diff options
Diffstat (limited to 'src/cpu.c')
| -rw-r--r-- | src/cpu.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/cpu.c b/src/cpu.c new file mode 100644 index 0000000..9c7c2a2 --- /dev/null +++ b/src/cpu.c @@ -0,0 +1,206 @@ +#include <cpu.h> +#include <load.h> +#include <log.h> +#include <linux.h> +#include <mem.h> + +#define MOD() ((modrm & 0xc0) >> 6) +#define RM() (modrm & 0x07) +#define DISP32() (U32()) +#define DISP8() (S8()) +#define REG() ((modrm & 0x38) >> 3) +#define ADDR() \ + __extension__({ \ + uint32_t _ret = 0; \ + if (MOD() == 0) { \ + if (RM() == 4) \ + errln("TODO."); \ + else if (RM() == 5) \ + _ret = DISP32(); \ + else \ + _ret = GET_R32(RM()); \ + } else if (MOD() == 1) { \ + if (RM() == 4) \ + errln("TODO."); \ + else \ + _ret = GET_R32(RM()) + DISP8(); \ + } else { \ + if (RM() == 4) \ + errln("TODO."); \ + else \ + _ret = GET_R32(RM()) + DISP32(); \ + } \ + _ret; \ + }) + +#define U8() (*(uint8_t *)mem_phys(rip++)) +#define S8() (*(int8_t *)mem_phys(rip++)) +#define U16() \ + __extension__({ \ + uint16_t ret = *(uint16_t *)mem_phys(rip); \ + rip += 2; \ + ret; \ + }) +#define S16() \ + __extension__({ \ + int16_t ret = *(int16_t *)mem_phys(rip); \ + rip += 2; \ + ret; \ + }) +#define U32() \ + __extension__({ \ + uint32_t ret = *(uint32_t *)mem_phys(rip); \ + rip += 4; \ + ret; \ + }) +#define S32() \ + __extension__({ \ + int32_t ret = *(int32_t *)mem_phys(rip); \ + rip += 4; \ + ret; \ + }) +#define U64() \ + __extension__({ \ + uint64_t ret = *(uint64_t *)mem_phys(rip); \ + rip += 8; \ + ret; \ + }) +#define S64() \ + __extension__({ \ + int64_t ret = *(int64_t *)mem_phys(rip); \ + rip += 8; \ + ret; \ + }) + +#define GET_R8(r) (r < 8 ? regs[r] & 0xff : (regs[r - 8] >> 8) & 0xff) +#define GET_R32(r) ((uint32_t)regs[r]) +#define GET_R64(r) ((uint64_t)regs[r]) +#define SET_R8(r, v) \ + __extension__({ \ + if (r < 8) \ + regs[r] = (regs[r] & 0xffffff00) | (uint32_t)v; \ + else \ + regs[r - 4] = (regs[r] = (regs[r] & 0xffff00ff) | \ + ((uint32_t)v << 8)) \ + }) +#define SET_R32(r, v) (regs[r] = v) +#define SET_R64(r, v) (regs[r] = v) + +#define GET_RM8() (MOD() == 3 ? GET_R8(RM()) : *(uint8_t *)mem_phys(ADDR())) +#define GET_RM32() (MOD() == 3 ? GET_R32(RM()) : *(uint32_t *)mem_phys(ADDR())) + +static uint64_t rip = 0; +static int (*pos_instructions[256])(void); +static int (*neg_instructions[256])(void); +static uint64_t regs[REGISTERS_COUNT] = { 0 }; + +static void print_state(void) +{ + logln("rip=%x, rax=%x, rcx=%x, rdx=%x, rbx=%x, rsp=%x, rbp=%x, rsi=%x, rdi=%x,\nr8=%x, r9=%x, r10=%x, r11=%x, r12=%x, r13=%x, r14=%x, r15=%x", + rip, regs[RAX], regs[RCX], regs[RDX], regs[RBX], regs[RSP], + regs[RBP], regs[RSI], regs[RSI], regs[RDI], regs[R8], regs[R9], + regs[R10], regs[R11], regs[R12], regs[R13], regs[R14], regs[R15]); +} + +static int pos_unknown_instruction(void) +{ + errln("unknown positive instruction at rip=%d", rip); + return ERR; +} + +static int neg_unknown_instruction(void) +{ + errln("unknown negative instruction at rip=%d", rip); + return ERR; +} + +static int pos_opcode(void) +{ + uint8_t op = U8(); + // TODO: is_*, j* + if (op == 0x05) { + return linux_call(); + } + return ERR; +} + +static int pos_mov_r32_rm32(void) +{ + uint8_t modrm = U8(); + SET_R32(REG(), GET_RM32()); + return OK; +} + +static int pos_mov_r32_imm32(void) +{ + rip--; + uint8_t reg = U8() - 0xb8; + SET_R32(reg, U32()); + return OK; +} + +static int pos_nop(void) +{ + return OK; +} + +static int pos_int(void) +{ + uint8_t op = U8(); + if (op == 0x80) { + // Linux syscall + // TODO: Support legacy syscalls (numbers are different) + return ERR; + } + return ERR; +} + +static void initialize(void) +{ + for (int i = 0; i < 256; i++) { + pos_instructions[i] = pos_unknown_instruction; + neg_instructions[i] = neg_unknown_instruction; + } + pos_instructions[0x0f] = pos_opcode; + pos_instructions[0x8b] = pos_mov_r32_rm32; + pos_instructions[0x90] = pos_nop; + pos_instructions[0xcd] = pos_int; + /* for (int i = 0; i < 8; i++) */ + /* pos_instructions[0xb0+i] = pos_mov_r8_imm8; */ + for (int i = 0; i < 8; i++) + pos_instructions[0xb8 + i] = pos_mov_r32_imm32; +} + +void *cpu_get_reg(uint8_t reg) +{ + return ®s[reg]; +} + +// TODO: Different signature? +void cpu_set_reg(uint8_t reg, uint64_t val) +{ + regs[reg] = val; +} + +void cpu_exec(const char *path) +{ + initialize(); + + vaddr addr = load(path); + if (!addr) { + errln("invalid entry address"); + return; + } + rip = addr; + + int ret = OK; + while (ret) { + uint8_t instr = U8(); + if (!instr) + return; + logln("%x", instr); + ret = pos_instructions[instr](); + print_state(); + } + errln("error while executing"); +} |