[PATCH] lib: sbi: Fix PMP address bits detection

[Dong Du]

On Nov 8, 2021, at 1:06 PM, anup patel anup.patel at wdc.com wrote:

> From: Vasan VS <vasan.vs at gmail.com>
> 
> We should ensure that pmpcfg0.pmp0cfg is set to zero before using
> pmpaddr0 CSR for detecting implemented PMP address bits.
> 
> Fixes: bf21632860b4 ("lib: sbi: Detect PMP granularity and number
> of address bits")
> Signed-off-by: Vasan VS <vasan.vs at gmail.com>
> Signed-off-by: Anup Patel <anup.patel at wdc.com>
> ---

Looks good to me.

Reviewed-by: Dong Du <Dd_nirvana at sjtu.edu.cn>

> lib/sbi/sbi_hart.c | 4 ++++
> 1 file changed, 4 insertions(+)
> 
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index 8eb0c38..366066b 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -339,6 +339,10 @@ static unsigned long hart_pmp_get_allowed_addr(void)
> 	unsigned long val = 0;
> 	struct sbi_trap_info trap = {0};
> 
> +	csr_write_allowed(CSR_PMPCFG0, (ulong)&trap, 0);
> +	if (trap.cause)
> +		return 0;
> +
> 	csr_write_allowed(CSR_PMPADDR0, (ulong)&trap, PMP_ADDR_MASK);
> 	if (!trap.cause) {
> 		val = csr_read_allowed(CSR_PMPADDR0, (ulong)&trap);
> --
> 2.25.1
> 
> 
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