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

From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Nicholas Piggin <npiggin@gmail.com>, linuxppc-dev@lists.ozlabs.org
Cc: Scott Wood <oss@buserror.net>
Subject: Re: [PATCH 03/10] powerpc/64e/interrupt: use new interrupt return
Date: Mon, 15 Mar 2021 14:30:53 +0100	[thread overview]
Message-ID: <a2c192a2-ebdb-d18a-6e21-b27d8890fe06@csgroup.eu> (raw)
In-Reply-To: <20210315031716.3940350-4-npiggin@gmail.com>

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 .

>   	CT_WARN_ON(ct_state() == CONTEXT_USER);
> +#endif
>   
>   	/*
>   	 * We don't need to restore AMR on the way back to userspace for KUAP.