lrmi.c

超强的嵌入式GUI系统

/*
Linux Real Mode Interface - A library of DPMI-like functions for Linux.

Copyright (C) 1998 by Josh Vanderhoof

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL JOSH VANDERHOOF BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
*/

#if defined(__i386__) && (defined(__linux__) || defined(__NetBSD__) \
	|| defined(__FreeBSD__) || defined(__OpenBSD__))

#include <stdio.h>
#include <string.h>

#if defined(__linux__)

#include <asm/vm86.h>
#include <signal.h>

#ifdef USE_LIBC_VM86
#include <sys/vm86.h>
#endif

#elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)

#include <sys/param.h>
#include <signal.h>
#include <setjmp.h>
#include <machine/psl.h>
#include <machine/vm86.h>
#include <machine/sysarch.h>

#endif /* __NetBSD__ || __FreeBSD__ || __OpenBSD__ */

#if defined(__FreeBSD__)
#include <sys/ucontext.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 	0x40000
#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
read_file(char *name, void *p, size_t n)
{
	int fd;

	fd = open(name, O_RDONLY);

	if (fd == -1) {
		perror("open");
		return 0;
	}

	if (read(fd, p, n) != n) {
		perror("read");
		close(fd);
		return 0;
	}

	close(fd);

	return 1;
}

static int
map_file(void *start, size_t length, int prot, int flags, char *name, long offset)
{
	void *m;
	int fd;

	fd = open(name, (flags & MAP_SHARED) ? O_RDWR : O_RDONLY);

	if (fd == -1) {
		perror("open");
		return 0;
	}

	m = mmap(start, length, prot, flags, fd, offset);

	if (m == (void *)-1) {
		perror("mmap");
		close(fd);
		return 0;
	}

	close(fd);
	return 1;
}

static int
real_mem_init(void)
{
	if (mem_info.ready)
		return 1;

	if (!map_file((void *)REAL_MEM_BASE, REAL_MEM_SIZE,
	 PROT_READ | PROT_WRITE | PROT_EXEC,
	 MAP_FIXED | MAP_PRIVATE, "/dev/zero", 0))
		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
real_mem_deinit(void)
{
	if (mem_info.ready) {
		munmap((void *)REAL_MEM_BASE, REAL_MEM_SIZE);
		mem_info.ready = 0;
	}
}


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);
	}
}


#if defined(__linux__)
#define DEFAULT_VM86_FLAGS 	(IF_MASK | IOPL_MASK)
#elif defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
#define DEFAULT_VM86_FLAGS  (PSL_I | PSL_IOPL)
#define TF_MASK         PSL_T
#define VIF_MASK        PSL_VIF
#endif
#define DEFAULT_STACK_SIZE 	0x1000
#define RETURN_TO_32_INT 	255

#if defined(__linux__)
#define CONTEXT_REGS	context.vm.regs
#define REG(x)			x
#elif defined(__NetBSD__) || defined(__OpenBSD__)
#define CONTEXT_REGS	context.vm.substr.regs
#define REG(x)			vmsc.sc_ ## x
#elif defined(__FreeBSD__)
#define CONTEXT_REGS	context.vm.uc
#define REG(x)			uc_mcontext.mc_ ## x
#endif

static struct {
	int ready;
	unsigned short ret_seg, ret_off;
	unsigned short stack_seg, stack_off;
#if defined(__linux__) || defined(__NetBSD__) || defined(__OpenBSD__)
	struct vm86_struct vm;
#elif defined(__FreeBSD__)
	struct {
		struct vm86_init_args init;
		ucontext_t uc;
	} vm;
#endif
#if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__OpenBSD__)
	int success;
	jmp_buf env;
	void *old_sighandler;
	int vret;
#endif
} 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)
{
	CONTEXT_REGS.REG(esp) -= 2;
	*(unsigned short *)(((unsigned int)CONTEXT_REGS.REG(ss) << 4) +
		CONTEXT_REGS.REG(esp)) = i;
}


int
LRMI_init(void)
{
	void *m;

	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)
	*/
	if (!map_file((void *)0, 0x502,
	 PROT_READ | PROT_WRITE | PROT_EXEC,
	 MAP_FIXED | MAP_PRIVATE, "/dev/zero", 0)) {
		real_mem_deinit();
		return 0;
	}

	if (!read_file("/dev/mem", (void *)0, 0x502)) {
		munmap((void *)0, 0x502);
		real_mem_deinit();
		return 0;
	}

	if (!map_file((void *)0xa0000, 0x100000 - 0xa0000,
	 PROT_READ | PROT_WRITE,
	 MAP_FIXED | MAP_SHARED, "/dev/mem", 0xa0000)) {
		munmap((void *)0, 0x502);
		real_mem_deinit();
		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
	*/
#if defined(__linux__)
	memset(&context.vm.int_revectored, 0, sizeof(context.vm.int_revectored));
	set_bit(RETURN_TO_32_INT, &context.vm.int_revectored);
#elif defined(__NetBSD__) || defined(__OpenBSD__)
	set_bit(RETURN_TO_32_INT, &context.vm.int_byuser);
#elif defined(__FreeBSD__)
	set_bit(RETURN_TO_32_INT, &context.vm.init.int_map);
#endif

	context.ready = 1;

	return 1;
}


static void
set_regs(struct LRMI_regs *r)
{
	CONTEXT_REGS.REG(edi) = r->edi;
	CONTEXT_REGS.REG(esi) = r->esi;
	CONTEXT_REGS.REG(ebp) = r->ebp;
	CONTEXT_REGS.REG(ebx) = r->ebx;
	CONTEXT_REGS.REG(edx) = r->edx;
	CONTEXT_REGS.REG(ecx) = r->ecx;
	CONTEXT_REGS.REG(eax) = r->eax;
	CONTEXT_REGS.REG(eflags) = DEFAULT_VM86_FLAGS;
	CONTEXT_REGS.REG(es) = r->es;
	CONTEXT_REGS.REG(ds) = r->ds;
	CONTEXT_REGS.REG(fs) = r->fs;
	CONTEXT_REGS.REG(gs) = r->gs;
}


static void
get_regs(struct LRMI_regs *r)
{
	r->edi = CONTEXT_REGS.REG(edi);
	r->esi = CONTEXT_REGS.REG(esi);
	r->ebp = CONTEXT_REGS.REG(ebp);
	r->ebx = CONTEXT_REGS.REG(ebx);
	r->edx = CONTEXT_REGS.REG(edx);
	r->ecx = CONTEXT_REGS.REG(ecx);
	r->eax = CONTEXT_REGS.REG(eax);
	r->flags = CONTEXT_REGS.REG(eflags);
	r->es = CONTEXT_REGS.REG(es);
	r->ds = CONTEXT_REGS.REG(ds);
	r->fs = CONTEXT_REGS.REG(fs);
	r->gs = CONTEXT_REGS.REG(gs);
}

#define DIRECTION_FLAG 	(1 << 10)

enum {
	CSEG = 0x2e, SSEG = 0x36, DSEG = 0x3e,
	ESEG = 0x26, FSEG = 0x64, GSEG = 0x65,
};

static void
em_ins(int size)
{
	unsigned int edx, edi;

	edx = CONTEXT_REGS.REG(edx) & 0xffff;
	edi = CONTEXT_REGS.REG(edi) & 0xffff;
	edi += (unsigned int)CONTEXT_REGS.REG(es) << 4;

	if (CONTEXT_REGS.REG(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_REGS.REG(es) << 4;

	CONTEXT_REGS.REG(edi) &= 0xffff0000;
	CONTEXT_REGS.REG(edi) |= edi & 0xffff;
}

static void
em_rep_ins(int size)
{
	unsigned int cx;

	cx = CONTEXT_REGS.REG(ecx) & 0xffff;

	while (cx--)
		em_ins(size);

	CONTEXT_REGS.REG(ecx) &= 0xffff0000;
}

static void
em_outs(int size, int seg)
{
	unsigned int edx, esi, base;

	edx = CONTEXT_REGS.REG(edx) & 0xffff;
	esi = CONTEXT_REGS.REG(esi) & 0xffff;

	switch (seg) {
	case CSEG: base = CONTEXT_REGS.REG(cs); break;
	case SSEG: base = CONTEXT_REGS.REG(ss); break;
	case ESEG: base = CONTEXT_REGS.REG(es); break;
	case FSEG: base = CONTEXT_REGS.REG(fs); break;
	case GSEG: base = CONTEXT_REGS.REG(gs); break;
	default:
	case DSEG: base = CONTEXT_REGS.REG(ds); break;
	}

	esi += base << 4;

	if (CONTEXT_REGS.REG(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 -= base << 4;

	CONTEXT_REGS.REG(esi) &= 0xffff0000;
	CONTEXT_REGS.REG(esi) |= esi & 0xffff;
}

static void
em_rep_outs(int size, int seg)
{
	unsigned int cx;