netdev - [PATCH v5 bpf-next 15/17] x32: bpf: eliminate zero extension code-gen

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Message-Id: <1556721842-29836-16-git-send-email-jiong.wang@netronome.com>
Date:   Wed,  1 May 2019 15:44:00 +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, Jiong Wang <jiong.wang@...ronome.com>,
        Wang YanQing <udknight@...il.com>
Subject: [PATCH v5 bpf-next 15/17] x32: bpf: eliminate zero extension code-gen

Cc: Wang YanQing <udknight@...il.com>
Signed-off-by: Jiong Wang <jiong.wang@...ronome.com>
---
 arch/x86/net/bpf_jit_comp32.c | 39 ++++++++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 11 deletions(-)

diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index 0d9cdff..8b2576e 100644
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/arch/x86/net/bpf_jit_comp32.c
@@ -567,7 +567,7 @@ static inline void emit_ia32_alu_r(const bool is64, const bool hi, const u8 op,
 static inline void emit_ia32_alu_r64(const bool is64, const u8 op,
 				     const u8 dst[], const u8 src[],
 				     bool dstk,  bool sstk,
-				     u8 **pprog)
+				     u8 **pprog, const struct bpf_prog_aux *aux)
 {
 	u8 *prog = *pprog;
 
@@ -575,7 +575,7 @@ static inline void emit_ia32_alu_r64(const bool is64, const u8 op,
 	if (is64)
 		emit_ia32_alu_r(is64, true, op, dst_hi, src_hi, dstk, sstk,
 				&prog);
-	else
+	else if (!aux->verifier_zext)
 		emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
 	*pprog = prog;
 }
@@ -666,7 +666,8 @@ static inline void emit_ia32_alu_i(const bool is64, const bool hi, const u8 op,
 /* ALU operation (64 bit) */
 static inline void emit_ia32_alu_i64(const bool is64, const u8 op,
 				     const u8 dst[], const u32 val,
-				     bool dstk, u8 **pprog)
+				     bool dstk, u8 **pprog,
+				     const struct bpf_prog_aux *aux)
 {
 	u8 *prog = *pprog;
 	u32 hi = 0;
@@ -677,7 +678,7 @@ static inline void emit_ia32_alu_i64(const bool is64, const u8 op,
 	emit_ia32_alu_i(is64, false, op, dst_lo, val, dstk, &prog);
 	if (is64)
 		emit_ia32_alu_i(is64, true, op, dst_hi, hi, dstk, &prog);
-	else
+	else if (!aux->verifier_zext)
 		emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
 
 	*pprog = prog;
@@ -1642,6 +1643,10 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 
 		switch (code) {
 		/* ALU operations */
+		/* Explicit zero extension */
+		case BPF_ALU | BPF_ZEXT:
+			emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
+			break;
 		/* dst = src */
 		case BPF_ALU | BPF_MOV | BPF_K:
 		case BPF_ALU | BPF_MOV | BPF_X:
@@ -1690,11 +1695,13 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 			switch (BPF_SRC(code)) {
 			case BPF_X:
 				emit_ia32_alu_r64(is64, BPF_OP(code), dst,
-						  src, dstk, sstk, &prog);
+						  src, dstk, sstk, &prog,
+						  bpf_prog->aux);
 				break;
 			case BPF_K:
 				emit_ia32_alu_i64(is64, BPF_OP(code), dst,
-						  imm32, dstk, &prog);
+						  imm32, dstk, &prog,
+						  bpf_prog->aux);
 				break;
 			}
 			break;
@@ -1713,7 +1720,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 						false, &prog);
 				break;
 			}
-			emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
+			if (!bpf_prog->aux->verifier_zext)
+				emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
 			break;
 		case BPF_ALU | BPF_LSH | BPF_X:
 		case BPF_ALU | BPF_RSH | BPF_X:
@@ -1733,7 +1741,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 						  &prog);
 				break;
 			}
-			emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
+			if (!bpf_prog->aux->verifier_zext)
+				emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
 			break;
 		/* dst = dst / src(imm) */
 		/* dst = dst % src(imm) */
@@ -1755,7 +1764,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 						    &prog);
 				break;
 			}
-			emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
+			if (!bpf_prog->aux->verifier_zext)
+				emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
 			break;
 		case BPF_ALU64 | BPF_DIV | BPF_K:
 		case BPF_ALU64 | BPF_DIV | BPF_X:
@@ -1772,7 +1782,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 			EMIT2_off32(0xC7, add_1reg(0xC0, IA32_ECX), imm32);
 			emit_ia32_shift_r(BPF_OP(code), dst_lo, IA32_ECX, dstk,
 					  false, &prog);
-			emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
+			if (!bpf_prog->aux->verifier_zext)
+				emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
 			break;
 		/* dst = dst << imm */
 		case BPF_ALU64 | BPF_LSH | BPF_K:
@@ -1808,7 +1819,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 		case BPF_ALU | BPF_NEG:
 			emit_ia32_alu_i(is64, false, BPF_OP(code),
 					dst_lo, 0, dstk, &prog);
-			emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
+			if (!bpf_prog->aux->verifier_zext)
+				emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
 			break;
 		/* dst = ~dst (64 bit) */
 		case BPF_ALU64 | BPF_NEG:
@@ -2367,6 +2379,11 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 	return proglen;
 }
 
+bool bpf_jit_hardware_zext(void)
+{
+	return false;
+}
+
 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 {
 	struct bpf_binary_header *header = NULL;
-- 
2.7.4