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 <Tony.Ambardar@xxxxxxxxx>
---
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 e8c403c6cfa3..f510c692975e 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
