git.joshuawise.com / netwatch.git / blame
| Commit | Line | Data |
|---|---|---|
| ed22a699 JP |
1 | #include <output.h> |
| 2 | #include <io.h> | |
| 3 | #include <paging.h> | |
| 4 | ||
| 5 | #include "traps.h" | |
| 6 | ||
| 7285933f | 7 | #define CS_SEGSEL 0x8 |
| ed22a699 JP |
8 | |
| 9 | #define FAULT_WRAPPER(func_name) asm ( \ | |
| 10 | ".global " #func_name "_wrapper\n" \ | |
| 11 | #func_name "_wrapper:\n" \ | |
| 12 | "mov %cr2, %eax\n" \ | |
| 13 | "push %eax\n" \ | |
| 14 | "push %esp\n" \ | |
| 15 | "call " #func_name "\n" \ | |
| 16 | ); void func_name##_wrapper(void); | |
| 17 | ||
| 18 | #define WRAPPER_INSTALL(idt, idt4_value, func_name, int_number) { \ | |
| 19 | *(int *)((void *)idt + (8 * int_number)) = \ | |
| 20 | ((int)func_name##_wrapper & 0xFFFF) | \ | |
| 21 | (CS_SEGSEL << 16); \ | |
| 22 | *(int *)((void *)idt + (8 * int_number) + 4) = \ | |
| 23 | ((int)func_name##_wrapper & 0xFFFF0000) | idt4_value; \ | |
| 24 | } | |
| 25 | ||
| 26 | /* The 16 bits at offset 4 from the start of an interrupt gate are a | |
| 27 | * bitfield, according to the Intel spec: | |
| 28 | * 15 P - Segment Present - set to 1 | |
| 29 | * 14-13 DPL - Descriptor privilege level - set to 11 for trap/int, 00 for IPI | |
| 30 | * 12-8 01111 for 32-bit trap gates, 01110 for 32-bit interrupt gates | |
| 31 | * 7-0 Set to 0 | |
| 32 | * Trap: binary 11101111 0000000, hex EF00. | |
| 33 | * Interrupt: binary 11101110 0000000, hex EE00. | |
| 34 | */ | |
| 35 | #define TRAP 0xEF00 | |
| 36 | #define INTERRUPT 0xEE00 | |
| 37 | ||
| 38 | typedef struct trap_t { | |
| 39 | int cr2; | |
| 40 | int error_code; | |
| 41 | int eip; | |
| 42 | int cs; | |
| 43 | int eflags; | |
| 44 | int esp; | |
| 45 | int ss; | |
| 46 | } trap_t; | |
| 47 | ||
| 48 | void die(struct trap_t * trap) { | |
| 49 | outputf("Error %08x %%eip %08x", trap->error_code, trap->eip); | |
| 50 | outputf("%%esp %08x %%eflags %08x", trap->esp, trap->eflags); | |
| 51 | while(1) asm("hlt"); | |
| 52 | } | |
| 53 | ||
| 54 | void fault_gp(struct trap_t * trap) { | |
| 55 | outputf("GENERAL PROTECTION FAULT"); | |
| 56 | die(trap); | |
| 57 | } | |
| 58 | ||
| 59 | void fault_page(struct trap_t * trap) { | |
| 60 | outputf("PAGE FAULT: %08x", trap->cr2); | |
| 61 | die(trap); | |
| 62 | } | |
| 63 | void fault_divide(struct trap_t * trap) { | |
| 64 | outputf("DIVISION FAULT"); | |
| 65 | die(trap); | |
| 66 | } | |
| 67 | void double_fault(struct trap_t * trap) { | |
| 68 | outputf("DOUBLE FAULT"); | |
| 69 | die(trap); | |
| 70 | } | |
| 71 | ||
| 72 | FAULT_WRAPPER(fault_gp); | |
| 73 | FAULT_WRAPPER(fault_page); | |
| 74 | FAULT_WRAPPER(fault_divide); | |
| 75 | FAULT_WRAPPER(double_fault); | |
| 76 | ||
| 77 | /* pseudo_descriptor and x86_gate structs from 15-410 basis code. */ | |
| 78 | ||
| 79 | struct x86_gate { | |
| 80 | unsigned int filler[2]; //64 bits; or 8 bytes. | |
| 81 | }; | |
| 82 | ||
| 83 | static struct x86_gate idt[64]; | |
| 84 | ||
| 85 | struct pseudo_descriptor { | |
| 86 | short pad; | |
| 87 | unsigned short limit; | |
| 88 | unsigned long linear_base; | |
| ea82a4d1 | 89 | } __attribute__((packed)); |
| ed22a699 JP |
90 | |
| 91 | void traps_install(void) { | |
| 92 | ||
| 93 | struct pseudo_descriptor pdesc; | |
| 94 | pdesc.limit = sizeof(idt) - 1; | |
| 923ea2c2 | 95 | pdesc.linear_base = v2p(&idt); |
| ed22a699 JP |
96 | |
| 97 | WRAPPER_INSTALL(idt, TRAP, fault_divide, T_DIVIDE_ERROR); | |
| 98 | WRAPPER_INSTALL(idt, TRAP, fault_gp, T_GENERAL_PROTECTION); | |
| 99 | WRAPPER_INSTALL(idt, TRAP, fault_page, T_PAGE_FAULT); | |
| 100 | WRAPPER_INSTALL(idt, TRAP, double_fault, T_DOUBLE_FAULT); | |
| 101 | ||
| 102 | outb(0x80, 0xCC); | |
| 103 | asm volatile("lidt %0" : : "m" (pdesc.limit)); | |
| 104 | outb(0x80, 0xCD); | |
| 105 | } |