.h>
+
+extern struct static_key_false disable_kuap_key;
+
+static __always_inline bool kuap_is_disabled(void)
+{
+	return static_branch_unlikely(&disable_kuap_key);
+}
+
+static inline void __kuap_lock(void)
+{
+	mtspr(SPRN_PID, 0);
+	isync();
+}
+
+static inline void __kuap_save_and_lock(struct pt_regs *regs)
+{
+	regs->kuap = mfspr(SPRN_PID);
+	mtspr(SPRN_PID, 0);
+	isync();
+}
+
+static inline void kuap_user_restore(struct pt_regs *regs)
+{
+	if (kuap_is_disabled())
+		return;
+
+	mtspr(SPRN_PID, current->thread.pid);
+
+	/* Context synchronisation is performed by rfi */
+}
+
+static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
+{
+	if (regs->kuap)
+		mtspr(SPRN_PID, current->thread.pid);
+
+	/* Context synchronisation is performed by rfi */
+}
+
+static inline unsigned long __kuap_get_and_assert_locked(void)
+{
+	unsigned long kuap = mfspr(SPRN_PID);
+
+	if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG))
+		WARN_ON_ONCE(kuap);
+
+	return kuap;
+}
+
+static inline void __allow_user_access(void __user *to, const void __user *from,
+				       unsigned long size, unsigned long dir)
+{
+	mtspr(SPRN_PID, current->thread.pid);
+	isync();
+}
+
+static inline void __prevent_user_access(unsigned long dir)
+{
+	mtspr(SPRN_PID, 0);
+	isync();
+}
+
+static inline unsigned long __prevent_user_access_return(void)
+{
+	unsigned long flags = mfspr(SPRN_PID);
+
+	mtspr(SPRN_PID, 0);
+	isync();
+
+	return flags;
+}
+
+static inline void __restore_user_access(unsigned long flags)
+{
+	if (flags) {
+		mtspr(SPRN_PID, current->thread.pid);
+		isync();
+	}
+}
+
+static inline bool
+__bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
+{
+	return !regs->kuap;
+}
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* CONFIG_PPC_KUAP */
+
+#endif /* _ASM_POWERPC_KUP_BOOKE_H_ */