Commit 1ab24a4e authored Jun 23, 2014 by Markos Chandras Committed by Ralf Baechle Jun 26, 2014

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>

parent 9eebfe47

arch/mips/net/bpf_jit.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1127,7 +1127,7 @@ static int build_body(struct jit_ctx *ctx)
	}		}
	/* A < (K\|X) ? r_scrach = 1 */		/* A < (K\|X) ? r_scrach = 1 */
	b_off = b_imm(i + inst->jf + 1, ctx);		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);		ctx);
	emit_nop(ctx);		emit_nop(ctx);
	/* A > (K\|X) ? scratch = 0 */		/* A > (K\|X) ? scratch = 0 */