| 1 |
/* |
| 2 |
* Copyright (C) 2005 Anders Gavare. All rights reserved. |
| 3 |
* |
| 4 |
* Redistribution and use in source and binary forms, with or without |
| 5 |
* modification, are permitted provided that the following conditions are met: |
| 6 |
* |
| 7 |
* 1. Redistributions of source code must retain the above copyright |
| 8 |
* notice, this list of conditions and the following disclaimer. |
| 9 |
* 2. Redistributions in binary form must reproduce the above copyright |
| 10 |
* notice, this list of conditions and the following disclaimer in the |
| 11 |
* documentation and/or other materials provided with the distribution. |
| 12 |
* 3. The name of the author may not be used to endorse or promote products |
| 13 |
* derived from this software without specific prior written permission. |
| 14 |
* |
| 15 |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| 16 |
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 17 |
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 18 |
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| 19 |
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 20 |
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 21 |
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 22 |
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 23 |
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 24 |
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 25 |
* SUCH DAMAGE. |
| 26 |
* |
| 27 |
* |
| 28 |
* $Id: memory_x86.c,v 1.18 2005/05/29 10:35:11 debug Exp $ |
| 29 |
* |
| 30 |
* Included from cpu_x86.c. |
| 31 |
* |
| 32 |
* |
| 33 |
* TODO: This is basically just a skeleton so far. |
| 34 |
*/ |
| 35 |
|
| 36 |
|
| 37 |
/* |
| 38 |
* translate_address(): |
| 39 |
* |
| 40 |
* Return values: |
| 41 |
* 0 Failure |
| 42 |
* 1 Success, the page is readable only |
| 43 |
* 2 Success, the page is read/write |
| 44 |
*/ |
| 45 |
int TRANSLATE_ADDRESS(struct cpu *cpu, uint64_t vaddr, |
| 46 |
uint64_t *return_addr, int flags) |
| 47 |
{ |
| 48 |
unsigned char pded[4]; |
| 49 |
unsigned char pted[4]; |
| 50 |
uint64_t table_addr; |
| 51 |
uint32_t pte=0, pde=0; |
| 52 |
int a, b, res, writable, usermode = 0; |
| 53 |
int writeflag = flags & FLAG_WRITEFLAG? MEM_WRITE : MEM_READ; |
| 54 |
int no_exceptions = flags & FLAG_NOEXCEPTIONS; |
| 55 |
int no_segmentation = flags & NO_SEGMENTATION; |
| 56 |
struct descriptor_cache *dc; |
| 57 |
|
| 58 |
if (cpu->cd.x86.cursegment < 0 || cpu->cd.x86.cursegment >= 8) { |
| 59 |
fatal("TODO: Weird x86 segment nr %i\n", |
| 60 |
cpu->cd.x86.cursegment); |
| 61 |
cpu->running = 0; |
| 62 |
return 0; |
| 63 |
} |
| 64 |
|
| 65 |
if ((vaddr >> 32) == 0xffffffff) |
| 66 |
vaddr &= 0xffffffff; |
| 67 |
|
| 68 |
dc = &cpu->cd.x86.descr_cache[cpu->cd.x86.cursegment & 7]; |
| 69 |
|
| 70 |
if (no_segmentation) { |
| 71 |
/* linear address */ |
| 72 |
writable = 1; |
| 73 |
} else { |
| 74 |
if (PROTECTED_MODE && vaddr > dc->limit) { |
| 75 |
fatal("TODO: vaddr=0x%llx > limit (0x%llx)\n", |
| 76 |
(long long)vaddr, (long long)dc->limit); |
| 77 |
/* goto fail; */ |
| 78 |
} |
| 79 |
|
| 80 |
/* TODO: Check the Privilege Level */ |
| 81 |
vaddr = (vaddr + dc->base) & 0xffffffff; |
| 82 |
writable = dc->writable; |
| 83 |
} |
| 84 |
|
| 85 |
usermode = (cpu->cd.x86.s[X86_S_CS] & X86_PL_MASK) == |
| 86 |
X86_RING3; |
| 87 |
|
| 88 |
/* Paging: */ |
| 89 |
if (cpu->cd.x86.cr[0] & X86_CR0_PG) { |
| 90 |
/* TODO: This should be cached somewhere, in some |
| 91 |
kind of simulated TLB. */ |
| 92 |
if (cpu->cd.x86.cr[3] & 0xfff) { |
| 93 |
fatal("TODO: cr3=%016llx (lowest bits non-zero)\n", |
| 94 |
(long long)cpu->cd.x86.cr[3]); |
| 95 |
goto fail; |
| 96 |
} |
| 97 |
|
| 98 |
a = (vaddr >> 22) & 1023; |
| 99 |
b = (vaddr >> 12) & 1023; |
| 100 |
/* fatal("vaddr = 0x%08x ==> %i, %i\n", (int)vaddr, a, b); */ |
| 101 |
|
| 102 |
/* Read the Page Directory Entry: */ |
| 103 |
table_addr = cpu->cd.x86.cr[3] & ~0xfff; |
| 104 |
if (table_addr == 0) |
| 105 |
fatal("WARNING: The page directory (cr3) is at" |
| 106 |
" physical address 0 (?)\n"); |
| 107 |
res = cpu->memory_rw(cpu, cpu->mem, table_addr + 4*a, pded, |
| 108 |
sizeof(pded), MEM_READ, PHYSICAL); |
| 109 |
if (!res) { |
| 110 |
fatal("TODO: could not read pde (table = 0x%llx)\n", |
| 111 |
(long long)table_addr); |
| 112 |
goto fail; |
| 113 |
} |
| 114 |
if ((pded[0] & 0x01) && !(pded[0] & 0x20)) { |
| 115 |
pded[0] |= 0x20; |
| 116 |
cpu->memory_rw(cpu, cpu->mem, table_addr + 4*a, pded, |
| 117 |
sizeof(pded), MEM_WRITE, PHYSICAL); |
| 118 |
} |
| 119 |
if ((pded[0] & 0x01) && writeflag == MEM_WRITE && |
| 120 |
!(pded[0] & 0x40)) { |
| 121 |
pded[0] |= 0x40; |
| 122 |
cpu->memory_rw(cpu, cpu->mem, table_addr + 4*a, pded, |
| 123 |
sizeof(pded), MEM_WRITE, PHYSICAL); |
| 124 |
} |
| 125 |
pde = pded[0] + (pded[1] << 8) + (pded[2] << 16) + |
| 126 |
(pded[3] << 24); |
| 127 |
/* fatal(" pde: 0x%08x\n", (int)pde); */ |
| 128 |
/* TODO: lowest bits of the pde */ |
| 129 |
if (!(pde & 0x01)) { |
| 130 |
fatal("PAGE FAULT: pde not present: vaddr=0x%08x, " |
| 131 |
"usermode=%i\n", (int)vaddr, usermode); |
| 132 |
fatal(" CS:EIP = 0x%04x:0x%016llx\n", |
| 133 |
(int)cpu->cd.x86.s[X86_S_CS], |
| 134 |
(long long)cpu->pc); |
| 135 |
if (!no_exceptions) { |
| 136 |
cpu->cd.x86.cr[2] = vaddr; |
| 137 |
x86_interrupt(cpu, 14, (writeflag? 2 : 0) + |
| 138 |
(usermode? 4 : 0)); |
| 139 |
} |
| 140 |
return 0; |
| 141 |
} |
| 142 |
|
| 143 |
/* Read the Page Table Entry: */ |
| 144 |
table_addr = pde & ~0xfff; |
| 145 |
res = cpu->memory_rw(cpu, cpu->mem, table_addr + 4*b, pted, |
| 146 |
sizeof(pted), MEM_READ, PHYSICAL); |
| 147 |
if (!res) { |
| 148 |
fatal("TODO: could not read pte (pt = 0x%llx)\n", |
| 149 |
(long long)table_addr); |
| 150 |
goto fail; |
| 151 |
} |
| 152 |
pte = pted[0] + (pted[1] << 8) + (pted[2] << 16) + |
| 153 |
(pted[3] << 24); |
| 154 |
if ((pted[0] & 0x01) && !(pted[0] & 0x20)) { |
| 155 |
pted[0] |= 0x20; |
| 156 |
cpu->memory_rw(cpu, cpu->mem, table_addr + 4*b, pted, |
| 157 |
sizeof(pted), MEM_WRITE, PHYSICAL); |
| 158 |
} |
| 159 |
if ((pted[0] & 0x01) && writeflag == MEM_WRITE && |
| 160 |
!(pted[0] & 0x40)) { |
| 161 |
pted[0] |= 0x40; |
| 162 |
cpu->memory_rw(cpu, cpu->mem, table_addr + 4*b, pted, |
| 163 |
sizeof(pted), MEM_WRITE, PHYSICAL); |
| 164 |
} |
| 165 |
/* fatal(" pte: 0x%08x\n", (int)pte); */ |
| 166 |
if (!(pte & 0x02)) |
| 167 |
writable = 0; |
| 168 |
if (!(pte & 0x01)) { |
| 169 |
fatal("TODO: pte not present: table_addr=0x%08x " |
| 170 |
"vaddr=0x%08x, usermode=%i wf=%i pte=0x%08x\n", |
| 171 |
(int)table_addr, (int)vaddr, usermode, writeflag, |
| 172 |
(int)pte); |
| 173 |
if (!no_exceptions) { |
| 174 |
cpu->cd.x86.cr[2] = vaddr; |
| 175 |
x86_interrupt(cpu, 14, (writeflag? 2 : 0) |
| 176 |
+ (usermode? 4 : 0)); |
| 177 |
} |
| 178 |
return 0; |
| 179 |
} |
| 180 |
|
| 181 |
(*return_addr) = (pte & ~0xfff) | (vaddr & 0xfff); |
| 182 |
} else |
| 183 |
*return_addr = vaddr; |
| 184 |
|
| 185 |
/* Code: */ |
| 186 |
if (flags & FLAG_INSTR) { |
| 187 |
if (dc->descr_type == DESCR_TYPE_CODE) |
| 188 |
return 1; |
| 189 |
fatal("TODO instr load but not code descriptor?\n"); |
| 190 |
goto fail; |
| 191 |
} |
| 192 |
|
| 193 |
/* We are here on non-instruction fetch. */ |
| 194 |
|
| 195 |
if (writeflag == MEM_WRITE && !writable) { |
| 196 |
if (!usermode && !(cpu->cd.x86.cr[0] & X86_CR0_WP)) { |
| 197 |
/* 80386 compatiblity: allow writes to userspace, |
| 198 |
if we are running in kernel mode. */ |
| 199 |
writable = 1; |
| 200 |
} else { |
| 201 |
fatal("TODO: write to nonwritable segment or page: " |
| 202 |
"vaddr=0x%08x pde=0x%08x pte=0x%08x\n", |
| 203 |
(int)vaddr, (int)pde, (int)pte); |
| 204 |
cpu->cd.x86.cr[2] = vaddr; |
| 205 |
x86_interrupt(cpu, 14, (writeflag? 2 : 0) |
| 206 |
+ (usermode? 4 : 0) + 1); |
| 207 |
return 0; |
| 208 |
} |
| 209 |
} |
| 210 |
|
| 211 |
return 1 + writable; |
| 212 |
|
| 213 |
fail: |
| 214 |
fatal("memory_x86 FAIL: TODO\n"); |
| 215 |
cpu->running = 0; |
| 216 |
return 0; |
| 217 |
} |
| 218 |
|
Parent Directory
| 
Revision Log