[PATCH v3 1/2] bsp/riscv: Work area size based on stack pointer

[Sebastian Huber]

On 14.07.22 16:03, Daniel Cederman wrote:
> diff --git a/bsps/riscv/shared/start/start.S b/bsps/riscv/shared/start/start.S
> index 3702f8ac2f..21945a99f5 100644
> --- a/bsps/riscv/shared/start/start.S
> +++ b/bsps/riscv/shared/start/start.S
> @@ -35,6 +35,16 @@
>   #include <bsp/linker-symbols.h>
>   #include <bspopts.h>
>   
> +#if __riscv_xlen == 32
> +#define PTR_ALIGN 2
> +#define PTR_SIZE 4
> +#define PTR_VALUE .word
> +#elif __riscv_xlen == 64
> +#define PTR_ALIGN 3
> +#define PTR_SIZE 8
> +#define PTR_VALUE .dword
> +#endif

Maybe this should move to asm.h.

> +
>   PUBLIC(_start)
>   
>   	.section	.bsp_start_text, "wax", @progbits
> @@ -60,6 +70,9 @@ SYM(_start):
>   	LADDR	t0, _RISCV_Exception_handler
>   	csrw	mtvec, t0
>   
> +	/* Save stack pointer so it can mark end of work area later on */
> +	mv	t3, sp
> +
>   	/* Load stack pointer and branch to secondary processor start if necessary */
>   #ifdef RTEMS_SMP
>   	LADDR	sp, _ISR_Stack_area_begin
> @@ -75,6 +88,9 @@ SYM(_start):
>   	LADDR	sp, _ISR_Stack_area_end
>   #endif
>   
> +	LADDR	t0, riscv_start_stack_pointer
> +	SREG	t3, 0(t0)
> +
>   #ifdef BSP_START_COPY_FDT_FROM_U_BOOT
>   	mv	a0, a1
>   	call	bsp_fdt_copy
> @@ -146,3 +162,12 @@ SYM(_start):
>   #endif
>   
>   #endif /* RTEMS_SMP */
> +
> +	.section	.data, "aw"

This should be .bsp_start_data

> +	.align	PTR_ALIGN
> +
> +	.globl	riscv_start_stack_pointer
> +	.type	riscv_start_stack_pointer, @object
> +	.size	riscv_start_stack_pointer, PTR_SIZE
> +riscv_start_stack_pointer:
> +	PTR_VALUE	0

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