From: Denis Kirjanov <kda@linux-powerpc.org>
Date: Mon, 1 Dec 2014 09:57:02 +0000 (+0300)
Subject: mips: bpf: Fix broken BPF_MOD
X-Git-Tag: v3.17.7~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=65f158039c9b916f677d26c76bbd64beffd0b1ee;p=thirdparty%2Fkernel%2Fstable.git

mips: bpf: Fix broken BPF_MOD

[ Upstream commit 2e46477a12f6fd273e31a220b155d66e8352198c ]

Remove optimize_div() from BPF_MOD | BPF_K case
since we don't know the dividend and fix the
emit_mod() by reading the mod operation result from HI register

Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Reviewed-by: Markos Chandras <markos.chandras@imgtec.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 9f7ecbda250c2..1588716e32be3 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -430,7 +430,7 @@ static inline void emit_mod(unsigned int dst, unsigned int src,
 		u32 *p = &ctx->target[ctx->idx];
 		uasm_i_divu(&p, dst, src);
 		p = &ctx->target[ctx->idx + 1];
-		uasm_i_mflo(&p, dst);
+		uasm_i_mfhi(&p, dst);
 	}
 	ctx->idx += 2; /* 2 insts */
 }
@@ -1006,7 +1006,7 @@ load_ind:
 			break;
 		case BPF_ALU | BPF_MOD | BPF_K:
 			/* A %= k */
-			if (k == 1 || optimize_div(&k)) {
+			if (k == 1) {
 				ctx->flags |= SEEN_A;
 				emit_jit_reg_move(r_A, r_zero, ctx);
 			} else {