linux-kernel - Re: [Patch 4/4] module: trim exception table in module

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Message-ID: <4A221280.1050406@redhat.com>
Date:	Sun, 31 May 2009 13:15:44 +0800
From:	Amerigo Wang <amwang@...hat.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
CC:	linux-alpha@...r.kernel.org, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org, jdike@...toit.com, mingo@...e.hu,
	sparclinux@...r.kernel.org, linux-ia64@...r.kernel.org
Subject: Re: [Patch 4/4] module: trim exception table in module_free()

Rusty Russell wrote:
> On Wed, 27 May 2009 05:16:11 pm Amerigo Wang wrote:
>   
>> Rusty Russell wrote:
>>     
>>> __ex_table ends up with two entries:
>>>
>>> Contents of section __ex_table:
>>>  0000 0c000000 00000000 0e000000 00000000  ................
>>>  0010 10000000 0a000000 12000000 0a000000  ................
>>>
>>> The first is for the __put_user in .text (extable_not_init()) and the
>>> second is for the one in .init.text (init()).
>>>
>>> Depending on how the module gets allocated, the one referring to
>>> .init.text may be first or last.
>>>       
>> Hmm, how about the following? :-)
>>
>> struct exception_table_entry *p = mod->extable;
>>
>> for (;p <= mod->extable+mod->num_exentries; p++ )
>>          if (with_in_module_init(p->insn, mod))
>>                    trim_it(p);
>>     
>
> More like this:
>
> void trim_init_extable(struct module *m)
> {
> 	/* Since entries are sorted, init entries are at the start... */
> 	while (m->num_exentries && within_module_init(m->extable[0].insn)) {
> 		m->extable++;
> 		m->num_exentries--;
> 	}
>
> 	/* ... or the end. */
> 	while (m->num_exentries && within_module_init(m->extable[m->num_exentries-1].insn))
> 		m->num_exentries--;
> }
>   

Great! Thank you!
But does this works on all arch? Or only except sparc32?

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