On 5/18/20 6:07 PM, Pierre Morel wrote:
> Allow the program to wait for an interrupt.
> 
> The interrupt handler is in charge to remove the WAIT bit
> when it finished handling the interrupt.
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

> ---
>  lib/s390x/asm/arch_def.h | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
> index 54ffd0b..f200e28 100644
> --- a/lib/s390x/asm/arch_def.h
> +++ b/lib/s390x/asm/arch_def.h
> @@ -10,9 +10,11 @@
>  #ifndef _ASM_S390X_ARCH_DEF_H_
>  #define _ASM_S390X_ARCH_DEF_H_
>  
> +#define PSW_MASK_IO			0x0200000000000000UL
>  #define PSW_MASK_EXT			0x0100000000000000UL
>  #define PSW_MASK_DAT			0x0400000000000000UL
>  #define PSW_MASK_SHORT_PSW		0x0008000000000000UL
> +#define PSW_MASK_WAIT			0x0002000000000000UL
>  #define PSW_MASK_PSTATE			0x0001000000000000UL
>  #define PSW_MASK_BA			0x0000000080000000UL
>  #define PSW_MASK_EA			0x0000000100000000UL
> @@ -253,6 +255,18 @@ static inline void load_psw_mask(uint64_t mask)
>  		: "+r" (tmp) :  "a" (&psw) : "memory", "cc" );
>  }
>  
> +static inline void wait_for_interrupt(uint64_t irq_mask)
> +{
> +	uint64_t psw_mask = extract_psw_mask();
> +
> +	load_psw_mask(psw_mask | irq_mask | PSW_MASK_WAIT);
> +	/*
> +	 * After being woken and having processed the interrupt, let's restore
> +	 * the PSW mask.
> +	 */
> +	load_psw_mask(psw_mask);
> +}
> +
>  static inline void enter_pstate(void)
>  {
>  	uint64_t mask;
>