locore.s revision 13228
1/*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * William Jolitz. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)locore.s 7.3 (Berkeley) 5/13/91 37 * $Id: locore.s,v 1.59 1995/12/28 21:01:54 davidg Exp $ 38 */ 39 40/* 41 * locore.s: FreeBSD machine support for the Intel 386 42 * originally from: locore.s, by William F. Jolitz 43 * 44 * Substantially rewritten by David Greenman, Rod Grimes, 45 * Bruce Evans, Wolfgang Solfrank, and many others. 46 */ 47 48#include "opt_ddb.h" 49#include "assym.s" /* system definitions */ 50#include <machine/psl.h> /* processor status longword defs */ 51#include <machine/pte.h> /* page table entry definitions */ 52#include <sys/errno.h> /* error return codes */ 53#include <machine/specialreg.h> /* x86 special registers */ 54#include <machine/cputypes.h> /* x86 cpu type definitions */ 55#include <sys/syscall.h> /* system call numbers */ 56#include <machine/asmacros.h> /* miscellaneous asm macros */ 57#include <sys/reboot.h> 58#include "apm.h" 59 60/* 61 * XXX 62 * 63 * Note: This version greatly munged to avoid various assembler errors 64 * that may be fixed in newer versions of gas. Perhaps newer versions 65 * will have more pleasant appearance. 66 */ 67 68/* 69 * PTmap is recursive pagemap at top of virtual address space. 70 * Within PTmap, the page directory can be found (third indirection). 71 */ 72 .globl _PTmap,_PTD,_PTDpde 73 .set _PTmap,PTDPTDI << PDRSHIFT 74 .set _PTD,_PTmap + (PTDPTDI * NBPG) 75 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE) 76 77/* 78 * Sysmap is the base address of the kernel page tables. 79 * It is a bogus interface for kgdb and isn't used by the kernel itself. 80 */ 81 .set _Sysmap,_PTmap + (KPTDI * NBPG) 82 83/* 84 * APTmap, APTD is the alternate recursive pagemap. 85 * It's used when modifying another process's page tables. 86 */ 87 .globl _APTmap,_APTD,_APTDpde 88 .set _APTmap,APTDPTDI << PDRSHIFT 89 .set _APTD,_APTmap + (APTDPTDI * NBPG) 90 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE) 91 92/* 93 * Access to each processes kernel stack is via a region of 94 * per-process address space (at the beginning), immediatly above 95 * the user process stack. 96 */ 97 .set _kstack,USRSTACK 98 .globl _kstack 99 100/* 101 * Globals 102 */ 103 .data 104 105 .globl tmpstk 106 .space 0x1000 /* space for tmpstk - temporary stack */ 107tmpstk: 108/* 109 * Dummy frame at top of tmpstk to help debuggers print a nice stack trace. 110 */ 111 .long tmpstk+8 /* caller's %ebp */ 112 .long _cpu_switch /* caller */ 113 .long 0 /* %ebp == 0 should terminate trace */ 114 .long _mvesp /* in case %ebp == 0 doesn't work ... */ 115 .long 0x11111111, 0x22222222, 0x33333333, 0x44444444, 0x55555555 116 117 .globl _boothowto,_bootdev 118 119 .globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id,_bootinfo 120 .globl _cpu_high, _cpu_feature 121 122_cpu: .long 0 /* are we 386, 386sx, or 486 */ 123_cpu_id: .long 0 /* stepping ID */ 124_cpu_high: .long 0 /* highest arg to CPUID */ 125_cpu_feature: .long 0 /* features */ 126_cpu_vendor: .space 20 /* CPU origin code */ 127_bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */ 128_cold: .long 1 /* cold till we are not */ 129_atdevbase: .long 0 /* location of start of iomem in virtual */ 130_atdevphys: .long 0 /* location of device mapping ptes (phys) */ 131 132_KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 133 134 .globl _IdlePTD 135_IdlePTD: .long 0 /* phys addr of kernel PTD */ 136 137_KPTphys: .long 0 /* phys addr of kernel page tables */ 138 139 .globl _proc0paddr 140_proc0paddr: .long 0 /* address of proc 0 address space */ 141 142#ifdef BDE_DEBUGGER 143 .globl _bdb_exists /* flag to indicate BDE debugger is available */ 144_bdb_exists: .long 0 145#endif 146 147/* 148 * System Initialization 149 */ 150 .text 151 152/* 153 * btext: beginning of text section. 154 * Also the entry point (jumped to directly from the boot blocks). 155 */ 156NON_GPROF_ENTRY(btext) 157 movw $0x1234,0x472 /* warm boot */ 158 159 /* Set up a real frame, some day we will be doing returns */ 160 pushl %ebp 161 movl %esp, %ebp 162 163 /* Don't trust what the BIOS gives for eflags. */ 164 pushl $PSL_KERNEL 165 popfl 166 167 /* Don't trust what the BIOS gives for %fs and %gs. */ 168 mov %ds, %ax 169 mov %ax, %fs 170 mov %ax, %gs 171 172 /* 173 * This code is called in different ways depending on what loaded 174 * and started the kernel. This is used to detect how we get the 175 * arguments from the other code and what we do with them. 176 * 177 * Old disk boot blocks: 178 * (*btext)(howto, bootdev, cyloffset, esym); 179 * [return address == 0, and can NOT be returned to] 180 * [cyloffset was not supported by the FreeBSD boot code 181 * and always passed in as 0] 182 * [esym is also known as total in the boot code, and 183 * was never properly supported by the FreeBSD boot code] 184 * 185 * Old diskless netboot code: 186 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 187 * [return address != 0, and can NOT be returned to] 188 * If we are being booted by this code it will NOT work, 189 * so we are just going to halt if we find this case. 190 * 191 * New uniform boot code: 192 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 193 * [return address != 0, and can be returned to] 194 * 195 * There may seem to be a lot of wasted arguments in here, but 196 * that is so the newer boot code can still load very old kernels 197 * and old boot code can load new kernels. 198 */ 199 200 /* 201 * The old style disk boot blocks fake a frame on the stack and 202 * did an lret to get here. The frame on the stack has a return 203 * address of 0. 204 */ 205 cmpl $0,4(%ebp) 206 je 2f /* olddiskboot: */ 207 208 /* 209 * We have some form of return address, so this is either the 210 * old diskless netboot code, or the new uniform code. That can 211 * be detected by looking at the 5th argument, it if is 0 we 212 * we are being booted by the new unifrom boot code. 213 */ 214 cmpl $0,24(%ebp) 215 je 1f /* newboot: */ 216 217 /* 218 * Seems we have been loaded by the old diskless boot code, we 219 * don't stand a chance of running as the diskless structure 220 * changed considerably between the two, so just halt. 221 */ 222 hlt 223 224 /* 225 * We have been loaded by the new uniform boot code. 226 * Lets check the bootinfo version, and if we do not understand 227 * it we return to the loader with a status of 1 to indicate this error 228 */ 2291: /* newboot: */ 230 movl 28(%ebp),%ebx /* &bootinfo.version */ 231 movl BI_VERSION(%ebx),%eax 232 cmpl $1,%eax /* We only understand version 1 */ 233 je 1f 234 movl $1,%eax /* Return status */ 235 leave 236 ret 237 2381: 239 /* 240 * If we have a kernelname copy it in 241 */ 242 movl BI_KERNELNAME(%ebx),%esi 243 cmpl $0,%esi 244 je 2f /* No kernelname */ 245 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 246 lea _kernelname-KERNBASE,%edi 247 cmpb $'/',(%esi) /* Make sure it starts with a slash */ 248 je 1f 249 movb $'/',(%edi) 250 incl %edi 251 decl %ecx 2521: 253 cld 254 rep 255 movsb 256 2572: 258 /* 259 * Determine the size of the boot loader's copy of the bootinfo 260 * struct. This is impossible to do properly because old versions 261 * of the struct don't contain a size field and there are 2 old 262 * versions with the same version number. 263 */ 264 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */ 265 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */ 266 je got_bi_size /* no, sizeless version */ 267 movl BI_SIZE(%ebx),%ecx 268got_bi_size: 269 270 /* 271 * Copy the common part of the bootinfo struct 272 */ 273 movl %ebx,%esi 274 movl $_bootinfo-KERNBASE,%edi 275 cmpl $BOOTINFO_SIZE,%ecx 276 jbe got_common_bi_size 277 movl $BOOTINFO_SIZE,%ecx 278got_common_bi_size: 279 cld 280 rep 281 movsb 282 283#ifdef NFS 284 /* 285 * If we have a nfs_diskless structure copy it in 286 */ 287 movl BI_NFS_DISKLESS(%ebx),%esi 288 cmpl $0,%esi 289 je 2f 290 lea _nfs_diskless-KERNBASE,%edi 291 movl $NFSDISKLESS_SIZE,%ecx 292 cld 293 rep 294 movsb 295 lea _nfs_diskless_valid-KERNBASE,%edi 296 movl $1,(%edi) 297#endif 298 299 /* 300 * The old style disk boot. 301 * (*btext)(howto, bootdev, cyloffset, esym); 302 * Note that the newer boot code just falls into here to pick 303 * up howto and bootdev, cyloffset and esym are no longer used 304 */ 3052: /* olddiskboot: */ 306 movl 8(%ebp),%eax 307 movl %eax,_boothowto-KERNBASE 308 movl 12(%ebp),%eax 309 movl %eax,_bootdev-KERNBASE 310 311#if NAPM > 0 312 /* call APM BIOS driver setup (i386/apm/apm_setup.s) */ 313 call _apm_setup 314#endif /* NAPM */ 315 316 /* Find out our CPU type. */ 317 318 /* Try to toggle alignment check flag; does not exist on 386. */ 319 pushfl 320 popl %eax 321 movl %eax,%ecx 322 orl $PSL_AC,%eax 323 pushl %eax 324 popfl 325 pushfl 326 popl %eax 327 xorl %ecx,%eax 328 andl $PSL_AC,%eax 329 pushl %ecx 330 popfl 331 332 testl %eax,%eax 333 jnz 1f 334 movl $CPU_386,_cpu-KERNBASE 335 jmp 3f 336 3371: /* Try to toggle identification flag; does not exist on early 486s. */ 338 pushfl 339 popl %eax 340 movl %eax,%ecx 341 xorl $PSL_ID,%eax 342 pushl %eax 343 popfl 344 pushfl 345 popl %eax 346 xorl %ecx,%eax 347 andl $PSL_ID,%eax 348 pushl %ecx 349 popfl 350 351 testl %eax,%eax 352 jnz 1f 353 movl $CPU_486,_cpu-KERNBASE 354 355 /* check for Cyrix 486DLC -- based on check routine */ 356 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 357 xorw %dx,%dx 358 cmpw %dx,%dx # set flags to known state 359 pushfw 360 popw %cx # store flags in ecx 361 movw $0xffff,%ax 362 movw $0x0004,%bx 363 divw %bx 364 pushfw 365 popw %ax 366 andw $0x08d5,%ax # mask off important bits 367 andw $0x08d5,%cx 368 cmpw %ax,%cx 369 370 jnz 3f # if flags changed, Intel chip 371 372 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 373 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 374 movw $0x0078,_cpu_vendor-KERNBASE+4 375 376#ifndef CYRIX_CACHE_WORKS 377 /* Disable caching of the ISA hole only. */ 378 invd 379 movb $CCR0,%al # Configuration Register index (CCR0) 380 outb %al,$0x22 381 inb $0x23,%al 382 orb $(CCR0_NC1|CCR0_BARB),%al 383 movb %al,%ah 384 movb $CCR0,%al 385 outb %al,$0x22 386 movb %ah,%al 387 outb %al,$0x23 388 invd 389#else /* CYRIX_CACHE_WORKS */ 390 /* Set cache parameters */ 391 invd # Start with guaranteed clean cache 392 movb $CCR0,%al # Configuration Register index (CCR0) 393 outb %al,$0x22 394 inb $0x23,%al 395 andb $~CCR0_NC0,%al 396#ifndef CYRIX_CACHE_REALLY_WORKS 397 orb $(CCR0_NC1|CCR0_BARB),%al 398#else 399 orb $CCR0_NC1,%al 400#endif 401 movb %al,%ah 402 movb $CCR0,%al 403 outb %al,$0x22 404 movb %ah,%al 405 outb %al,$0x23 406 /* clear non-cacheable region 1 */ 407 movb $(NCR1+2),%al 408 outb %al,$0x22 409 movb $NCR_SIZE_0K,%al 410 outb %al,$0x23 411 /* clear non-cacheable region 2 */ 412 movb $(NCR2+2),%al 413 outb %al,$0x22 414 movb $NCR_SIZE_0K,%al 415 outb %al,$0x23 416 /* clear non-cacheable region 3 */ 417 movb $(NCR3+2),%al 418 outb %al,$0x22 419 movb $NCR_SIZE_0K,%al 420 outb %al,$0x23 421 /* clear non-cacheable region 4 */ 422 movb $(NCR4+2),%al 423 outb %al,$0x22 424 movb $NCR_SIZE_0K,%al 425 outb %al,$0x23 426 /* enable caching in CR0 */ 427 movl %cr0,%eax 428 andl $~(CR0_CD|CR0_NW),%eax 429 movl %eax,%cr0 430 invd 431#endif /* CYRIX_CACHE_WORKS */ 432 jmp 3f 433 4341: /* Use the `cpuid' instruction. */ 435 xorl %eax,%eax 436 .byte 0x0f,0xa2 # cpuid 0 437 movl %eax,_cpu_high-KERNBASE # highest capability 438 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 439 movl %edx,_cpu_vendor+4-KERNBASE 440 movl %ecx,_cpu_vendor+8-KERNBASE 441 movb $0,_cpu_vendor+12-KERNBASE 442 443 movl $1,%eax 444 .byte 0x0f,0xa2 # cpuid 1 445 movl %eax,_cpu_id-KERNBASE # store cpu_id 446 movl %edx,_cpu_feature-KERNBASE # store cpu_feature 447 rorl $8,%eax # extract family type 448 andl $15,%eax 449 cmpl $5,%eax 450 jae 1f 451 452 /* less than Pentium; must be 486 */ 453 movl $CPU_486,_cpu-KERNBASE 454 jmp 3f 4551: 456 /* a Pentium? */ 457 cmpl $5,%eax 458 jne 2f 459 movl $CPU_586,_cpu-KERNBASE 460 jmp 3f 4612: 462 /* Greater than Pentium...call it a Pentium Pro */ 463 movl $CPU_686,_cpu-KERNBASE 4643: 465 466 /* 467 * Finished with old stack; load new %esp now instead of later so 468 * we can trace this code without having to worry about the trace 469 * trap clobbering the memory test or the zeroing of the bss+bootstrap 470 * page tables. 471 * 472 * XXX - wdboot clears the bss after testing that this is safe. 473 * This is too wasteful - memory below 640K is scarce. The boot 474 * program should check: 475 * text+data <= &stack_variable - more_space_for_stack 476 * text+data+bss+pad+space_for_page_tables <= end_of_memory 477 * Oops, the gdt is in the carcass of the boot program so clearing 478 * the rest of memory is still not possible. 479 */ 480 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 481 482/* 483 * Virtual address space of kernel: 484 * 485 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 486 * pages: 1 UPAGES (2) 1 NKPT (7) 487 */ 488 489/* find end of kernel image */ 490 movl $_end-KERNBASE,%ecx 491 addl $NBPG-1,%ecx /* page align up */ 492 andl $~(NBPG-1),%ecx 493 movl %ecx,%esi /* esi = start of free memory */ 494 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 495 496/* clear bss */ 497 movl $_edata-KERNBASE,%edi 498 subl %edi,%ecx /* get amount to clear */ 499 xorl %eax,%eax /* specify zero fill */ 500 cld 501 rep 502 stosb 503 504#ifdef DDB 505/* include symbols in "kernel image" if they are loaded */ 506 movl _bootinfo+BI_ESYMTAB-KERNBASE,%edi 507 testl %edi,%edi 508 je over_symalloc 509 addl $NBPG-1,%edi 510 andl $~(NBPG-1),%edi 511 movl %edi,%esi 512 movl %esi,_KERNend-KERNBASE 513 movl $KERNBASE,%edi 514 addl %edi,_bootinfo+BI_SYMTAB-KERNBASE 515 addl %edi,_bootinfo+BI_ESYMTAB-KERNBASE 516over_symalloc: 517#endif 518 519/* 520 * The value in esi is both the end of the kernel bss and a pointer to 521 * the kernel page directory, and is used by the rest of locore to build 522 * the tables. 523 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 524 * page table pages) is then passed on the stack to init386(first) as 525 * the value first. esi should ALWAYS be page aligned!! 526 */ 527 movl %esi,%ecx /* Get current first availiable address */ 528 529/* clear pagetables, page directory, stack, etc... */ 530 movl %esi,%edi /* base (page directory) */ 531 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 532 xorl %eax,%eax /* specify zero fill */ 533 cld 534 rep 535 stosb 536 537/* physical address of Idle proc/kernel page directory */ 538 movl %esi,_IdlePTD-KERNBASE 539 540/* 541 * fillkpt 542 * eax = (page frame address | control | status) == pte 543 * ebx = address of page table 544 * ecx = how many pages to map 545 */ 546#define fillkpt \ 5471: movl %eax,(%ebx) ; \ 548 addl $NBPG,%eax ; /* increment physical address */ \ 549 addl $4,%ebx ; /* next pte */ \ 550 loop 1b ; 551 552/* 553 * Map Kernel 554 * 555 * First step - build page tables 556 */ 557#if defined (KGDB) || defined (BDE_DEBUGGER) 558 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 559 shrl $PGSHIFT,%ecx /* for this many PTEs */ 560#ifdef BDE_DEBUGGER 561 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 562 jae 1f 563 movl $0xa0,%ecx 5641: 565#endif /* BDE_DEBUGGER */ 566 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 567 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 568 movl %ebx,_KPTphys-KERNBASE /* save in global */ 569 fillkpt 570 571#else /* !KGDB && !BDE_DEBUGGER */ 572 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 573 movl $_etext-KERNBASE,%ecx /* get size of text */ 574 addl $NBPG-1,%ecx /* round up to page */ 575 shrl $PGSHIFT,%ecx /* for this many PTEs */ 576 movl $PG_V|PG_KR,%eax /* specify read only */ 577#if 0 578 movl $_etext,%ecx /* get size of text */ 579 subl $_btext,%ecx 580 addl $NBPG-1,%ecx /* round up to page */ 581 shrl $PGSHIFT,%ecx /* for this many PTEs */ 582 movl $_btext-KERNBASE,%eax /* get offset to physical memory */ 583 orl $PG_V|PG_KR,%eax /* specify read only */ 584#endif 585 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 586 movl %ebx,_KPTphys-KERNBASE /* save in global */ 587 fillkpt 588 589 /* data and bss are r/w */ 590 andl $PG_FRAME,%eax /* strip to just addr of bss */ 591 movl _KERNend-KERNBASE,%ecx /* calculate size */ 592 subl %eax,%ecx 593 shrl $PGSHIFT,%ecx 594 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 595 fillkpt 596#endif /* KGDB || BDE_DEBUGGER */ 597 598/* now initialize the page dir, upages, and p0stack PT */ 599 600 movl $(1+UPAGES+1),%ecx /* number of PTEs */ 601 movl %esi,%eax /* phys address of PTD */ 602 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 603 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 604 movl %esi,%ebx /* calculate pte offset to ptd */ 605 shrl $PGSHIFT-2,%ebx 606 addl %esi,%ebx /* address of page directory */ 607 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 608 fillkpt 609 610/* map I/O memory map */ 611 612 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 613 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 614 movl $0x100-0xa0,%ecx /* for this many pte s, */ 615 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 616 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 617 fillkpt 618 619 /* map proc 0's kernel stack into user page table page */ 620 621 movl $UPAGES,%ecx /* for this many pte s, */ 622 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 623 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 624 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 625 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 626 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 627 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 628 fillkpt 629 630/* 631 * Initialize kernel page table directory 632 */ 633 /* install a pde for temporary double map of bottom of VA */ 634 movl _KPTphys-KERNBASE,%eax 635 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 636 movl %eax,(%esi) /* which is where temp maps! */ 637 638 /* initialize kernel pde's */ 639 movl $(NKPT),%ecx /* for this many PDEs */ 640 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 641 fillkpt 642 643 /* install a pde recursively mapping page directory as a page table! */ 644 movl %esi,%eax /* phys address of ptd in proc 0 */ 645 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 646 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 647 648 /* install a pde to map kernel stack for proc 0 */ 649 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 650 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 651 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 652 653#ifdef BDE_DEBUGGER 654 /* copy and convert stuff from old gdt and idt for debugger */ 655 656 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 657 jne 1f 658 movb $1,_bdb_exists-KERNBASE 6591: 660 pushal 661 subl $2*6,%esp 662 663 sgdt (%esp) 664 movl 2(%esp),%esi /* base address of current gdt */ 665 movl $_gdt-KERNBASE,%edi 666 movl %edi,2(%esp) 667 movl $8*18/4,%ecx 668 cld 669 rep /* copy gdt */ 670 movsl 671 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 672 movb $0x92,-8+5(%edi) 673 674 sidt 6(%esp) 675 movl 6+2(%esp),%esi /* base address of current idt */ 676 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 677 movw 8(%esi),%ax 678 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 679 movl 8+2(%esi),%eax 680 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 681 movl 24+4(%esi),%eax /* same for bpt descriptor */ 682 movw 24(%esi),%ax 683 movl %eax,bdb_bpt_ljmp+1-KERNBASE 684 movl 24+2(%esi),%eax 685 movw %ax,bdb_bpt_ljmp+5-KERNBASE 686 687 movl $_idt-KERNBASE,%edi 688 movl %edi,6+2(%esp) 689 movl $8*4/4,%ecx 690 cld 691 rep /* copy idt */ 692 movsl 693 694 lgdt (%esp) 695 lidt 6(%esp) 696 697 addl $2*6,%esp 698 popal 699#endif /* BDE_DEBUGGER */ 700 701 /* load base of page directory and enable mapping */ 702 movl %esi,%eax /* phys address of ptd in proc 0 */ 703 movl %eax,%cr3 /* load ptd addr into mmu */ 704 movl %cr0,%eax /* get control word */ 705 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 706 movl %eax,%cr0 /* and let's page NOW! */ 707 708 pushl $begin /* jump to high mem */ 709 ret 710 711begin: /* now running relocated at KERNBASE where the system is linked to run */ 712 movl _atdevphys,%edx /* get pte PA */ 713 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 714 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 715 addl $KERNBASE,%edx /* add virtual base */ 716 movl %edx,_atdevbase 717 718 /* set up bootstrap stack */ 719 movl $_kstack+UPAGES*NBPG,%esp /* bootstrap stack end location */ 720 xorl %eax,%eax /* mark end of frames */ 721 movl %eax,%ebp 722 movl _proc0paddr,%eax 723 movl %esi,PCB_CR3(%eax) 724 725#ifdef BDE_DEBUGGER 726 /* relocate debugger gdt entries */ 727 728 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 729 movl $9,%ecx 730reloc_gdt: 731 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 732 addl $8,%eax /* now KERNBASE>>24 */ 733 loop reloc_gdt 734 735 cmpl $0,_bdb_exists 736 je 1f 737 int $3 7381: 739#endif /* BDE_DEBUGGER */ 740 741 /* 742 * Prepare "first" - physical address of first available page 743 * after the kernel+pdir+upages+p0stack+page tables 744 */ 745 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 746 747 pushl %esi /* value of first for init386(first) */ 748 call _init386 /* wire 386 chip for unix operation */ 749 popl %esi 750 751 .globl __ucodesel,__udatasel 752 753 pushl $0 /* unused */ 754 pushl __udatasel /* ss */ 755 pushl $0 /* esp - filled in by execve() */ 756 pushl $PSL_USER /* eflags (IOPL 0, int enab) */ 757 pushl __ucodesel /* cs */ 758 pushl $0 /* eip - filled in by execve() */ 759 subl $(12*4),%esp /* space for rest of registers */ 760 761 pushl %esp /* call main with frame pointer */ 762 call _main /* autoconfiguration, mountroot etc */ 763 764 addl $(13*4),%esp /* back to a frame we can return with */ 765 766 /* 767 * now we've run main() and determined what cpu-type we are, we can 768 * enable write protection and alignment checking on i486 cpus and 769 * above. 770 */ 771#if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU) 772 cmpl $CPUCLASS_386,_cpu_class 773 je 1f 774 movl %cr0,%eax /* get control word */ 775 orl $CR0_WP|CR0_AM,%eax /* enable i486 features */ 776 movl %eax,%cr0 /* and do it */ 777#endif 778 /* 779 * on return from main(), we are process 1 780 * set up address space and stack so that we can 'return' to user mode 781 */ 7821: 783 movl __ucodesel,%eax 784 movl __udatasel,%ecx 785 786 movl %cx,%ds 787 movl %cx,%es 788 movl %ax,%fs /* double map cs to fs */ 789 movl %cx,%gs /* and ds to gs */ 790 iret /* goto user! */ 791 792#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 793 794NON_GPROF_ENTRY(sigcode) 795 call SIGF_HANDLER(%esp) 796 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 797 /* copy at 8(%esp)) */ 798 pushl %eax 799 pushl %eax /* junk to fake return address */ 800 movl $103,%eax /* XXX sigreturn() */ 801 LCALL(0x7,0) /* enter kernel with args on stack */ 802 hlt /* never gets here */ 803 804 .globl _szsigcode 805_szsigcode: 806 .long _szsigcode-_sigcode 807