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Message-ID: <4C6FCFC7.7020903@mvista.com>
Date:   Sat, 21 Aug 2010 17:08:23 +0400
From:   Sergei Shtylyov <sshtylyov@mvista.com>
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To:     jiang.adam@gmail.com
CC:     ralf@linux-mips.org, dmitri.vorobiev@movial.com,
        wuzhangjin@gmail.com, ddaney@caviumnetworks.com,
        peterz@infradead.org, fweisbec@gmail.com, tj@kernel.org,
        tglx@linutronix.de, mingo@elte.hu, linux-mips@linux-mips.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mips: irq: add statckoverflow detection
References: <1282372293-30211-1-git-send-email-jiang.adam@gmail.com>
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Hello.

jiang.adam@gmail.com wrote:

> From: Adam Jiang <jiang.adam@gmail.com>

> Add stackoverflow detection to mips arch

> Signed-off-by: Adam Jiang <jiang.adam@gmail.com>
[...]
> diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
> index c6345f5..6334037 100644
> --- a/arch/mips/kernel/irq.c
> +++ b/arch/mips/kernel/irq.c
> @@ -151,6 +151,22 @@ void __init init_IRQ(void)
>  #endif
>  }
>  
> +static inline void check_stack_overflow(void)
> +{
> +#ifdef CONFIG_DEBUG_STACKOVERFLOW

    #ifdef within function is considered bad style. Better do it this way:

#ifdef CONFIG_DEBUG_STACKOVERFLOW
static inline void check_stack_overflow(void)
{
[...]
}
#else
static inline void check_stack_overflow(void) {}
#endif

> +	long sp;
> +
> +	asm volatile("move %0, $sp" : "=r" (sp));
> +	sp = sp & (THREAD_SIZE-1);
> +
> +	/* check for stack overflow: is there less then 2KB free? */

    Hm, 2KB seems pretty large margin...

WBR, Sergei