From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Tue, 09 Oct 2012 17:27:35 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai] Exporting __ipipe_get_cs_tsc
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To: Henri Roosen <henriroosen@gmail.com>
Cc: xenomai@xenomai.org

On 10/09/2012 05:24 PM, Henri Roosen wrote:
> On Tue, Oct 9, 2012 at 4:10 PM, Philippe Gerum <rpm@xenomai.org> wrote:
>> On 10/09/2012 02:32 PM, Henri Roosen wrote:
>>> Hi,
>>>
>>> I'm using the current git heads of core-3.4 and xenomai 2.6.1 for x86
>>> with the attached config file.
>>>
>>> When compiling the modules I get undefined symbols:
>>> ERROR: "__ipipe_get_cs_tsc" [kernel/xenomai/skins/posix/xeno_posix.ko]
>>> undefined!
>>>
>>> This is because the run time seleted __ipipe_get_cs_tsc assembly
>>> function is not exported for module use.
>>> I don't know how to export this or whether the symbol should be used
>>> by modules in the first place.
>>>
>>
>> Please try this:
>>
>> diff --git a/arch/x86/kernel/ipipe.c b/arch/x86/kernel/ipipe.c
>> index 430aeea..2d2f83c 100644
>> --- a/arch/x86/kernel/ipipe.c
>> +++ b/arch/x86/kernel/ipipe.c
>> @@ -634,6 +634,11 @@ void update_vsyscall(struct timespec *wall_time,
>> struct timespec *wtm,
>>  void update_vsyscall_tz(void)
>>  {
>>  }
>> +
>> +#ifdef CONFIG_IPIPE_WANT_CLOCKSOURCE
>> +EXPORT_SYMBOL_GPL(__ipipe_get_cs_tsc);
>> +#endif
>> +
>>  #endif /* CONFIG_X86_32 */
>>
>>  struct task_struct *__switch_to(struct task_struct *prev_p,
> 
> Thanks for looking into this.
> 
> Unfortunately with the patch the compile results in:
> arch/x86/kernel/ipipe.c:640: error: ‘__ipipe_get_cs_tsc’ undeclared
> here (not in a function)

The function is declared nowhere, because it was supposedly only be used
in assembly. So, you need to declare the function before the
EXPORT_SYMBOL. Its prototype would be:

unsigned long long __ipipe_get_tsc_tsc(void);

-- 
					    Gilles.