locore.s revision 10826
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 1.55 1995/09/15 02:13:18 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 "assym.s" /* system definitions */ 49#include <machine/psl.h> /* processor status longword defs */ 50#include <machine/pte.h> /* page table entry definitions */ 51#include <sys/errno.h> /* error return codes */ 52#include <machine/specialreg.h> /* x86 special registers */ 53#include <machine/cputypes.h> /* x86 cpu type definitions */ 54#include <sys/syscall.h> /* system call numbers */ 55#include <machine/asmacros.h> /* miscellaneous asm macros */ 56#include <sys/reboot.h> 57#include "apm.h" 58 59/* 60 * XXX 61 * 62 * Note: This version greatly munged to avoid various assembler errors 63 * that may be fixed in newer versions of gas. Perhaps newer versions 64 * will have more pleasant appearance. 65 */ 66 67/* 68 * PTmap is recursive pagemap at top of virtual address space. 69 * Within PTmap, the page directory can be found (third indirection). 70 */ 71 .globl _PTmap,_PTD,_PTDpde 72 .set _PTmap,PTDPTDI << PDRSHIFT 73 .set _PTD,_PTmap + (PTDPTDI * NBPG) 74 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE) 75 76/* 77 * Sysmap is the base address of the kernel page tables. 78 * It is a bogus interface for kgdb and isn't used by the kernel itself. 79 */ 80 .set _Sysmap,_PTmap + (KPTDI * NBPG) 81 82/* 83 * APTmap, APTD is the alternate recursive pagemap. 84 * It's used when modifying another process's page tables. 85 */ 86 .globl _APTmap,_APTD,_APTDpde 87 .set _APTmap,APTDPTDI << PDRSHIFT 88 .set _APTD,_APTmap + (APTDPTDI * NBPG) 89 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE) 90 91/* 92 * Access to each processes kernel stack is via a region of 93 * per-process address space (at the beginning), immediatly above 94 * the user process stack. 95 */ 96 .set _kstack,USRSTACK 97 .globl _kstack 98 99/* 100 * Globals 101 */ 102 .data 103 104 .globl tmpstk 105 .space 0x1000 /* space for tmpstk - temporary stack */ 106tmpstk: 107/* 108 * Dummy frame at top of tmpstk to help debuggers print a nice stack trace. 109 */ 110 .long tmpstk+8 /* caller's %ebp */ 111 .long _cpu_switch /* caller */ 112 .long 0 /* %ebp == 0 should terminate trace */ 113 .long _mvesp /* in case %ebp == 0 doesn't work ... */ 114 .long 0x11111111, 0x22222222, 0x33333333, 0x44444444, 0x55555555 115 116 .globl _boothowto,_bootdev 117 118 .globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id,_bootinfo 119 .globl _cpu_high, _cpu_feature 120 121_cpu: .long 0 /* are we 386, 386sx, or 486 */ 122_cpu_id: .long 0 /* stepping ID */ 123_cpu_high: .long 0 /* highest arg to CPUID */ 124_cpu_feature: .long 0 /* features */ 125_cpu_vendor: .space 20 /* CPU origin code */ 126_bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */ 127_cold: .long 1 /* cold till we are not */ 128_atdevbase: .long 0 /* location of start of iomem in virtual */ 129_atdevphys: .long 0 /* location of device mapping ptes (phys) */ 130 131_KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 132 133 .globl _IdlePTD 134_IdlePTD: .long 0 /* phys addr of kernel PTD */ 135 136_KPTphys: .long 0 /* phys addr of kernel page tables */ 137 138 .globl _proc0paddr 139_proc0paddr: .long 0 /* address of proc 0 address space */ 140 141#ifdef BDE_DEBUGGER 142 .globl _bdb_exists /* flag to indicate BDE debugger is available */ 143_bdb_exists: .long 0 144#endif 145 146/* 147 * System Initialization 148 */ 149 .text 150 151/* 152 * btext: beginning of text section. 153 * Also the entry point (jumped to directly from the boot blocks). 154 */ 155NON_GPROF_ENTRY(btext) 156 movw $0x1234,0x472 /* warm boot */ 157 158 /* Set up a real frame, some day we will be doing returns */ 159 pushl %ebp 160 movl %esp, %ebp 161 162 /* Don't trust what the BIOS gives for eflags. */ 163 pushl $PSL_KERNEL 164 popfl 165 166 /* Don't trust what the BIOS gives for %fs and %gs. */ 167 mov %ds, %ax 168 mov %ax, %fs 169 mov %ax, %gs 170 171 /* 172 * This code is called in different ways depending on what loaded 173 * and started the kernel. This is used to detect how we get the 174 * arguments from the other code and what we do with them. 175 * 176 * Old disk boot blocks: 177 * (*btext)(howto, bootdev, cyloffset, esym); 178 * [return address == 0, and can NOT be returned to] 179 * [cyloffset was not supported by the FreeBSD boot code 180 * and always passed in as 0] 181 * [esym is also known as total in the boot code, and 182 * was never properly supported by the FreeBSD boot code] 183 * 184 * Old diskless netboot code: 185 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 186 * [return address != 0, and can NOT be returned to] 187 * If we are being booted by this code it will NOT work, 188 * so we are just going to halt if we find this case. 189 * 190 * New uniform boot code: 191 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 192 * [return address != 0, and can be returned to] 193 * 194 * There may seem to be a lot of wasted arguments in here, but 195 * that is so the newer boot code can still load very old kernels 196 * and old boot code can load new kernels. 197 */ 198 199 /* 200 * The old style disk boot blocks fake a frame on the stack and 201 * did an lret to get here. The frame on the stack has a return 202 * address of 0. 203 */ 204 cmpl $0,4(%ebp) 205 je 2f /* olddiskboot: */ 206 207 /* 208 * We have some form of return address, so this is either the 209 * old diskless netboot code, or the new uniform code. That can 210 * be detected by looking at the 5th argument, it if is 0 we 211 * we are being booted by the new unifrom boot code. 212 */ 213 cmpl $0,24(%ebp) 214 je 1f /* newboot: */ 215 216 /* 217 * Seems we have been loaded by the old diskless boot code, we 218 * don't stand a chance of running as the diskless structure 219 * changed considerably between the two, so just halt. 220 */ 221 hlt 222 223 /* 224 * We have been loaded by the new uniform boot code. 225 * Lets check the bootinfo version, and if we do not understand 226 * it we return to the loader with a status of 1 to indicate this error 227 */ 2281: /* newboot: */ 229 movl 28(%ebp),%ebx /* &bootinfo.version */ 230 movl BI_VERSION(%ebx),%eax 231 cmpl $1,%eax /* We only understand version 1 */ 232 je 1f 233 movl $1,%eax /* Return status */ 234 leave 235 ret 236 2371: 238 /* 239 * If we have a kernelname copy it in 240 */ 241 movl BI_KERNELNAME(%ebx),%esi 242 cmpl $0,%esi 243 je 2f /* No kernelname */ 244 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 245 lea _kernelname-KERNBASE,%edi 246 cmpb $'/',(%esi) /* Make sure it starts with a slash */ 247 je 1f 248 movb $'/',(%edi) 249 incl %edi 250 decl %ecx 2511: 252 cld 253 rep 254 movsb 255 2562: 257 /* 258 * Determine the size of the boot loader's copy of the bootinfo 259 * struct. This is impossible to do properly because old versions 260 * of the struct don't contain a size field and there are 2 old 261 * versions with the same version number. 262 */ 263 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */ 264 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */ 265 je got_bi_size /* no, sizeless version */ 266 movl BI_SIZE(%ebx),%ecx 267got_bi_size: 268 269 /* 270 * Copy the common part of the bootinfo struct 271 */ 272 movl %ebx,%esi 273 movl $_bootinfo-KERNBASE,%edi 274 cmpl $BOOTINFO_SIZE,%ecx 275 jbe got_common_bi_size 276 movl $BOOTINFO_SIZE,%ecx 277got_common_bi_size: 278 cld 279 rep 280 movsb 281 282#ifdef NFS 283 /* 284 * If we have a nfs_diskless structure copy it in 285 */ 286 movl BI_NFS_DISKLESS(%ebx),%esi 287 cmpl $0,%esi 288 je 2f 289 lea _nfs_diskless-KERNBASE,%edi 290 movl $NFSDISKLESS_SIZE,%ecx 291 cld 292 rep 293 movsb 294 lea _nfs_diskless_valid-KERNBASE,%edi 295 movl $1,(%edi) 296#endif 297 298 /* 299 * The old style disk boot. 300 * (*btext)(howto, bootdev, cyloffset, esym); 301 * Note that the newer boot code just falls into here to pick 302 * up howto and bootdev, cyloffset and esym are no longer used 303 */ 3042: /* olddiskboot: */ 305 movl 8(%ebp),%eax 306 movl %eax,_boothowto-KERNBASE 307 movl 12(%ebp),%eax 308 movl %eax,_bootdev-KERNBASE 309 310#if NAPM > 0 311 /* call APM BIOS driver setup (i386/apm/apm_setup.s) */ 312 call _apm_setup 313#endif /* NAPM */ 314 315 /* Find out our CPU type. */ 316 317 /* Try to toggle alignment check flag; does not exist on 386. */ 318 pushfl 319 popl %eax 320 movl %eax,%ecx 321 orl $PSL_AC,%eax 322 pushl %eax 323 popfl 324 pushfl 325 popl %eax 326 xorl %ecx,%eax 327 andl $PSL_AC,%eax 328 pushl %ecx 329 popfl 330 331 testl %eax,%eax 332 jnz 1f 333 movl $CPU_386,_cpu-KERNBASE 334 jmp 2f 335 3361: /* Try to toggle identification flag; does not exist on early 486s. */ 337 pushfl 338 popl %eax 339 movl %eax,%ecx 340 xorl $PSL_ID,%eax 341 pushl %eax 342 popfl 343 pushfl 344 popl %eax 345 xorl %ecx,%eax 346 andl $PSL_ID,%eax 347 pushl %ecx 348 popfl 349 350 testl %eax,%eax 351 jnz 1f 352 movl $CPU_486,_cpu-KERNBASE 353 354 /* check for Cyrix 486DLC -- based on check routine */ 355 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 356 xorw %dx,%dx 357 cmpw %dx,%dx # set flags to known state 358 pushfw 359 popw %cx # store flags in ecx 360 movw $0xffff,%ax 361 movw $0x0004,%bx 362 divw %bx 363 pushfw 364 popw %ax 365 andw $0x08d5,%ax # mask off important bits 366 andw $0x08d5,%cx 367 cmpw %ax,%cx 368 369 jnz 2f # if flags changed, Intel chip 370 371 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 372 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 373 movw $0x0078,_cpu_vendor-KERNBASE+4 374 375#ifndef CYRIX_CACHE_WORKS 376 /* Disable caching of the ISA hole only. */ 377 invd 378 movb $CCR0,%al # Configuration Register index (CCR0) 379 outb %al,$0x22 380 inb $0x23,%al 381 orb $(CCR0_NC1|CCR0_BARB),%al 382 movb %al,%ah 383 movb $CCR0,%al 384 outb %al,$0x22 385 movb %ah,%al 386 outb %al,$0x23 387 invd 388#else /* CYRIX_CACHE_WORKS */ 389 /* Set cache parameters */ 390 invd # Start with guaranteed clean cache 391 movb $CCR0,%al # Configuration Register index (CCR0) 392 outb %al,$0x22 393 inb $0x23,%al 394 andb $~CCR0_NC0,%al 395#ifndef CYRIX_CACHE_REALLY_WORKS 396 orb $(CCR0_NC1|CCR0_BARB),%al 397#else 398 orb $CCR0_NC1,%al 399#endif 400 movb %al,%ah 401 movb $CCR0,%al 402 outb %al,$0x22 403 movb %ah,%al 404 outb %al,$0x23 405 /* clear non-cacheable region 1 */ 406 movb $(NCR1+2),%al 407 outb %al,$0x22 408 movb $NCR_SIZE_0K,%al 409 outb %al,$0x23 410 /* clear non-cacheable region 2 */ 411 movb $(NCR2+2),%al 412 outb %al,$0x22 413 movb $NCR_SIZE_0K,%al 414 outb %al,$0x23 415 /* clear non-cacheable region 3 */ 416 movb $(NCR3+2),%al 417 outb %al,$0x22 418 movb $NCR_SIZE_0K,%al 419 outb %al,$0x23 420 /* clear non-cacheable region 4 */ 421 movb $(NCR4+2),%al 422 outb %al,$0x22 423 movb $NCR_SIZE_0K,%al 424 outb %al,$0x23 425 /* enable caching in CR0 */ 426 movl %cr0,%eax 427 andl $~(CR0_CD|CR0_NW),%eax 428 movl %eax,%cr0 429 invd 430#endif /* CYRIX_CACHE_WORKS */ 431 jmp 2f 432 4331: /* Use the `cpuid' instruction. */ 434 xorl %eax,%eax 435 .byte 0x0f,0xa2 # cpuid 0 436 movl %eax,_cpu_high-KERNBASE # highest capability 437 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 438 movl %edx,_cpu_vendor+4-KERNBASE 439 movl %ecx,_cpu_vendor+8-KERNBASE 440 movb $0,_cpu_vendor+12-KERNBASE 441 442 movl $1,%eax 443 .byte 0x0f,0xa2 # cpuid 1 444 movl %eax,_cpu_id-KERNBASE # store cpu_id 445 movl %edx,_cpu_feature-KERNBASE # store cpu_feature 446 rorl $8,%eax # extract family type 447 andl $15,%eax 448 cmpl $5,%eax 449 jae 1f 450 451 /* less than Pentium; must be 486 */ 452 movl $CPU_486,_cpu-KERNBASE 453 jmp 2f 454 4551: movl $CPU_586,_cpu-KERNBASE 4562: 457 458 /* 459 * Finished with old stack; load new %esp now instead of later so 460 * we can trace this code without having to worry about the trace 461 * trap clobbering the memory test or the zeroing of the bss+bootstrap 462 * page tables. 463 * 464 * XXX - wdboot clears the bss after testing that this is safe. 465 * This is too wasteful - memory below 640K is scarce. The boot 466 * program should check: 467 * text+data <= &stack_variable - more_space_for_stack 468 * text+data+bss+pad+space_for_page_tables <= end_of_memory 469 * Oops, the gdt is in the carcass of the boot program so clearing 470 * the rest of memory is still not possible. 471 */ 472 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 473 474/* 475 * Virtual address space of kernel: 476 * 477 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 478 * pages: 1 UPAGES (2) 1 NKPT (7) 479 */ 480 481/* find end of kernel image */ 482 movl $_end-KERNBASE,%ecx 483 addl $NBPG-1,%ecx /* page align up */ 484 andl $~(NBPG-1),%ecx 485 movl %ecx,%esi /* esi = start of free memory */ 486 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 487 488/* clear bss */ 489 movl $_edata-KERNBASE,%edi 490 subl %edi,%ecx /* get amount to clear */ 491 xorl %eax,%eax /* specify zero fill */ 492 cld 493 rep 494 stosb 495 496#ifdef DDB 497/* include symbols in "kernel image" if they are loaded */ 498 movl _bootinfo+BI_ESYMTAB-KERNBASE,%edi 499 testl %edi,%edi 500 je over_symalloc 501 addl $NBPG-1,%edi 502 andl $~(NBPG-1),%edi 503 movl %edi,%esi 504 movl %esi,_KERNend-KERNBASE 505 movl $KERNBASE,%edi 506 addl %edi,_bootinfo+BI_SYMTAB-KERNBASE 507 addl %edi,_bootinfo+BI_ESYMTAB-KERNBASE 508over_symalloc: 509#endif 510 511/* 512 * The value in esi is both the end of the kernel bss and a pointer to 513 * the kernel page directory, and is used by the rest of locore to build 514 * the tables. 515 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 516 * page table pages) is then passed on the stack to init386(first) as 517 * the value first. esi should ALWAYS be page aligned!! 518 */ 519 movl %esi,%ecx /* Get current first availiable address */ 520 521/* clear pagetables, page directory, stack, etc... */ 522 movl %esi,%edi /* base (page directory) */ 523 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 524 xorl %eax,%eax /* specify zero fill */ 525 cld 526 rep 527 stosb 528 529/* physical address of Idle proc/kernel page directory */ 530 movl %esi,_IdlePTD-KERNBASE 531 532/* 533 * fillkpt 534 * eax = (page frame address | control | status) == pte 535 * ebx = address of page table 536 * ecx = how many pages to map 537 */ 538#define fillkpt \ 5391: movl %eax,(%ebx) ; \ 540 addl $NBPG,%eax ; /* increment physical address */ \ 541 addl $4,%ebx ; /* next pte */ \ 542 loop 1b ; 543 544/* 545 * Map Kernel 546 * 547 * First step - build page tables 548 */ 549#if defined (KGDB) || defined (BDE_DEBUGGER) 550 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 551 shrl $PGSHIFT,%ecx /* for this many PTEs */ 552#ifdef BDE_DEBUGGER 553 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 554 jae 1f 555 movl $0xa0,%ecx 5561: 557#endif /* BDE_DEBUGGER */ 558 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 559 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 560 movl %ebx,_KPTphys-KERNBASE /* save in global */ 561 fillkpt 562 563#else /* !KGDB && !BDE_DEBUGGER */ 564 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 565 movl $_etext-KERNBASE,%ecx /* get size of text */ 566 addl $NBPG-1,%ecx /* round up to page */ 567 shrl $PGSHIFT,%ecx /* for this many PTEs */ 568 movl $PG_V|PG_KR,%eax /* specify read only */ 569#if 0 570 movl $_etext,%ecx /* get size of text */ 571 subl $_btext,%ecx 572 addl $NBPG-1,%ecx /* round up to page */ 573 shrl $PGSHIFT,%ecx /* for this many PTEs */ 574 movl $_btext-KERNBASE,%eax /* get offset to physical memory */ 575 orl $PG_V|PG_KR,%eax /* specify read only */ 576#endif 577 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 578 movl %ebx,_KPTphys-KERNBASE /* save in global */ 579 fillkpt 580 581 /* data and bss are r/w */ 582 andl $PG_FRAME,%eax /* strip to just addr of bss */ 583 movl _KERNend-KERNBASE,%ecx /* calculate size */ 584 subl %eax,%ecx 585 shrl $PGSHIFT,%ecx 586 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 587 fillkpt 588#endif /* KGDB || BDE_DEBUGGER */ 589 590/* now initialize the page dir, upages, and p0stack PT */ 591 592 movl $(1+UPAGES+1),%ecx /* number of PTEs */ 593 movl %esi,%eax /* phys address of PTD */ 594 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 595 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 596 movl %esi,%ebx /* calculate pte offset to ptd */ 597 shrl $PGSHIFT-2,%ebx 598 addl %esi,%ebx /* address of page directory */ 599 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 600 fillkpt 601 602/* map I/O memory map */ 603 604 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 605 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 606 movl $0x100-0xa0,%ecx /* for this many pte s, */ 607 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 608 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 609 fillkpt 610 611 /* map proc 0's kernel stack into user page table page */ 612 613 movl $UPAGES,%ecx /* for this many pte s, */ 614 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 615 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 616 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 617 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 618 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 619 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 620 fillkpt 621 622/* 623 * Initialize kernel page table directory 624 */ 625 /* install a pde for temporary double map of bottom of VA */ 626 movl _KPTphys-KERNBASE,%eax 627 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 628 movl %eax,(%esi) /* which is where temp maps! */ 629 630 /* initialize kernel pde's */ 631 movl $(NKPT),%ecx /* for this many PDEs */ 632 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 633 fillkpt 634 635 /* install a pde recursively mapping page directory as a page table! */ 636 movl %esi,%eax /* phys address of ptd in proc 0 */ 637 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 638 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 639 640 /* install a pde to map kernel stack for proc 0 */ 641 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 642 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 643 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 644 645#ifdef BDE_DEBUGGER 646 /* copy and convert stuff from old gdt and idt for debugger */ 647 648 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 649 jne 1f 650 movb $1,_bdb_exists-KERNBASE 6511: 652 pushal 653 subl $2*6,%esp 654 655 sgdt (%esp) 656 movl 2(%esp),%esi /* base address of current gdt */ 657 movl $_gdt-KERNBASE,%edi 658 movl %edi,2(%esp) 659 movl $8*18/4,%ecx 660 cld 661 rep /* copy gdt */ 662 movsl 663 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 664 movb $0x92,-8+5(%edi) 665 666 sidt 6(%esp) 667 movl 6+2(%esp),%esi /* base address of current idt */ 668 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 669 movw 8(%esi),%ax 670 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 671 movl 8+2(%esi),%eax 672 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 673 movl 24+4(%esi),%eax /* same for bpt descriptor */ 674 movw 24(%esi),%ax 675 movl %eax,bdb_bpt_ljmp+1-KERNBASE 676 movl 24+2(%esi),%eax 677 movw %ax,bdb_bpt_ljmp+5-KERNBASE 678 679 movl $_idt-KERNBASE,%edi 680 movl %edi,6+2(%esp) 681 movl $8*4/4,%ecx 682 cld 683 rep /* copy idt */ 684 movsl 685 686 lgdt (%esp) 687 lidt 6(%esp) 688 689 addl $2*6,%esp 690 popal 691#endif /* BDE_DEBUGGER */ 692 693 /* load base of page directory and enable mapping */ 694 movl %esi,%eax /* phys address of ptd in proc 0 */ 695 movl %eax,%cr3 /* load ptd addr into mmu */ 696 movl %cr0,%eax /* get control word */ 697 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 698 movl %eax,%cr0 /* and let's page NOW! */ 699 700 pushl $begin /* jump to high mem */ 701 ret 702 703begin: /* now running relocated at KERNBASE where the system is linked to run */ 704 movl _atdevphys,%edx /* get pte PA */ 705 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 706 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 707 addl $KERNBASE,%edx /* add virtual base */ 708 movl %edx,_atdevbase 709 710 /* set up bootstrap stack */ 711 movl $_kstack+UPAGES*NBPG,%esp /* bootstrap stack end location */ 712 xorl %eax,%eax /* mark end of frames */ 713 movl %eax,%ebp 714 movl _proc0paddr,%eax 715 movl %esi,PCB_CR3(%eax) 716 717#ifdef BDE_DEBUGGER 718 /* relocate debugger gdt entries */ 719 720 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 721 movl $9,%ecx 722reloc_gdt: 723 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 724 addl $8,%eax /* now KERNBASE>>24 */ 725 loop reloc_gdt 726 727 cmpl $0,_bdb_exists 728 je 1f 729 int $3 7301: 731#endif /* BDE_DEBUGGER */ 732 733 /* 734 * Prepare "first" - physical address of first available page 735 * after the kernel+pdir+upages+p0stack+page tables 736 */ 737 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 738 739 pushl %esi /* value of first for init386(first) */ 740 call _init386 /* wire 386 chip for unix operation */ 741 popl %esi 742 743 .globl __ucodesel,__udatasel 744 745 pushl $0 /* unused */ 746 pushl __udatasel /* ss */ 747 pushl $0 /* esp - filled in by execve() */ 748 pushl $PSL_USER /* eflags (IOPL 0, int enab) */ 749 pushl __ucodesel /* cs */ 750 pushl $0 /* eip - filled in by execve() */ 751 subl $(12*4),%esp /* space for rest of registers */ 752 753 pushl %esp /* call main with frame pointer */ 754 call _main /* autoconfiguration, mountroot etc */ 755 756 addl $(13*4),%esp /* back to a frame we can return with */ 757 758 /* 759 * now we've run main() and determined what cpu-type we are, we can 760 * enable write protection and alignment checking on i486 cpus and 761 * above. 762 */ 763#if defined(I486_CPU) || defined(I586_CPU) 764 cmpl $CPUCLASS_386,_cpu_class 765 je 1f 766 movl %cr0,%eax /* get control word */ 767 orl $CR0_WP|CR0_AM,%eax /* enable i486 features */ 768 movl %eax,%cr0 /* and do it */ 769#endif 770 /* 771 * on return from main(), we are process 1 772 * set up address space and stack so that we can 'return' to user mode 773 */ 7741: 775 movl __ucodesel,%eax 776 movl __udatasel,%ecx 777 778 movl %cx,%ds 779 movl %cx,%es 780 movl %ax,%fs /* double map cs to fs */ 781 movl %cx,%gs /* and ds to gs */ 782 iret /* goto user! */ 783 784#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 785 786NON_GPROF_ENTRY(sigcode) 787 call SIGF_HANDLER(%esp) 788 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 789 /* copy at 8(%esp)) */ 790 pushl %eax 791 pushl %eax /* junk to fake return address */ 792 movl $103,%eax /* XXX sigreturn() */ 793 LCALL(0x7,0) /* enter kernel with args on stack */ 794 hlt /* never gets here */ 795 796 .globl _szsigcode 797_szsigcode: 798 .long _szsigcode-_sigcode 799