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#include "bios.h"
#include "pci.h"
#include "string.h"
#include "segment.h"
#define PCI_VENDOR_ID_INTEL 0x8086
#define PCI_DEVICE_ID_INTEL_82441 0x1237
#define PCI_DEVICE_ID_INTEL_Q35_MCH 0x29c0
#define I440FX_PAM0 0x59
#define Q35_HOST_BRIDGE_PAM0 0x90
static void make_bios_writable(void)
{
const int bdf = 0;
const uint8_t *bios_start = (uint8_t *)0xffff0000;
uint8_t *low_start = (uint8_t *)0xf0000;
int pambase;
uint32_t id = pci_config_readl(bdf, 0);
if (id == (PCI_VENDOR_ID_INTEL | (PCI_DEVICE_ID_INTEL_82441 << 16)))
pambase = I440FX_PAM0;
else if (id == (PCI_VENDOR_ID_INTEL | (PCI_DEVICE_ID_INTEL_Q35_MCH << 16)))
pambase = Q35_HOST_BRIDGE_PAM0;
else
panic();
// Make ram from 0xc0000-0xf0000 read-write
int i;
for (i=0; i<6; i++) {
int pam = pambase + 1 + i;
pci_config_writeb(bdf, pam, 0x33);
}
// Make ram from 0xf0000-0x100000 read-write and shadow BIOS
// We're still running from 0xffff0000
pci_config_writeb(bdf, pambase, 0x30);
memcpy(low_start, bios_start, 0x10000);
}
static void set_realmode_int(int vec, void *p)
{
uint16_t *realmode_idt = (uint16_t *) 0;
realmode_idt[vec * 2] = flat_to_off16((uintptr_t) p);
realmode_idt[vec * 2 + 1] = flat_to_seg16((uintptr_t) p);
}
static void setup_pic(void)
{
/* Send ICW1 (select OCW1 + will send ICW4) */
outb(0x20, 0x11);
outb(0xa0, 0x11);
/* Send ICW2 (base irqs: 0x08-0x0f for irq0-7, 0x70-0x77 for irq8-15) */
outb(0x21, 8);
outb(0xa1, 0x70);
/* Send ICW3 (cascaded pic ids) */
outb(0x21, 0x04);
outb(0xa1, 0x02);
/* Send ICW4 (enable 8086 mode) */
outb(0x21, 0x01);
outb(0xa1, 0x01);
/* Mask all irqs (except cascaded PIC2 irq) */
outb(0x21, ~(1 << 2));
outb(0xa1, ~0);
}
static void setup_idt(void)
{
int i;
for (i = 0; i < 0x1f; i++)
set_realmode_int(i, bios_intfake);
for (i = 8; i < 16; i++)
set_realmode_int(i, bios_irq);
for (i = 0x70; i < 0x78; i++)
set_realmode_int(i, bios_irq);
set_realmode_int(0x10, bios_int10);
set_realmode_int(0x15, bios_int15);
}
int main(void)
{
make_bios_writable();
setup_pic();
setup_idt();
// extract_acpi();
// extract_e820();
// extract_smbios();
// extract_kernel();
// make_bios_readonly();
// boot_linux();
panic();
}
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