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// 16bit system callbacks
//
// Copyright (C) 2008 Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2002 MandrakeSoft S.A.
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include "util.h" // irq_restore
#include "biosvar.h" // CONFIG_BIOS_TABLE
#include "ioport.h" // inb
#include "cmos.h" // inb_cmos
// Use PS2 System Control port A to set A20 enable
static inline u8
set_a20(u8 cond)
{
// get current setting first
u8 newval, oldval = inb(PORT_A20);
if (cond)
newval = oldval | 0x02;
else
newval = oldval & ~0x02;
outb(newval, PORT_A20);
return (newval & 0x02) != 0;
}
static void
handle_152400(struct bregs *regs)
{
set_a20(0);
handle_ret(regs, 0);
}
static void
handle_152401(struct bregs *regs)
{
set_a20(1);
handle_ret(regs, 0);
}
static void
handle_152402(struct bregs *regs)
{
regs->al = !!(inb(PORT_A20) & 0x20);
handle_ret(regs, 0);
}
static void
handle_152403(struct bregs *regs)
{
regs->bx = 3;
handle_ret(regs, 0);
}
static void
handle_1524XX(struct bregs *regs)
{
handle_ret(regs, RET_EUNSUPPORTED);
}
// removable media eject
static void
handle_1552(struct bregs *regs)
{
handle_ret(regs, 0);
}
static void
handle_1553(struct bregs *regs)
{
// XXX - APM call
handle_ret(regs, RET_EUNSUPPORTED);
}
// Sleep for n microseconds. currently using the
// refresh request port 0x61 bit4, toggling every 15usec
static void
usleep(u32 count)
{
count = count / 15;
u8 kbd = inb(PORT_KBD_CTRLB);
while (count)
if ((inb(PORT_KBD_CTRLB) ^ kbd) & KBD_REFRESH)
count--;
}
// Wait for CX:DX microseconds. currently using the
// refresh request port 0x61 bit4, toggling every 15usec
static void
handle_1586(struct bregs *regs)
{
irq_enable();
usleep((regs->cx << 16) | regs->dx);
irq_disable();
}
static void
handle_1587(struct bregs *regs)
{
// +++ should probably have descriptor checks
// +++ should have exception handlers
// turn off interrupts
unsigned long flags = irq_save();
u8 prev_a20_enable = set_a20(1); // enable A20 line
// 128K max of transfer on 386+ ???
// source == destination ???
// ES:SI points to descriptor table
// offset use initially comments
// ==============================================
// 00..07 Unused zeros Null descriptor
// 08..0f GDT zeros filled in by BIOS
// 10..17 source ssssssss source of data
// 18..1f dest dddddddd destination of data
// 20..27 CS zeros filled in by BIOS
// 28..2f SS zeros filled in by BIOS
//es:si
//eeee0
//0ssss
//-----
// check for access rights of source & dest here
// Initialize GDT descriptor
u16 si = regs->si;
u16 base15_00 = (regs->es << 4) + si;
u16 base23_16 = regs->es >> 12;
if (base15_00 < (regs->es<<4))
base23_16++;
SET_VAR(ES, *(u16*)(si+0x08+0), 47); // limit 15:00 = 6 * 8bytes/descriptor
SET_VAR(ES, *(u16*)(si+0x08+2), base15_00);// base 15:00
SET_VAR(ES, *(u8 *)(si+0x08+4), base23_16);// base 23:16
SET_VAR(ES, *(u8 *)(si+0x08+5), 0x93); // access
SET_VAR(ES, *(u16*)(si+0x08+6), 0x0000); // base 31:24/reserved/limit 19:16
// Initialize CS descriptor
SET_VAR(ES, *(u16*)(si+0x20+0), 0xffff);// limit 15:00 = normal 64K limit
SET_VAR(ES, *(u16*)(si+0x20+2), 0x0000);// base 15:00
SET_VAR(ES, *(u8 *)(si+0x20+4), 0x000f);// base 23:16
SET_VAR(ES, *(u8 *)(si+0x20+5), 0x9b); // access
SET_VAR(ES, *(u16*)(si+0x20+6), 0x0000);// base 31:24/reserved/limit 19:16
// Initialize SS descriptor
u16 ss = GET_SEG(SS);
base15_00 = ss << 4;
base23_16 = ss >> 12;
SET_VAR(ES, *(u16*)(si+0x28+0), 0xffff); // limit 15:00 = normal 64K limit
SET_VAR(ES, *(u16*)(si+0x28+2), base15_00);// base 15:00
SET_VAR(ES, *(u8 *)(si+0x28+4), base23_16);// base 23:16
SET_VAR(ES, *(u8 *)(si+0x28+5), 0x93); // access
SET_VAR(ES, *(u16*)(si+0x28+6), 0x0000); // base 31:24/reserved/limit 19:16
asm volatile(
// Save registers
"pushw %%ds\n"
"pushw %%es\n"
"pushal\n"
// Load new descriptor tables
"lgdt %%es:(%1)\n"
"lidt %%cs:pmode_IDT_info\n"
// set PE bit in CR0
"movl %%cr0, %%eax\n"
"orb $0x01, %%al\n"
"movl %%eax, %%cr0\n"
// far jump to flush CPU queue after transition to protected mode
"ljmpw $0xf000, $1f\n"
"1:\n"
// GDT points to valid descriptor table, now load DS, ES
"movw $0x10, %%ax\n" // 010 000 = 2nd descriptor in table, TI=GDT, RPL=00
"movw %%ax, %%ds\n"
"movw $0x18, %%ax\n" // 011 000 = 3rd descriptor in table, TI=GDT, RPL=00
"movw %%ax, %%es\n"
// move CX words from DS:SI to ES:DI
"xorw %%si, %%si\n"
"xorw %%di, %%di\n"
"cld\n"
"rep movsw\n"
// reset PG bit in CR0 ???
"movl %%cr0, %%eax\n"
"andb $0xfe, %%al\n"
"movl %%eax, %%cr0\n"
// far jump to flush CPU queue after transition to real mode
"ljmpw $0xf000, $2f\n"
"2:\n"
// restore IDT to normal real-mode defaults
"lidt %%cs:rmode_IDT_info\n"
// restore regisers
"popal\n"
"popw %%es\n"
"popw %%ds\n" : : "c" (regs->cx), "r" (si + 8));
set_a20(prev_a20_enable);
irq_restore(flags);
handle_ret(regs, 0);
}
// Get the amount of extended memory (above 1M)
static void
handle_1588(struct bregs *regs)
{
regs->al = inb_cmos(CMOS_EXTMEM_LOW);
regs->ah = inb_cmos(CMOS_EXTMEM_HIGH);
// According to Ralf Brown's interrupt the limit should be 15M,
// but real machines mostly return max. 63M.
if (regs->ax > 0xffc0)
regs->ax = 0xffc0;
set_cf(regs, 0);
}
// Device busy interrupt. Called by Int 16h when no key available
static void
handle_1590(struct bregs *regs)
{
}
// Interrupt complete. Called by Int 16h when key becomes available
static void
handle_1591(struct bregs *regs)
{
}
// keyboard intercept
static void
handle_154f(struct bregs *regs)
{
set_cf(regs, 1);
}
static void
handle_15c0(struct bregs *regs)
{
regs->es = SEG_BIOS;
regs->bx = (u16)&BIOS_CONFIG_TABLE;
}
static void
handle_15c1(struct bregs *regs)
{
regs->es = GET_BDA(ebda_seg);
set_cf(regs, 0);
}
static void
handle_15e801(struct bregs *regs)
{
// my real system sets ax and bx to 0
// this is confirmed by Ralph Brown list
// but syslinux v1.48 is known to behave
// strangely if ax is set to 0
// regs.u.r16.ax = 0;
// regs.u.r16.bx = 0;
// Get the amount of extended memory (above 1M)
regs->cl = inb_cmos(CMOS_EXTMEM_LOW);
regs->ch = inb_cmos(CMOS_EXTMEM_HIGH);
// limit to 15M
if (regs->cx > 0x3c00)
regs->cx = 0x3c00;
// Get the amount of extended memory above 16M in 64k blocs
regs->dl = inb_cmos(CMOS_EXTMEM2_LOW);
regs->dh = inb_cmos(CMOS_EXTMEM2_HIGH);
// Set configured memory equal to extended memory
regs->ax = regs->cx;
regs->bx = regs->dx;
set_cf(regs, 0);
}
#define ACPI_DATA_SIZE 0x00010000L
static void
set_e820_range(u16 DI, u32 start, u32 end, u16 type)
{
SET_VAR(ES, *(u16*)(DI+0), start);
SET_VAR(ES, *(u16*)(DI+2), start >> 16);
SET_VAR(ES, *(u16*)(DI+4), 0x00);
SET_VAR(ES, *(u16*)(DI+6), 0x00);
end -= start;
SET_VAR(ES, *(u16*)(DI+8), end);
SET_VAR(ES, *(u16*)(DI+10), end >> 16);
SET_VAR(ES, *(u16*)(DI+12), 0x0000);
SET_VAR(ES, *(u16*)(DI+14), 0x0000);
SET_VAR(ES, *(u16*)(DI+16), type);
SET_VAR(ES, *(u16*)(DI+18), 0x0);
}
// XXX - should create e820 memory map in post and just copy it here.
static void
handle_15e820(struct bregs *regs)
{
if (regs->edx != 0x534D4150) {
handle_ret(regs, RET_EUNSUPPORTED);
return;
}
u32 extended_memory_size = inb_cmos(CMOS_EXTMEM2_HIGH);
extended_memory_size <<= 8;
extended_memory_size |= inb_cmos(CMOS_EXTMEM2_LOW);
extended_memory_size *= 64;
// greater than EFF00000???
if (extended_memory_size > 0x3bc000)
// everything after this is reserved memory until we get to 0x100000000
extended_memory_size = 0x3bc000;
extended_memory_size *= 1024;
extended_memory_size += (16L * 1024 * 1024);
if (extended_memory_size <= (16L * 1024 * 1024)) {
extended_memory_size = inb_cmos(CMOS_EXTMEM_HIGH);
extended_memory_size <<= 8;
extended_memory_size |= inb_cmos(CMOS_EXTMEM_LOW);
extended_memory_size *= 1024;
}
switch (regs->bx) {
case 0:
set_e820_range(regs->di, 0x0000000L, 0x0009fc00L, 1);
regs->ebx = 1;
regs->eax = 0x534D4150;
regs->ecx = 0x14;
set_cf(regs, 0);
break;
case 1:
set_e820_range(regs->di, 0x0009fc00L, 0x000a0000L, 2);
regs->ebx = 2;
regs->eax = 0x534D4150;
regs->ecx = 0x14;
set_cf(regs, 0);
break;
case 2:
set_e820_range(regs->di, 0x000e8000L, 0x00100000L, 2);
regs->ebx = 3;
regs->eax = 0x534D4150;
regs->ecx = 0x14;
set_cf(regs, 0);
break;
case 3:
set_e820_range(regs->di, 0x00100000L,
extended_memory_size - ACPI_DATA_SIZE, 1);
regs->ebx = 4;
regs->eax = 0x534D4150;
regs->ecx = 0x14;
set_cf(regs, 0);
break;
case 4:
set_e820_range(regs->di,
extended_memory_size - ACPI_DATA_SIZE,
extended_memory_size, 3); // ACPI RAM
regs->ebx = 5;
regs->eax = 0x534D4150;
regs->ecx = 0x14;
set_cf(regs, 0);
break;
case 5:
/* 256KB BIOS area at the end of 4 GB */
set_e820_range(regs->di, 0xfffc0000L, 0x00000000L, 2);
regs->ebx = 0;
regs->eax = 0x534D4150;
regs->ecx = 0x14;
set_cf(regs, 0);
break;
default: /* AX=E820, DX=534D4150, BX unrecognized */
handle_ret(regs, RET_EUNSUPPORTED);
}
}
static void
handle_15e8XX(struct bregs *regs)
{
handle_ret(regs, RET_EUNSUPPORTED);
}
static void
handle_15XX(struct bregs *regs)
{
handle_ret(regs, RET_EUNSUPPORTED);
}
// INT 15h System Services Entry Point
void VISIBLE
handle_15(struct bregs *regs)
{
debug_enter(regs);
switch (regs->ah) {
case 0x24:
switch (regs->al) {
case 0x00: handle_152400(regs); break;
case 0x01: handle_152401(regs); break;
case 0x02: handle_152402(regs); break;
case 0x03: handle_152403(regs); break;
default: handle_1524XX(regs); break;
}
break;
case 0x4f: handle_154f(regs); break;
case 0x52: handle_1552(regs); break;
case 0x53: handle_1553(regs); break;
case 0x83: handle_1583(regs); break;
case 0x86: handle_1586(regs); break;
case 0x87: handle_1587(regs); break;
case 0x88: handle_1588(regs); break;
case 0x90: handle_1590(regs); break;
case 0x91: handle_1591(regs); break;
case 0xc0: handle_15c0(regs); break;
case 0xc1: handle_15c1(regs); break;
case 0xc2: handle_15c2(regs); break;
case 0xe8:
switch (regs->al) {
case 0x01: handle_15e801(regs); break;
case 0x20: handle_15e820(regs); break;
default: handle_15e8XX(regs); break;
}
break;
default: handle_15XX(regs); break;
}
debug_exit(regs);
}
// INT 12h Memory Size Service Entry Point
void VISIBLE
handle_12(struct bregs *regs)
{
debug_enter(regs);
regs->ax = GET_BDA(mem_size_kb);
debug_exit(regs);
}
// INT 11h Equipment List Service Entry Point
void VISIBLE
handle_11(struct bregs *regs)
{
debug_enter(regs);
regs->ax = GET_BDA(equipment_list_flags);
debug_exit(regs);
}
// INT 05h Print Screen Service Entry Point
void VISIBLE
handle_05(struct bregs *regs)
{
debug_enter(regs);
}
// INT 10h Video Support Service Entry Point
void VISIBLE
handle_10(struct bregs *regs)
{
debug_enter(regs);
// dont do anything, since the VGA BIOS handles int10h requests
}
void VISIBLE
handle_nmi(struct bregs *regs)
{
debug_enter(regs);
// XXX
}
// INT 75 - IRQ13 - MATH COPROCESSOR EXCEPTION
void VISIBLE
handle_75(struct bregs *regs)
{
debug_enter(regs);
// clear irq13
outb(0, PORT_MATH_CLEAR);
// clear interrupt
eoi_both_pics();
// legacy nmi call
struct bregs br;
memset(&br, 0, sizeof(br));
call16_int(0x02, &br);
}