riscv, bpf: Fix incorrect runtime stats

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: 49b5e77ae3 ("riscv, bpf: Add bpf trampoline support for RV64")
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Pu Lehui <pulehui@huawei.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20240416064208.2919073-3-xukuohai@huaweicloud.com
This commit is contained in:
Xu Kuohai 2024-04-16 14:42:08 +08:00 committed by Daniel Borkmann
parent dc7d7447b5
commit 10541b374a

View File

@ -722,6 +722,9 @@ 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;
*/
@ -729,9 +732,6 @@ 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)