Subject: Re: [PATCH 1/4] powerpc/kprobe: introduce a new thread flag

From: "tiejun.chen" <[email-masked]>
Date: Tue, 13 Dec 2011 12:56:02 +0800

Benjamin Herrenschmidt wrote:
> On Mon, 2011-12-12 at 16:50 +0800, Tiejun Chen wrote:
>> We need to add a new thread flag, TIF_KPROBE/_TIF_DELAYED_KPROBE,
>> for handling kprobe operation while exiting exception.
> 
> The basic idea is sane, however the instruction emulation isn't per-se
> kprobe specific. It could be used by xmon too for example. I'd rather
> use a different name, something like TIF_EMULATE_STACK_STORE or

Its good term so I'll use this directly :)

Thanks
Tiejun

> something like that.
> 
> Cheers,
> Ben.
> 
>> Signed-off-by: Tiejun Chen <[email-masked]>
>> ---
>>  arch/powerpc/include/asm/thread_info.h |    2 ++
>>  1 files changed, 2 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
>> index 836f231..3378734 100644
>> --- a/arch/powerpc/include/asm/thread_info.h
>> +++ b/arch/powerpc/include/asm/thread_info.h
>> @@ -112,6 +112,7 @@ static inline struct thread_info *current_thread_info(void)
>>  #define TIF_FREEZE		14	/* Freezing for suspend */
>>  #define TIF_SYSCALL_TRACEPOINT	15	/* syscall tracepoint instrumentation */
>>  #define TIF_RUNLATCH		16	/* Is the runlatch enabled? */
>> +#define TIF_KPROBE		17	/* Is the delayed kprobe operation? */
>>  
>>  /* as above, but as bit values */
>>  #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
>> @@ -130,6 +131,7 @@ static inline struct thread_info *current_thread_info(void)
>>  #define _TIF_FREEZE		(1<<TIF_FREEZE)
>>  #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
>>  #define _TIF_RUNLATCH		(1<<TIF_RUNLATCH)
>> +#define _TIF_DELAYED_KPROBE	(1<<TIF_KPROBE)
>>  #define _TIF_SYSCALL_T_OR_A	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
>>  				 _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT)
>>  
> 
> 
>