linux-kernel - Re: [PATCH] x86: traps_xx: modify default_do

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Message-ID: <20080702161220.GA7003@cvg>
Date:	Wed, 2 Jul 2008 20:12:20 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Alexander van Heukelum <heukelum@...lshack.com>
Cc:	Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: traps_xx: modify default_do_nmi

[Alexander van Heukelum - Wed, Jul 02, 2008 at 01:32:28AM +0200]
|  - local caching of smp_processor_id()
| 
| Signed-off-by: Alexander van Heukelum <heukelum@...tmail.fm>
| ---
|  arch/x86/kernel/traps_32.c |   12 ++++++++----
|  arch/x86/kernel/traps_64.c |    3 ++-
|  2 files changed, 10 insertions(+), 5 deletions(-)
| 
| diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c
| index 68e800f..14fe3cd 100644
| --- a/arch/x86/kernel/traps_32.c
| +++ b/arch/x86/kernel/traps_32.c
| @@ -790,12 +790,16 @@ void notrace __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
|  	do_exit(SIGSEGV);
|  }
|  
| -static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
| +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 +813,7 @@ 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 677b4e5..2f8d87d 100644
| --- a/arch/x86/kernel/traps_64.c
| +++ b/arch/x86/kernel/traps_64.c
| @@ -832,7 +832,8 @@ 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;
| -- 
| 1.5.4.3
| 
| 

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)

		- Cyrill -
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