MIPS: bpf: Fix branch conditional for BPF_J{GT/GE} cases

The sltiu and sltu instructions will set the scratch register
to 1 if A <= X|K so fix the emitted branch conditional to check
for scratch != zero rather than scratch >= zero which would complicate
the resuling branch logic given that MIPS does not have a BGT or BGET
instructions to compare general purpose registers directly.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: netdev@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7126/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 8cae27af03dac7a4b3f2d777e9f42c0c29f88d71..500f97fdc0e148b2638ae74666bbf6cf282f46b5 100644 (file)
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -1127,7 +1127,7 @@ jmp_cmp:
                                }
                                /* A < (K|X) ? r_scrach = 1 */
                                b_off = b_imm(i + inst->jf + 1, ctx);
-                               emit_bcond(MIPS_COND_GT, r_s0, r_zero, b_off,
+                               emit_bcond(MIPS_COND_NE, r_s0, r_zero, b_off,
                                           ctx);
                                emit_nop(ctx);
                                /* A > (K|X) ? scratch = 0 */