linux-kernel - [PATCHv2 6/7] x86: traps_xx: modify default_do

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Date:	Wed, 2 Jul 2008 18:39:01 +0200
From:	Alexander van Heukelum <heukelum@...lshack.com>
To:	Cyrill Gorcunov <gorcunov@...il.com>, Ingo Molnar <mingo@...e.hu>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCHv2 6/7] x86: traps_xx: modify default_do_nmi

 - local caching of smp_processor_id() in default_do_nmi()
 - v2: do not split default_do_nmi over two lines

Signed-off-by: Alexander van Heukelum <heukelum@...tmail.fm>

---

On Wed, Jul 02, 2008 at 08:12:20PM +0400, Cyrill Gorcunov wrote:
> | -static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
> | +static notrace __kprobes void
> | +default_do_nmi(struct pt_regs *regs)
> | [ ... ]
> | -asmlinkage notrace  __kprobes void default_do_nmi(struct pt_regs *regs)
> | +asmlinkage notrace __kprobes void
> | +default_do_nmi(struct pt_regs *regs)
> 
> Hi Alexander, good done, thanks! But why did you split default_do_nmi
> definition by two lines? I think it would be better to keep them as it
> was before, ie by a single line
> 
> 	static notrace __kprobes void default_do_nmi(struct pt_regs *regs)

Thanks! Here is the replacement patch with default_do_nmi left on
a single line. Patch 7 applies with 1 line fuzz.

Greetings,
    Alexander

> 		- Cyrill -

diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
index bed6e72..9e3b0c4 100644
--- a/arch/x86/kernel/traps_32.c
+++ b/arch/x86/kernel/traps_32.c
@@ -793,9 +793,12 @@ void notrace __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
 static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 {
 	unsigned char reason = 0;
+	int cpu;
+
+	cpu = smp_processor_id();
 
-	/* Only the BSP gets external NMIs from the system: */
-	if (!smp_processor_id())
+	/* Only the BSP gets external NMIs from the system. */
+	if (!cpu)
 		reason = get_nmi_reason();
 
 	if (!(reason & 0xc0)) {
@@ -809,7 +812,7 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 		 */
 		if (nmi_watchdog_tick(regs, reason))
 			return;
-		if (!do_nmi_callback(regs, smp_processor_id()))
+		if (!do_nmi_callback(regs, cpu))
 			unknown_nmi_error(reason, regs);
 #else
 		unknown_nmi_error(reason, regs);
diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c
index 7511553..26ab0be 100644
--- a/arch/x86/kernel/traps_64.c
+++ b/arch/x86/kernel/traps_64.c
@@ -832,7 +832,7 @@ unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
 
 /* Runs on IST stack. This code must keep interrupts off all the time.
    Nested NMIs are prevented by the CPU. */
-asmlinkage notrace  __kprobes void default_do_nmi(struct pt_regs *regs)
+asmlinkage notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 {
 	unsigned char reason = 0;
 	int cpu;
--
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