Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 | /*
* linux/arch/i386/mm/init.c
*
* Copyright (C) 1995 Linus Torvalds
*/
#include <linux/config.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/head.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/blk.h>
#endif
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/dma.h>
const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";
extern void die_if_kernel(char *,struct pt_regs *,long);
extern void show_net_buffers(void);
/*
* BAD_PAGE is the page that is used for page faults when linux
* is out-of-memory. Older versions of linux just did a
* do_exit(), but using this instead means there is less risk
* for a process dying in kernel mode, possibly leaving an inode
* unused etc..
*
* BAD_PAGETABLE is the accompanying page-table: it is initialized
* to point to BAD_PAGE entries.
*
* ZERO_PAGE is a special page that is used for zero-initialized
* data and COW.
*/
pte_t * __bad_pagetable(void)
{
extern char empty_bad_page_table[PAGE_SIZE];
__asm__ __volatile__("cld ; rep ; stosl":
:"a" (pte_val(BAD_PAGE)),
"D" ((long) empty_bad_page_table),
"c" (PAGE_SIZE/4)
:"di","cx");
return (pte_t *) empty_bad_page_table;
}
pte_t __bad_page(void)
{
extern char empty_bad_page[PAGE_SIZE];
__asm__ __volatile__("cld ; rep ; stosl":
:"a" (0),
"D" ((long) empty_bad_page),
"c" (PAGE_SIZE/4)
:"di","cx");
return pte_mkdirty(mk_pte((unsigned long) empty_bad_page, PAGE_SHARED));
}
void show_mem(void)
{
int i,free = 0,total = 0,reserved = 0;
int shared = 0;
printk("Mem-info:\n");
show_free_areas();
printk("Free swap: %6dkB\n",nr_swap_pages<<(PAGE_SHIFT-10));
i = max_mapnr;
while (i-- > 0) {
total++;
if (PageReserved(mem_map+i))
reserved++;
else if (!atomic_read(&mem_map[i].count))
free++;
else
shared += atomic_read(&mem_map[i].count) - 1;
}
printk("%d pages of RAM\n",total);
printk("%d free pages\n",free);
printk("%d reserved pages\n",reserved);
printk("%d pages shared\n",shared);
show_buffers();
#ifdef CONFIG_NET
show_net_buffers();
#endif
}
extern unsigned long free_area_init(unsigned long, unsigned long);
/* References to section boundaries */
extern char _text, _etext, _edata, __bss_start, _end;
extern char __init_begin, __init_end;
#define X86_CR4_VME 0x0001 /* enable vm86 extensions */
#define X86_CR4_PVI 0x0002 /* virtual interrupts flag enable */
#define X86_CR4_TSD 0x0004 /* disable time stamp at ipl 3 */
#define X86_CR4_DE 0x0008 /* enable debugging extensions */
#define X86_CR4_PSE 0x0010 /* enable page size extensions */
#define X86_CR4_PAE 0x0020 /* enable physical address extensions */
#define X86_CR4_MCE 0x0040 /* Machine check enable */
#define X86_CR4_PGE 0x0080 /* enable global pages */
#define X86_CR4_PCE 0x0100 /* enable performance counters at ipl 3 */
#define X86_FEATURE_FPU 0x0001 /* internal FPU */
#define X86_FEATURE_VME 0x0002 /* vm86 extensions */
#define X86_FEATURE_DE 0x0004 /* debugging extensions */
#define X86_FEATURE_PSE 0x0008 /* Page size extensions */
#define X86_FEATURE_TSC 0x0010 /* Time stamp counter */
#define X86_FEATURE_MSR 0x0020 /* RDMSR/WRMSR */
#define X86_FEATURE_PAE 0x0040 /* Physical address extension */
#define X86_FEATURE_MCE 0x0080 /* Machine check exception */
#define X86_FEATURE_CXS 0x0100 /* cmpxchg8 available */
#define X86_FEATURE_APIC 0x0200 /* internal APIC */
#define X86_FEATURE_10 0x0400
#define X86_FEATURE_11 0x0800
#define X86_FEATURE_MTRR 0x1000 /* memory type registers */
#define X86_FEATURE_PGE 0x2000 /* Global page */
#define X86_FEATURE_MCA 0x4000 /* Machine Check Architecture */
#define X86_FEATURE_CMOV 0x8000 /* Cmov/fcomi */
#ifdef GAS_KNOWS_CR4
#define read_cr4 "movl %%cr4,%%eax"
#define write_cr4 "movl %%eax,%%cr4"
#else
#define read_cr4 ".byte 0x0f,0x20,0xe0"
#define write_cr4 ".byte 0x0f,0x22,0xe0"
#endif
/*
* Save the cr4 feature set we're using (ie
* Pentium 4MB enable and PPro Global page
* enable), so that any CPU's that boot up
* after us can get the correct flags.
*/
unsigned long mmu_cr4_features __initdata = 0;
static inline void set_in_cr4(unsigned long mask)
{
mmu_cr4_features |= mask;
__asm__(read_cr4 "\n\t"
"orl %0,%%eax\n\t"
write_cr4
: : "irg" (mask)
:"ax");
}
/*
* paging_init() sets up the page tables - note that the first 4MB are
* already mapped by head.S.
*
* This routines also unmaps the page at virtual kernel address 0, so
* that we can trap those pesky NULL-reference errors in the kernel.
*/
__initfunc(unsigned long paging_init(unsigned long start_mem, unsigned long end_mem))
{
pgd_t * pg_dir;
pte_t * pg_table;
unsigned long tmp;
unsigned long address;
/*
* Physical page 0 is special; it's not touched by Linux since BIOS
* and SMM (for laptops with [34]86/SL chips) may need it. It is read
* and write protected to detect null pointer references in the
* kernel.
* It may also hold the MP configuration table when we are booting SMP.
*/
#if 0
memset((void *) 0, 0, PAGE_SIZE);
#endif
#ifdef __SMP__
if (!smp_scan_config(0x0,0x400)) /* Scan the bottom 1K for a signature */
{
/*
* FIXME: Linux assumes you have 640K of base ram.. this continues
* the error...
*/
if (!smp_scan_config(639*0x400,0x400)) /* Scan the top 1K of base RAM */
smp_scan_config(0xF0000,0x10000); /* Scan the 64K of bios */
}
/*
* If it is an SMP machine we should know now, unless the configuration
* is in an EISA/MCA bus machine with an extended bios data area. I don't
* have such a machine so someone else can fill in the check of the EBDA
* here.
*/
/* smp_alloc_memory(8192); */
#endif
#ifdef TEST_VERIFY_AREA
wp_works_ok = 0;
#endif
start_mem = PAGE_ALIGN(start_mem);
address = PAGE_OFFSET;
pg_dir = swapper_pg_dir;
/* unmap the original low memory mappings */
pgd_val(pg_dir[0]) = 0;
/* Map whole memory from 0xC0000000 */
while (address < end_mem) {
/*
* If we're running on a Pentium CPU, we can use the 4MB
* page tables.
*
* The page tables we create span up to the next 4MB
* virtual memory boundary, but that's OK as we won't
* use that memory anyway.
*/
if (x86_capability & X86_FEATURE_PSE) {
unsigned long __pe;
set_in_cr4(X86_CR4_PSE);
wp_works_ok = 1;
__pe = _PAGE_TABLE + _PAGE_4M + __pa(address);
/* Make it "global" too if supported */
if (x86_capability & X86_FEATURE_PGE) {
set_in_cr4(X86_CR4_PGE);
__pe += _PAGE_GLOBAL;
}
pgd_val(pg_dir[768]) = _PAGE_TABLE + _PAGE_4M + __pa(address);
pg_dir++;
address += 4*1024*1024;
continue;
}
/*
* We're on a [34]86, use normal page tables.
* pg_table is physical at this point
*/
pg_table = (pte_t *) (PAGE_MASK & pgd_val(pg_dir[768]));
if (!pg_table) {
pg_table = (pte_t *) __pa(start_mem);
start_mem += PAGE_SIZE;
}
pgd_val(pg_dir[768]) = _PAGE_TABLE | (unsigned long) pg_table;
pg_dir++;
/* now change pg_table to kernel virtual addresses */
pg_table = (pte_t *) __va(pg_table);
for (tmp = 0 ; tmp < PTRS_PER_PTE ; tmp++,pg_table++) {
pte_t pte = mk_pte(address, PAGE_KERNEL);
if (address >= end_mem)
pte_val(pte) = 0;
set_pte(pg_table, pte);
address += PAGE_SIZE;
}
}
local_flush_tlb();
return free_area_init(start_mem, end_mem);
}
__initfunc(void mem_init(unsigned long start_mem, unsigned long end_mem))
{
unsigned long start_low_mem = PAGE_SIZE;
int codepages = 0;
int reservedpages = 0;
int datapages = 0;
int initpages = 0;
unsigned long tmp;
end_mem &= PAGE_MASK;
high_memory = (void *) end_mem;
max_mapnr = num_physpages = MAP_NR(end_mem);
/* clear the zero-page */
memset(empty_zero_page, 0, PAGE_SIZE);
/* mark usable pages in the mem_map[] */
start_low_mem = PAGE_ALIGN(start_low_mem)+PAGE_OFFSET;
#ifdef __SMP__
/*
* But first pinch a few for the stack/trampoline stuff
* FIXME: Don't need the extra page at 4K, but need to fix
* trampoline before removing it. (see the GDT stuff)
*
*/
start_low_mem += PAGE_SIZE; /* 32bit startup code */
start_low_mem = smp_alloc_memory(start_low_mem); /* AP processor stacks */
#endif
start_mem = PAGE_ALIGN(start_mem);
/*
* IBM messed up *AGAIN* in their thinkpad: 0xA0000 -> 0x9F000.
* They seem to have done something stupid with the floppy
* controller as well..
*/
while (start_low_mem < 0x9f000+PAGE_OFFSET) {
clear_bit(PG_reserved, &mem_map[MAP_NR(start_low_mem)].flags);
start_low_mem += PAGE_SIZE;
}
while (start_mem < end_mem) {
clear_bit(PG_reserved, &mem_map[MAP_NR(start_mem)].flags);
start_mem += PAGE_SIZE;
}
for (tmp = PAGE_OFFSET ; tmp < end_mem ; tmp += PAGE_SIZE) {
if (tmp >= MAX_DMA_ADDRESS)
clear_bit(PG_DMA, &mem_map[MAP_NR(tmp)].flags);
if (PageReserved(mem_map+MAP_NR(tmp))) {
if (tmp >= (unsigned long) &_text && tmp < (unsigned long) &_edata) {
if (tmp < (unsigned long) &_etext)
codepages++;
else
datapages++;
} else if (tmp >= (unsigned long) &__init_begin
&& tmp < (unsigned long) &__init_end)
initpages++;
else if (tmp >= (unsigned long) &__bss_start
&& tmp < (unsigned long) start_mem)
datapages++;
else
reservedpages++;
continue;
}
atomic_set(&mem_map[MAP_NR(tmp)].count, 1);
#ifdef CONFIG_BLK_DEV_INITRD
if (!initrd_start || (tmp < initrd_start || tmp >=
initrd_end))
#endif
free_page(tmp);
}
printk("Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init)\n",
(unsigned long) nr_free_pages << (PAGE_SHIFT-10),
max_mapnr << (PAGE_SHIFT-10),
codepages << (PAGE_SHIFT-10),
reservedpages << (PAGE_SHIFT-10),
datapages << (PAGE_SHIFT-10),
initpages << (PAGE_SHIFT-10));
/* test if the WP bit is honoured in supervisor mode */
if (wp_works_ok < 0) {
unsigned char tmp_reg;
unsigned long old = pg0[0];
printk("Checking if this processor honours the WP bit even in supervisor mode... ");
pg0[0] = pte_val(mk_pte(PAGE_OFFSET, PAGE_READONLY));
local_flush_tlb();
current->mm->mmap->vm_start += PAGE_SIZE;
__asm__ __volatile__(
"movb %0,%1 ; movb %1,%0"
:"=m" (*(char *) __va(0)),
"=q" (tmp_reg)
:/* no inputs */
:"memory");
pg0[0] = old;
local_flush_tlb();
current->mm->mmap->vm_start -= PAGE_SIZE;
if (wp_works_ok < 0) {
wp_works_ok = 0;
printk("No.\n");
} else
printk("Ok.\n");
}
return;
}
void free_initmem(void)
{
unsigned long addr;
addr = (unsigned long)(&__init_begin);
for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) {
mem_map[MAP_NR(addr)].flags &= ~(1 << PG_reserved);
atomic_set(&mem_map[MAP_NR(addr)].count, 1);
free_page(addr);
}
printk ("Freeing unused kernel memory: %dk freed\n", (&__init_end - &__init_begin) >> 10);
}
void si_meminfo(struct sysinfo *val)
{
int i;
i = max_mapnr;
val->totalram = 0;
val->sharedram = 0;
val->freeram = nr_free_pages << PAGE_SHIFT;
val->bufferram = buffermem;
while (i-- > 0) {
if (PageReserved(mem_map+i))
continue;
val->totalram++;
if (!atomic_read(&mem_map[i].count))
continue;
val->sharedram += atomic_read(&mem_map[i].count) - 1;
}
val->totalram <<= PAGE_SHIFT;
val->sharedram <<= PAGE_SHIFT;
return;
}
|