diff options
Diffstat (limited to 'arch/x86/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 106 |
1 files changed, 75 insertions, 31 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 0554e8aef4d5..4923d92f918d 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -15,8 +15,6 @@ #include <asm/set_memory.h> #include <linux/bpf.h> -int bpf_jit_enable __read_mostly; - /* * assembly code in arch/x86/net/bpf_jit.S */ @@ -154,6 +152,11 @@ static bool is_ereg(u32 reg) BIT(BPF_REG_AX)); } +static bool is_axreg(u32 reg) +{ + return reg == BPF_REG_0; +} + /* add modifiers if 'reg' maps to x64 registers r8..r15 */ static u8 add_1mod(u8 byte, u32 reg) { @@ -447,16 +450,36 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, else if (is_ereg(dst_reg)) EMIT1(add_1mod(0x40, dst_reg)); + /* b3 holds 'normal' opcode, b2 short form only valid + * in case dst is eax/rax. + */ switch (BPF_OP(insn->code)) { - case BPF_ADD: b3 = 0xC0; break; - case BPF_SUB: b3 = 0xE8; break; - case BPF_AND: b3 = 0xE0; break; - case BPF_OR: b3 = 0xC8; break; - case BPF_XOR: b3 = 0xF0; break; + case BPF_ADD: + b3 = 0xC0; + b2 = 0x05; + break; + case BPF_SUB: + b3 = 0xE8; + b2 = 0x2D; + break; + case BPF_AND: + b3 = 0xE0; + b2 = 0x25; + break; + case BPF_OR: + b3 = 0xC8; + b2 = 0x0D; + break; + case BPF_XOR: + b3 = 0xF0; + b2 = 0x35; + break; } if (is_imm8(imm32)) EMIT3(0x83, add_1reg(b3, dst_reg), imm32); + else if (is_axreg(dst_reg)) + EMIT1_off32(b2, imm32); else EMIT2_off32(0x81, add_1reg(b3, dst_reg), imm32); break; @@ -545,26 +568,6 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, */ EMIT2(0x31, 0xd2); - if (BPF_SRC(insn->code) == BPF_X) { - /* if (src_reg == 0) return 0 */ - - /* cmp r11, 0 */ - EMIT4(0x49, 0x83, 0xFB, 0x00); - - /* jne .+9 (skip over pop, pop, xor and jmp) */ - EMIT2(X86_JNE, 1 + 1 + 2 + 5); - EMIT1(0x5A); /* pop rdx */ - EMIT1(0x58); /* pop rax */ - EMIT2(0x31, 0xc0); /* xor eax, eax */ - - /* jmp cleanup_addr - * addrs[i] - 11, because there are 11 bytes - * after this insn: div, mov, pop, pop, mov - */ - jmp_offset = ctx->cleanup_addr - (addrs[i] - 11); - EMIT1_off32(0xE9, jmp_offset); - } - if (BPF_CLASS(insn->code) == BPF_ALU64) /* div r11 */ EMIT3(0x49, 0xF7, 0xF3); @@ -1109,19 +1112,29 @@ common_load: return proglen; } +struct x64_jit_data { + struct bpf_binary_header *header; + int *addrs; + u8 *image; + int proglen; + struct jit_context ctx; +}; + struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) { struct bpf_binary_header *header = NULL; struct bpf_prog *tmp, *orig_prog = prog; + struct x64_jit_data *jit_data; int proglen, oldproglen = 0; struct jit_context ctx = {}; bool tmp_blinded = false; + bool extra_pass = false; u8 *image = NULL; int *addrs; int pass; int i; - if (!bpf_jit_enable) + if (!prog->jit_requested) return orig_prog; tmp = bpf_jit_blind_constants(prog); @@ -1135,10 +1148,28 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) prog = tmp; } + jit_data = prog->aux->jit_data; + if (!jit_data) { + jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL); + if (!jit_data) { + prog = orig_prog; + goto out; + } + prog->aux->jit_data = jit_data; + } + addrs = jit_data->addrs; + if (addrs) { + ctx = jit_data->ctx; + oldproglen = jit_data->proglen; + image = jit_data->image; + header = jit_data->header; + extra_pass = true; + goto skip_init_addrs; + } addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL); if (!addrs) { prog = orig_prog; - goto out; + goto out_addrs; } /* Before first pass, make a rough estimation of addrs[] @@ -1149,6 +1180,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) addrs[i] = proglen; } ctx.cleanup_addr = proglen; +skip_init_addrs: /* JITed image shrinks with every pass and the loop iterates * until the image stops shrinking. Very large bpf programs @@ -1189,7 +1221,15 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) if (image) { bpf_flush_icache(header, image + proglen); - bpf_jit_binary_lock_ro(header); + if (!prog->is_func || extra_pass) { + bpf_jit_binary_lock_ro(header); + } else { + jit_data->addrs = addrs; + jit_data->ctx = ctx; + jit_data->proglen = proglen; + jit_data->image = image; + jit_data->header = header; + } prog->bpf_func = (void *)image; prog->jited = 1; prog->jited_len = proglen; @@ -1197,8 +1237,12 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) prog = orig_prog; } + if (!prog->is_func || extra_pass) { out_addrs: - kfree(addrs); + kfree(addrs); + kfree(jit_data); + prog->aux->jit_data = NULL; + } out: if (tmp_blinded) bpf_jit_prog_release_other(prog, prog == orig_prog ? |