linux-kernel - Re: [PATCH 3/4] printk: use a clever macro

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Message-ID: <53BD86B1.7050003@linaro.org>
Date:	Wed, 09 Jul 2014 13:15:13 -0500
From:	Alex Elder <elder@...aro.org>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Andi Kleen <ak@...ux.intel.com>, bp@...e.de,
	Jan Kara <jack@...e.cz>, John Stultz <john.stultz@...aro.org>,
	pmladek@...e.cz, Steven Rostedt <rostedt@...dmis.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/4] printk: use a clever macro

On 07/09/2014 12:58 PM, Geert Uytterhoeven wrote:
> Hi Alex,
> 
> On Wed, Jul 9, 2014 at 3:04 PM, Alex Elder <elder@...aro.org> wrote:
>> --- a/kernel/printk/printk.c
>> +++ b/kernel/printk/printk.c
>> @@ -453,11 +453,7 @@ static int log_store(int facility, int level,
>>         return msg->text_len;
>>  }
>>
>> -#ifdef CONFIG_SECURITY_DMESG_RESTRICT
>> -int dmesg_restrict = 1;
>> -#else
>> -int dmesg_restrict;
>> -#endif
>> +int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT);
> 
> Doesn't this move dmesg_restrict from the bss to the data section
> in case CONFIG_SECURITY_DMESG_RESTRICT is not enabled, due
> to the explicit initialization to zero?

I honestly don't know.  Is that even a well-defined behavior?
Couldn't the compiler, noting an explicit 0 initialization,
put it into BSS anyway?

In any case, does this distinction matter?

					-Alex

> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
> 

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