linux-kernel - Re: [PATCH v5 09/22] powerpc/syscall: Make interrupt.c buildable on PPC32

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Message-Id: <1612857002.ckz8h2ixz5.astroid@bobo.none>
Date:   Tue, 09 Feb 2021 17:50:36 +1000
From:   Nicholas Piggin <npiggin@...il.com>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Michael Ellerman <mpe@...erman.id.au>, msuchanek@...e.de,
        Paul Mackerras <paulus@...ba.org>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v5 09/22] powerpc/syscall: Make interrupt.c buildable on
 PPC32

Excerpts from Christophe Leroy's message of February 9, 2021 4:02 pm:
> 
> 
> Le 09/02/2021 à 02:27, Nicholas Piggin a écrit :
>> Excerpts from Christophe Leroy's message of February 9, 2021 1:10 am:
>>> To allow building interrupt.c on PPC32, ifdef out specific PPC64
>>> code or use helpers which are available on both PP32 and PPC64
>>>
>>> Modify Makefile to always build interrupt.o
>>>
>>> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
>>> ---
>>> v5:
>>> - Also for interrupt exit preparation
>>> - Opted out kuap related code, ppc32 keeps it in ASM for the time being
>>> ---
>>>   arch/powerpc/kernel/Makefile    |  4 ++--
>>>   arch/powerpc/kernel/interrupt.c | 31 ++++++++++++++++++++++++-------
>>>   2 files changed, 26 insertions(+), 9 deletions(-)
>>>
> 
>>> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
>>> index d6be4f9a67e5..2dac4d2bb1cf 100644
>>> --- a/arch/powerpc/kernel/interrupt.c
>>> +++ b/arch/powerpc/kernel/interrupt.c
>>> @@ -39,7 +39,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
>>>   		BUG_ON(!(regs->msr & MSR_RI));
>>>   	BUG_ON(!(regs->msr & MSR_PR));
>>>   	BUG_ON(!FULL_REGS(regs));
>>> -	BUG_ON(regs->softe != IRQS_ENABLED);
>>> +	BUG_ON(arch_irq_disabled_regs(regs));
>>>   
>>>   #ifdef CONFIG_PPC_PKEY
>>>   	if (mmu_has_feature(MMU_FTR_PKEY)) {
>>> @@ -65,7 +65,9 @@ notrace long system_call_exception(long r3, long r4, long r5,
>>>   			isync();
>>>   	} else
>>>   #endif
>>> +#ifdef CONFIG_PPC64
>>>   		kuap_check_amr();
>>> +#endif
>> 
>> Wouldn't mind trying to get rid of these ifdefs at some point, but
>> there's some kuap / keys changes going on recently so I'm happy enough
>> to let this settle then look at whether we can refactor.
> 
> I have a follow up series that implements interrupts entries/exits in C and that removes all kuap 
> assembly, I will likely release it as RFC later today.
> 
>> 
>>>   
>>>   	account_cpu_user_entry();
>>>   
>>> @@ -318,7 +323,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
>>>   	return ret;
>>>   }
>>>   
>>> -#ifdef CONFIG_PPC_BOOK3S /* BOOK3E not yet using this */
>>> +#ifndef CONFIG_PPC_BOOK3E_64 /* BOOK3E not yet using this */
>>>   notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned long msr)
>>>   {
>>>   #ifdef CONFIG_PPC_BOOK3E
>> 
>> Why are you building this for 32? I don't mind if it's just to keep
>> things similar and make it build for now, but you're not using it yet,
>> right?
> 
> The series using that will follow, I thought it would be worth doing this at once.

Yeah that's fine by me then.

Thanks,
Nick