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Groups > linux.kernel > #1609290

[RFC PATCH tip/master 5/8] kprobes/x86: Make boostable flag boolean

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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@kernel.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 ea3b8e5..b358c84 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -410,9 +410,9 @@ static void prepare_boost(struct kprobe *p, int length)
 		 */
 		synthesize_reljump((void *)p->ainsn.insn + length,
 				   (void *)p->addr + length);
-		p->ainsn.boostable = 1;
+		p->ainsn.boostable = true;
 	} else
-		p->ainsn.boostable = -1;
+		p->ainsn.boostable = false;
 }
 
 static int arch_copy_kprobe(struct kprobe *p)
@@ -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;
 }

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[RFC PATCH tip/master 0/8] kprobes/x86: Make kprobes instruction buffers read-only Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-26 05:30 +0200
  [RFC PATCH tip/master 2/8] kprobes/x86: Fix the description of __copy_instruction() Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-26 05:30 +0200
  [RFC PATCH tip/master 3/8] kprobes/x86: Use instruction decoder for booster Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-26 05:30 +0200
  [RFC PATCH tip/master 6/8] kprobes/x86: Set kprobes pages readonly Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-26 05:40 +0200
  [RFC PATCH tip/master 8/8] kprobes/x86: Consolidate insn decoder users for copying code Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-26 05:40 +0200
    Re: [RFC PATCH tip/master 8/8] kprobes/x86: Consolidate insn  decoder users for copying code Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-27 00:50 +0200
  [RFC PATCH tip/master 5/8] kprobes/x86: Make boostable flag boolean Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-26 05:40 +0200
  [RFC PATCH tip/master 7/8] kprobes/x86: Use probe_kernel_read instead of memcpy Masami Hiramatsu <mhiramat@kernel.org> - 2017-03-26 06:00 +0200

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