WebSVN - shark - Rev 1618 - /shark/branches/xen/arch/x86/vm86.c

/* Project: OSLib
* Description: The OS Construction Kit
* Date: 1.6.2000
* Idea by: Luca Abeni & Gerardo Lamastra
*
* OSLib is an SO project aimed at developing a common, easy-to-use
* low-level infrastructure for developing OS kernels and Embedded
* Applications; it partially derives from the HARTIK project but it
* currently is independently developed.
*
* OSLib is distributed under GPL License, and some of its code has
* been derived from the Linux kernel source; also some important
* ideas come from studying the DJGPP go32 extender.
*
* We acknowledge the Linux Community, Free Software Foundation,
* D.J. Delorie and all the other developers who believe in the
* freedom of software and ideas.
*
* For legalese, check out the included GPL license.
*/

/* File: Vm86.C
*
* VM86 mode switch routines!
* This is basically an alternative way of invoking the
* BIOS service routines; it is very useful to support
* native VBE compliant Video card, without writing an explicit driver
*/

#include <ll/i386/hw-data.h>
#include <ll/i386/hw-instr.h>
#include <ll/i386/hw-func.h>
#include <ll/i386/mem.h>
#include <ll/i386/x-bios.h>
#include <ll/i386/x-dosmem.h>
#include <ll/i386/cons.h>
#include <ll/i386/error.h>
#include <ll/i386/apic.h>
#include <ll/i386/advtimer.h>

FILE(VM-86);

/*
#define __LL_DEBUG__
#define __DUMB_CODE__
#define __CHK_IO__
*/

//#define __LL_DEBUG__

#define VM86_STACK_SIZE 8192

extern DWORD ll_irq_table[256];
extern unsigned char use_apic, use_tsc;

/* TSS optional section */
static BYTE vm86_stack0[VM86_STACK_SIZE];

static BYTE init = 0;

static struct {
TSS t;
DWORD io_map[2048];
} vm86_TSS;
static LIN_ADDR vm86_stack;
static LIN_ADDR vm86_iretAddress;

struct registers *global_regs;
WORD VM86_ret_ctx;

#ifdef __DUMB_CODE__
static LIN_ADDR vm86_code;
static BYTE prova86[] = {
0x1e, /* push ds */
0xb8,0x00,0xb8, /* mov ax,0xb800 */
0x8e,0xd8, /* mov ds,ax */
0xbf,0x9e,0x00, /* mov di,0x009e (158) */
0xb0,0x2a, /* mov ax,'*' */
0x88,0x05, /* mov ds:[di],al */
0x1f, /* pop ds */
0xcd, 0x40, /*???*/
#ifdef __CHK_IO__
0xb0, 0x00, /* movb $0x0,%al*/
0x66,0xba, 0x80, 0x00, /* movw $0x80,%dx */
0x66,0xef, /* outw %ax, (%dx) */
#endif
0xcf, /* iret */
0xf4, /* hlt */
0};
#endif

static BYTE vm86_retAddr[] = {0xcd, 0x48, /* int 48h */
0xf4,
0};

TSS *vm86_get_tss(void)
{
return &(vm86_TSS.t);
}

/* Just a debugging function; it dumps the status of the TSS */
void vm86_dump_TSS(void)
{
BYTE acc,gran;
DWORD base,lim;
message("vm86_TSS.t dump\n");
message("Flag: %lx\n",vm86_TSS.t.eflags);
message("SS: %hx SP:%lx\n", vm86_TSS.t.ss,vm86_TSS.t.esp);
message("Stack0: %hx:%lx\n",vm86_TSS.t.ss0,vm86_TSS.t.esp0);
message("Stack1: %hx:%lx\n",vm86_TSS.t.ss1,vm86_TSS.t.esp1);
message("Stack2: %hx:%lx\n",vm86_TSS.t.ss2,vm86_TSS.t.esp2);
message("CS: %hx IP: %lx",vm86_TSS.t.cs, vm86_TSS.t.eip);
message("DS: %hx\n",vm86_TSS.t.ds);
base = GDT_read(X_VM86_TSS,&lim,&acc,&gran);
message("Base : %lx Lim : %lx Acc : %x Gran %x\n",
base,lim,(unsigned)(acc),(unsigned)(gran));
}

void vm86_init(void)
{
int register i;

if (init != 0) return;
init = 1;

/* First of all, we need to setup a GDT entries to
* allow vm86 task execution. We just need a free 386 TSS, which
* will be used to store the execution context of the virtual 8086
* task
*/
GDT_place(X_VM86_TSS,(DWORD)(&vm86_TSS),
sizeof(vm86_TSS),FREE_TSS386,GRAN_16);

/* Return Registers */
global_regs = DOS_alloc(sizeof(struct registers));

/* Prepare a real-mode stack, obtaining it from the
* DOS memory allocator!
* 8K should be OK! Stack top is vm86_stack + SIZE!
*/
vm86_stack = DOS_alloc(VM86_STACK_SIZE*2);
vm86_stack += VM86_STACK_SIZE/2;

vm86_iretAddress = DOS_alloc(sizeof(vm86_retAddr));
memcpy(vm86_iretAddress,vm86_retAddr,sizeof(vm86_retAddr));
#ifdef __LL_DEBUG__
message("PM reentry linear address=0x%lx\n", (DWORD)vm86_iretAddress);
#endif
#ifdef __DUMB_CODE__
vm86_code = DOS_alloc(2048);
lmemcpy(vm86_code,prova86,sizeof(prova86));
#endif
/* Zero the PM/Ring[1,2] ss:esp; they're unused! */
vm86_TSS.t.esp1 = 0;
vm86_TSS.t.esp2 = 0;
vm86_TSS.t.ss1 = 0;
vm86_TSS.t.ss2 = 0;
/* Use only the GDT */
vm86_TSS.t.ldt = 0;
/* No paging activated */
vm86_TSS.t.cr3 = 0;
vm86_TSS.t.trap = 0;
/* Yeah, free access to any I/O port; we trust BIOS anyway! */
/* Here is the explanation: we have 65536 I/O ports... each bit
* in the io_map masks/unmasks the exception for the given I/O port
* If the bit is set, an exception is generated; otherwise, if the bit
* is clear, everythings works fine...
* Because of alignment problem, we need to add an extra byte all set
* to 1, according to Intel manuals
*/
vm86_TSS.t.io_base = (DWORD)(&(vm86_TSS.io_map)) -
(DWORD)(&(vm86_TSS));
for (i = 0; i < 2047; i++) vm86_TSS.io_map[i] = 0;
vm86_TSS.io_map[2047] = 0xFF000000;
}

int vm86_callBIOS(int service,X_REGS16 *in,X_REGS16 *out,X_SREGS16 *s)
{
DWORD vm86_tmpAddr;
DWORD vm86_flags, vm86_cs,vm86_ip;
LIN_ADDR vm86_stackPtr;
DWORD *IRQTable_entry;
BYTE p1,p2;
DWORD msr1 = 0,msr2 = 0;

SYS_FLAGS f;

if (service < 0x10 || in == NULL) return -1;

f = ll_fsave();

/* Setup the stack frame */
vm86_tmpAddr = (DWORD)(vm86_stack);
vm86_TSS.t.ss = (vm86_tmpAddr & 0xFF000) >> 4;
vm86_TSS.t.ebp = vm86_TSS.t.esp = (vm86_tmpAddr & 0x0FFF)
+ VM86_STACK_SIZE - 6;
/* Build an iret stack frame which returns to vm86_iretAddress */
vm86_tmpAddr = (DWORD)(vm86_iretAddress);
vm86_cs = (vm86_tmpAddr & 0xFF000) >> 4;
vm86_ip = (vm86_tmpAddr & 0xFFF);
vm86_flags = 0;
vm86_stackPtr = vm86_stack + VM86_STACK_SIZE;
lmempokew(vm86_stackPtr-6,vm86_ip);
lmempokew(vm86_stackPtr-4,vm86_cs);
lmempokew(vm86_stackPtr-2,vm86_flags);
#ifdef __LL_DEBUG__
message("Stack: %lx SS: %lx SP: %lx\n",
vm86_tmpAddr + VM86_STACK_SIZE,(DWORD)vm86_TSS.t.ss,vm86_TSS.t.esp);
#endif
/* Wanted VM86 mode + IOPL = 3! */
vm86_TSS.t.eflags = CPU_FLAG_VM + CPU_FLAG_IOPL;
/* Preload some standard values into the registers */
vm86_TSS.t.ss0 = X_FLATDATA_SEL;
vm86_TSS.t.esp0 = (DWORD)&(vm86_stack0[VM86_STACK_SIZE-1]);

#ifdef __DUMB_CODE__
vm86_TSS.t.cs = ((DWORD)(vm86_code) & 0xFFFF0) >> 4;
vm86_TSS.t.eip = ((DWORD)(vm86_code) & 0x000F);
#ifdef __LL_DEBUG_
message("(DUMB CODE) CS:%x IP:%x/%x\n",
(DWORD)vm86_TSS.t.cs,vm86_TSS.t.eip,&prova86);
message("(DUMB CODE) Go...\n");
#endif

p1 = inp(0x21);
p2 = inp(0xA1);
outp(0x21,0xFF);
outp(0xA1,0xFF);

if (use_apic) {
rdmsr(APIC_BASE_MSR,msr1,msr2);
disable_APIC_timer();
}

vm86_TSS.t.back_link = ll_context_save();
VM86_ret_ctx = vm86_TSS.t.back_link
sti();
ll_context_load(X_VM86_TSS);
cli();

if (use_apic) {
wrmsr(APIC_BASE_MSR,msr1,msr2);
enable_APIC_timer();
}

outp(0x21,p1);
outp(0xA1,p2);

#ifdef __LL_DEBUG_
message("(DUMB CODE) I am back...\n");
#endif
#else
/* Copy the parms from the X_*REGS structures in the vm86 TSS */
vm86_TSS.t.eax = (DWORD)in->x.ax;
vm86_TSS.t.ebx = (DWORD)in->x.bx;
vm86_TSS.t.ecx = (DWORD)in->x.cx;
vm86_TSS.t.edx = (DWORD)in->x.dx;
vm86_TSS.t.esi = (DWORD)in->x.si;
vm86_TSS.t.edi = (DWORD)in->x.di;
/* IF Segment registers are required, copy them... */
if (s != NULL) {
vm86_TSS.t.es = (WORD)s->es;
vm86_TSS.t.ds = (WORD)s->ds;
} else {
vm86_TSS.t.ds = vm86_TSS.t.ss;
vm86_TSS.t.es = vm86_TSS.t.ss;
}
vm86_TSS.t.gs = vm86_TSS.t.ss;
vm86_TSS.t.fs = vm86_TSS.t.ss;
/* Execute the BIOS call, fetching the CS:IP of the real interrupt
* handler from 0:0 (DOS irq table!)
*/
IRQTable_entry = (void *)(0L);
vm86_TSS.t.cs= ((IRQTable_entry[service]) & 0xFFFF0000) >> 16;
vm86_TSS.t.eip = ((IRQTable_entry[service]) & 0x0000FFFF);
#ifdef __LL_DEBUG__
message("CS:%x IP:%lx\n", vm86_TSS.t.cs, vm86_TSS.t.eip);
#endif
/* Let's use the ll standard call... */

p1 = inp(0x21);
p2 = inp(0xA1);
outp(0x21,0xFF);
outp(0xA1,0xFF);

if (use_apic) {
rdmsr(APIC_BASE_MSR,msr1,msr2);
disable_APIC_timer();
}

vm86_TSS.t.back_link = ll_context_save();
VM86_ret_ctx = vm86_TSS.t.back_link;
sti();
ll_context_load(X_VM86_TSS);
cli();

if (use_apic) {
wrmsr(APIC_BASE_MSR,msr1,msr2);
enable_APIC_timer();
}

outp(0x21,p1);
outp(0xA1,p2);

#ifdef __LL_DEBUG__
message("I am back...\n");
message("TSS CS=%hx IP=%lx\n", vm86_TSS.t.cs, vm86_TSS.t.eip);
#endif
/* Send back in the X_*REGS structure the value obtained with
* the real-mode interrupt call
*/
if (out != NULL) {

out->x.ax = global_regs->eax;
out->x.bx = global_regs->ebx;
out->x.cx = global_regs->ecx;
out->x.dx = global_regs->edx;
out->x.si = global_regs->esi;
out->x.di = global_regs->edi;
out->x.cflag = global_regs->flags;

//message("ax = %d bx = %d cx = %d dx = %d\n",out->x.ax,out->x.bx,out->x.cx,out->x.dx);
//message("si = %d di = %d\n",out->x.si,out->x.di);

}
if (s != NULL) {
s->es = vm86_TSS.t.es;
s->ds = vm86_TSS.t.ds;
}
#endif

ll_frestore(f);

return 1;

}

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