| 1 | #if defined (__x86_64__) || defined (__i386__) |
| 2 | |
| 3 | #include <stdint.h> |
| 4 | #include <sys/gdt.h> |
| 5 | #include <mm/pmm.h> |
| 6 | #include <lib/libc.h> |
| 7 | |
| 8 | static struct gdt_desc gdt_descs[] = { |
| 9 | {0}, |
| 10 | |
| 11 | { |
| 12 | .limit = 0xffff, |
| 13 | .base_low = 0x0000, |
| 14 | .base_mid = 0x00, |
| 15 | .access = 0b10011011, |
| 16 | .granularity = 0b00000000, |
| 17 | .base_hi = 0x00 |
| 18 | }, |
| 19 | |
| 20 | { |
| 21 | .limit = 0xffff, |
| 22 | .base_low = 0x0000, |
| 23 | .base_mid = 0x00, |
| 24 | .access = 0b10010011, |
| 25 | .granularity = 0b00000000, |
| 26 | .base_hi = 0x00 |
| 27 | }, |
| 28 | |
| 29 | { |
| 30 | .limit = 0xffff, |
| 31 | .base_low = 0x0000, |
| 32 | .base_mid = 0x00, |
| 33 | .access = 0b10011011, |
| 34 | .granularity = 0b11001111, |
| 35 | .base_hi = 0x00 |
| 36 | }, |
| 37 | |
| 38 | { |
| 39 | .limit = 0xffff, |
| 40 | .base_low = 0x0000, |
| 41 | .base_mid = 0x00, |
| 42 | .access = 0b10010011, |
| 43 | .granularity = 0b11001111, |
| 44 | .base_hi = 0x00 |
| 45 | }, |
| 46 | |
| 47 | { |
| 48 | .limit = 0x0000, |
| 49 | .base_low = 0x0000, |
| 50 | .base_mid = 0x00, |
| 51 | .access = 0b10011011, |
| 52 | .granularity = 0b00100000, |
| 53 | .base_hi = 0x00 |
| 54 | }, |
| 55 | |
| 56 | { |
| 57 | .limit = 0x0000, |
| 58 | .base_low = 0x0000, |
| 59 | .base_mid = 0x00, |
| 60 | .access = 0b10010011, |
| 61 | .granularity = 0b00000000, |
| 62 | .base_hi = 0x00 |
| 63 | }, |
| 64 | |
| 65 | { // 0x38: TSS descriptor low (base 0, limit 0) |
| 66 | .limit = 0x0000, |
| 67 | .base_low = 0x0000, |
| 68 | .base_mid = 0x00, |
| 69 | .access = 0x89, |
| 70 | .granularity = 0x00, |
| 71 | .base_hi = 0x00 |
| 72 | }, |
| 73 | {0} // 0x40: TSS descriptor high (base upper = 0) |
| 74 | }; |
| 75 | |
| 76 | #if defined (BIOS) |
| 77 | __attribute__((section(".realmode"))) |
| 78 | #endif |
| 79 | struct gdtr gdt = { |
| 80 | sizeof(gdt_descs) - 1, |
| 81 | (uintptr_t)gdt_descs, |
| 82 | #if defined (__i386__) |
| 83 | 0 |
| 84 | #endif |
| 85 | }; |
| 86 | |
| 87 | #if defined (UEFI) |
| 88 | void init_gdt(void) { |
| 89 | struct gdt_desc *gdt_copy = ext_mem_alloc(sizeof(gdt_descs)); |
| 90 | memcpy(gdt_copy, gdt_descs, sizeof(gdt_descs)); |
| 91 | gdt.ptr = (uintptr_t)gdt_copy; |
| 92 | } |
| 93 | #endif |
| 94 | |
| 95 | #endif |
