LoongArch: BPF: Adjust the jump offset of tail calls

Call the next bpf prog and skip the first instruction of TCC
initialization.

A total of 7 instructions are skipped:
'move t0, ra'			1 inst
'move_imm + jirl'		5 inst
'addid REG_TCC, zero, 0'	1 inst

Relevant test cases: the tailcalls test item in selftests/bpf.

Cc: stable@vger.kernel.org
Fixes: 677e6123e3d2 ("LoongArch: BPF: Disable trampoline for kernel module function trace")
Signed-off-by: Chenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c
index 9729c0ff7bfcc7b2e79c2504b5664364a617187d..e6aeaec46969d0984ab192f969fb450d4ed85916 100644 (file)
--- a/arch/loongarch/net/bpf_jit.c
+++ b/arch/loongarch/net/bpf_jit.c
@@ -239,7 +239,7 @@ static void __build_epilogue(struct jit_ctx *ctx, bool is_tail_call)
                 * Call the next bpf prog and skip the first instruction
                 * of TCC initialization.
                 */
-               emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T3, 6);
+               emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T3, 7);
        }
 }