linux-kernel - [RFC PATCH 4/6] x86/jump_label: Add __jump_label_set_jump

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Date:   Mon,  8 Oct 2018 14:53:03 +0200
From:   Daniel Bristot de Oliveira <bristot@...hat.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Pavel Tatashin <pasha.tatashin@...cle.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Zhou Chengming <zhouchengming1@...wei.com>,
        Jiri Kosina <jkosina@...e.cz>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Chris von Recklinghausen <crecklin@...hat.com>,
        Jason Baron <jbaron@...mai.com>, Scott Wood <swood@...hat.com>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Clark Williams <williams@...hat.com>
Subject: [RFC PATCH 4/6] x86/jump_label: Add __jump_label_set_jump_code() helper

Move the definition of the code to be written from
__jump_label_transform() to a specialized function.

Signed-off-by: Daniel Bristot de Oliveira <bristot@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Pavel Tatashin <pasha.tatashin@...cle.com>
Cc: Masami Hiramatsu <mhiramat@...nel.org>
Cc: "Steven Rostedt (VMware)" <rostedt@...dmis.org>
Cc: Zhou Chengming <zhouchengming1@...wei.com>
Cc: Jiri Kosina <jkosina@...e.cz>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@...radead.org>
Cc: Chris von Recklinghausen <crecklin@...hat.com>
Cc: Jason Baron <jbaron@...mai.com>
Cc: Scott Wood <swood@...hat.com>
Cc: Marcelo Tosatti <mtosatti@...hat.com>
Cc: Clark Williams <williams@...hat.com>
Cc: x86@...nel.org
Cc: linux-kernel@...r.kernel.org
---
 arch/x86/kernel/jump_label.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index a11d836d9aaa..de588ff47f81 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -88,6 +88,22 @@ static inline void __jump_label_disabling_check(struct jump_entry *entry,
 	}
 }
 
+static void __jump_label_set_jump_code(struct jump_entry *entry,
+				     enum jump_label_type type,
+				     int init,
+				     union jump_code_union *code)
+{
+	if (type == JUMP_LABEL_JMP) {
+		__jump_label_enabling_check(entry, type, init);
+
+		code->jump = 0xe9;
+		code->offset = entry->target - (entry->code + JUMP_LABEL_NOP_SIZE);
+	} else {
+		__jump_label_disabling_check(entry, type, init);
+		memcpy(code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE);
+	}
+}
+
 static void __ref __jump_label_transform(struct jump_entry *entry,
 					 enum jump_label_type type,
 					 void *(*poker)(void *, const void *, size_t),
@@ -98,16 +114,7 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
 	if (early_boot_irqs_disabled)
 		poker = text_poke_early;
 
-	if (type == JUMP_LABEL_JMP) {
-		__jump_label_enabling_check(entry, type, init);
-
-		code.jump = 0xe9;
-		code.offset = entry->target -
-				(entry->code + JUMP_LABEL_NOP_SIZE);
-	} else {
-		__jump_label_disabling_check(entry, type, init);
-		memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE);
-	}
+	__jump_label_set_jump_code(entry, type, init, &code);
 
 	/*
 	 * Make text_poke_bp() a default fallback poker.
-- 
2.17.1