[PATCH 1/4] powerpc: convert to copy_thread_tls

Christophe Leroy christophe.leroy at c-s.fr
Wed Aug 28 00:00:40 AEST 2019



Le 27/08/2019 à 12:13, Nicholas Piggin a écrit :
> Christophe Leroy's on August 27, 2019 4:07 pm:
>>
>>
>> Le 27/08/2019 à 05:30, Nicholas Piggin a écrit :
>>> Commit 3033f14ab78c3 ("clone: support passing tls argument via C rather
>>> than pt_regs magic") introduced the HAVE_COPY_THREAD_TLS option. Use it
>>> to avoid a subtle assumption about the argument ordering of clone type
>>> syscalls.
>>>
>>> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
>>> ---
>>>    arch/powerpc/Kconfig          | 1 +
>>>    arch/powerpc/kernel/process.c | 9 +++++----
>>>    2 files changed, 6 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>>> index d8dcd8820369..7477a3263225 100644
>>> --- a/arch/powerpc/Kconfig
>>> +++ b/arch/powerpc/Kconfig
>>> @@ -182,6 +182,7 @@ config PPC
>>>    	select HAVE_STACKPROTECTOR		if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
>>>    	select HAVE_STACKPROTECTOR		if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
>>>    	select HAVE_CONTEXT_TRACKING		if PPC64
>>> +	select HAVE_COPY_THREAD_TLS
>>>    	select HAVE_DEBUG_KMEMLEAK
>>>    	select HAVE_DEBUG_STACKOVERFLOW
>>>    	select HAVE_DYNAMIC_FTRACE
>>> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
>>> index 8fc4de0d22b4..24621e7e5033 100644
>>> --- a/arch/powerpc/kernel/process.c
>>> +++ b/arch/powerpc/kernel/process.c
>>> @@ -1600,8 +1600,9 @@ static void setup_ksp_vsid(struct task_struct *p, unsigned long sp)
>>>    /*
>>>     * Copy architecture-specific thread state
>>>     */
>>> -int copy_thread(unsigned long clone_flags, unsigned long usp,
>>> -		unsigned long kthread_arg, struct task_struct *p)
>>> +int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
>>> +		unsigned long kthread_arg, struct task_struct *p,
>>> +		unsigned long tls)
>>>    {
>>>    	struct pt_regs *childregs, *kregs;
>>>    	extern void ret_from_fork(void);
>>> @@ -1642,10 +1643,10 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
>>>    		if (clone_flags & CLONE_SETTLS) {
>>>    #ifdef CONFIG_PPC64
>>
>> is_32bit_task() exists and always returns 1 on PPC32 so this gross ifdef
>> in the middle of an if/else is pointless, it should be dropped.
> 
> I could do that as another patch in the series.


Yes, would be good, because if I do an independant patch for that it 
will conflict with your series.

Thanks
Christophe


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