x32: bpf: eliminate zero extension code-gen

Cc: Wang YanQing <udknight@gmail.com>
Tested-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index b29e82f190c761cd322591f122dcb1d6f02a6398..133433d181ba73b18ca7f866c5a332ccd87ff94b 100644 (file)
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/arch/x86/net/bpf_jit_comp32.c
@@ -253,13 +253,14 @@ static inline void emit_ia32_mov_r(const u8 dst, const u8 src, bool dstk,
 /* dst = src */
 static inline void emit_ia32_mov_r64(const bool is64, const u8 dst[],
                                     const u8 src[], bool dstk,
-                                    bool sstk, u8 **pprog)
+                                    bool sstk, u8 **pprog,
+                                    const struct bpf_prog_aux *aux)
 {
        emit_ia32_mov_r(dst_lo, src_lo, dstk, sstk, pprog);
        if (is64)
                /* complete 8 byte move */
                emit_ia32_mov_r(dst_hi, src_hi, dstk, sstk, pprog);
-       else
+       else if (!aux->verifier_zext)
                /* zero out high 4 bytes */
                emit_ia32_mov_i(dst_hi, 0, dstk, pprog);
 }
@@ -313,7 +314,8 @@ static inline void emit_ia32_mul_r(const u8 dst, const u8 src, bool dstk,
 }
 
 static inline void emit_ia32_to_le_r64(const u8 dst[], s32 val,
-                                        bool dstk, u8 **pprog)
+                                        bool dstk, u8 **pprog,
+                                        const struct bpf_prog_aux *aux)
 {
        u8 *prog = *pprog;
        int cnt = 0;
@@ -334,12 +336,14 @@ static inline void emit_ia32_to_le_r64(const u8 dst[], s32 val,
                 */
                EMIT2(0x0F, 0xB7);
                EMIT1(add_2reg(0xC0, dreg_lo, dreg_lo));
-               /* xor dreg_hi,dreg_hi */
-               EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
+               if (!aux->verifier_zext)
+                       /* xor dreg_hi,dreg_hi */
+                       EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
                break;
        case 32:
-               /* xor dreg_hi,dreg_hi */
-               EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
+               if (!aux->verifier_zext)
+                       /* xor dreg_hi,dreg_hi */
+                       EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
                break;
        case 64:
                /* nop */
@@ -358,7 +362,8 @@ static inline void emit_ia32_to_le_r64(const u8 dst[], s32 val,
 }
 
 static inline void emit_ia32_to_be_r64(const u8 dst[], s32 val,
-                                      bool dstk, u8 **pprog)
+                                      bool dstk, u8 **pprog,
+                                      const struct bpf_prog_aux *aux)
 {
        u8 *prog = *pprog;
        int cnt = 0;
@@ -380,16 +385,18 @@ static inline void emit_ia32_to_be_r64(const u8 dst[], s32 val,
                EMIT2(0x0F, 0xB7);
                EMIT1(add_2reg(0xC0, dreg_lo, dreg_lo));
 
-               /* xor dreg_hi,dreg_hi */
-               EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
+               if (!aux->verifier_zext)
+                       /* xor dreg_hi,dreg_hi */
+                       EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
                break;
        case 32:
                /* Emit 'bswap eax' to swap lower 4 bytes */
                EMIT1(0x0F);
                EMIT1(add_1reg(0xC8, dreg_lo));
 
-               /* xor dreg_hi,dreg_hi */
-               EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
+               if (!aux->verifier_zext)
+                       /* xor dreg_hi,dreg_hi */
+                       EMIT2(0x33, add_2reg(0xC0, dreg_hi, dreg_hi));
                break;
        case 64:
                /* Emit 'bswap eax' to swap lower 4 bytes */
@@ -569,7 +576,7 @@ 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;
 
@@ -577,7 +584,7 @@ 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;
 }
@@ -668,7 +675,8 @@ 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;
@@ -679,7 +687,7 @@ 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;
@@ -1713,8 +1721,13 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
                case BPF_ALU64 | BPF_MOV | BPF_X:
                        switch (BPF_SRC(code)) {
                        case BPF_X:
-                               emit_ia32_mov_r64(is64, dst, src, dstk,
-                                                 sstk, &prog);
+                               if (imm32 == 1) {
+                                       /* Special mov32 for zext. */
+                                       emit_ia32_mov_i(dst_hi, 0, dstk, &prog);
+                                       break;
+                               }
+                               emit_ia32_mov_r64(is64, dst, src, dstk, sstk,
+                                                 &prog, bpf_prog->aux);
                                break;
                        case BPF_K:
                                /* Sign-extend immediate value to dst reg */
@@ -1754,11 +1767,13 @@ 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;
@@ -1777,7 +1792,8 @@ 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:
@@ -1797,7 +1813,8 @@ 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) */
@@ -1819,7 +1836,8 @@ 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:
@@ -1836,7 +1854,8 @@ 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:
@@ -1872,7 +1891,8 @@ 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:
@@ -1892,11 +1912,13 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
                        break;
                /* dst = htole(dst) */
                case BPF_ALU | BPF_END | BPF_FROM_LE:
-                       emit_ia32_to_le_r64(dst, imm32, dstk, &prog);
+                       emit_ia32_to_le_r64(dst, imm32, dstk, &prog,
+                                           bpf_prog->aux);
                        break;
                /* dst = htobe(dst) */
                case BPF_ALU | BPF_END | BPF_FROM_BE:
-                       emit_ia32_to_be_r64(dst, imm32, dstk, &prog);
+                       emit_ia32_to_be_r64(dst, imm32, dstk, &prog,
+                                           bpf_prog->aux);
                        break;
                /* dst = imm64 */
                case BPF_LD | BPF_IMM | BPF_DW: {
@@ -2051,6 +2073,8 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
                        case BPF_B:
                        case BPF_H:
                        case BPF_W:
+                               if (!bpf_prog->aux->verifier_zext)
+                                       break;
                                if (dstk) {
                                        EMIT3(0xC7, add_1reg(0x40, IA32_EBP),
                                              STACK_VAR(dst_hi));
@@ -2475,6 +2499,11 @@ emit_cond_jmp:           jmp_cond = get_cond_jmp_opcode(BPF_OP(code), false);
        return proglen;
 }
 
+bool bpf_jit_needs_zext(void)
+{
+       return true;
+}
+
 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
 {
        struct bpf_binary_header *header = NULL;