1 files changed, 175 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
new file mode 100644
index 000000000..4e14a5427
--- /dev/null
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -0,0 +1,175 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_BOOK3S_32_KUP_H
+#define _ASM_POWERPC_BOOK3S_32_KUP_H
+
+#include <asm/bug.h>
+#include <asm/book3s/32/mmu-hash.h>
+#include <asm/mmu.h>
+#include <asm/synch.h>
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_PPC_KUAP
+
+#include <linux/sched.h>
+
+#define KUAP_NONE	(~0UL)
+
+static __always_inline void kuap_lock_one(unsigned long addr)
+{
+	mtsr(mfsr(addr) | SR_KS, addr);
+	isync();	/* Context sync required after mtsr() */
+}
+
+static __always_inline void kuap_unlock_one(unsigned long addr)
+{
+	mtsr(mfsr(addr) & ~SR_KS, addr);
+	isync();	/* Context sync required after mtsr() */
+}
+
+static __always_inline void uaccess_begin_32s(unsigned long addr)
+{
+	unsigned long tmp;
+
+	asm volatile(ASM_MMU_FTR_IFSET(
+		"mfsrin %0, %1;"
+		"rlwinm %0, %0, 0, %2;"
+		"mtsrin %0, %1;"
+		"isync", "", %3)
+		: "=&r"(tmp)
+		: "r"(addr), "i"(~SR_KS), "i"(MMU_FTR_KUAP)
+		: "memory");
+}
+
+static __always_inline void uaccess_end_32s(unsigned long addr)
+{
+	unsigned long tmp;
+
+	asm volatile(ASM_MMU_FTR_IFSET(
+		"mfsrin %0, %1;"
+		"oris %0, %0, %2;"
+		"mtsrin %0, %1;"
+		"isync", "", %3)
+		: "=&r"(tmp)
+		: "r"(addr), "i"(SR_KS >> 16), "i"(MMU_FTR_KUAP)
+		: "memory");
+}
+
+static __always_inline void __kuap_save_and_lock(struct pt_regs *regs)
+{
+	unsigned long kuap = current->thread.kuap;
+
+	regs->kuap = kuap;
+	if (unlikely(kuap == KUAP_NONE))
+		return;
+
+	current->thread.kuap = KUAP_NONE;
+	kuap_lock_one(kuap);
+}
+#define __kuap_save_and_lock __kuap_save_and_lock
+
+static __always_inline void kuap_user_restore(struct pt_regs *regs)
+{
+}
+
+static __always_inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long kuap)
+{
+	if (unlikely(kuap != KUAP_NONE)) {
+		current->thread.kuap = KUAP_NONE;
+		kuap_lock_one(kuap);
+	}
+
+	if (likely(regs->kuap == KUAP_NONE))
+		return;
+
+	current->thread.kuap = regs->kuap;
+
+	kuap_unlock_one(regs->kuap);
+}
+
+static __always_inline unsigned long __kuap_get_and_assert_locked(void)
+{
+	unsigned long kuap = current->thread.kuap;
+
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && kuap != KUAP_NONE);
+
+	return kuap;
+}
+#define __kuap_get_and_assert_locked __kuap_get_and_assert_locked
+
+static __always_inline void allow_user_access(void __user *to, const void __user *from,
+					      u32 size, unsigned long dir)
+{
+	BUILD_BUG_ON(!__builtin_constant_p(dir));
+
+	if (!(dir & KUAP_WRITE))
+		return;
+
+	current->thread.kuap = (__force u32)to;
+	uaccess_begin_32s((__force u32)to);
+}
+
+static __always_inline void prevent_user_access(unsigned long dir)
+{
+	u32 kuap = current->thread.kuap;
+
+	BUILD_BUG_ON(!__builtin_constant_p(dir));
+
+	if (!(dir & KUAP_WRITE))
+		return;
+
+	current->thread.kuap = KUAP_NONE;
+	uaccess_end_32s(kuap);
+}
+
+static __always_inline unsigned long prevent_user_access_return(void)
+{
+	unsigned long flags = current->thread.kuap;
+
+	if (flags != KUAP_NONE) {
+		current->thread.kuap = KUAP_NONE;
+		uaccess_end_32s(flags);
+	}
+
+	return flags;
+}
+
+static __always_inline void restore_user_access(unsigned long flags)
+{
+	if (flags != KUAP_NONE) {
+		current->thread.kuap = flags;
+		uaccess_begin_32s(flags);
+	}
+}
+
+static __always_inline bool
+__bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
+{
+	unsigned long kuap = regs->kuap;
+
+	if (!is_write)
+		return false;
+	if (kuap == KUAP_NONE)
+		return true;
+
+	/*
+	 * If faulting address doesn't match unlocked segment, change segment.
+	 * In case of unaligned store crossing two segments, emulate store.
+	 */
+	if ((kuap ^ address) & 0xf0000000) {
+		if (!(kuap & 0x0fffffff) && address > kuap - 4 && fix_alignment(regs)) {
+			regs_add_return_ip(regs, 4);
+			emulate_single_step(regs);
+		} else {
+			regs->kuap = address;
+		}
+	}
+
+	return false;
+}
+
+#endif /* CONFIG_PPC_KUAP */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_POWERPC_BOOK3S_32_KUP_H */