netdev - [PATCH v9 bpf-next 14/17] sparc: bpf: eliminate zero extension code-gen

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Date:   Fri, 24 May 2019 23:25:25 +0100
From:   Jiong Wang <jiong.wang@...ronome.com>
To:     alexei.starovoitov@...il.com, daniel@...earbox.net
Cc:     bpf@...r.kernel.org, netdev@...r.kernel.org,
        oss-drivers@...ronome.com, davem@...emloft.net,
        paul.burton@...s.com, udknight@...il.com, zlim.lnx@...il.com,
        illusionist.neo@...il.com, naveen.n.rao@...ux.ibm.com,
        sandipan@...ux.ibm.com, schwidefsky@...ibm.com,
        heiko.carstens@...ibm.com, jakub.kicinski@...ronome.com,
        Jiong Wang <jiong.wang@...ronome.com>
Subject: [PATCH v9 bpf-next 14/17] sparc: bpf: eliminate zero extension code-gen

Cc: David S. Miller <davem@...emloft.net>
Signed-off-by: Jiong Wang <jiong.wang@...ronome.com>
---
 arch/sparc/net/bpf_jit_comp_64.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c
index 65428e7..3364e2a 100644
--- a/arch/sparc/net/bpf_jit_comp_64.c
+++ b/arch/sparc/net/bpf_jit_comp_64.c
@@ -908,6 +908,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 	/* dst = src */
 	case BPF_ALU | BPF_MOV | BPF_X:
 		emit_alu3_K(SRL, src, 0, dst, ctx);
+		if (insn_is_zext(&insn[1]))
+			return 1;
 		break;
 	case BPF_ALU64 | BPF_MOV | BPF_X:
 		emit_reg_move(src, dst, ctx);
@@ -942,6 +944,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 	case BPF_ALU | BPF_DIV | BPF_X:
 		emit_write_y(G0, ctx);
 		emit_alu(DIV, src, dst, ctx);
+		if (insn_is_zext(&insn[1]))
+			return 1;
 		break;
 	case BPF_ALU64 | BPF_DIV | BPF_X:
 		emit_alu(UDIVX, src, dst, ctx);
@@ -975,6 +979,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		break;
 	case BPF_ALU | BPF_RSH | BPF_X:
 		emit_alu(SRL, src, dst, ctx);
+		if (insn_is_zext(&insn[1]))
+			return 1;
 		break;
 	case BPF_ALU64 | BPF_RSH | BPF_X:
 		emit_alu(SRLX, src, dst, ctx);
@@ -997,9 +1003,12 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		case 16:
 			emit_alu_K(SLL, dst, 16, ctx);
 			emit_alu_K(SRL, dst, 16, ctx);
+			if (insn_is_zext(&insn[1]))
+				return 1;
 			break;
 		case 32:
-			emit_alu_K(SRL, dst, 0, ctx);
+			if (!ctx->prog->aux->verifier_zext)
+				emit_alu_K(SRL, dst, 0, ctx);
 			break;
 		case 64:
 			/* nop */
@@ -1021,6 +1030,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 			emit_alu3_K(AND, dst, 0xff, dst, ctx);
 			emit_alu3_K(SLL, tmp, 8, tmp, ctx);
 			emit_alu(OR, tmp, dst, ctx);
+			if (insn_is_zext(&insn[1]))
+				return 1;
 			break;
 
 		case 32:
@@ -1037,6 +1048,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 			emit_alu3_K(AND, dst, 0xff, dst, ctx);	/* dst	= dst & 0xff */
 			emit_alu3_K(SLL, dst, 24, dst, ctx);	/* dst  = dst << 24 */
 			emit_alu(OR, tmp, dst, ctx);		/* dst  = dst | tmp */
+			if (insn_is_zext(&insn[1]))
+				return 1;
 			break;
 
 		case 64:
@@ -1050,6 +1063,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 	/* dst = imm */
 	case BPF_ALU | BPF_MOV | BPF_K:
 		emit_loadimm32(imm, dst, ctx);
+		if (insn_is_zext(&insn[1]))
+			return 1;
 		break;
 	case BPF_ALU64 | BPF_MOV | BPF_K:
 		emit_loadimm_sext(imm, dst, ctx);
@@ -1132,6 +1147,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		break;
 	case BPF_ALU | BPF_RSH | BPF_K:
 		emit_alu_K(SRL, dst, imm, ctx);
+		if (insn_is_zext(&insn[1]))
+			return 1;
 		break;
 	case BPF_ALU64 | BPF_RSH | BPF_K:
 		emit_alu_K(SRLX, dst, imm, ctx);
@@ -1144,7 +1161,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 		break;
 
 	do_alu32_trunc:
-		if (BPF_CLASS(code) == BPF_ALU)
+		if (BPF_CLASS(code) == BPF_ALU &&
+		    !ctx->prog->aux->verifier_zext)
 			emit_alu_K(SRL, dst, 0, ctx);
 		break;
 
@@ -1265,6 +1283,8 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
 			rs2 = RS2(tmp);
 		}
 		emit(opcode | RS1(src) | rs2 | RD(dst), ctx);
+		if (opcode != LD64 && insn_is_zext(&insn[1]))
+			return 1;
 		break;
 	}
 	/* ST: *(size *)(dst + off) = imm */
@@ -1432,6 +1452,11 @@ static void jit_fill_hole(void *area, unsigned int size)
 		*ptr++ = 0x91d02005; /* ta 5 */
 }
 
+bool bpf_jit_needs_zext(void)
+{
+	return true;
+}
+
 struct sparc64_jit_data {
 	struct bpf_binary_header *header;
 	u8 *image;
-- 
2.7.4