linux-kernel - [PATCH RFC V3 8/8] x86/jump_label: add arch_jump_label_transform

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Message-Id: <a41a06725b61aa91dcd5606e18a159d3b44cf6ba.1317755691.git.jeremy.fitzhardinge@citrix.com>
Date:	Tue,  4 Oct 2011 12:18:09 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	"David S. Miller" <davem@...emloft.net>,
	David Daney <david.daney@...ium.com>,
	Michael Ellerman <michael@...erman.id.au>,
	Jan Glauber <jang@...ux.vnet.ibm.com>,
	Jason Baron <jbaron@...hat.com>,
	the arch/x86 maintainers <x86@...nel.org>,
	Xen Devel <xen-devel@...ts.xensource.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Subject: [PATCH RFC V3 8/8] x86/jump_label: add arch_jump_label_transform_static()

From: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>

This allows jump-label entries to be cheaply updated on code which is
not yet live.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Cc: Jason Baron <jbaron@...hat.com>
---
 arch/x86/kernel/jump_label.c |   20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index 2ad0298..ea9d5f2f 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -24,8 +24,9 @@ union jump_code_union {
 	} __attribute__((packed));
 };
 
-void arch_jump_label_transform(struct jump_entry *entry,
-			       enum jump_label_type type)
+static void __jump_label_transform(struct jump_entry *entry,
+				   enum jump_label_type type,
+				   void *(*poker)(void *, const void *, size_t))
 {
 	union jump_code_union code;
 
@@ -35,11 +36,24 @@ void arch_jump_label_transform(struct jump_entry *entry,
 				(entry->code + JUMP_LABEL_NOP_SIZE);
 	} else
 		memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE);
+
+	(*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
+}
+
+void arch_jump_label_transform(struct jump_entry *entry,
+			       enum jump_label_type type)
+{
 	get_online_cpus();
 	mutex_lock(&text_mutex);
-	text_poke_smp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
+	__jump_label_transform(entry, type, text_poke_smp);
 	mutex_unlock(&text_mutex);
 	put_online_cpus();
 }
 
+void arch_jump_label_transform_static(struct jump_entry *entry,
+				      enum jump_label_type type)
+{
+	__jump_label_transform(entry, type, text_poke_early);
+}
+
 #endif
-- 
1.7.6.4

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