[PATCH] lib: sbi: sse: handle missing writable attributes

[Samuel Holland]

On 2024-05-16 7:30 AM, Clément Léger wrote:
> The spec states that a6, a7, flags and sepc are writable but the
> implementation was not allowing that. Add support for these 4 writable
> attributes.
> 
> Signed-off-by: Clément Léger <cleger at rivosinc.com>
> ---
>  lib/sbi/sbi_sse.c | 66 +++++++++++++++++++++++++++++++++--------------
>  1 file changed, 47 insertions(+), 19 deletions(-)
> 
> diff --git a/lib/sbi/sbi_sse.c b/lib/sbi/sbi_sse.c
> index 0cd6ba6..e39963f 100644
> --- a/lib/sbi/sbi_sse.c
> +++ b/lib/sbi/sbi_sse.c
> @@ -335,30 +335,49 @@ static int sse_event_set_hart_id_check(struct sbi_sse_event *e,
>  static int sse_event_set_attr_check(struct sbi_sse_event *e, uint32_t attr_id,
>  				    unsigned long val)
>  {
> -	int ret = SBI_OK;
> -
>  	switch (attr_id) {
>  	case SBI_SSE_ATTR_CONFIG:
> +		if (sse_event_state(e) >= SBI_SSE_STATE_ENABLED)
> +			return SBI_EINVALID_STATE;
> +
>  		if (val & ~SBI_SSE_ATTR_CONFIG_ONESHOT)
> -			ret = SBI_EINVAL;
> -		break;
> +			return SBI_EINVAL;
> +
> +		return SBI_OK;
>  	case SBI_SSE_ATTR_PRIO:
> +		if (sse_event_state(e) >= SBI_SSE_STATE_ENABLED)
> +			return SBI_EINVALID_STATE;
> +
>  #if __riscv_xlen > 32
> -		if (val != (uint32_t)val) {
> -			ret = SBI_EINVAL;
> -			break;
> -		}
> +		if (val != (uint32_t)val)

The preprocessor check is not needed here because if __riscv_xlen == 32, then
sizeof(val) == sizeof(uint32_t), so the cast is a no-op. But this was already
the case, so:

Reviewed-by: Samuel Holland <samuel.holland at sifive.com>

> +			return SBI_EINVAL;
>  #endif
> -		break;
> +		return SBI_OK;
>  	case SBI_SSE_ATTR_PREFERRED_HART:
> -		ret = sse_event_set_hart_id_check(e, val);
> -		break;
> +		if (sse_event_state(e) >= SBI_SSE_STATE_ENABLED)
> +			return SBI_EINVALID_STATE;
> +
> +		return sse_event_set_hart_id_check(e, val);
> +	case SBI_SSE_ATTR_INTERRUPTED_FLAGS:
> +		if (val & ~(SBI_SSE_ATTR_INTERRUPTED_FLAGS_STATUS_SPP |
> +			    SBI_SSE_ATTR_INTERRUPTED_FLAGS_STATUS_SPIE |
> +			    SBI_SSE_ATTR_INTERRUPTED_FLAGS_HSTATUS_SPV |
> +			    SBI_SSE_ATTR_INTERRUPTED_FLAGS_HSTATUS_SPVP))
> +			return SBI_EINVAL;
> +		__attribute__((__fallthrough__));
> +	case SBI_SSE_ATTR_INTERRUPTED_SEPC:
> +	case SBI_SSE_ATTR_INTERRUPTED_A6:
> +	case SBI_SSE_ATTR_INTERRUPTED_A7:
> +		if (sse_event_state(e) != SBI_SSE_STATE_RUNNING)
> +			return SBI_EINVALID_STATE;
> +
> +		if (current_hartid() != e->attrs.hartid)
> +			return SBI_EINVAL;
> +
> +		return SBI_OK;
>  	default:
> -		ret = SBI_EBAD_RANGE;
> -		break;
> +		return SBI_EBAD_RANGE;
>  	}
> -
> -	return ret;
>  }
>  
>  static void sse_event_set_attr(struct sbi_sse_event *e, uint32_t attr_id,
> @@ -375,6 +394,19 @@ static void sse_event_set_attr(struct sbi_sse_event *e, uint32_t attr_id,
>  		e->attrs.hartid = val;
>  		sse_event_invoke_cb(e, set_hartid_cb, val);
>  		break;
> +
> +	case SBI_SSE_ATTR_INTERRUPTED_SEPC:
> +		e->attrs.interrupted.sepc = val;
> +		break;
> +	case SBI_SSE_ATTR_INTERRUPTED_FLAGS:
> +		e->attrs.interrupted.flags = val;
> +		break;
> +	case SBI_SSE_ATTR_INTERRUPTED_A6:
> +		e->attrs.interrupted.a6 = val;
> +		break;
> +	case SBI_SSE_ATTR_INTERRUPTED_A7:
> +		e->attrs.interrupted.a7 = val;
> +		break;
>  	}
>  }
>  
> @@ -903,9 +935,6 @@ static int sse_write_attrs(struct sbi_sse_event *e, uint32_t base_attr_id,
>  	uint32_t id, end_id = base_attr_id + attr_count;
>  	unsigned long *attrs = (unsigned long *)input_phys;
>  
> -	if (sse_event_state(e) >= SBI_SSE_STATE_ENABLED)
> -		return SBI_EINVALID_STATE;
> -
>  	sbi_hart_map_saddr(input_phys, sizeof(unsigned long) * attr_count);
>  
>  	for (id = base_attr_id; id < end_id; id++) {
> @@ -944,7 +973,6 @@ int sbi_sse_write_attrs(uint32_t event_id, uint32_t base_attr_id,
>  		return SBI_EINVAL;
>  
>  	ret = sse_write_attrs(e, base_attr_id, attr_count, input_phys_lo);
> -
>  	sse_event_put(e);
>  
>  	return ret;