linux-kernel - [tip:perf/core] kprobes/x86: Make boostable flag boolean

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Message-ID: <tip-490154bc68d15de9e38fbb850fe470e32cc66407@git.kernel.org>
Date:   Wed, 12 Apr 2017 00:34:04 -0700
From:   tip-bot for Masami Hiramatsu <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, mhiramat@...nel.org, bp@...en8.de,
        ananth@...ux.vnet.ibm.com, xiaolong.ye@...el.com,
        torvalds@...ux-foundation.org, tglx@...utronix.de,
        brgerst@...il.com, davem@...emloft.net, hpa@...or.com,
        anil.s.keshavamurthy@...el.com, peterz@...radead.org,
        dvlasenk@...hat.com, mingo@...nel.org, jpoimboe@...hat.com,
        aryabinin@...tuozzo.com
Subject: [tip:perf/core] kprobes/x86: Make boostable flag boolean

Commit-ID:  490154bc68d15de9e38fbb850fe470e32cc66407
Gitweb:     http://git.kernel.org/tip/490154bc68d15de9e38fbb850fe470e32cc66407
Author:     Masami Hiramatsu <mhiramat@...nel.org>
AuthorDate: Wed, 29 Mar 2017 14:01:35 +0900
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Wed, 12 Apr 2017 09:23:46 +0200

kprobes/x86: Make boostable flag boolean

Make arch_specific_insn.boostable to boolean, since it has
only 2 states, boostable or not. So it is better to use
boolean from the viewpoint of code readability.

Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>
Cc: Andrey Ryabinin <aryabinin@...tuozzo.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: David S . Miller <davem@...emloft.net>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ye Xiaolong <xiaolong.ye@...el.com>
Link: http://lkml.kernel.org/r/149076368566.22469.6322906866458231844.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/kprobes.h   |  7 +++----
 arch/x86/kernel/kprobes/core.c   | 12 ++++++------
 arch/x86/kernel/kprobes/ftrace.c |  2 +-
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index 2005816..34b984c 100644
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -72,14 +72,13 @@ struct arch_specific_insn {
 	/* copy of the original instruction */
 	kprobe_opcode_t *insn;
 	/*
-	 * boostable = -1: This instruction type is not boostable.
-	 * boostable = 0: This instruction type is boostable.
-	 * boostable = 1: This instruction has been boosted: we have
+	 * boostable = false: This instruction type is not boostable.
+	 * boostable = true: This instruction has been boosted: we have
 	 * added a relative jump after the instruction copy in insn,
 	 * so no single-step and fixup are needed (unless there's
 	 * a post_handler or break_handler).
 	 */
-	int boostable;
+	bool boostable;
 	bool if_modifier;
 };
 
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index a654054..3f084a0 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -409,9 +409,9 @@ static void prepare_boost(struct kprobe *p, int length)
 		 * jumps back to correct address.
 		 */
 		synthesize_reljump(p->ainsn.insn + length, p->addr + length);
-		p->ainsn.boostable = 1;
+		p->ainsn.boostable = true;
 	} else {
-		p->ainsn.boostable = -1;
+		p->ainsn.boostable = false;
 	}
 }
 
@@ -467,7 +467,7 @@ void arch_disarm_kprobe(struct kprobe *p)
 void arch_remove_kprobe(struct kprobe *p)
 {
 	if (p->ainsn.insn) {
-		free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
+		free_insn_slot(p->ainsn.insn, p->ainsn.boostable);
 		p->ainsn.insn = NULL;
 	}
 }
@@ -539,7 +539,7 @@ static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
 		return;
 
 #if !defined(CONFIG_PREEMPT)
-	if (p->ainsn.boostable == 1 && !p->post_handler) {
+	if (p->ainsn.boostable && !p->post_handler) {
 		/* Boost up -- we can execute copied instructions directly */
 		if (!reenter)
 			reset_current_kprobe();
@@ -859,7 +859,7 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs,
 	case 0xcf:
 	case 0xea:	/* jmp absolute -- ip is correct */
 		/* ip is already adjusted, no more changes required */
-		p->ainsn.boostable = 1;
+		p->ainsn.boostable = true;
 		goto no_change;
 	case 0xe8:	/* call relative - Fix return addr */
 		*tos = orig_ip + (*tos - copy_ip);
@@ -884,7 +884,7 @@ static void resume_execution(struct kprobe *p, struct pt_regs *regs,
 			 * jmp near and far, absolute indirect
 			 * ip is correct. And this is boostable
 			 */
-			p->ainsn.boostable = 1;
+			p->ainsn.boostable = true;
 			goto no_change;
 		}
 	default:
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
index 5f8f0b3..041f7b6 100644
--- a/arch/x86/kernel/kprobes/ftrace.c
+++ b/arch/x86/kernel/kprobes/ftrace.c
@@ -94,6 +94,6 @@ NOKPROBE_SYMBOL(kprobe_ftrace_handler);
 int arch_prepare_kprobe_ftrace(struct kprobe *p)
 {
 	p->ainsn.insn = NULL;
-	p->ainsn.boostable = -1;
+	p->ainsn.boostable = false;
 	return 0;
 }