| #include <stdbool.h> |
| #include "bios.h" |
| #include "stdio.h" |
| #include "e820.h" |
| #include "pci.h" |
| #include "string.h" |
| #include "segment.h" |
| #include "fw_cfg.h" |
| #include "pflash.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) |
| { |
| // NOTE: this runs from ROM at 0xFFFF0000, so it is not possible to use any |
| // static data. |
| |
| 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); |
| |
| // Now go to the F-segment: we need to move away from flash area |
| // in order to probe CBFS! |
| asm("ljmp $0x8, $1f; 1:"); |
| } |
| |
| 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); |
| } |
| |
| /* Top of memory below 4GB. */ |
| uint32_t lowmem; |
| |
| static void extract_e820(void) |
| { |
| int id = fw_cfg_file_id("etc/e820"); |
| uint32_t size; |
| int nr_map; |
| struct e820map *e820; |
| int i; |
| |
| if (id == -1) |
| panic(); |
| |
| size = fw_cfg_file_size(id); |
| nr_map = size / sizeof(e820->map[0]) + 4; |
| fw_cfg_file_select(id); |
| |
| e820 = malloc(offsetof(struct e820map, map[nr_map])); |
| e820->nr_map = nr_map; |
| e820->map[0] = (struct e820entry) |
| { .addr = 0, .size = 639 * 1024, .type = E820_RAM }; /* low RAM */ |
| e820->map[1] = (struct e820entry) |
| { .addr = 639 * 1024, .size = 1024, .type = E820_RESERVED }; /* EBDA */ |
| e820->map[2] = (struct e820entry) |
| { .addr = 0xe0000, .size = 64 * 1024, .type = E820_NVS }; /* ACPI tables */ |
| e820->map[3] = (struct e820entry) |
| { .addr = 0xf0000, .size = 64 * 1024, .type = E820_RESERVED }; /* firmware */ |
| fw_cfg_read(&e820->map[4], size); |
| for (i = 4; i < e820->nr_map; i++) |
| if (e820->map[i].addr == 0) { |
| lowmem = e820->map[i].size; |
| e820->map[i].addr = 1024 * 1024; |
| e820->map[i].size -= 1024 * 1024; |
| break; |
| } |
| |
| e820_seg = ((uintptr_t) e820) >> 4; |
| } |
| |
| static bool detect_cbfs_and_boot(void) |
| { |
| size_t sz; |
| void *base = pflash_base(1, &sz); |
| |
| if (!base) |
| return false; |
| |
| return boot_from_cbfs(base, sz); |
| } |
| |
| int main(void) |
| { |
| make_bios_writable(); |
| setup_pic(); |
| setup_idt(); |
| fw_cfg_setup(); |
| // extract_acpi(); |
| extract_e820(); |
| // extract_smbios(); |
| if (!detect_cbfs_and_boot()) |
| boot_from_fwcfg(); |
| panic(); |
| } |