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

[Xu Kuohai]

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)
-- 
2.40.1