| /* |
| * Copyright 2016, The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdarg.h> |
| |
| typedef enum { false, true } bool; |
| |
| #include "v5/apf_defs.h" |
| #include "v5/apf.h" |
| #include "disassembler.h" |
| |
| // If "c" is of a signed type, generate a compile warning that gets promoted to an error. |
| // This makes bounds checking simpler because ">= 0" can be avoided. Otherwise adding |
| // superfluous ">= 0" with unsigned expressions generates compile warnings. |
| #define ENFORCE_UNSIGNED(c) ((c)==(uint32_t)(c)) |
| |
| char print_buf[1024]; |
| char* buf_ptr; |
| int buf_remain; |
| |
| __attribute__ ((format (printf, 1, 2) )) |
| static void bprintf(const char* format, ...) { |
| va_list args; |
| va_start(args, format); |
| int ret = vsnprintf(buf_ptr, buf_remain, format, args); |
| va_end(args); |
| if (ret < 0) return; |
| if (ret >= buf_remain) ret = buf_remain; |
| buf_ptr += ret; |
| buf_remain -= ret; |
| } |
| |
| static void print_opcode(const char* opcode) { |
| bprintf("%-12s", opcode); |
| } |
| |
| // Mapping from opcode number to opcode name. |
| static const char* opcode_names [] = { |
| [LDB_OPCODE] = "ldb", |
| [LDH_OPCODE] = "ldh", |
| [LDW_OPCODE] = "ldw", |
| [LDBX_OPCODE] = "ldbx", |
| [LDHX_OPCODE] = "ldhx", |
| [LDWX_OPCODE] = "ldwx", |
| [ADD_OPCODE] = "add", |
| [MUL_OPCODE] = "mul", |
| [DIV_OPCODE] = "div", |
| [AND_OPCODE] = "and", |
| [OR_OPCODE] = "or", |
| [SH_OPCODE] = "sh", |
| [LI_OPCODE] = "li", |
| [JMP_OPCODE] = "jmp", |
| [JEQ_OPCODE] = "jeq", |
| [JNE_OPCODE] = "jne", |
| [JGT_OPCODE] = "jgt", |
| [JLT_OPCODE] = "jlt", |
| [JSET_OPCODE] = "jset", |
| [JBSMATCH_OPCODE] = NULL, |
| [LDDW_OPCODE] = "lddw", |
| [STDW_OPCODE] = "stdw", |
| [WRITE_OPCODE] = "write", |
| }; |
| |
| static void print_jump_target(uint32_t target, uint32_t program_len) { |
| if (target == program_len) { |
| bprintf("PASS"); |
| } else if (target == program_len + 1) { |
| bprintf("DROP"); |
| } else { |
| bprintf("%u", target); |
| } |
| } |
| |
| const char* apf_disassemble(const uint8_t* program, uint32_t program_len, uint32_t* const ptr2pc) { |
| buf_ptr = print_buf; |
| buf_remain = sizeof(print_buf); |
| if (*ptr2pc > program_len + 1) { |
| bprintf("pc is overflow: pc %d, program_len: %d", *ptr2pc, program_len); |
| return print_buf; |
| } |
| |
| bprintf("%8u: ", *ptr2pc); |
| |
| if (*ptr2pc == program_len) { |
| bprintf("PASS"); |
| ++(*ptr2pc); |
| return print_buf; |
| } |
| |
| if (*ptr2pc == program_len + 1) { |
| bprintf("DROP"); |
| ++(*ptr2pc); |
| return print_buf; |
| } |
| |
| const uint8_t bytecode = program[(*ptr2pc)++]; |
| const uint32_t opcode = EXTRACT_OPCODE(bytecode); |
| |
| #define PRINT_OPCODE() print_opcode(opcode_names[opcode]) |
| #define DECODE_IMM(length) ({ \ |
| uint32_t value = 0; \ |
| for (uint32_t i = 0; i < (length) && *ptr2pc < program_len; i++) \ |
| value = (value << 8) | program[(*ptr2pc)++]; \ |
| value;}) |
| |
| const uint32_t reg_num = EXTRACT_REGISTER(bytecode); |
| // All instructions have immediate fields, so load them now. |
| const uint32_t len_field = EXTRACT_IMM_LENGTH(bytecode); |
| uint32_t imm = 0; |
| int32_t signed_imm = 0; |
| if (len_field != 0) { |
| const uint32_t imm_len = 1 << (len_field - 1); |
| imm = DECODE_IMM(imm_len); |
| // Sign extend imm into signed_imm. |
| signed_imm = imm << ((4 - imm_len) * 8); |
| signed_imm >>= (4 - imm_len) * 8; |
| } |
| switch (opcode) { |
| case PASSDROP_OPCODE: |
| if (reg_num == 0) { |
| print_opcode("pass"); |
| } else { |
| print_opcode("drop"); |
| } |
| if (imm > 0) { |
| bprintf(" %d", imm); |
| } |
| break; |
| case LDB_OPCODE: |
| case LDH_OPCODE: |
| case LDW_OPCODE: |
| PRINT_OPCODE(); |
| bprintf("r%d, [%u]", reg_num, imm); |
| break; |
| case LDBX_OPCODE: |
| case LDHX_OPCODE: |
| case LDWX_OPCODE: |
| PRINT_OPCODE(); |
| if (imm) { |
| bprintf("r%d, [r1+%u]", reg_num, imm); |
| } else { |
| bprintf("r%d, [r1]", reg_num); |
| } |
| break; |
| case JMP_OPCODE: |
| if (reg_num == 0) { |
| PRINT_OPCODE(); |
| print_jump_target(*ptr2pc + imm, program_len); |
| } else { |
| print_opcode("data"); |
| bprintf("%d, ", imm); |
| uint32_t len = imm; |
| while (len--) bprintf("%02x", program[(*ptr2pc)++]); |
| } |
| break; |
| case JEQ_OPCODE: |
| case JNE_OPCODE: |
| case JGT_OPCODE: |
| case JLT_OPCODE: |
| case JSET_OPCODE: { |
| PRINT_OPCODE(); |
| bprintf("r0, "); |
| // Load second immediate field. |
| if (reg_num == 1) { |
| bprintf("r1, "); |
| } else if (len_field == 0) { |
| bprintf("0, "); |
| } else { |
| uint32_t cmp_imm = DECODE_IMM(1 << (len_field - 1)); |
| bprintf("0x%x, ", cmp_imm); |
| } |
| print_jump_target(*ptr2pc + imm, program_len); |
| break; |
| } |
| case JBSMATCH_OPCODE: { |
| if (reg_num == 0) { |
| print_opcode("jbsne"); |
| } else { |
| print_opcode("jbseq"); |
| } |
| bprintf("r0, "); |
| uint32_t cmp_imm = DECODE_IMM(1 << (len_field - 1)); |
| bprintf("0x%x, ", cmp_imm); |
| print_jump_target(*ptr2pc + imm + cmp_imm, program_len); |
| bprintf(", "); |
| while (cmp_imm--) { |
| uint8_t byte = program[(*ptr2pc)++]; |
| bprintf("%02x", byte); |
| } |
| break; |
| } |
| case SH_OPCODE: |
| PRINT_OPCODE(); |
| if (reg_num) { |
| bprintf("r0, r1"); |
| } else { |
| bprintf("r0, %d", signed_imm); |
| } |
| break; |
| case ADD_OPCODE: |
| case MUL_OPCODE: |
| case DIV_OPCODE: |
| case AND_OPCODE: |
| case OR_OPCODE: |
| PRINT_OPCODE(); |
| if (reg_num) { |
| bprintf("r0, r1"); |
| } else if (!imm && opcode == DIV_OPCODE) { |
| bprintf("pass (div 0)"); |
| } else { |
| bprintf("r0, %u", imm); |
| } |
| break; |
| case LI_OPCODE: |
| PRINT_OPCODE(); |
| bprintf("r%d, %d", reg_num, signed_imm); |
| break; |
| case EXT_OPCODE: |
| if ( |
| // If LDM_EXT_OPCODE is 0 and imm is compared with it, a compiler error will result, |
| // instead just enforce that imm is unsigned (so it's always greater or equal to 0). |
| #if LDM_EXT_OPCODE == 0 |
| ENFORCE_UNSIGNED(imm) && |
| #else |
| imm >= LDM_EXT_OPCODE && |
| #endif |
| imm < (LDM_EXT_OPCODE + MEMORY_ITEMS)) { |
| print_opcode("ldm"); |
| bprintf("r%d, m[%u]", reg_num, imm - LDM_EXT_OPCODE); |
| } else if (imm >= STM_EXT_OPCODE && imm < (STM_EXT_OPCODE + MEMORY_ITEMS)) { |
| print_opcode("stm"); |
| bprintf("r%d, m[%u]", reg_num, imm - STM_EXT_OPCODE); |
| } else switch (imm) { |
| case NOT_EXT_OPCODE: |
| print_opcode("not"); |
| bprintf("r%d", reg_num); |
| break; |
| case NEG_EXT_OPCODE: |
| print_opcode("neg"); |
| bprintf("r%d", reg_num); |
| break; |
| case SWAP_EXT_OPCODE: |
| print_opcode("swap"); |
| break; |
| case MOV_EXT_OPCODE: |
| print_opcode("mov"); |
| bprintf("r%d, r%d", reg_num, reg_num ^ 1); |
| break; |
| case ALLOCATE_EXT_OPCODE: |
| print_opcode("allocate"); |
| if (reg_num == 0) { |
| bprintf("r%d", reg_num); |
| } else { |
| uint32_t alloc_len = DECODE_IMM(2); |
| bprintf("%d", alloc_len); |
| } |
| break; |
| case TRANSMIT_EXT_OPCODE: |
| print_opcode(reg_num ? "transmitudp" : "transmit"); |
| u8 ip_ofs = DECODE_IMM(1); |
| u8 csum_ofs = DECODE_IMM(1); |
| if (csum_ofs < 255) { |
| u8 csum_start = DECODE_IMM(1); |
| u16 partial_csum = DECODE_IMM(2); |
| bprintf("ip_ofs=%d, csum_ofs=%d, csum_start=%d, partial_csum=0x%04x", |
| ip_ofs, csum_ofs, csum_start, partial_csum); |
| } else { |
| bprintf("ip_ofs=%d", ip_ofs); |
| } |
| break; |
| case EWRITE1_EXT_OPCODE: print_opcode("ewrite1"); bprintf("r%d", reg_num); break; |
| case EWRITE2_EXT_OPCODE: print_opcode("ewrite2"); bprintf("r%d", reg_num); break; |
| case EWRITE4_EXT_OPCODE: print_opcode("ewrite4"); bprintf("r%d", reg_num); break; |
| case EPKTDATACOPYIMM_EXT_OPCODE: |
| case EPKTDATACOPYR1_EXT_OPCODE: { |
| if (reg_num == 0) { |
| print_opcode("epktcopy"); |
| } else { |
| print_opcode("edatacopy"); |
| } |
| if (imm == EPKTDATACOPYIMM_EXT_OPCODE) { |
| uint32_t len = DECODE_IMM(1); |
| bprintf(" src=r0, len=%d", len); |
| } else { |
| bprintf(" src=r0, len=r1"); |
| } |
| |
| break; |
| } |
| case JDNSQMATCH_EXT_OPCODE: // 43 |
| case JDNSAMATCH_EXT_OPCODE: // 44 |
| case JDNSQMATCHSAFE_EXT_OPCODE: // 45 |
| case JDNSAMATCHSAFE_EXT_OPCODE: { // 46 |
| uint32_t offs = DECODE_IMM(1 << (len_field - 1)); |
| int qtype = -1; |
| switch(imm) { |
| case JDNSQMATCH_EXT_OPCODE: |
| print_opcode(reg_num ? "jdnsqeq" : "jdnsqne"); |
| qtype = DECODE_IMM(1); |
| break; |
| case JDNSQMATCHSAFE_EXT_OPCODE: |
| print_opcode(reg_num ? "jdnsqeqsafe" : "jdnsqnesafe"); |
| qtype = DECODE_IMM(1); |
| break; |
| case JDNSAMATCH_EXT_OPCODE: |
| print_opcode(reg_num ? "jdnsaeq" : "jdnsane"); break; |
| case JDNSAMATCHSAFE_EXT_OPCODE: |
| print_opcode(reg_num ? "jdnsaeqsafe" : "jdnsanesafe"); break; |
| default: |
| bprintf("unknown_ext %u", imm); break; |
| } |
| bprintf("r0, "); |
| uint32_t end = *ptr2pc; |
| while (end + 1 < program_len && !(program[end] == 0 && program[end + 1] == 0)) { |
| end++; |
| } |
| end += 2; |
| print_jump_target(end + offs, program_len); |
| bprintf(", "); |
| if (imm == JDNSQMATCH_EXT_OPCODE || imm == JDNSQMATCHSAFE_EXT_OPCODE) { |
| bprintf("%d, ", qtype); |
| } |
| while (*ptr2pc < end) { |
| uint8_t byte = program[(*ptr2pc)++]; |
| // values < 0x40 could be lengths, but - and 0..9 are in practice usually |
| // too long to be lengths so print them as characters. All other chars < 0x40 |
| // are not valid in dns character. |
| if (byte == '-' || (byte >= '0' && byte <= '9') || byte >= 0x40) { |
| bprintf("%c", byte); |
| } else { |
| bprintf("(%d)", byte); |
| } |
| } |
| break; |
| } |
| default: |
| bprintf("unknown_ext %u", imm); |
| break; |
| } |
| break; |
| case LDDW_OPCODE: |
| case STDW_OPCODE: |
| PRINT_OPCODE(); |
| if (signed_imm > 0) { |
| bprintf("r%u, [r%u+%d]", reg_num, reg_num ^ 1, signed_imm); |
| } else if (signed_imm < 0) { |
| bprintf("r%u, [r%u-%d]", reg_num, reg_num ^ 1, -signed_imm); |
| } else { |
| bprintf("r%u, [r%u]", reg_num, reg_num ^ 1); |
| } |
| break; |
| case WRITE_OPCODE: { |
| PRINT_OPCODE(); |
| uint32_t write_len = 1 << (len_field - 1); |
| if (write_len > 0) { |
| bprintf("0x"); |
| } |
| for (uint32_t i = 0; i < write_len; ++i) { |
| uint8_t byte = |
| (uint8_t) ((imm >> (write_len - 1 - i) * 8) & 0xff); |
| bprintf("%02x", byte); |
| |
| } |
| break; |
| } |
| case PKTDATACOPY_OPCODE: { |
| if (reg_num == 0) { |
| print_opcode("pktcopy"); |
| } else { |
| print_opcode("datacopy"); |
| } |
| uint32_t src_offs = imm; |
| uint32_t copy_len = DECODE_IMM(1); |
| bprintf("src=%d, len=%d", src_offs, copy_len); |
| break; |
| } |
| // Unknown opcode |
| default: |
| bprintf("unknown %u", opcode); |
| break; |
| } |
| return print_buf; |
| } |
