[PATCH bpf-next 2/2] riscv, bpf: Fix incorrect runtime stats

[Pu Lehui]

On 2024/4/16 14:42, Xu Kuohai wrote:
> From: Xu Kuohai <xukuohai at huawei.com>
> 
> When __bpf_prog_enter() returns zero, the s1 register is not set to zero,
> resulting in incorrect runtime stats. Fix it by setting s1 immediately upon
> the return of __bpf_prog_enter().
> 
> Fixes: 49b5e77ae3e2 ("riscv, bpf: Add bpf trampoline support for RV64")
> Signed-off-by: Xu Kuohai <xukuohai at huawei.com>
> ---
>   arch/riscv/net/bpf_jit_comp64.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
> index 15e482f2c657..e713704be837 100644
> --- a/arch/riscv/net/bpf_jit_comp64.c
> +++ b/arch/riscv/net/bpf_jit_comp64.c
> @@ -730,6 +730,9 @@ static int invoke_bpf_prog(struct bpf_tramp_link *l, int args_off, int retval_of
>   	if (ret)
>   		return ret;
>   
> +	/* store prog start time */
> +	emit_mv(RV_REG_S1, RV_REG_A0, ctx);
> +
>   	/* if (__bpf_prog_enter(prog) == 0)
>   	 *	goto skip_exec_of_prog;
>   	 */
> @@ -737,9 +740,6 @@ static int invoke_bpf_prog(struct bpf_tramp_link *l, int args_off, int retval_of
>   	/* nop reserved for conditional jump */
>   	emit(rv_nop(), ctx);
>   
> -	/* store prog start time */
> -	emit_mv(RV_REG_S1, RV_REG_A0, ctx);
> -
>   	/* arg1: &args_off */
>   	emit_addi(RV_REG_A0, RV_REG_FP, -args_off, ctx);
>   	if (!p->jited)

Thanks.

Reviewed-by: Pu Lehui <pulehui at huawei.com>