locore.s revision 14331
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 1.62 1996/02/04 21:20:32 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 .align 2 /* Just to be sure */ 105 106 .globl tmpstk 107 .space 0x2000 /* space for tmpstk - temporary stack */ 108tmpstk: 109 .long 0x11111111, 0x22222222, 0x33333333, 0x44444444, 0x55555555 110 111 .globl _boothowto,_bootdev 112 113 .globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id,_bootinfo 114 .globl _cpu_high, _cpu_feature 115 116_cpu: .long 0 /* are we 386, 386sx, or 486 */ 117_cpu_id: .long 0 /* stepping ID */ 118_cpu_high: .long 0 /* highest arg to CPUID */ 119_cpu_feature: .long 0 /* features */ 120_cpu_vendor: .space 20 /* CPU origin code */ 121_bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */ 122_cold: .long 1 /* cold till we are not */ 123_atdevbase: .long 0 /* location of start of iomem in virtual */ 124_atdevphys: .long 0 /* location of device mapping ptes (phys) */ 125 126_KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 127 128 .globl _IdlePTD 129_IdlePTD: .long 0 /* phys addr of kernel PTD */ 130 131_KPTphys: .long 0 /* phys addr of kernel page tables */ 132 133 .globl _proc0paddr 134_proc0paddr: .long 0 /* address of proc 0 address space */ 135 136#ifdef BDE_DEBUGGER 137 .globl _bdb_exists /* flag to indicate BDE debugger is available */ 138_bdb_exists: .long 0 139#endif 140 141/* 142 * System Initialization 143 */ 144 .text 145 146/* 147 * btext: beginning of text section. 148 * Also the entry point (jumped to directly from the boot blocks). 149 */ 150NON_GPROF_ENTRY(btext) 151 movw $0x1234,0x472 /* warm boot */ 152 153 /* Set up a real frame, some day we will be doing returns */ 154 pushl %ebp 155 movl %esp, %ebp 156 157 /* Don't trust what the BIOS gives for eflags. */ 158 pushl $PSL_KERNEL 159 popfl 160 161 /* Don't trust what the BIOS gives for %fs and %gs. */ 162 mov %ds, %ax 163 mov %ax, %fs 164 mov %ax, %gs 165 166 /* 167 * This code is called in different ways depending on what loaded 168 * and started the kernel. This is used to detect how we get the 169 * arguments from the other code and what we do with them. 170 * 171 * Old disk boot blocks: 172 * (*btext)(howto, bootdev, cyloffset, esym); 173 * [return address == 0, and can NOT be returned to] 174 * [cyloffset was not supported by the FreeBSD boot code 175 * and always passed in as 0] 176 * [esym is also known as total in the boot code, and 177 * was never properly supported by the FreeBSD boot code] 178 * 179 * Old diskless netboot code: 180 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 181 * [return address != 0, and can NOT be returned to] 182 * If we are being booted by this code it will NOT work, 183 * so we are just going to halt if we find this case. 184 * 185 * New uniform boot code: 186 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 187 * [return address != 0, and can be returned to] 188 * 189 * There may seem to be a lot of wasted arguments in here, but 190 * that is so the newer boot code can still load very old kernels 191 * and old boot code can load new kernels. 192 */ 193 194 /* 195 * The old style disk boot blocks fake a frame on the stack and 196 * did an lret to get here. The frame on the stack has a return 197 * address of 0. 198 */ 199 cmpl $0,4(%ebp) 200 je 2f /* olddiskboot: */ 201 202 /* 203 * We have some form of return address, so this is either the 204 * old diskless netboot code, or the new uniform code. That can 205 * be detected by looking at the 5th argument, it if is 0 we 206 * we are being booted by the new unifrom boot code. 207 */ 208 cmpl $0,24(%ebp) 209 je 1f /* newboot: */ 210 211 /* 212 * Seems we have been loaded by the old diskless boot code, we 213 * don't stand a chance of running as the diskless structure 214 * changed considerably between the two, so just halt. 215 */ 216 hlt 217 218 /* 219 * We have been loaded by the new uniform boot code. 220 * Lets check the bootinfo version, and if we do not understand 221 * it we return to the loader with a status of 1 to indicate this error 222 */ 2231: /* newboot: */ 224 movl 28(%ebp),%ebx /* &bootinfo.version */ 225 movl BI_VERSION(%ebx),%eax 226 cmpl $1,%eax /* We only understand version 1 */ 227 je 1f 228 movl $1,%eax /* Return status */ 229 leave 230 ret 231 2321: 233 /* 234 * If we have a kernelname copy it in 235 */ 236 movl BI_KERNELNAME(%ebx),%esi 237 cmpl $0,%esi 238 je 2f /* No kernelname */ 239 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 240 lea _kernelname-KERNBASE,%edi 241 cmpb $'/',(%esi) /* Make sure it starts with a slash */ 242 je 1f 243 movb $'/',(%edi) 244 incl %edi 245 decl %ecx 2461: 247 cld 248 rep 249 movsb 250 2512: 252 /* 253 * Determine the size of the boot loader's copy of the bootinfo 254 * struct. This is impossible to do properly because old versions 255 * of the struct don't contain a size field and there are 2 old 256 * versions with the same version number. 257 */ 258 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */ 259 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */ 260 je got_bi_size /* no, sizeless version */ 261 movl BI_SIZE(%ebx),%ecx 262got_bi_size: 263 264 /* 265 * Copy the common part of the bootinfo struct 266 */ 267 movl %ebx,%esi 268 movl $_bootinfo-KERNBASE,%edi 269 cmpl $BOOTINFO_SIZE,%ecx 270 jbe got_common_bi_size 271 movl $BOOTINFO_SIZE,%ecx 272got_common_bi_size: 273 cld 274 rep 275 movsb 276 277#ifdef NFS 278 /* 279 * If we have a nfs_diskless structure copy it in 280 */ 281 movl BI_NFS_DISKLESS(%ebx),%esi 282 cmpl $0,%esi 283 je 2f 284 lea _nfs_diskless-KERNBASE,%edi 285 movl $NFSDISKLESS_SIZE,%ecx 286 cld 287 rep 288 movsb 289 lea _nfs_diskless_valid-KERNBASE,%edi 290 movl $1,(%edi) 291#endif 292 293 /* 294 * The old style disk boot. 295 * (*btext)(howto, bootdev, cyloffset, esym); 296 * Note that the newer boot code just falls into here to pick 297 * up howto and bootdev, cyloffset and esym are no longer used 298 */ 2992: /* olddiskboot: */ 300 movl 8(%ebp),%eax 301 movl %eax,_boothowto-KERNBASE 302 movl 12(%ebp),%eax 303 movl %eax,_bootdev-KERNBASE 304 305#if NAPM > 0 306 /* call APM BIOS driver setup (i386/apm/apm_setup.s) */ 307 call _apm_setup 308#endif /* NAPM */ 309 310 /* Find out our CPU type. */ 311 312 /* Try to toggle alignment check flag; does not exist on 386. */ 313 pushfl 314 popl %eax 315 movl %eax,%ecx 316 orl $PSL_AC,%eax 317 pushl %eax 318 popfl 319 pushfl 320 popl %eax 321 xorl %ecx,%eax 322 andl $PSL_AC,%eax 323 pushl %ecx 324 popfl 325 326 testl %eax,%eax 327 jnz 1f 328 movl $CPU_386,_cpu-KERNBASE 329 jmp 3f 330 3311: /* Try to toggle identification flag; does not exist on early 486s. */ 332 pushfl 333 popl %eax 334 movl %eax,%ecx 335 xorl $PSL_ID,%eax 336 pushl %eax 337 popfl 338 pushfl 339 popl %eax 340 xorl %ecx,%eax 341 andl $PSL_ID,%eax 342 pushl %ecx 343 popfl 344 345 testl %eax,%eax 346 jnz 1f 347 movl $CPU_486,_cpu-KERNBASE 348 349 /* check for Cyrix 486DLC -- based on check routine */ 350 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 351 xorw %dx,%dx 352 cmpw %dx,%dx # set flags to known state 353 pushfw 354 popw %cx # store flags in ecx 355 movw $0xffff,%ax 356 movw $0x0004,%bx 357 divw %bx 358 pushfw 359 popw %ax 360 andw $0x08d5,%ax # mask off important bits 361 andw $0x08d5,%cx 362 cmpw %ax,%cx 363 364 jnz 3f # if flags changed, Intel chip 365 366 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 367 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 368 movw $0x0078,_cpu_vendor-KERNBASE+4 369 370#ifndef CYRIX_CACHE_WORKS 371 /* Disable caching of the ISA hole only. */ 372 invd 373 movb $CCR0,%al # Configuration Register index (CCR0) 374 outb %al,$0x22 375 inb $0x23,%al 376 orb $(CCR0_NC1|CCR0_BARB),%al 377 movb %al,%ah 378 movb $CCR0,%al 379 outb %al,$0x22 380 movb %ah,%al 381 outb %al,$0x23 382 invd 383#else /* CYRIX_CACHE_WORKS */ 384 /* Set cache parameters */ 385 invd # Start with guaranteed clean cache 386 movb $CCR0,%al # Configuration Register index (CCR0) 387 outb %al,$0x22 388 inb $0x23,%al 389 andb $~CCR0_NC0,%al 390#ifndef CYRIX_CACHE_REALLY_WORKS 391 orb $(CCR0_NC1|CCR0_BARB),%al 392#else 393 orb $CCR0_NC1,%al 394#endif 395 movb %al,%ah 396 movb $CCR0,%al 397 outb %al,$0x22 398 movb %ah,%al 399 outb %al,$0x23 400 /* clear non-cacheable region 1 */ 401 movb $(NCR1+2),%al 402 outb %al,$0x22 403 movb $NCR_SIZE_0K,%al 404 outb %al,$0x23 405 /* clear non-cacheable region 2 */ 406 movb $(NCR2+2),%al 407 outb %al,$0x22 408 movb $NCR_SIZE_0K,%al 409 outb %al,$0x23 410 /* clear non-cacheable region 3 */ 411 movb $(NCR3+2),%al 412 outb %al,$0x22 413 movb $NCR_SIZE_0K,%al 414 outb %al,$0x23 415 /* clear non-cacheable region 4 */ 416 movb $(NCR4+2),%al 417 outb %al,$0x22 418 movb $NCR_SIZE_0K,%al 419 outb %al,$0x23 420 /* enable caching in CR0 */ 421 movl %cr0,%eax 422 andl $~(CR0_CD|CR0_NW),%eax 423 movl %eax,%cr0 424 invd 425#endif /* CYRIX_CACHE_WORKS */ 426 jmp 3f 427 4281: /* Use the `cpuid' instruction. */ 429 xorl %eax,%eax 430 .byte 0x0f,0xa2 # cpuid 0 431 movl %eax,_cpu_high-KERNBASE # highest capability 432 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 433 movl %edx,_cpu_vendor+4-KERNBASE 434 movl %ecx,_cpu_vendor+8-KERNBASE 435 movb $0,_cpu_vendor+12-KERNBASE 436 437 movl $1,%eax 438 .byte 0x0f,0xa2 # cpuid 1 439 movl %eax,_cpu_id-KERNBASE # store cpu_id 440 movl %edx,_cpu_feature-KERNBASE # store cpu_feature 441 rorl $8,%eax # extract family type 442 andl $15,%eax 443 cmpl $5,%eax 444 jae 1f 445 446 /* less than Pentium; must be 486 */ 447 movl $CPU_486,_cpu-KERNBASE 448 jmp 3f 4491: 450 /* a Pentium? */ 451 cmpl $5,%eax 452 jne 2f 453 movl $CPU_586,_cpu-KERNBASE 454 jmp 3f 4552: 456 /* Greater than Pentium...call it a Pentium Pro */ 457 movl $CPU_686,_cpu-KERNBASE 4583: 459 460 /* 461 * Finished with old stack; load new %esp now instead of later so 462 * we can trace this code without having to worry about the trace 463 * trap clobbering the memory test or the zeroing of the bss+bootstrap 464 * page tables. 465 * 466 * XXX - wdboot clears the bss after testing that this is safe. 467 * This is too wasteful - memory below 640K is scarce. The boot 468 * program should check: 469 * text+data <= &stack_variable - more_space_for_stack 470 * text+data+bss+pad+space_for_page_tables <= end_of_memory 471 * Oops, the gdt is in the carcass of the boot program so clearing 472 * the rest of memory is still not possible. 473 */ 474 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 475 476/* 477 * Virtual address space of kernel: 478 * 479 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 480 * pages: 1 UPAGES (2) 1 NKPT (7) 481 */ 482 483/* find end of kernel image */ 484 movl $_end-KERNBASE,%ecx 485 addl $NBPG-1,%ecx /* page align up */ 486 andl $~(NBPG-1),%ecx 487 movl %ecx,%esi /* esi = start of free memory */ 488 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 489 490/* clear bss */ 491 movl $_edata-KERNBASE,%edi 492 subl %edi,%ecx /* get amount to clear */ 493 xorl %eax,%eax /* specify zero fill */ 494 cld 495 rep 496 stosb 497 498#ifdef DDB 499/* include symbols in "kernel image" if they are loaded */ 500 movl _bootinfo+BI_ESYMTAB-KERNBASE,%edi 501 testl %edi,%edi 502 je over_symalloc 503 addl $NBPG-1,%edi 504 andl $~(NBPG-1),%edi 505 movl %edi,%esi 506 movl %esi,_KERNend-KERNBASE 507 movl $KERNBASE,%edi 508 addl %edi,_bootinfo+BI_SYMTAB-KERNBASE 509 addl %edi,_bootinfo+BI_ESYMTAB-KERNBASE 510over_symalloc: 511#endif 512 513/* 514 * The value in esi is both the end of the kernel bss and a pointer to 515 * the kernel page directory, and is used by the rest of locore to build 516 * the tables. 517 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 518 * page table pages) is then passed on the stack to init386(first) as 519 * the value first. esi should ALWAYS be page aligned!! 520 */ 521 movl %esi,%ecx /* Get current first availiable address */ 522 523/* clear pagetables, page directory, stack, etc... */ 524 movl %esi,%edi /* base (page directory) */ 525 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 526 xorl %eax,%eax /* specify zero fill */ 527 cld 528 rep 529 stosb 530 531/* physical address of Idle proc/kernel page directory */ 532 movl %esi,_IdlePTD-KERNBASE 533 534/* 535 * fillkpt 536 * eax = (page frame address | control | status) == pte 537 * ebx = address of page table 538 * ecx = how many pages to map 539 */ 540#define fillkpt \ 5411: movl %eax,(%ebx) ; \ 542 addl $NBPG,%eax ; /* increment physical address */ \ 543 addl $4,%ebx ; /* next pte */ \ 544 loop 1b ; 545 546/* 547 * Map Kernel 548 * 549 * First step - build page tables 550 */ 551#if defined (KGDB) || defined (BDE_DEBUGGER) 552 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 553 shrl $PGSHIFT,%ecx /* for this many PTEs */ 554#ifdef BDE_DEBUGGER 555 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 556 jae 1f 557 movl $0xa0,%ecx 5581: 559#endif /* BDE_DEBUGGER */ 560 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 561 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 562 movl %ebx,_KPTphys-KERNBASE /* save in global */ 563 fillkpt 564 565#else /* !KGDB && !BDE_DEBUGGER */ 566 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 567 movl $_etext-KERNBASE,%ecx /* get size of text */ 568 addl $NBPG-1,%ecx /* round up to page */ 569 shrl $PGSHIFT,%ecx /* for this many PTEs */ 570 movl $PG_V|PG_KR,%eax /* specify read only */ 571#if 0 572 movl $_etext,%ecx /* get size of text */ 573 subl $_btext,%ecx 574 addl $NBPG-1,%ecx /* round up to page */ 575 shrl $PGSHIFT,%ecx /* for this many PTEs */ 576 movl $_btext-KERNBASE,%eax /* get offset to physical memory */ 577 orl $PG_V|PG_KR,%eax /* specify read only */ 578#endif 579 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 580 movl %ebx,_KPTphys-KERNBASE /* save in global */ 581 fillkpt 582 583 /* data and bss are r/w */ 584 andl $PG_FRAME,%eax /* strip to just addr of bss */ 585 movl _KERNend-KERNBASE,%ecx /* calculate size */ 586 subl %eax,%ecx 587 shrl $PGSHIFT,%ecx 588 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 589 fillkpt 590#endif /* KGDB || BDE_DEBUGGER */ 591 592/* now initialize the page dir, upages, and p0stack PT */ 593 594 movl $(1+UPAGES+1),%ecx /* number of PTEs */ 595 movl %esi,%eax /* phys address of PTD */ 596 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 597 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 598 movl %esi,%ebx /* calculate pte offset to ptd */ 599 shrl $PGSHIFT-2,%ebx 600 addl %esi,%ebx /* address of page directory */ 601 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 602 fillkpt 603 604/* map I/O memory map */ 605 606 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 607 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 608 movl $0x100-0xa0,%ecx /* for this many pte s, */ 609 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 610 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 611 fillkpt 612 613 /* map proc 0's kernel stack into user page table page */ 614 615 movl $UPAGES,%ecx /* for this many pte s, */ 616 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 617 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 618 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 619 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 620 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 621 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 622 fillkpt 623 624/* 625 * Initialize kernel page table directory 626 */ 627 /* install a pde for temporary double map of bottom of VA */ 628 movl _KPTphys-KERNBASE,%eax 629 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 630 movl %eax,(%esi) /* which is where temp maps! */ 631 632 /* initialize kernel pde's */ 633 movl $(NKPT),%ecx /* for this many PDEs */ 634 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 635 fillkpt 636 637 /* install a pde recursively mapping page directory as a page table! */ 638 movl %esi,%eax /* phys address of ptd in proc 0 */ 639 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 640 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 641 642 /* install a pde to map kernel stack for proc 0 */ 643 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 644 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 645 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 646 647#ifdef BDE_DEBUGGER 648 /* copy and convert stuff from old gdt and idt for debugger */ 649 650 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 651 jne 1f 652 movb $1,_bdb_exists-KERNBASE 6531: 654 pushal 655 subl $2*6,%esp 656 657 sgdt (%esp) 658 movl 2(%esp),%esi /* base address of current gdt */ 659 movl $_gdt-KERNBASE,%edi 660 movl %edi,2(%esp) 661 movl $8*18/4,%ecx 662 cld 663 rep /* copy gdt */ 664 movsl 665 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 666 movb $0x92,-8+5(%edi) 667 668 sidt 6(%esp) 669 movl 6+2(%esp),%esi /* base address of current idt */ 670 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 671 movw 8(%esi),%ax 672 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 673 movl 8+2(%esi),%eax 674 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 675 movl 24+4(%esi),%eax /* same for bpt descriptor */ 676 movw 24(%esi),%ax 677 movl %eax,bdb_bpt_ljmp+1-KERNBASE 678 movl 24+2(%esi),%eax 679 movw %ax,bdb_bpt_ljmp+5-KERNBASE 680 681 movl $_idt-KERNBASE,%edi 682 movl %edi,6+2(%esp) 683 movl $8*4/4,%ecx 684 cld 685 rep /* copy idt */ 686 movsl 687 688 lgdt (%esp) 689 lidt 6(%esp) 690 691 addl $2*6,%esp 692 popal 693#endif /* BDE_DEBUGGER */ 694 695 /* load base of page directory and enable mapping */ 696 movl %esi,%eax /* phys address of ptd in proc 0 */ 697 movl %eax,%cr3 /* load ptd addr into mmu */ 698 movl %cr0,%eax /* get control word */ 699 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 700 movl %eax,%cr0 /* and let's page NOW! */ 701 702 pushl $begin /* jump to high mem */ 703 ret 704 705begin: /* now running relocated at KERNBASE where the system is linked to run */ 706 movl _atdevphys,%edx /* get pte PA */ 707 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 708 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 709 addl $KERNBASE,%edx /* add virtual base */ 710 movl %edx,_atdevbase 711 712 /* set up bootstrap stack */ 713 movl $_kstack+UPAGES*NBPG,%esp /* bootstrap stack end location */ 714 xorl %eax,%eax /* mark end of frames */ 715 movl %eax,%ebp 716 movl _proc0paddr,%eax 717 movl %esi,PCB_CR3(%eax) 718 719#ifdef BDE_DEBUGGER 720 /* relocate debugger gdt entries */ 721 722 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 723 movl $9,%ecx 724reloc_gdt: 725 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 726 addl $8,%eax /* now KERNBASE>>24 */ 727 loop reloc_gdt 728 729 cmpl $0,_bdb_exists 730 je 1f 731 int $3 7321: 733#endif /* BDE_DEBUGGER */ 734 735 /* 736 * Prepare "first" - physical address of first available page 737 * after the kernel+pdir+upages+p0stack+page tables 738 */ 739 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 740 741 pushl %esi /* value of first for init386(first) */ 742 call _init386 /* wire 386 chip for unix operation */ 743 popl %esi 744 745 .globl __ucodesel,__udatasel 746 747 pushl $0 /* unused */ 748 pushl __udatasel /* ss */ 749 pushl $0 /* esp - filled in by execve() */ 750 pushl $PSL_USER /* eflags (IOPL 0, int enab) */ 751 pushl __ucodesel /* cs */ 752 pushl $0 /* eip - filled in by execve() */ 753 subl $(12*4),%esp /* space for rest of registers */ 754 755 pushl %esp /* call main with frame pointer */ 756 call _main /* autoconfiguration, mountroot etc */ 757 758 addl $(13*4),%esp /* back to a frame we can return with */ 759 760 /* 761 * now we've run main() and determined what cpu-type we are, we can 762 * enable write protection and alignment checking on i486 cpus and 763 * above. 764 */ 765#if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU) 766 cmpl $CPUCLASS_386,_cpu_class 767 je 1f 768 movl %cr0,%eax /* get control word */ 769 orl $CR0_WP|CR0_AM,%eax /* enable i486 features */ 770 movl %eax,%cr0 /* and do it */ 771#endif 772 /* 773 * on return from main(), we are process 1 774 * set up address space and stack so that we can 'return' to user mode 775 */ 7761: 777 movl __ucodesel,%eax 778 movl __udatasel,%ecx 779 780 movl %cx,%ds 781 movl %cx,%es 782 movl %ax,%fs /* double map cs to fs */ 783 movl %cx,%gs /* and ds to gs */ 784 iret /* goto user! */ 785 786#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 787 788/* 789 * Signal trampoline, copied to top of user stack 790 */ 791NON_GPROF_ENTRY(sigcode) 792 call SIGF_HANDLER(%esp) 793 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 794 /* copy at 8(%esp)) */ 795 pushl %eax 796 pushl %eax /* junk to fake return address */ 797 movl $SYS_sigreturn,%eax /* sigreturn() */ 798 LCALL(0x7,0) /* enter kernel with args on stack */ 799 hlt /* never gets here */ 800 .align 2 /* long word align */ 801_esigcode: 802 .data 803 .globl _szsigcode 804_szsigcode: 805 .long _esigcode-_sigcode 806 .text 807