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From: Huang Ying <ying.huang@intel.com>
To: Simon Horman <horms@verge.net.au>
Cc: nigel@nigel.suspend2.net,
	Kexec Mailing List <kexec@lists.infradead.org>,
	linux-kernel@vger.kernel.org, "Rafael J. Wysocki" <rjw@sisk.pl>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Pavel Machek <pavel@ucw.cz>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	mingo@elte.hu, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH] kexec jump: fix code size checking
Date: Wed, 13 Aug 2008 11:05:15 +0800	[thread overview]
Message-ID: <1218596715.24951.69.camel@caritas-dev.intel.com> (raw)
In-Reply-To: <20080813024701.GA19201@verge.net.au>

On Wed, 2008-08-13 at 12:47 +1000, Simon Horman wrote:
> On Wed, Aug 13, 2008 at 09:04:35AM +0800, Huang Ying wrote:
> > Fix building issue when CONFIG_KEXEC=n. Thanks to Vivek Goyal for his
> > reminding.
> > 
> > Signed-off-by: Huang Ying <ying.huang@intel.com>
> > 
> > ---
> >  include/asm-x86/kexec.h |    3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > --- a/include/asm-x86/kexec.h
> > +++ b/include/asm-x86/kexec.h
> > @@ -43,6 +43,9 @@
> >  
> >  #ifdef CONFIG_X86_32
> >  # define KEXEC_CONTROL_CODE_MAX_SIZE	2048
> > +# ifndef CONFIG_KEXEC
> > +#  define kexec_control_code_size	0
> > +# endif
> >  #endif
> >  
> >  #ifndef __ASSEMBLY__
> 
> Is it impossible to skip the linker check in the !CONFIG_KEXEC case?

It is possible. I think there are several ways to do that.

1) use #ifdef in vmlinux_32.lds.S, such as:

#ifdef CONFIG_KEXEC
ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
       "kexec control code size is too big")
#endif

2) #define a macro for kexec check ld script in asm/kexec.h, such as:

#define LD_CHECK_KEXEC()	ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, \
				       "kexec control code size is too big")

and use that in vmlinux_32.lds.S.

3) #define kexec_control_code_size 0. So that the check can be passed
always. And, code size = 0 is reasonable for no code (CONFIG_KEXEC=n).


I think 3) is better. What do you think about?

Best Regards,
Huang Ying



_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

WARNING: multiple messages have this Message-ID (diff)
From: Huang Ying <ying.huang@intel.com>
To: Simon Horman <horms@verge.net.au>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	Pavel Machek <pavel@ucw.cz>,
	nigel@nigel.suspend2.net, "Rafael J. Wysocki" <rjw@sisk.pl>,
	Andrew Morton <akpm@linux-foundation.org>,
	Vivek Goyal <vgoyal@redhat.com>,
	mingo@elte.hu, Linus Torvalds <torvalds@linux-foundation.org>,
	Kexec Mailing List <kexec@lists.infradead.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kexec jump: fix code size checking
Date: Wed, 13 Aug 2008 11:05:15 +0800	[thread overview]
Message-ID: <1218596715.24951.69.camel@caritas-dev.intel.com> (raw)
In-Reply-To: <20080813024701.GA19201@verge.net.au>

On Wed, 2008-08-13 at 12:47 +1000, Simon Horman wrote:
> On Wed, Aug 13, 2008 at 09:04:35AM +0800, Huang Ying wrote:
> > Fix building issue when CONFIG_KEXEC=n. Thanks to Vivek Goyal for his
> > reminding.
> > 
> > Signed-off-by: Huang Ying <ying.huang@intel.com>
> > 
> > ---
> >  include/asm-x86/kexec.h |    3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > --- a/include/asm-x86/kexec.h
> > +++ b/include/asm-x86/kexec.h
> > @@ -43,6 +43,9 @@
> >  
> >  #ifdef CONFIG_X86_32
> >  # define KEXEC_CONTROL_CODE_MAX_SIZE	2048
> > +# ifndef CONFIG_KEXEC
> > +#  define kexec_control_code_size	0
> > +# endif
> >  #endif
> >  
> >  #ifndef __ASSEMBLY__
> 
> Is it impossible to skip the linker check in the !CONFIG_KEXEC case?

It is possible. I think there are several ways to do that.

1) use #ifdef in vmlinux_32.lds.S, such as:

#ifdef CONFIG_KEXEC
ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE,
       "kexec control code size is too big")
#endif

2) #define a macro for kexec check ld script in asm/kexec.h, such as:

#define LD_CHECK_KEXEC()	ASSERT(kexec_control_code_size <= KEXEC_CONTROL_CODE_MAX_SIZE, \
				       "kexec control code size is too big")

and use that in vmlinux_32.lds.S.

3) #define kexec_control_code_size 0. So that the check can be passed
always. And, code size = 0 is reasonable for no code (CONFIG_KEXEC=n).


I think 3) is better. What do you think about?

Best Regards,
Huang Ying



  reply	other threads:[~2008-08-13  3:05 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-13  1:04 [PATCH] kexec jump: fix code size checking Huang Ying
2008-08-13  1:04 ` Huang Ying
2008-08-13  2:47 ` Simon Horman
2008-08-13  2:47   ` Simon Horman
2008-08-13  3:05   ` Huang Ying [this message]
2008-08-13  3:05     ` Huang Ying
2008-08-13  3:40     ` Eric W. Biederman
2008-08-13  3:40       ` Eric W. Biederman
2008-08-13  5:18       ` Huang Ying
2008-08-13  5:18         ` Huang Ying
2008-08-13  5:51         ` Simon Horman
2008-08-13  5:51           ` Simon Horman
2008-08-13  3:48     ` Simon Horman
2008-08-13  3:48       ` Simon Horman
2008-08-13 13:21     ` Vivek Goyal
2008-08-13 13:21       ` Vivek Goyal
2008-08-13 13:19 ` Vivek Goyal
2008-08-13 13:19   ` Vivek Goyal
2008-08-13 17:07   ` Andrew Morton
2008-08-13 17:07     ` Andrew Morton

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