diff options
Diffstat (limited to 'lrmi.c')
| -rw-r--r-- | lrmi.c | 871 |
1 files changed, 0 insertions, 871 deletions
@@ -1,871 +0,0 @@ -/* -Linux Real Mode Interface - A library of DPMI-like functions for Linux. - -Copyright (C) 1998 by Josh Vanderhoof - -You are free to distribute and modify this file, as long as you -do not remove this copyright notice and clearly label modified -versions as being modified. - -This software has NO WARRANTY. Use it at your own risk. -*/ - -#include <stdio.h> -#include <string.h> -#include <sys/io.h> -#include <asm/vm86.h> - -#ifdef USE_LIBC_VM86 -#include <sys/vm86.h> -#endif - -#include <sys/types.h> -#include <sys/stat.h> -#include <sys/mman.h> -#include <unistd.h> -#include <fcntl.h> - -#include "lrmi.h" - -#define REAL_MEM_BASE ((void *)0x10000) -#define REAL_MEM_SIZE 0x10000 -#define REAL_MEM_BLOCKS 0x100 - -struct mem_block - { - unsigned int size : 20; - unsigned int free : 1; - }; - -static struct - { - int ready; - int count; - struct mem_block blocks[REAL_MEM_BLOCKS]; - } mem_info = { 0 }; - -static int -real_mem_init(void) - { - void *m; - int fd_zero; - - if (mem_info.ready) - return 1; - - fd_zero = open("/dev/zero", O_RDONLY); - if (fd_zero == -1) - { - perror("open /dev/zero"); - return 0; - } - - m = mmap((void *)REAL_MEM_BASE, REAL_MEM_SIZE, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE, fd_zero, 0); - - if (m == (void *)-1) - { - perror("mmap /dev/zero"); - close(fd_zero); - return 0; - } - - mem_info.ready = 1; - mem_info.count = 1; - mem_info.blocks[0].size = REAL_MEM_SIZE; - mem_info.blocks[0].free = 1; - - return 1; - } - - -static void -insert_block(int i) - { - memmove( - mem_info.blocks + i + 1, - mem_info.blocks + i, - (mem_info.count - i) * sizeof(struct mem_block)); - - mem_info.count++; - } - -static void -delete_block(int i) - { - mem_info.count--; - - memmove( - mem_info.blocks + i, - mem_info.blocks + i + 1, - (mem_info.count - i) * sizeof(struct mem_block)); - } - -void * -LRMI_alloc_real(int size) - { - int i; - char *r = (char *)REAL_MEM_BASE; - - if (!mem_info.ready) - return NULL; - - if (mem_info.count == REAL_MEM_BLOCKS) - return NULL; - - size = (size + 15) & ~15; - - for (i = 0; i < mem_info.count; i++) - { - if (mem_info.blocks[i].free && size < mem_info.blocks[i].size) - { - insert_block(i); - - mem_info.blocks[i].size = size; - mem_info.blocks[i].free = 0; - mem_info.blocks[i + 1].size -= size; - - return (void *)r; - } - - r += mem_info.blocks[i].size; - } - - return NULL; - } - - -void -LRMI_free_real(void *m) - { - int i; - char *r = (char *)REAL_MEM_BASE; - - if (!mem_info.ready) - return; - - i = 0; - while (m != (void *)r) - { - r += mem_info.blocks[i].size; - i++; - if (i == mem_info.count) - return; - } - - mem_info.blocks[i].free = 1; - - if (i + 1 < mem_info.count && mem_info.blocks[i + 1].free) - { - mem_info.blocks[i].size += mem_info.blocks[i + 1].size; - delete_block(i + 1); - } - - if (i - 1 >= 0 && mem_info.blocks[i - 1].free) - { - mem_info.blocks[i - 1].size += mem_info.blocks[i].size; - delete_block(i); - } - } - - -#define DEFAULT_VM86_FLAGS (IF_MASK | IOPL_MASK) -#define DEFAULT_STACK_SIZE 0x1000 -#define RETURN_TO_32_INT 255 - -static struct - { - int ready; - unsigned short ret_seg, ret_off; - unsigned short stack_seg, stack_off; - struct vm86_struct vm; - } context = { 0 }; - - -static inline void -set_bit(unsigned int bit, void *array) - { - unsigned char *a = array; - - a[bit / 8] |= (1 << (bit % 8)); - } - - -static inline unsigned int -get_int_seg(int i) - { - return *(unsigned short *)(i * 4 + 2); - } - - -static inline unsigned int -get_int_off(int i) - { - return *(unsigned short *)(i * 4); - } - - -static inline void -pushw(unsigned short i) - { - struct vm86_regs *r = &context.vm.regs; - r->esp -= 2; - *(unsigned short *)(((unsigned int)r->ss << 4) + r->esp) = i; - } - - -int -LRMI_init(void) - { - void *m; - int fd_mem; - - if (context.ready) - return 1; - - if (!real_mem_init()) - return 0; - - /* - Map the Interrupt Vectors (0x0 - 0x400) + BIOS data (0x400 - 0x502) - and the ROM (0xa0000 - 0x100000) - */ - fd_mem = open("/dev/mem", O_RDWR); - - if (fd_mem == -1) - { - perror("open /dev/mem"); - return 0; - } - - m = mmap((void *)0, 0x502, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE, fd_mem, 0); - - if (m == (void *)-1) - { - perror("mmap /dev/mem"); - return 0; - } - - m = mmap((void *)0xa0000, 0x100000 - 0xa0000, - PROT_READ | PROT_WRITE, - MAP_FIXED | MAP_SHARED, fd_mem, 0xa0000); - - if (m == (void *)-1) - { - perror("mmap /dev/mem"); - return 0; - } - - - /* - Allocate a stack - */ - m = LRMI_alloc_real(DEFAULT_STACK_SIZE); - - context.stack_seg = (unsigned int)m >> 4; - context.stack_off = DEFAULT_STACK_SIZE; - - /* - Allocate the return to 32 bit routine - */ - m = LRMI_alloc_real(2); - - context.ret_seg = (unsigned int)m >> 4; - context.ret_off = (unsigned int)m & 0xf; - - ((unsigned char *)m)[0] = 0xcd; /* int opcode */ - ((unsigned char *)m)[1] = RETURN_TO_32_INT; - - memset(&context.vm, 0, sizeof(context.vm)); - - /* - Enable kernel emulation of all ints except RETURN_TO_32_INT - */ - memset(&context.vm.int_revectored, 0, sizeof(context.vm.int_revectored)); - set_bit(RETURN_TO_32_INT, &context.vm.int_revectored); - - context.ready = 1; - - return 1; - } - - -static void -set_regs(struct LRMI_regs *r) - { - context.vm.regs.edi = r->edi; - context.vm.regs.esi = r->esi; - context.vm.regs.ebp = r->ebp; - context.vm.regs.ebx = r->ebx; - context.vm.regs.edx = r->edx; - context.vm.regs.ecx = r->ecx; - context.vm.regs.eax = r->eax; - context.vm.regs.eflags = DEFAULT_VM86_FLAGS; - context.vm.regs.es = r->es; - context.vm.regs.ds = r->ds; - context.vm.regs.fs = r->fs; - context.vm.regs.gs = r->gs; - } - - -static void -get_regs(struct LRMI_regs *r) - { - r->edi = context.vm.regs.edi; - r->esi = context.vm.regs.esi; - r->ebp = context.vm.regs.ebp; - r->ebx = context.vm.regs.ebx; - r->edx = context.vm.regs.edx; - r->ecx = context.vm.regs.ecx; - r->eax = context.vm.regs.eax; - r->flags = context.vm.regs.eflags; - r->es = context.vm.regs.es; - r->ds = context.vm.regs.ds; - r->fs = context.vm.regs.fs; - r->gs = context.vm.regs.gs; - } - -#define DIRECTION_FLAG (1 << 10) - -static void -em_ins(int size) - { - unsigned int edx, edi; - - edx = context.vm.regs.edx & 0xffff; - edi = context.vm.regs.edi & 0xffff; - edi += (unsigned int)context.vm.regs.ds << 4; - - if (context.vm.regs.eflags & DIRECTION_FLAG) - { - if (size == 4) - asm volatile ("std; insl; cld" - : "=D" (edi) : "d" (edx), "0" (edi)); - else if (size == 2) - asm volatile ("std; insw; cld" - : "=D" (edi) : "d" (edx), "0" (edi)); - else - asm volatile ("std; insb; cld" - : "=D" (edi) : "d" (edx), "0" (edi)); - } - else - { - if (size == 4) - asm volatile ("cld; insl" - : "=D" (edi) : "d" (edx), "0" (edi)); - else if (size == 2) - asm volatile ("cld; insw" - : "=D" (edi) : "d" (edx), "0" (edi)); - else - asm volatile ("cld; insb" - : "=D" (edi) : "d" (edx), "0" (edi)); - } - - edi -= (unsigned int)context.vm.regs.ds << 4; - - context.vm.regs.edi &= 0xffff0000; - context.vm.regs.edi |= edi & 0xffff; - } - -static void -em_rep_ins(int size) - { - unsigned int ecx, edx, edi; - - ecx = context.vm.regs.ecx & 0xffff; - edx = context.vm.regs.edx & 0xffff; - edi = context.vm.regs.edi & 0xffff; - edi += (unsigned int)context.vm.regs.ds << 4; - - if (context.vm.regs.eflags & DIRECTION_FLAG) - { - if (size == 4) - asm volatile ("std; rep; insl; cld" - : "=D" (edi), "=c" (ecx) - : "d" (edx), "0" (edi), "1" (ecx)); - else if (size == 2) - asm volatile ("std; rep; insw; cld" - : "=D" (edi), "=c" (ecx) - : "d" (edx), "0" (edi), "1" (ecx)); - else - asm volatile ("std; rep; insb; cld" - : "=D" (edi), "=c" (ecx) - : "d" (edx), "0" (edi), "1" (ecx)); - } - else - { - if (size == 4) - asm volatile ("cld; rep; insl" - : "=D" (edi), "=c" (ecx) - : "d" (edx), "0" (edi), "1" (ecx)); - else if (size == 2) - asm volatile ("cld; rep; insw" - : "=D" (edi), "=c" (ecx) - : "d" (edx), "0" (edi), "1" (ecx)); - else - asm volatile ("cld; rep; insb" - : "=D" (edi), "=c" (ecx) - : "d" (edx), "0" (edi), "1" (ecx)); - } - - edi -= (unsigned int)context.vm.regs.ds << 4; - - context.vm.regs.edi &= 0xffff0000; - context.vm.regs.edi |= edi & 0xffff; - - context.vm.regs.ecx &= 0xffff0000; - context.vm.regs.ecx |= ecx & 0xffff; - } - -static void -em_outs(int size) - { - unsigned int edx, esi; - - edx = context.vm.regs.edx & 0xffff; - esi = context.vm.regs.esi & 0xffff; - esi += (unsigned int)context.vm.regs.ds << 4; - - if (context.vm.regs.eflags & DIRECTION_FLAG) - { - if (size == 4) - asm volatile ("std; outsl; cld" - : "=S" (esi) : "d" (edx), "0" (esi)); - else if (size == 2) - asm volatile ("std; outsw; cld" - : "=S" (esi) : "d" (edx), "0" (esi)); - else - asm volatile ("std; outsb; cld" - : "=S" (esi) : "d" (edx), "0" (esi)); - } - else - { - if (size == 4) - asm volatile ("cld; outsl" - : "=S" (esi) : "d" (edx), "0" (esi)); - else if (size == 2) - asm volatile ("cld; outsw" - : "=S" (esi) : "d" (edx), "0" (esi)); - else - asm volatile ("cld; outsb" - : "=S" (esi) : "d" (edx), "0" (esi)); - } - - esi -= (unsigned int)context.vm.regs.ds << 4; - - context.vm.regs.esi &= 0xffff0000; - context.vm.regs.esi |= esi & 0xffff; - } - -static void -em_rep_outs(int size) - { - unsigned int ecx, edx, esi; - - ecx = context.vm.regs.ecx & 0xffff; - edx = context.vm.regs.edx & 0xffff; - esi = context.vm.regs.esi & 0xffff; - esi += (unsigned int)context.vm.regs.ds << 4; - - if (context.vm.regs.eflags & DIRECTION_FLAG) - { - if (size == 4) - asm volatile ("std; rep; outsl; cld" - : "=S" (esi), "=c" (ecx) - : "d" (edx), "0" (esi), "1" (ecx)); - else if (size == 2) - asm volatile ("std; rep; outsw; cld" - : "=S" (esi), "=c" (ecx) - : "d" (edx), "0" (esi), "1" (ecx)); - else - asm volatile ("std; rep; outsb; cld" - : "=S" (esi), "=c" (ecx) - : "d" (edx), "0" (esi), "1" (ecx)); - } - else - { - if (size == 4) - asm volatile ("cld; rep; outsl" - : "=S" (esi), "=c" (ecx) - : "d" (edx), "0" (esi), "1" (ecx)); - else if (size == 2) - asm volatile ("cld; rep; outsw" - : "=S" (esi), "=c" (ecx) - : "d" (edx), "0" (esi), "1" (ecx)); - else - asm volatile ("cld; rep; outsb" - : "=S" (esi), "=c" (ecx) - : "d" (edx), "0" (esi), "1" (ecx)); - } - - esi -= (unsigned int)context.vm.regs.ds << 4; - - context.vm.regs.esi &= 0xffff0000; - context.vm.regs.esi |= esi & 0xffff; - - context.vm.regs.ecx &= 0xffff0000; - context.vm.regs.ecx |= ecx & 0xffff; - } - -static void -em_inbl(unsigned char literal) - { - context.vm.regs.eax = inb(literal) & 0xff; - } - -static void -em_inb(void) - { - asm volatile ("inb (%w1), %b0" - : "=a" (context.vm.regs.eax) - : "d" (context.vm.regs.edx), "0" (context.vm.regs.eax)); - } - -static void -em_inw(void) - { - asm volatile ("inw (%w1), %w0" - : "=a" (context.vm.regs.eax) - : "d" (context.vm.regs.edx), "0" (context.vm.regs.eax)); - } - -static void -em_inl(void) - { - asm volatile ("inl (%w1), %0" - : "=a" (context.vm.regs.eax) - : "d" (context.vm.regs.edx)); - } - -static void -em_outbl(unsigned char literal) - { - outb(context.vm.regs.eax & 0xff, literal); - } - -static void -em_outb(void) - { - asm volatile ("outb %b0, (%w1)" - : : "a" (context.vm.regs.eax), - "d" (context.vm.regs.edx)); - } - -static void -em_outw(void) - { - asm volatile ("outw %w0, (%w1)" - : : "a" (context.vm.regs.eax), - "d" (context.vm.regs.edx)); - } - -static void -em_outl(void) - { - asm volatile ("outl %0, (%w1)" - : : "a" (context.vm.regs.eax), - "d" (context.vm.regs.edx)); - } - -static int -emulate(void) - { - unsigned char *insn; - struct - { - unsigned int size : 1; - unsigned int rep : 1; - } prefix = { 0, 0 }; - int i = 0; - - insn = (unsigned char *)((unsigned int)context.vm.regs.cs << 4); - insn += context.vm.regs.eip; - - while (1) - { - if (insn[i] == 0x66) - { - prefix.size = 1 - prefix.size; - i++; - } - else if (insn[i] == 0xf3) - { - prefix.rep = 1; - i++; - } - else if (insn[i] == 0xf0 || insn[i] == 0xf2 - || insn[i] == 0x26 || insn[i] == 0x2e - || insn[i] == 0x36 || insn[i] == 0x3e - || insn[i] == 0x64 || insn[i] == 0x65 - || insn[i] == 0x67) - { - /* these prefixes are just ignored */ - i++; - } - else if (insn[i] == 0x6c) - { - if (prefix.rep) - em_rep_ins(1); - else - em_ins(1); - i++; - break; - } - else if (insn[i] == 0x6d) - { - if (prefix.rep) - { - if (prefix.size) - em_rep_ins(4); - else - em_rep_ins(2); - } - else - { - if (prefix.size) - em_ins(4); - else - em_ins(2); - } - i++; - break; - } - else if (insn[i] == 0x6e) - { - if (prefix.rep) - em_rep_outs(1); - else - em_outs(1); - i++; - break; - } - else if (insn[i] == 0x6f) - { - if (prefix.rep) - { - if (prefix.size) - em_rep_outs(4); - else - em_rep_outs(2); - } - else - { - if (prefix.size) - em_outs(4); - else - em_outs(2); - } - i++; - break; - } - else if (insn[i] == 0xe4) - { - em_inbl(insn[i + 1]); - i += 2; - break; - } - else if (insn[i] == 0xe6) - { - em_outbl(insn[i + 1]); - i += 2; - break; - } - else if (insn[i] == 0xec) - { - em_inb(); - i++; - break; - } - else if (insn[i] == 0xed) - { - if (prefix.size) - em_inl(); - else - em_inw(); - i++; - break; - } - else if (insn[i] == 0xee) - { - em_outb(); - i++; - break; - } - else if (insn[i] == 0xef) - { - if (prefix.size) - em_outl(); - else - em_outw(); - - i++; - break; - } - else - return 0; - } - - context.vm.regs.eip += i; - return 1; - } - - -/* - I don't know how to make sure I get the right vm86() from libc. - The one I want is syscall # 113 (vm86old() in libc 5, vm86() in glibc) - which should be declared as "int vm86(struct vm86_struct *);" in - <sys/vm86.h>. - - This just does syscall 113 with inline asm, which should work - for both libc's (I hope). -*/ -#if !defined(USE_LIBC_VM86) -static int -lrmi_vm86(struct vm86_struct *vm) - { - int r; -#if 1 - asm volatile ( - "pushl %%ebx\n\t" - "movl %2, %%ebx\n\t" - "int $0x80\n\t" - "popl %%ebx" - : "=a" (r) - : "0" (113), "r" (vm)); -#else - asm volatile ( - "int $0x80" - : "=a" (r) - : "0" (113), "b" (vm)); -#endif - return r; - } -#else -#define lrmi_vm86 vm86 -#endif - -static int -run_vm86(void) - { - unsigned int vret; - - while (1) - { - vret = lrmi_vm86(&context.vm); - - if (VM86_TYPE(vret) == VM86_INTx) - { - unsigned int v = VM86_ARG(vret); - - if (v == RETURN_TO_32_INT) - return 1; - - pushw(context.vm.regs.eflags); - pushw(context.vm.regs.cs); - pushw(context.vm.regs.eip); - - context.vm.regs.cs = get_int_seg(v); - context.vm.regs.eip = get_int_off(v); - context.vm.regs.eflags &= ~(VIF_MASK | TF_MASK); - - continue; - } - - if (VM86_TYPE(vret) != VM86_UNKNOWN) - break; - - if (!emulate()) - break; - } - - return 0; - } - - -int -LRMI_call(struct LRMI_regs *r) - { - unsigned int vret; - - memset(&context.vm.regs, 0, sizeof(context.vm.regs)); - - set_regs(r); - - context.vm.regs.cs = r->cs; - context.vm.regs.eip = r->ip; - - if (r->ss == 0 && r->sp == 0) - { - context.vm.regs.ss = context.stack_seg; - context.vm.regs.esp = context.stack_off; - } - else - { - context.vm.regs.ss = r->ss; - context.vm.regs.esp = r->sp; - } - - pushw(context.ret_seg); - pushw(context.ret_off); - - vret = run_vm86(); - - get_regs(r); - - return vret; - } - - -int -LRMI_int(int i, struct LRMI_regs *r) - { - unsigned int vret; - unsigned int seg, off; - - seg = get_int_seg(i); - off = get_int_off(i); - - /* - If the interrupt is in regular memory, it's probably - still pointing at a dos TSR (which is now gone). - */ - if (seg < 0xa000 || (seg << 4) + off >= 0x100000) - { -#ifdef ORIGINAL_LRMI_CODE_THAT_GOT_IFDEFED_OUT - fprintf(stderr, "Int 0x%x is not in rom (%04x:%04x)\n", i, seg, off); -#endif - return 0; - } - - memset(&context.vm.regs, 0, sizeof(context.vm.regs)); - - set_regs(r); - - context.vm.regs.cs = seg; - context.vm.regs.eip = off; - - if (r->ss == 0 && r->sp == 0) - { - context.vm.regs.ss = context.stack_seg; - context.vm.regs.esp = context.stack_off; - } - else - { - context.vm.regs.ss = r->ss; - context.vm.regs.esp = r->sp; - } - - pushw(DEFAULT_VM86_FLAGS); - pushw(context.ret_seg); - pushw(context.ret_off); - - vret = run_vm86(); - - get_regs(r); - - return vret; - } - |