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>

2 files changed, 21 insertions, 0 deletions

diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h
index 0baf2b826e25..9aee27c582dc 100644
--- a/arch/powerpc/net/bpf_jit.h
+++ b/arch/powerpc/net/bpf_jit.h
@@ -39,6 +39,7 @@
 #define r_X             5
 #define r_addr          6
 #define r_scratch1      7
+#define r_scratch2      8
 #define r_D             14
 #define r_HL            15
 #define r_M             16
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
index 81cd6c79babe..475d4f26fc6e 100644
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ b/arch/powerpc/net/bpf_jit_comp.c
@@ -187,6 +187,26 @@ static int bpf_jit_build_body(struct sk_filter *fp, u32 *image,
                                 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);