powerpc/kuap: Add kuap_lock()

Add kuap_lock() and call it when entering interrupts from user.

It is called kuap_lock() as it is similar to kuap_save_and_lock()
without the save.

However book3s/32 already have a kuap_lock(). Rename it
kuap_lock_addr().

Signed-off-by: Christophe Leroy <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/4437e2de[e-mail]

arch/powerpc/include/asm/book3s/32/kup.h

···
 void kuap_lock_all_ool(void);
 void kuap_unlock_all_ool(void);
 
-static inline void kuap_lock(unsigned long addr, bool ool)
+static inline void kuap_lock_addr(unsigned long addr, bool ool)
 {
 	if (likely(addr != KUAP_ALL))
 		kuap_lock_one(addr);
···
 		kuap_unlock_all_ool();
 }
 
+static inline void __kuap_lock(void)
+{
+}
+
 static inline void __kuap_save_and_lock(struct pt_regs *regs)
 {
 	unsigned long kuap = current->thread.kuap;
···
 		return;
 
 	current->thread.kuap = KUAP_NONE;
-	kuap_lock(kuap, false);
+	kuap_lock_addr(kuap, false);
 }
 
 static inline void kuap_user_restore(struct pt_regs *regs)
···
 {
 	if (unlikely(kuap != KUAP_NONE)) {
 		current->thread.kuap = KUAP_NONE;
-		kuap_lock(kuap, false);
+		kuap_lock_addr(kuap, false);
 	}
 
 	if (likely(regs->kuap == KUAP_NONE))
···
 		return;
 
 	current->thread.kuap = KUAP_NONE;
-	kuap_lock(kuap, true);
+	kuap_lock_addr(kuap, true);
 }
 
 static inline unsigned long __prevent_user_access_return(void)
···
 
 	if (flags != KUAP_NONE) {
 		current->thread.kuap = KUAP_NONE;
-		kuap_lock(flags, true);
+		kuap_lock_addr(flags, true);
 	}
 
 	return flags;

arch/powerpc/include/asm/interrupt.h

···
 		trace_hardirqs_off();
 
 	if (user_mode(regs))
-		account_cpu_user_entry();
+		kuap_lock();
 	else
 		kuap_save_and_lock(regs);
+
+	if (user_mode(regs))
+		account_cpu_user_entry();
 #endif
 
 #ifdef CONFIG_PPC64

arch/powerpc/include/asm/kup.h

···
 }
 
 static inline void __kuap_assert_locked(void) { }
+static inline void __kuap_lock(void) { }
 static inline void __kuap_save_and_lock(struct pt_regs *regs) { }
 static inline void kuap_user_restore(struct pt_regs *regs) { }
 static inline void __kuap_kernel_restore(struct pt_regs *regs, unsigned long amr) { }
···
 }
 
 #ifdef CONFIG_PPC32
+static __always_inline void kuap_lock(void)
+{
+	if (kuap_is_disabled())
+		return;
+
+	__kuap_lock();
+}
+
 static __always_inline void kuap_save_and_lock(struct pt_regs *regs)
 {
 	if (kuap_is_disabled())

arch/powerpc/include/asm/nohash/32/kup-8xx.h

···
 	return static_branch_unlikely(&disable_kuap_key);
 }
 
+static inline void __kuap_lock(void)
+{
+}
+
 static inline void __kuap_save_and_lock(struct pt_regs *regs)
 {
 	regs->kuap = mfspr(SPRN_MD_AP);

arch/powerpc/kernel/interrupt.c

···
 {
 	syscall_fn f;
 
+	kuap_lock();
+
 	regs->orig_gpr3 = r3;
 
 	if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))