[PATCH] lib: sbi: dbtr: Fix shared memory layout

[Charlie Jenkins]

On Tue, May 27, 2025 at 11:27:13AM -0700, Jesse Taube wrote:
> The existing sbi_dbtr_shmem_entry has a size of 5 * XLEN with the final
> entry being idx. This is in contrast to the SBI v3.0-rc7 Chapter 19.
> Debug Triggers Extension [0] where idx and trig_state share the same
> offset (0) in shared memory, with a total size of 4 * XLEN for all the
> SBI calls.
> 
> Add union to match memory layout described in SBI.
> 
> [0] https://github.com/riscv-non-isa/riscv-sbi-doc/tree/v3.0-rc7/src/ext-debug-triggers.adoc
> 
> Fixes: 97f234f15c96 ("lib: sbi: Introduce the SBI debug triggers extension support")
> Signed-off-by: Jesse Taube <jesse at rivosinc.com>

Thanks!

This will need to be reflected in the linux patch as well.

Tested-by: Charlie Jenkins <charlie at rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie at rivosinc.com>

[1] https://lore.kernel.org/all/20240222125059.13331-3-hchauhan@ventanamicro.com/

> ---
>  include/sbi/sbi_dbtr.h | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/include/sbi/sbi_dbtr.h b/include/sbi/sbi_dbtr.h
> index a8b3a02..8cb776c 100644
> --- a/include/sbi/sbi_dbtr.h
> +++ b/include/sbi/sbi_dbtr.h
> @@ -91,8 +91,10 @@ struct sbi_dbtr_hart_triggers_state {
>  
>  /** SBI shared mem messages layout */
>  struct sbi_dbtr_shmem_entry {
> -	struct sbi_dbtr_data_msg data;
> -	struct sbi_dbtr_id_msg id;
> +	union {
> +		struct sbi_dbtr_data_msg data;
> +		struct sbi_dbtr_id_msg id;
> +	};
>  };
>  
>  #define SBI_DBTR_SHMEM_ALIGN_MASK	((__riscv_xlen / 8) - 1)
> -- 
> 2.43.0
>