[PATCH 3.17 37/47] mips: bpf: Fix broken BPF_MOD

Greg Kroah-Hartman
2014-12-14T20:28:52Z

From: Denis Kirjanov <kda@linux-powerpc.org>

[ 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>
---
arch/mips/net/bpf_jit.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- 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
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 {