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Date: Wed, 26 Feb 2014 14:06:17 +0800
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Subject: Re: [PATCH] powerpc: ftrace: bugfix for test_24bit_addr
From: Liu ping fan <kernelfans@gmail.com>
To: ananth@in.ibm.com
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Cc: Paul Mackerras <paulus@samba.org>, linuxppc-dev@lists.ozlabs.org,
 Anton Blanchard <anton@samba.org>
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On Wed, Feb 26, 2014 at 12:35 PM, Ananth N Mavinakayanahalli
<ananth@in.ibm.com> wrote:
> On Wed, Feb 26, 2014 at 10:23:01AM +0800, Liu Ping Fan wrote:
>> The branch target should be the func addr, not the addr of func_descr_t.
>> So using ppc_function_entry() to generate the right target addr.
>>
>> Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
>> ---
>> This bug will make ftrace fail to work. It can be triggered when the kernel
>> size grows up.
>> ---
>>  arch/powerpc/kernel/ftrace.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
>> index 9b27b29..b0ded97 100644
>> --- a/arch/powerpc/kernel/ftrace.c
>> +++ b/arch/powerpc/kernel/ftrace.c
>> @@ -74,6 +74,7 @@ ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
>>   */
>>  static int test_24bit_addr(unsigned long ip, unsigned long addr)
>>  {
>> +     addr = ppc_function_entry((void *)addr);
>
> Won't this break on LE?
>
How? I can not figure out it. Anyway, ppc_function_entry() is already
used in other places with LE.

Thx,
Fan