powerpc/bpf: Support MOD operation

commit b6069a9570 (filter: add MOD operation) added generic
support for modulus operation in BPF.

This patch brings JIT support for PPC64

Signed-off-by: Vladimir Murzin <murzin.v@gmail.com>
Acked-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 81cd6c7..475d4f2 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -187,6 +187,26 @@
 				PPC_MUL(r_A, r_A, r_scratch1);
 			}
 			break;
+		case BPF_S_ALU_MOD_X: /* A %= X; */
+			ctx->seen |= SEEN_XREG;
+			PPC_CMPWI(r_X, 0);
+			if (ctx->pc_ret0 != -1) {
+				PPC_BCC(COND_EQ, addrs[ctx->pc_ret0]);
+			} else {
+				PPC_BCC_SHORT(COND_NE, (ctx->idx*4)+12);
+				PPC_LI(r_ret, 0);
+				PPC_JMP(exit_addr);
+			}
+			PPC_DIVWU(r_scratch1, r_A, r_X);
+			PPC_MUL(r_scratch1, r_X, r_scratch1);
+			PPC_SUB(r_A, r_A, r_scratch1);
+			break;
+		case BPF_S_ALU_MOD_K: /* A %= K; */
+			PPC_LI32(r_scratch2, K);
+			PPC_DIVWU(r_scratch1, r_A, r_scratch2);
+			PPC_MUL(r_scratch1, r_scratch2, r_scratch1);
+			PPC_SUB(r_A, r_A, r_scratch1);
+			break;
 		case BPF_S_ALU_DIV_X: /* A /= X; */
 			ctx->seen |= SEEN_XREG;
 			PPC_CMPWI(r_X, 0);