Existing JIT code supports only short (18-bit) branches for BPF EXIT, and
results in some tests from module test_bpf not being jited. Update code
to fall back to long (28-bit) jumps if short branches are insufficient.

Before:
  test_bpf: #296 BPF_MAXINSNS: exec all MSH jited:0 1556004 PASS
  test_bpf: #297 BPF_MAXINSNS: ld_abs+get_processor_id jited:0 824957 PASS
  test_bpf: Summary: 378 PASSED, 0 FAILED, [364/366 JIT'ed]

After:
  test_bpf: #296 BPF_MAXINSNS: exec all MSH jited:1 221998 PASS
  test_bpf: #297 BPF_MAXINSNS: ld_abs+get_processor_id jited:1 490507 PASS
  test_bpf: Summary: 378 PASSED, 0 FAILED, [366/366 JIT'ed]

Fixes: b6bd53f9c4e8 ("MIPS: Add missing file for eBPF JIT.")
Signed-off-by: Tony Ambardar <redacted>
---
 arch/mips/net/ebpf_jit.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c
index 00dc20bc0def..7252cd44ff63 100644
--- a/arch/mips/net/ebpf_jit.c
+++ b/arch/mips/net/ebpf_jit.c

@@ -994,9 +994,14 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
 	case BPF_JMP | BPF_EXIT:
 		if (this_idx + 1 < exit_idx) {
 			b_off = b_imm(exit_idx, ctx);
-			if (is_bad_offset(b_off))
-				return -E2BIG;
-			emit_instr(ctx, beq, MIPS_R_ZERO, MIPS_R_ZERO, b_off);
+			if (is_bad_offset(b_off)) {
+				target = j_target(ctx, exit_idx);
+				if (target == (unsigned int)-1)
+					return -E2BIG;
+				emit_instr(ctx, j, target);
+			} else {
+				emit_instr(ctx, b, b_off);
+			}
 			emit_instr(ctx, nop);
 		}
 		break;

-- 
2.25.1