git.joshuawise.com / netwatch.git / blame
| Commit | Line | Data |
|---|---|---|
| 3c4e084d JP |
1 | /* packet.c |
| 2 | * OS-to-NetWatch communication packet interface | |
| 3 | * NetWatch system management mode administration console | |
| 4 | * | |
| 5 | * Copyright (c) 2008 Jacob Potter and Joshua Wise. All rights reserved. | |
| 6 | * This program is free software; you can redistribute and/or modify it under | |
| 7 | * the terms found in the file LICENSE in the root of this source tree. | |
| 8 | * | |
| 9 | */ | |
| 10 | ||
| 05c5b136 JP |
11 | #include <stdint.h> |
| 12 | #include "packet.h" | |
| 13 | ||
| 14 | #define PTE_FOR(x) (((unsigned int)(x) >> 12) & 0x3FF) | |
| 15 | #define PDE_FOR(x) ((unsigned int)(x) >> 22) | |
| 16 | #define ADDR_12_MASK(x) ((unsigned int)(x) & ~((1 << 12) - 1)) | |
| 17 | #define ADDR_22_MASK(x) ((unsigned int)(x) & ~((1 << 22) - 1)) | |
| 18 | #define LOWER_12(x) ((unsigned int)(x) & ((1 << 12) - 1)) | |
| 19 | #define LOWER_22(x) ((unsigned int)(x) & ((1 << 22) - 1)) | |
| 20 | ||
| 21 | #define PDE_4M_ADDR_SHIFT 22 | |
| 22 | #define PTE_4K_ADDR_SHIFT 12 | |
| 23 | #define PDE_TABLE_ADDR_SHIFT 12 | |
| 24 | #define PTE_FRAME_ADDR_MASK (~((1 << PTE_4K_ADDR_SHIFT) - 1)) | |
| 25 | #define PDE_TABLE_ADDR_MASK (~((1 << PDE_TABLE_ADDR_SHIFT) - 1)) | |
| 26 | ||
| 27 | #define PDE_ATTRIB_INDEX (1 << 12) | |
| 28 | #define PDE_GLOBAL (1 << 8) | |
| 29 | #define PDE_PAGE_SIZE (1 << 7) | |
| 30 | #define PDE_DIRTY (1 << 6) | |
| 31 | #define PDE_ACCESSED (1 << 5) | |
| 32 | #define PDE_NO_CACHE (1 << 4) | |
| 33 | #define PDE_WRITE_THROUGH (1 << 3) | |
| 34 | #define PDE_USER (1 << 2) | |
| 35 | #define PDE_READ_WRITE (1 << 1) | |
| 36 | #define PDE_PRESENT (1 << 0) | |
| 37 | ||
| 38 | #define PTE_GLOBAL (1 << 8) | |
| 39 | #define PTE_ATTRIB_INDEX (1 << 7) | |
| 40 | #define PTE_DIRTY (1 << 6) | |
| 41 | #define PTE_ACCESSED (1 << 5) | |
| 42 | #define PTE_NO_CACHE (1 << 4) | |
| 43 | #define PTE_WRITE_THROUGH (1 << 3) | |
| 44 | #define PTE_USER (1 << 2) | |
| 45 | #define PTE_READ_WRITE (1 << 1) | |
| 46 | #define PTE_PRESENT (1 << 0) | |
| 47 | ||
| 48 | asm ("get_cr3: mov %cr3, %eax \n ret"); | |
| 49 | uint32_t * get_cr3(); | |
| 50 | ||
| 51 | void * l2p (void * addr) { | |
| 52 | ||
| 53 | uint32_t * cr3 = get_cr3(); | |
| 54 | uint32_t * page_table; | |
| 55 | uint32_t pde, pte; | |
| 56 | ||
| 57 | pde = cr3[PDE_FOR(addr)]; | |
| 58 | ||
| 59 | if (!(pde & PDE_PRESENT)) { | |
| 60 | return 0; | |
| 61 | } | |
| 62 | ||
| 63 | if (pde & PDE_PAGE_SIZE) { | |
| 64 | return (void *)(ADDR_22_MASK(pde) | LOWER_22(addr)); | |
| 65 | } else { | |
| 66 | page_table = (uint32_t *)(ADDR_12_MASK(pde)); | |
| 67 | pte = page_table[PTE_FOR(addr)]; | |
| 68 | ||
| 69 | if (!pte & PTE_PRESENT) { | |
| 70 | return 0; | |
| 71 | } | |
| 72 | return (void *)(ADDR_12_MASK(pte) | LOWER_12(addr)); | |
| 73 | } | |
| 74 | } | |
| 75 | ||
| 76 | packet_t * check_packet (uint32_t logical_base) { | |
| 77 | packet_t * physical_base; | |
| 78 | ||
| 79 | if (LOWER_12(logical_base) != 0) return 0; | |
| 80 | ||
| 81 | physical_base = l2p((void *)logical_base); | |
| 82 | ||
| 83 | if (!physical_base) return 0; | |
| 84 | if (physical_base->signature != 0x1BADD00D) return 0; | |
| 85 | ||
| 86 | return physical_base; | |
| 87 | } |