X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;ds=sidebyside;f=arch%2Farm64%2Fnet%2Fbpf_jit_comp.c;h=cf3c7d4a1b585a928d9b4451ee268141d95d7088;hb=a18e2fa5e670a1b84e66522b221c42875b02028a;hp=a44e5293c6f58adb288e9c0d0549fcbe26c98daa;hpb=0280d1a099da1d211e76ec47cc0944c993a36316;p=firefly-linux-kernel-4.4.55.git

diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index a44e5293c6f5..cf3c7d4a1b58 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1,7 +1,7 @@
 /*
  * BPF JIT compiler for ARM64
  *
- * Copyright (C) 2014 Zi Shen Lim <zlim.lnx@gmail.com>
+ * Copyright (C) 2014-2015 Zi Shen Lim <zlim.lnx@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -225,6 +225,17 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 	u8 jmp_cond;
 	s32 jmp_offset;
 
+#define check_imm(bits, imm) do {				\
+	if ((((imm) > 0) && ((imm) >> (bits))) ||		\
+	    (((imm) < 0) && (~(imm) >> (bits)))) {		\
+		pr_info("[%2d] imm=%d(0x%x) out of range\n",	\
+			i, imm, imm);				\
+		return -EINVAL;					\
+	}							\
+} while (0)
+#define check_imm19(imm) check_imm(19, imm)
+#define check_imm26(imm) check_imm(26, imm)
+
 	switch (code) {
 	/* dst = src */
 	case BPF_ALU | BPF_MOV | BPF_X:
@@ -258,15 +269,33 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		break;
 	case BPF_ALU | BPF_DIV | BPF_X:
 	case BPF_ALU64 | BPF_DIV | BPF_X:
-		emit(A64_UDIV(is64, dst, dst, src), ctx);
-		break;
 	case BPF_ALU | BPF_MOD | BPF_X:
 	case BPF_ALU64 | BPF_MOD | BPF_X:
-		ctx->tmp_used = 1;
-		emit(A64_UDIV(is64, tmp, dst, src), ctx);
-		emit(A64_MUL(is64, tmp, tmp, src), ctx);
-		emit(A64_SUB(is64, dst, dst, tmp), ctx);
+	{
+		const u8 r0 = bpf2a64[BPF_REG_0];
+
+		/* if (src == 0) return 0 */
+		jmp_offset = 3; /* skip ahead to else path */
+		check_imm19(jmp_offset);
+		emit(A64_CBNZ(is64, src, jmp_offset), ctx);
+		emit(A64_MOVZ(1, r0, 0, 0), ctx);
+		jmp_offset = epilogue_offset(ctx);
+		check_imm26(jmp_offset);
+		emit(A64_B(jmp_offset), ctx);
+		/* else */
+		switch (BPF_OP(code)) {
+		case BPF_DIV:
+			emit(A64_UDIV(is64, dst, dst, src), ctx);
+			break;
+		case BPF_MOD:
+			ctx->tmp_used = 1;
+			emit(A64_UDIV(is64, tmp, dst, src), ctx);
+			emit(A64_MUL(is64, tmp, tmp, src), ctx);
+			emit(A64_SUB(is64, dst, dst, tmp), ctx);
+			break;
+		}
 		break;
+	}
 	case BPF_ALU | BPF_LSH | BPF_X:
 	case BPF_ALU64 | BPF_LSH | BPF_X:
 		emit(A64_LSLV(is64, dst, dst, src), ctx);
@@ -393,17 +422,6 @@ emit_bswap_uxt:
 		emit(A64_ASR(is64, dst, dst, imm), ctx);
 		break;
 
-#define check_imm(bits, imm) do {				\
-	if ((((imm) > 0) && ((imm) >> (bits))) ||		\
-	    (((imm) < 0) && (~(imm) >> (bits)))) {		\
-		pr_info("[%2d] imm=%d(0x%x) out of range\n",	\
-			i, imm, imm);				\
-		return -EINVAL;					\
-	}							\
-} while (0)
-#define check_imm19(imm) check_imm(19, imm)
-#define check_imm26(imm) check_imm(26, imm)
-
 	/* JUMP off */
 	case BPF_JMP | BPF_JA:
 		jmp_offset = bpf2a64_offset(i + off, i, ctx);