[tip: x86/debug] x86/tracing, x86/mm: Remove redundant trace_pagefault_key

[tip: x86/debug] x86/tracing, x86/mm: Remove redundant trace_pagefault_key

[tip-bot2 for Nam Cao]

The following commit has been merged into the x86/debug branch of tip:

Commit-ID:     d49ae4172cffa51cc72bdbd668fdd2e64b0a929f
Gitweb:        https://git.kernel.org/tip/d49ae4172cffa51cc72bdbd668fdd2e64b0a929f
Author:        Nam Cao <namcao@linutronix.de>
AuthorDate:    Mon, 12 May 2025 12:50:58 +02:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Fri, 16 May 2025 10:13:59 +02:00

x86/tracing, x86/mm: Remove redundant trace_pagefault_key

trace_pagefault_key is used to optimize the pagefault tracepoints when it
is disabled. However, tracepoints already have built-in static_key for this
exact purpose.

Remove this redundant key.

Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-trace-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/827c7666d2989f08742a4fb869b1ed5bfaaf1dbf.1747046848.git.namcao@linutronix.de
---
 arch/x86/include/asm/trace/common.h      | 12 ------------
 arch/x86/include/asm/trace/exceptions.h  | 18 ++++++------------
 arch/x86/include/asm/trace/irq_vectors.h |  1 -
 arch/x86/kernel/Makefile                 |  1 -
 arch/x86/kernel/tracepoint.c             | 21 ---------------------
 arch/x86/mm/fault.c                      |  3 ---
 6 files changed, 6 insertions(+), 50 deletions(-)
 delete mode 100644 arch/x86/include/asm/trace/common.h
 delete mode 100644 arch/x86/kernel/tracepoint.c

diff --git a/arch/x86/include/asm/trace/common.h b/arch/x86/include/asm/trace/common.h
deleted file mode 100644
index f0f9bcd..0000000
--- a/arch/x86/include/asm/trace/common.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef _ASM_TRACE_COMMON_H
-#define _ASM_TRACE_COMMON_H
-
-#ifdef CONFIG_TRACING
-DECLARE_STATIC_KEY_FALSE(trace_pagefault_key);
-#define trace_pagefault_enabled()			\
-	static_branch_unlikely(&trace_pagefault_key)
-#else
-static inline bool trace_pagefault_enabled(void) { return false; }
-#endif
-
-#endif
diff --git a/arch/x86/include/asm/trace/exceptions.h b/arch/x86/include/asm/trace/exceptions.h
index 6b1e871..34bc821 100644
--- a/arch/x86/include/asm/trace/exceptions.h
+++ b/arch/x86/include/asm/trace/exceptions.h
@@ -6,10 +6,6 @@
 #define _TRACE_PAGE_FAULT_H
 
 #include <linux/tracepoint.h>
-#include <asm/trace/common.h>
-
-extern int trace_pagefault_reg(void);
-extern void trace_pagefault_unreg(void);
 
 DECLARE_EVENT_CLASS(x86_exceptions,
 
@@ -34,15 +30,13 @@ DECLARE_EVENT_CLASS(x86_exceptions,
 		  (void *)__entry->address, (void *)__entry->ip,
 		  __entry->error_code) );
 
-#define DEFINE_PAGE_FAULT_EVENT(name)				\
-DEFINE_EVENT_FN(x86_exceptions, name,				\
-	TP_PROTO(unsigned long address,	struct pt_regs *regs,	\
-		 unsigned long error_code),			\
-	TP_ARGS(address, regs, error_code),			\
-	trace_pagefault_reg, trace_pagefault_unreg);
+DEFINE_EVENT(x86_exceptions, page_fault_user,
+	TP_PROTO(unsigned long address,	struct pt_regs *regs, unsigned long error_code),
+	TP_ARGS(address, regs, error_code));
 
-DEFINE_PAGE_FAULT_EVENT(page_fault_user);
-DEFINE_PAGE_FAULT_EVENT(page_fault_kernel);
+DEFINE_EVENT(x86_exceptions, page_fault_kernel,
+	TP_PROTO(unsigned long address,	struct pt_regs *regs, unsigned long error_code),
+	TP_ARGS(address, regs, error_code));
 
 #undef TRACE_INCLUDE_PATH
 #undef TRACE_INCLUDE_FILE
diff --git a/arch/x86/include/asm/trace/irq_vectors.h b/arch/x86/include/asm/trace/irq_vectors.h
index 88e7f0f..7408beb 100644
--- a/arch/x86/include/asm/trace/irq_vectors.h
+++ b/arch/x86/include/asm/trace/irq_vectors.h
@@ -6,7 +6,6 @@
 #define _TRACE_IRQ_VECTORS_H
 
 #include <linux/tracepoint.h>
-#include <asm/trace/common.h>
 
 #ifdef CONFIG_X86_LOCAL_APIC
 
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 84cfa17..99a783f 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -141,7 +141,6 @@ obj-$(CONFIG_OF)			+= devicetree.o
 obj-$(CONFIG_UPROBES)			+= uprobes.o
 
 obj-$(CONFIG_PERF_EVENTS)		+= perf_regs.o
-obj-$(CONFIG_TRACING)			+= tracepoint.o
 obj-$(CONFIG_SCHED_MC_PRIO)		+= itmt.o
 obj-$(CONFIG_X86_UMIP)			+= umip.o
 
diff --git a/arch/x86/kernel/tracepoint.c b/arch/x86/kernel/tracepoint.c
deleted file mode 100644
index 03ae1ca..0000000
--- a/arch/x86/kernel/tracepoint.c
+++ /dev/null
@@ -1,21 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2013 Seiji Aguchi <seiji.aguchi@hds.com>
- */
-#include <linux/jump_label.h>
-#include <linux/atomic.h>
-
-#include <asm/trace/exceptions.h>
-
-DEFINE_STATIC_KEY_FALSE(trace_pagefault_key);
-
-int trace_pagefault_reg(void)
-{
-	static_branch_inc(&trace_pagefault_key);
-	return 0;
-}
-
-void trace_pagefault_unreg(void)
-{
-	static_branch_dec(&trace_pagefault_key);
-}
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 296d294..7e3e51f 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1455,9 +1455,6 @@ static __always_inline void
 trace_page_fault_entries(struct pt_regs *regs, unsigned long error_code,
 			 unsigned long address)
 {
-	if (!trace_pagefault_enabled())
-		return;
-
 	if (user_mode(regs))
 		trace_page_fault_user(address, regs, error_code);
 	else