From 836256bf5f379c298ffa99f62e329d9f40f060ac Mon Sep 17 00:00:00 2001 From: Jiong Wang Date: Fri, 24 May 2019 23:25:26 +0100 Subject: [PATCH] x32: bpf: eliminate zero extension code-gen Cc: Wang YanQing Tested-by: Wang YanQing Signed-off-by: Jiong Wang Signed-off-by: Alexei Starovoitov --- arch/x86/net/bpf_jit_comp32.c | 83 +++++++++++++++++++++++------------ 1 file changed, 56 insertions(+), 27 deletions(-) diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c index b29e82f190c7..133433d181ba 100644 --- 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; -- 2.45.2