1 files changed, 112 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..0c7c3258134c
--- /dev/null
+++ b/arch/powerpc/include/asm/nohash/kup-booke.h
@@ -0,0 +1,112 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_KUP_BOOKE_H_
+#define _ASM_POWERPC_KUP_BOOKE_H_
+
+#include <asm/bug.h>
+#include <asm/mmu.h>
+
+#ifdef CONFIG_PPC_KUAP
+
+#ifdef __ASSEMBLY__
+
+.macro kuap_check_amr	gpr1, gpr2
+.endm
+
+#else
+
+#include <linux/sched.h>
+
+#include <asm/reg.h>
+
+static __always_inline void __kuap_lock(void)
+{
+	mtspr(SPRN_PID, 0);
+	isync();
+}
+#define __kuap_lock __kuap_lock
+
+static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
+{
+	regs->kuap = mfspr(SPRN_PID);
+	mtspr(SPRN_PID, 0);
+	isync();
+}
+#define __kuap_save_and_lock __kuap_save_and_lock
+
+static __always_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 __always_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 */
+}
+
+#ifdef CONFIG_PPC_KUAP_DEBUG
+static __always_inline unsigned long __kuap_get_and_assert_locked(void)
+{
+	WARN_ON_ONCE(mfspr(SPRN_PID));
+
+	return 0;
+}
+#define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
+#endif
+
+static __always_inline void uaccess_begin_booke(unsigned long val)
+{
+	asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
+	    "i"(SPRN_PID), "r"(val), "i"(MMU_FTR_KUAP) : "memory");
+}
+
+static __always_inline void uaccess_end_booke(void)
+{
+	asm(ASM_MMU_FTR_IFSET("mtspr %0, %1; isync", "", %2) : :
+	    "i"(SPRN_PID), "r"(0), "i"(MMU_FTR_KUAP) : "memory");
+}
+
+static __always_inline void allow_user_access(void __user *to, const void __user *from,
+					      unsigned long size, unsigned long dir)
+{
+	uaccess_begin_booke(current->thread.pid);
+}
+
+static __always_inline void prevent_user_access(unsigned long dir)
+{
+	uaccess_end_booke();
+}
+
+static __always_inline unsigned long prevent_user_access_return(void)
+{
+	unsigned long flags = mfspr(SPRN_PID);
+
+	uaccess_end_booke();
+
+	return flags;
+}
+
+static __always_inline void restore_user_access(unsigned long flags)
+{
+	if (flags)
+		uaccess_begin_booke(current->thread.pid);
+}
+
+static __always_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_ */