| | 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 | |
| | 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 | } |
git.joshuawise.com / netwatch.git / blame_incremental