x86/entry: Rename trace_hardirqs_off_prepare()

The typical pattern for trace_hardirqs_off_prepare() is:

  ENTRY
    lockdep_hardirqs_off(); // because hardware
    ... do entry magic
    instrumentation_begin();
    trace_hardirqs_off_prepare();
    ... do actual work
    trace_hardirqs_on_prepare();
    lockdep_hardirqs_on_prepare();
    instrumentation_end();
    ... do exit magic
    lockdep_hardirqs_on();

which shows that it's named wrong, rename it to
trace_hardirqs_off_finish(), as it concludes the hardirq_off transition.

Also, given that the above is the only correct order, make the traditional
all-in-one trace_hardirqs_off() follow suit.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.415774872@infradead.org

arch/x86/entry/common.c

@@ -65,7 +65,7 @@ static noinstr void enter_from_user_mode(void)
 
 	instrumentation_begin();
 	CT_WARN_ON(state != CONTEXT_USER);
-	trace_hardirqs_off_prepare();
+	trace_hardirqs_off_finish();
 	instrumentation_end();
 }
 #else
@@ -73,7 +73,7 @@ static __always_inline void enter_from_user_mode(void)
 {
 	lockdep_hardirqs_off(CALLER_ADDR0);
 	instrumentation_begin();
-	trace_hardirqs_off_prepare();
+	trace_hardirqs_off_finish();
 	instrumentation_end();
 }
 #endif
@@ -569,7 +569,7 @@ bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs)
 		lockdep_hardirqs_off(CALLER_ADDR0);
 		rcu_irq_enter();
 		instrumentation_begin();
-		trace_hardirqs_off_prepare();
+		trace_hardirqs_off_finish();
 		instrumentation_end();
 
 		return true;

arch/x86/kernel/cpu/mce/core.c

@@ -1922,7 +1922,7 @@ static __always_inline void exc_machine_check_kernel(struct pt_regs *regs)
 	 * that out because it's an indirect call. Annotate it.
 	 */
 	instrumentation_begin();
-	trace_hardirqs_off_prepare();
+	trace_hardirqs_off_finish();
 	machine_check_vector(regs);
 	if (regs->flags & X86_EFLAGS_IF)
 		trace_hardirqs_on_prepare();

arch/x86/kernel/nmi.c

@@ -330,7 +330,7 @@ static noinstr void default_do_nmi(struct pt_regs *regs)
 	__this_cpu_write(last_nmi_rip, regs->ip);
 
 	instrumentation_begin();
-	trace_hardirqs_off_prepare();
+	trace_hardirqs_off_finish();
 
 	handled = nmi_handle(NMI_LOCAL, regs);
 	__this_cpu_add(nmi_stats.normal, handled);

arch/x86/kernel/traps.c

@@ -634,7 +634,7 @@ DEFINE_IDTENTRY_RAW(exc_int3)
 	} else {
 		nmi_enter();
 		instrumentation_begin();
-		trace_hardirqs_off_prepare();
+		trace_hardirqs_off_finish();
 		if (!do_int3(regs))
 			die("int3", regs, 0);
 		if (regs->flags & X86_EFLAGS_IF)
@@ -833,7 +833,7 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs,
 {
 	nmi_enter();
 	instrumentation_begin();
-	trace_hardirqs_off_prepare();
+	trace_hardirqs_off_finish();
 	instrumentation_end();
 
 	/*

include/linux/irqflags.h

@@ -32,7 +32,7 @@
 
 #ifdef CONFIG_TRACE_IRQFLAGS
   extern void trace_hardirqs_on_prepare(void);
-  extern void trace_hardirqs_off_prepare(void);
+  extern void trace_hardirqs_off_finish(void);
   extern void trace_hardirqs_on(void);
   extern void trace_hardirqs_off(void);
 # define lockdep_hardirq_context(p)	((p)->hardirq_context)
@@ -101,7 +101,7 @@ do {						\
 
 #else
 # define trace_hardirqs_on_prepare()		do { } while (0)
-# define trace_hardirqs_off_prepare()		do { } while (0)
+# define trace_hardirqs_off_finish()		do { } while (0)
 # define trace_hardirqs_on()		do { } while (0)
 # define trace_hardirqs_off()		do { } while (0)
 # define lockdep_hardirq_context(p)	0

kernel/trace/trace_preemptirq.c

@@ -58,7 +58,7 @@ NOKPROBE_SYMBOL(trace_hardirqs_on);
  * and lockdep uses a staged approach which splits the lockdep hardirq
  * tracking into a RCU on and a RCU off section.
  */
-void trace_hardirqs_off_prepare(void)
+void trace_hardirqs_off_finish(void)
 {
 	if (!this_cpu_read(tracing_irq_cpu)) {
 		this_cpu_write(tracing_irq_cpu, 1);
@@ -68,19 +68,19 @@ void trace_hardirqs_off_prepare(void)
 	}
 
 }
-EXPORT_SYMBOL(trace_hardirqs_off_prepare);
-NOKPROBE_SYMBOL(trace_hardirqs_off_prepare);
+EXPORT_SYMBOL(trace_hardirqs_off_finish);
+NOKPROBE_SYMBOL(trace_hardirqs_off_finish);
 
 void trace_hardirqs_off(void)
 {
+	lockdep_hardirqs_off(CALLER_ADDR0);
+
 	if (!this_cpu_read(tracing_irq_cpu)) {
 		this_cpu_write(tracing_irq_cpu, 1);
 		tracer_hardirqs_off(CALLER_ADDR0, CALLER_ADDR1);
 		if (!in_nmi())
 			trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
 	}
-
-	lockdep_hardirqs_off(CALLER_ADDR0);
 }
 EXPORT_SYMBOL(trace_hardirqs_off);
 NOKPROBE_SYMBOL(trace_hardirqs_off);