Re: [RFC PATCH v2 11/45] arm64: irqflags: save and use both DAIF and PMR

[Jinjie Ruan <ruanjinjie@huawei.com>]

在 2026/7/28 0:34, Vladimir Murzin 写道:
> From: Ada Couprie Diaz <ada.coupriediaz@arm.com>
> 
> With pseudo-NMIs enabled, both DAIF and the PMR affect interrupt masking.
> Now that we have a type which can track both of them at the same time,
> update our irqflags implementation to use it.
> 
> Save DAIF flags in all cases, as they can be manipulated directly by other
> code, and the PMR if it is in use.
> 
> When checking if IRQs are disabled, now that we always save DAIF we can
> check that the I flag is set and bypass checking the PMR if it is.
> We can also properly check if PMR masks interrupts (PMR < GIC_PRIO_IRQON),

This commit message need to be updated, we now do not use "<"

> now that we don't need to rely on the GIC_PRIO_PSR_I_SET bit being set in
> the PMR to know if DAIF is already masking interrupts.
> Update `irqs_priority_unmasked()` to align with this change.
> 
> This allows us to remove the `__daif_...` and `__pmr_...` versions
> of the save and check functions, as they are now unified.
> 
> We can reasonably merge the two `__{daif,pmr}_irq_restore()` functions
> in the main one, as the DAIF and PMR values are properly split now.
> 
> Signed-off-by: Ada Couprie Diaz <ada.coupriediaz@arm.com>
> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
> ---
>  arch/arm64/include/asm/irqflags.h | 118 +++++++-----------------------
>  arch/arm64/include/asm/ptrace.h   |  18 +++--
>  2 files changed, 38 insertions(+), 98 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h
> index 1863a955d119..50720a01bde4 100644
> --- a/arch/arm64/include/asm/irqflags.h
> +++ b/arch/arm64/include/asm/irqflags.h
> @@ -96,135 +96,69 @@ static __always_inline void arch_local_irq_disable(void)
>  	}
>  }
>  

[...]

> -
> -static __always_inline unsigned long __pmr_local_irq_save(void)
> +static __always_inline unsigned long arch_local_irq_save(void)
>  {
> -	unsigned long flags = __pmr_local_save_flags();
> +	unsigned long flags = arch_local_save_flags();
>  
> -	/*
> -	 * There are too many states with IRQs disabled, just keep the current
> -	 * state if interrupts are already disabled/masked.
> -	 */
> -	if (!__pmr_irqs_disabled_flags(flags))
> +	if (system_uses_irq_prio_masking())
>  		__pmr_local_irq_disable();
> +	else
> +		__daif_local_irq_disable();


Now we do not check whether pmr is GIC_PRIO_IRQON for
__pmr_local_irq_disable(), however, it doesn't seem to be mentioned
in the commit message.


And the previous "arm64: suspend: Initialize PMR on resume" patch should
be merged into this patch, Otherwise, you cannot understand its commit
message or associate it with the patch.

>  
>  	return flags;
>  }
>  

[..]

>  }
>  
>  #endif /* __ASM_IRQFLAGS_H */
> diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
> index f7dc5fb9427d..e4c7e6bafa3d 100644
> --- a/arch/arm64/include/asm/ptrace.h
> +++ b/arch/arm64/include/asm/ptrace.h
> @@ -203,14 +203,20 @@ static inline void forget_syscall(struct pt_regs *regs)
>  #define processor_mode(regs) \
>  	((regs)->pstate & PSR_MODE_MASK)
>  
> -#define irqs_priority_unmasked(regs)					\
> -	(system_uses_irq_prio_masking() ?				\
> -		(regs)->pmr == GIC_PRIO_IRQON :				\
> -		true)
> -
>  static __always_inline bool regs_irqs_disabled(const struct pt_regs *regs)
>  {
> -	return (regs->pstate & PSR_I_BIT) || !irqs_priority_unmasked(regs);
> +	if (regs->pstate & PSR_I_BIT)
> +		return true;
> +
> +	if (system_uses_irq_prio_masking()) {
> +		WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_IRQFLAGS) &&
> +			     regs->pmr != GIC_PRIO_IRQOFF &&
> +			     regs->pmr != GIC_PRIO_IRQON);
> +
> +		return regs->pmr != GIC_PRIO_IRQON;
> +	}
> +
> +	return false;

Looks fine to me.

otherwise, LGTM
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>

>  }
>  
>  #define interrupts_enabled(regs)	(!regs_irqs_disabled(regs))