[PATCH 1/2] powerpc: Apply __always_inline to interrupt_{enter,exit}_prepare()

[Christophe Leroy]

Le 04/04/2024 à 06:45, Rohan McLure a écrit :
> In keeping with the advice given by Documentation/core-api/entry.rst,
> entry and exit handlers for interrupts should not be instrumented.
> Guarantee that the interrupt_{enter,exit}_prepare() routines are inlined
> so that they will inheret instrumentation from their caller.
> 
> KCSAN kernels were observed to compile without inlining these routines,
> which would lead to grief on NMI handlers.
> 
> Signed-off-by: Rohan McLure <rmclure at linux.ibm.com>

Reviewed-by: Christophe Leroy <christophe.leroy at csgroup.eu>

> ---
>   arch/powerpc/include/asm/interrupt.h | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
> index 7b610864b364..f4343e0bfb13 100644
> --- a/arch/powerpc/include/asm/interrupt.h
> +++ b/arch/powerpc/include/asm/interrupt.h
> @@ -150,7 +150,7 @@ static inline void booke_restore_dbcr0(void)
>   #endif
>   }
>   
> -static inline void interrupt_enter_prepare(struct pt_regs *regs)
> +static __always_inline void interrupt_enter_prepare(struct pt_regs *regs)
>   {
>   #ifdef CONFIG_PPC64
>   	irq_soft_mask_set(IRQS_ALL_DISABLED);
> @@ -215,11 +215,11 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs)
>    * However interrupt_nmi_exit_prepare does return directly to regs, because
>    * NMIs do not do "exit work" or replay soft-masked interrupts.
>    */
> -static inline void interrupt_exit_prepare(struct pt_regs *regs)
> +static __always_inline void interrupt_exit_prepare(struct pt_regs *regs)
>   {
>   }
>   
> -static inline void interrupt_async_enter_prepare(struct pt_regs *regs)
> +static __always_inline void interrupt_async_enter_prepare(struct pt_regs *regs)
>   {
>   #ifdef CONFIG_PPC64
>   	/* Ensure interrupt_enter_prepare does not enable MSR[EE] */
> @@ -238,7 +238,7 @@ static inline void interrupt_async_enter_prepare(struct pt_regs *regs)
>   	irq_enter();
>   }
>   
> -static inline void interrupt_async_exit_prepare(struct pt_regs *regs)
> +static __always_inline void interrupt_async_exit_prepare(struct pt_regs *regs)
>   {
>   	/*
>   	 * Adjust at exit so the main handler sees the true NIA. This must
> @@ -278,7 +278,7 @@ static inline bool nmi_disables_ftrace(struct pt_regs *regs)
>   	return true;
>   }
>   
> -static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)
> +static __always_inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)
>   {
>   #ifdef CONFIG_PPC64
>   	state->irq_soft_mask = local_paca->irq_soft_mask;
> @@ -340,7 +340,7 @@ static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct inte
>   	nmi_enter();
>   }
>   
> -static inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)
> +static __always_inline void interrupt_nmi_exit_prepare(struct pt_regs *regs, struct interrupt_nmi_state *state)
>   {
>   	if (mfmsr() & MSR_DR) {
>   		// nmi_exit if relocations are on