Re: [PATCH 03/10] powerpc/64e/interrupt: use new interrupt return

[Nicholas Piggin <npiggin@gmail.com>]

Excerpts from Nicholas Piggin's message of March 16, 2021 5:04 pm:
> Excerpts from Christophe Leroy's message of March 15, 2021 11:30 pm:
>> 
>> 
>> Le 15/03/2021 à 04:17, Nicholas Piggin a écrit :
>>> Update the new C and asm interrupt return code to account for 64e
>>> specifics, switch over to use it.
>>> 
>>> The now-unused old ret_from_except code, that was moved to 64e after the
>>> 64s conversion, is removed.
>>> 
>>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>>> ---
>>>   arch/powerpc/include/asm/asm-prototypes.h |   2 -
>>>   arch/powerpc/kernel/entry_64.S            |   9 +-
>>>   arch/powerpc/kernel/exceptions-64e.S      | 321 ++--------------------
>>>   arch/powerpc/kernel/interrupt.c           |  27 +-
>>>   arch/powerpc/kernel/irq.c                 |  76 -----
>>>   5 files changed, 56 insertions(+), 379 deletions(-)
>>> 
>>> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
>>> index fbabb49888d3..ae7b058b2970 100644
>>> --- a/arch/powerpc/kernel/interrupt.c
>>> +++ b/arch/powerpc/kernel/interrupt.c
>>> @@ -235,6 +235,10 @@ static notrace void booke_load_dbcr0(void)
>>>   #endif
>>>   }
>>>   
>>> +/* temporary hack for context tracking, removed in later patch */
>>> +#include <linux/sched/debug.h>
>>> +asmlinkage __visible void __sched schedule_user(void);
>>> +
>>>   /*
>>>    * This should be called after a syscall returns, with r3 the return value
>>>    * from the syscall. If this function returns non-zero, the system call
>>> @@ -292,7 +296,11 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
>>>   	while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) {
>>>   		local_irq_enable();
>>>   		if (ti_flags & _TIF_NEED_RESCHED) {
>>> +#ifdef CONFIG_PPC_BOOK3E_64
>>> +			schedule_user();
>>> +#else
>>>   			schedule();
>>> +#endif
>>>   		} else {
>>>   			/*
>>>   			 * SIGPENDING must restore signal handler function
>>> @@ -360,7 +368,6 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
>>>   	return ret;
>>>   }
>>>   
>>> -#ifndef CONFIG_PPC_BOOK3E_64 /* BOOK3E not yet using this */
>>>   notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long msr)
>>>   {
>>>   	unsigned long ti_flags;
>>> @@ -372,7 +379,9 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
>>>   	BUG_ON(!(regs->msr & MSR_PR));
>>>   	BUG_ON(!FULL_REGS(regs));
>>>   	BUG_ON(arch_irq_disabled_regs(regs));
>>> +#ifdef CONFIG_PPC_BOOK3S_64
>> 
>> Shouldn't this go away in patch 6 as well ?
>> Or is that needed at all ? In syscall_exit_prepare() it is not ifdefed .
> 
> Hmm, not sure. I'll take a look. It probably shouldn't be ifdefed at all 
> but definitely by the end it should run without warning.

Oh I got confused and thought that was the syscall exit. Interrupt exit 
has to keep this until patch 6 because 64e context tracking does 
everything in interrupt wrappers, so by the time we get here it will
already be set to CONTEXT_USER.

Thanks,
Nick