On Thu, Sep 30, 2021 at 09:17:07PM +0800, Pingfan Liu wrote:
> From: Mark Rutland <[email protected]>
>
> Currently we distinguish IRQ and definitely-PNMI at entry/exit time
> via the enter_el1_irq_or_nmi() and enter_el1_irq_or_nmi() helpers. In
> subsequent patches we'll need to handle the two cases more distinctly
> in the body of the exception handler.
>
> To make this possible, this patch refactors el1_interrupt to be a
> top-level dispatcher to separate handlers for the IRQ and PNMI cases,
> removing the need for the enter_el1_irq_or_nmi() and
> exit_el1_irq_or_nmi() helpers.
>
> Note that since arm64_enter_nmi() calls __nmi_enter(), which
> increments the preemt_count, we could never preempt when handling a
> PNMI. We now only check for preemption in the IRQ case, which makes
> this clearer.
>
> There should be no functional change as a result of this patch.
>
> Signed-off-by: Mark Rutland <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Marc Zyngier <[email protected]>
> Cc: Joey Gouly <[email protected]>
> Cc: Sami Tolvanen <[email protected]>
> Cc: Julien Thierry <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Yuichi Ito <[email protected]>
> Cc: Pingfan Liu <[email protected]>
> Cc: [email protected]
> To: [email protected]
As a heads-up, you need to add your Signed-off-by tag when you post
patches from other people, even if you make no changes. See:
https://www.kernel.org/doc/html/v5.14/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
Other than that, this looks fine to me.
Mark.
> ---
> arch/arm64/kernel/entry-common.c | 44 ++++++++++++++++----------------
> 1 file changed, 22 insertions(+), 22 deletions(-)
>
> diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
> index 32f9796c4ffe..5f1473319fb0 100644
> --- a/arch/arm64/kernel/entry-common.c
> +++ b/arch/arm64/kernel/entry-common.c
> @@ -219,22 +219,6 @@ static void noinstr arm64_exit_el1_dbg(struct pt_regs *regs)
> lockdep_hardirqs_on(CALLER_ADDR0);
> }
>
> -static void noinstr enter_el1_irq_or_nmi(struct pt_regs *regs)
> -{
> - if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))
> - arm64_enter_nmi(regs);
> - else
> - enter_from_kernel_mode(regs);
> -}
> -
> -static void noinstr exit_el1_irq_or_nmi(struct pt_regs *regs)
> -{
> - if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))
> - arm64_exit_nmi(regs);
> - else
> - exit_to_kernel_mode(regs);
> -}
> -
> static void __sched arm64_preempt_schedule_irq(void)
> {
> lockdep_assert_irqs_disabled();
> @@ -432,14 +416,19 @@ asmlinkage void noinstr el1h_64_sync_handler(struct pt_regs *regs)
> }
> }
>
> -static void noinstr el1_interrupt(struct pt_regs *regs,
> - void (*handler)(struct pt_regs *))
> +static __always_inline void
> +__el1_pnmi(struct pt_regs *regs, void (*handler)(struct pt_regs *))
> {
> - write_sysreg(DAIF_PROCCTX_NOIRQ, daif);
> -
> - enter_el1_irq_or_nmi(regs);
> + arm64_enter_nmi(regs);
> do_interrupt_handler(regs, handler);
> + arm64_exit_nmi(regs);
> +}
>
> +static __always_inline void
> +__el1_interrupt(struct pt_regs *regs, void (*handler)(struct pt_regs *))
> +{
> + enter_from_kernel_mode(regs);
> + do_interrupt_handler(regs, handler);
> /*
> * Note: thread_info::preempt_count includes both thread_info::count
> * and thread_info::need_resched, and is not equivalent to
> @@ -448,8 +437,19 @@ static void noinstr el1_interrupt(struct pt_regs *regs,
> if (IS_ENABLED(CONFIG_PREEMPTION) &&
> READ_ONCE(current_thread_info()->preempt_count) == 0)
> arm64_preempt_schedule_irq();
> + exit_to_kernel_mode(regs);
> +}
> +
> +static void noinstr el1_interrupt(struct pt_regs *regs,
> + void (*handler)(struct pt_regs *))
> +{
> + write_sysreg(DAIF_PROCCTX_NOIRQ, daif);
> +
> + if (IS_ENABLED(CONFIG_ARM64_PSEUDO_NMI) && !interrupts_enabled(regs))
> + __el1_pnmi(regs, handler);
> + else
> + __el1_interrupt(regs, handler);
>
> - exit_el1_irq_or_nmi(regs);
> }
>
> asmlinkage void noinstr el1h_64_irq_handler(struct pt_regs *regs)
> --
> 2.31.1
>
On Thu, Sep 30, 2021 at 03:00:59PM +0100, Mark Rutland wrote:
> On Thu, Sep 30, 2021 at 09:17:07PM +0800, Pingfan Liu wrote:
> > From: Mark Rutland <[email protected]>
> >
> > Currently we distinguish IRQ and definitely-PNMI at entry/exit time
> > via the enter_el1_irq_or_nmi() and enter_el1_irq_or_nmi() helpers. In
> > subsequent patches we'll need to handle the two cases more distinctly
> > in the body of the exception handler.
> >
> > To make this possible, this patch refactors el1_interrupt to be a
> > top-level dispatcher to separate handlers for the IRQ and PNMI cases,
> > removing the need for the enter_el1_irq_or_nmi() and
> > exit_el1_irq_or_nmi() helpers.
> >
> > Note that since arm64_enter_nmi() calls __nmi_enter(), which
> > increments the preemt_count, we could never preempt when handling a
> > PNMI. We now only check for preemption in the IRQ case, which makes
> > this clearer.
> >
> > There should be no functional change as a result of this patch.
> >
> > Signed-off-by: Mark Rutland <[email protected]>
> > Cc: "Paul E. McKenney" <[email protected]>
> > Cc: Catalin Marinas <[email protected]>
> > Cc: Will Deacon <[email protected]>
> > Cc: Marc Zyngier <[email protected]>
> > Cc: Joey Gouly <[email protected]>
> > Cc: Sami Tolvanen <[email protected]>
> > Cc: Julien Thierry <[email protected]>
> > Cc: Thomas Gleixner <[email protected]>
> > Cc: Yuichi Ito <[email protected]>
> > Cc: Pingfan Liu <[email protected]>
> > Cc: [email protected]
> > To: [email protected]
>
> As a heads-up, you need to add your Signed-off-by tag when you post
> patches from other people, even if you make no changes. See:
>
> https://www.kernel.org/doc/html/v5.14/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
>
Oh, thanks and I realize it is a serious license issue.
> Other than that, this looks fine to me.
>
Thank you very much.
Regards,
Pingfan