locore.s revision 13729
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 1.60 1996/01/04 21:10:48 wollman 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/* 110 * Dummy frame at top of tmpstk to help debuggers print a nice stack trace. 111 */ 112 .long tmpstk+8 /* caller's %ebp */ 113 .long _cpu_switch /* caller */ 114 .long 0 /* %ebp == 0 should terminate trace */ 115 .long _mvesp /* in case %ebp == 0 doesn't work ... */ 116 .long 0x11111111, 0x22222222, 0x33333333, 0x44444444, 0x55555555 117 118 .globl _boothowto,_bootdev 119 120 .globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id,_bootinfo 121 .globl _cpu_high, _cpu_feature 122 123_cpu: .long 0 /* are we 386, 386sx, or 486 */ 124_cpu_id: .long 0 /* stepping ID */ 125_cpu_high: .long 0 /* highest arg to CPUID */ 126_cpu_feature: .long 0 /* features */ 127_cpu_vendor: .space 20 /* CPU origin code */ 128_bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */ 129_cold: .long 1 /* cold till we are not */ 130_atdevbase: .long 0 /* location of start of iomem in virtual */ 131_atdevphys: .long 0 /* location of device mapping ptes (phys) */ 132 133_KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 134 135 .globl _IdlePTD 136_IdlePTD: .long 0 /* phys addr of kernel PTD */ 137 138_KPTphys: .long 0 /* phys addr of kernel page tables */ 139 140 .globl _proc0paddr 141_proc0paddr: .long 0 /* address of proc 0 address space */ 142 143#ifdef BDE_DEBUGGER 144 .globl _bdb_exists /* flag to indicate BDE debugger is available */ 145_bdb_exists: .long 0 146#endif 147 148/* 149 * System Initialization 150 */ 151 .text 152 153/* 154 * btext: beginning of text section. 155 * Also the entry point (jumped to directly from the boot blocks). 156 */ 157NON_GPROF_ENTRY(btext) 158 movw $0x1234,0x472 /* warm boot */ 159 160 /* Set up a real frame, some day we will be doing returns */ 161 pushl %ebp 162 movl %esp, %ebp 163 164 /* Don't trust what the BIOS gives for eflags. */ 165 pushl $PSL_KERNEL 166 popfl 167 168 /* Don't trust what the BIOS gives for %fs and %gs. */ 169 mov %ds, %ax 170 mov %ax, %fs 171 mov %ax, %gs 172 173 /* 174 * This code is called in different ways depending on what loaded 175 * and started the kernel. This is used to detect how we get the 176 * arguments from the other code and what we do with them. 177 * 178 * Old disk boot blocks: 179 * (*btext)(howto, bootdev, cyloffset, esym); 180 * [return address == 0, and can NOT be returned to] 181 * [cyloffset was not supported by the FreeBSD boot code 182 * and always passed in as 0] 183 * [esym is also known as total in the boot code, and 184 * was never properly supported by the FreeBSD boot code] 185 * 186 * Old diskless netboot code: 187 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 188 * [return address != 0, and can NOT be returned to] 189 * If we are being booted by this code it will NOT work, 190 * so we are just going to halt if we find this case. 191 * 192 * New uniform boot code: 193 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 194 * [return address != 0, and can be returned to] 195 * 196 * There may seem to be a lot of wasted arguments in here, but 197 * that is so the newer boot code can still load very old kernels 198 * and old boot code can load new kernels. 199 */ 200 201 /* 202 * The old style disk boot blocks fake a frame on the stack and 203 * did an lret to get here. The frame on the stack has a return 204 * address of 0. 205 */ 206 cmpl $0,4(%ebp) 207 je 2f /* olddiskboot: */ 208 209 /* 210 * We have some form of return address, so this is either the 211 * old diskless netboot code, or the new uniform code. That can 212 * be detected by looking at the 5th argument, it if is 0 we 213 * we are being booted by the new unifrom boot code. 214 */ 215 cmpl $0,24(%ebp) 216 je 1f /* newboot: */ 217 218 /* 219 * Seems we have been loaded by the old diskless boot code, we 220 * don't stand a chance of running as the diskless structure 221 * changed considerably between the two, so just halt. 222 */ 223 hlt 224 225 /* 226 * We have been loaded by the new uniform boot code. 227 * Lets check the bootinfo version, and if we do not understand 228 * it we return to the loader with a status of 1 to indicate this error 229 */ 2301: /* newboot: */ 231 movl 28(%ebp),%ebx /* &bootinfo.version */ 232 movl BI_VERSION(%ebx),%eax 233 cmpl $1,%eax /* We only understand version 1 */ 234 je 1f 235 movl $1,%eax /* Return status */ 236 leave 237 ret 238 2391: 240 /* 241 * If we have a kernelname copy it in 242 */ 243 movl BI_KERNELNAME(%ebx),%esi 244 cmpl $0,%esi 245 je 2f /* No kernelname */ 246 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 247 lea _kernelname-KERNBASE,%edi 248 cmpb $'/',(%esi) /* Make sure it starts with a slash */ 249 je 1f 250 movb $'/',(%edi) 251 incl %edi 252 decl %ecx 2531: 254 cld 255 rep 256 movsb 257 2582: 259 /* 260 * Determine the size of the boot loader's copy of the bootinfo 261 * struct. This is impossible to do properly because old versions 262 * of the struct don't contain a size field and there are 2 old 263 * versions with the same version number. 264 */ 265 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */ 266 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */ 267 je got_bi_size /* no, sizeless version */ 268 movl BI_SIZE(%ebx),%ecx 269got_bi_size: 270 271 /* 272 * Copy the common part of the bootinfo struct 273 */ 274 movl %ebx,%esi 275 movl $_bootinfo-KERNBASE,%edi 276 cmpl $BOOTINFO_SIZE,%ecx 277 jbe got_common_bi_size 278 movl $BOOTINFO_SIZE,%ecx 279got_common_bi_size: 280 cld 281 rep 282 movsb 283 284#ifdef NFS 285 /* 286 * If we have a nfs_diskless structure copy it in 287 */ 288 movl BI_NFS_DISKLESS(%ebx),%esi 289 cmpl $0,%esi 290 je 2f 291 lea _nfs_diskless-KERNBASE,%edi 292 movl $NFSDISKLESS_SIZE,%ecx 293 cld 294 rep 295 movsb 296 lea _nfs_diskless_valid-KERNBASE,%edi 297 movl $1,(%edi) 298#endif 299 300 /* 301 * The old style disk boot. 302 * (*btext)(howto, bootdev, cyloffset, esym); 303 * Note that the newer boot code just falls into here to pick 304 * up howto and bootdev, cyloffset and esym are no longer used 305 */ 3062: /* olddiskboot: */ 307 movl 8(%ebp),%eax 308 movl %eax,_boothowto-KERNBASE 309 movl 12(%ebp),%eax 310 movl %eax,_bootdev-KERNBASE 311 312#if NAPM > 0 313 /* call APM BIOS driver setup (i386/apm/apm_setup.s) */ 314 call _apm_setup 315#endif /* NAPM */ 316 317 /* Find out our CPU type. */ 318 319 /* Try to toggle alignment check flag; does not exist on 386. */ 320 pushfl 321 popl %eax 322 movl %eax,%ecx 323 orl $PSL_AC,%eax 324 pushl %eax 325 popfl 326 pushfl 327 popl %eax 328 xorl %ecx,%eax 329 andl $PSL_AC,%eax 330 pushl %ecx 331 popfl 332 333 testl %eax,%eax 334 jnz 1f 335 movl $CPU_386,_cpu-KERNBASE 336 jmp 3f 337 3381: /* Try to toggle identification flag; does not exist on early 486s. */ 339 pushfl 340 popl %eax 341 movl %eax,%ecx 342 xorl $PSL_ID,%eax 343 pushl %eax 344 popfl 345 pushfl 346 popl %eax 347 xorl %ecx,%eax 348 andl $PSL_ID,%eax 349 pushl %ecx 350 popfl 351 352 testl %eax,%eax 353 jnz 1f 354 movl $CPU_486,_cpu-KERNBASE 355 356 /* check for Cyrix 486DLC -- based on check routine */ 357 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 358 xorw %dx,%dx 359 cmpw %dx,%dx # set flags to known state 360 pushfw 361 popw %cx # store flags in ecx 362 movw $0xffff,%ax 363 movw $0x0004,%bx 364 divw %bx 365 pushfw 366 popw %ax 367 andw $0x08d5,%ax # mask off important bits 368 andw $0x08d5,%cx 369 cmpw %ax,%cx 370 371 jnz 3f # if flags changed, Intel chip 372 373 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 374 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 375 movw $0x0078,_cpu_vendor-KERNBASE+4 376 377#ifndef CYRIX_CACHE_WORKS 378 /* Disable caching of the ISA hole only. */ 379 invd 380 movb $CCR0,%al # Configuration Register index (CCR0) 381 outb %al,$0x22 382 inb $0x23,%al 383 orb $(CCR0_NC1|CCR0_BARB),%al 384 movb %al,%ah 385 movb $CCR0,%al 386 outb %al,$0x22 387 movb %ah,%al 388 outb %al,$0x23 389 invd 390#else /* CYRIX_CACHE_WORKS */ 391 /* Set cache parameters */ 392 invd # Start with guaranteed clean cache 393 movb $CCR0,%al # Configuration Register index (CCR0) 394 outb %al,$0x22 395 inb $0x23,%al 396 andb $~CCR0_NC0,%al 397#ifndef CYRIX_CACHE_REALLY_WORKS 398 orb $(CCR0_NC1|CCR0_BARB),%al 399#else 400 orb $CCR0_NC1,%al 401#endif 402 movb %al,%ah 403 movb $CCR0,%al 404 outb %al,$0x22 405 movb %ah,%al 406 outb %al,$0x23 407 /* clear non-cacheable region 1 */ 408 movb $(NCR1+2),%al 409 outb %al,$0x22 410 movb $NCR_SIZE_0K,%al 411 outb %al,$0x23 412 /* clear non-cacheable region 2 */ 413 movb $(NCR2+2),%al 414 outb %al,$0x22 415 movb $NCR_SIZE_0K,%al 416 outb %al,$0x23 417 /* clear non-cacheable region 3 */ 418 movb $(NCR3+2),%al 419 outb %al,$0x22 420 movb $NCR_SIZE_0K,%al 421 outb %al,$0x23 422 /* clear non-cacheable region 4 */ 423 movb $(NCR4+2),%al 424 outb %al,$0x22 425 movb $NCR_SIZE_0K,%al 426 outb %al,$0x23 427 /* enable caching in CR0 */ 428 movl %cr0,%eax 429 andl $~(CR0_CD|CR0_NW),%eax 430 movl %eax,%cr0 431 invd 432#endif /* CYRIX_CACHE_WORKS */ 433 jmp 3f 434 4351: /* Use the `cpuid' instruction. */ 436 xorl %eax,%eax 437 .byte 0x0f,0xa2 # cpuid 0 438 movl %eax,_cpu_high-KERNBASE # highest capability 439 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 440 movl %edx,_cpu_vendor+4-KERNBASE 441 movl %ecx,_cpu_vendor+8-KERNBASE 442 movb $0,_cpu_vendor+12-KERNBASE 443 444 movl $1,%eax 445 .byte 0x0f,0xa2 # cpuid 1 446 movl %eax,_cpu_id-KERNBASE # store cpu_id 447 movl %edx,_cpu_feature-KERNBASE # store cpu_feature 448 rorl $8,%eax # extract family type 449 andl $15,%eax 450 cmpl $5,%eax 451 jae 1f 452 453 /* less than Pentium; must be 486 */ 454 movl $CPU_486,_cpu-KERNBASE 455 jmp 3f 4561: 457 /* a Pentium? */ 458 cmpl $5,%eax 459 jne 2f 460 movl $CPU_586,_cpu-KERNBASE 461 jmp 3f 4622: 463 /* Greater than Pentium...call it a Pentium Pro */ 464 movl $CPU_686,_cpu-KERNBASE 4653: 466 467 /* 468 * Finished with old stack; load new %esp now instead of later so 469 * we can trace this code without having to worry about the trace 470 * trap clobbering the memory test or the zeroing of the bss+bootstrap 471 * page tables. 472 * 473 * XXX - wdboot clears the bss after testing that this is safe. 474 * This is too wasteful - memory below 640K is scarce. The boot 475 * program should check: 476 * text+data <= &stack_variable - more_space_for_stack 477 * text+data+bss+pad+space_for_page_tables <= end_of_memory 478 * Oops, the gdt is in the carcass of the boot program so clearing 479 * the rest of memory is still not possible. 480 */ 481 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 482 483/* 484 * Virtual address space of kernel: 485 * 486 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 487 * pages: 1 UPAGES (2) 1 NKPT (7) 488 */ 489 490/* find end of kernel image */ 491 movl $_end-KERNBASE,%ecx 492 addl $NBPG-1,%ecx /* page align up */ 493 andl $~(NBPG-1),%ecx 494 movl %ecx,%esi /* esi = start of free memory */ 495 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 496 497/* clear bss */ 498 movl $_edata-KERNBASE,%edi 499 subl %edi,%ecx /* get amount to clear */ 500 xorl %eax,%eax /* specify zero fill */ 501 cld 502 rep 503 stosb 504 505#ifdef DDB 506/* include symbols in "kernel image" if they are loaded */ 507 movl _bootinfo+BI_ESYMTAB-KERNBASE,%edi 508 testl %edi,%edi 509 je over_symalloc 510 addl $NBPG-1,%edi 511 andl $~(NBPG-1),%edi 512 movl %edi,%esi 513 movl %esi,_KERNend-KERNBASE 514 movl $KERNBASE,%edi 515 addl %edi,_bootinfo+BI_SYMTAB-KERNBASE 516 addl %edi,_bootinfo+BI_ESYMTAB-KERNBASE 517over_symalloc: 518#endif 519 520/* 521 * The value in esi is both the end of the kernel bss and a pointer to 522 * the kernel page directory, and is used by the rest of locore to build 523 * the tables. 524 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 525 * page table pages) is then passed on the stack to init386(first) as 526 * the value first. esi should ALWAYS be page aligned!! 527 */ 528 movl %esi,%ecx /* Get current first availiable address */ 529 530/* clear pagetables, page directory, stack, etc... */ 531 movl %esi,%edi /* base (page directory) */ 532 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 533 xorl %eax,%eax /* specify zero fill */ 534 cld 535 rep 536 stosb 537 538/* physical address of Idle proc/kernel page directory */ 539 movl %esi,_IdlePTD-KERNBASE 540 541/* 542 * fillkpt 543 * eax = (page frame address | control | status) == pte 544 * ebx = address of page table 545 * ecx = how many pages to map 546 */ 547#define fillkpt \ 5481: movl %eax,(%ebx) ; \ 549 addl $NBPG,%eax ; /* increment physical address */ \ 550 addl $4,%ebx ; /* next pte */ \ 551 loop 1b ; 552 553/* 554 * Map Kernel 555 * 556 * First step - build page tables 557 */ 558#if defined (KGDB) || defined (BDE_DEBUGGER) 559 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 560 shrl $PGSHIFT,%ecx /* for this many PTEs */ 561#ifdef BDE_DEBUGGER 562 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 563 jae 1f 564 movl $0xa0,%ecx 5651: 566#endif /* BDE_DEBUGGER */ 567 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 568 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 569 movl %ebx,_KPTphys-KERNBASE /* save in global */ 570 fillkpt 571 572#else /* !KGDB && !BDE_DEBUGGER */ 573 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 574 movl $_etext-KERNBASE,%ecx /* get size of text */ 575 addl $NBPG-1,%ecx /* round up to page */ 576 shrl $PGSHIFT,%ecx /* for this many PTEs */ 577 movl $PG_V|PG_KR,%eax /* specify read only */ 578#if 0 579 movl $_etext,%ecx /* get size of text */ 580 subl $_btext,%ecx 581 addl $NBPG-1,%ecx /* round up to page */ 582 shrl $PGSHIFT,%ecx /* for this many PTEs */ 583 movl $_btext-KERNBASE,%eax /* get offset to physical memory */ 584 orl $PG_V|PG_KR,%eax /* specify read only */ 585#endif 586 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 587 movl %ebx,_KPTphys-KERNBASE /* save in global */ 588 fillkpt 589 590 /* data and bss are r/w */ 591 andl $PG_FRAME,%eax /* strip to just addr of bss */ 592 movl _KERNend-KERNBASE,%ecx /* calculate size */ 593 subl %eax,%ecx 594 shrl $PGSHIFT,%ecx 595 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 596 fillkpt 597#endif /* KGDB || BDE_DEBUGGER */ 598 599/* now initialize the page dir, upages, and p0stack PT */ 600 601 movl $(1+UPAGES+1),%ecx /* number of PTEs */ 602 movl %esi,%eax /* phys address of PTD */ 603 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 604 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 605 movl %esi,%ebx /* calculate pte offset to ptd */ 606 shrl $PGSHIFT-2,%ebx 607 addl %esi,%ebx /* address of page directory */ 608 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 609 fillkpt 610 611/* map I/O memory map */ 612 613 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 614 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 615 movl $0x100-0xa0,%ecx /* for this many pte s, */ 616 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 617 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 618 fillkpt 619 620 /* map proc 0's kernel stack into user page table page */ 621 622 movl $UPAGES,%ecx /* for this many pte s, */ 623 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 624 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 625 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 626 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 627 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 628 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 629 fillkpt 630 631/* 632 * Initialize kernel page table directory 633 */ 634 /* install a pde for temporary double map of bottom of VA */ 635 movl _KPTphys-KERNBASE,%eax 636 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 637 movl %eax,(%esi) /* which is where temp maps! */ 638 639 /* initialize kernel pde's */ 640 movl $(NKPT),%ecx /* for this many PDEs */ 641 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 642 fillkpt 643 644 /* install a pde recursively mapping page directory as a page table! */ 645 movl %esi,%eax /* phys address of ptd in proc 0 */ 646 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 647 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 648 649 /* install a pde to map kernel stack for proc 0 */ 650 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 651 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 652 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 653 654#ifdef BDE_DEBUGGER 655 /* copy and convert stuff from old gdt and idt for debugger */ 656 657 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 658 jne 1f 659 movb $1,_bdb_exists-KERNBASE 6601: 661 pushal 662 subl $2*6,%esp 663 664 sgdt (%esp) 665 movl 2(%esp),%esi /* base address of current gdt */ 666 movl $_gdt-KERNBASE,%edi 667 movl %edi,2(%esp) 668 movl $8*18/4,%ecx 669 cld 670 rep /* copy gdt */ 671 movsl 672 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 673 movb $0x92,-8+5(%edi) 674 675 sidt 6(%esp) 676 movl 6+2(%esp),%esi /* base address of current idt */ 677 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 678 movw 8(%esi),%ax 679 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 680 movl 8+2(%esi),%eax 681 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 682 movl 24+4(%esi),%eax /* same for bpt descriptor */ 683 movw 24(%esi),%ax 684 movl %eax,bdb_bpt_ljmp+1-KERNBASE 685 movl 24+2(%esi),%eax 686 movw %ax,bdb_bpt_ljmp+5-KERNBASE 687 688 movl $_idt-KERNBASE,%edi 689 movl %edi,6+2(%esp) 690 movl $8*4/4,%ecx 691 cld 692 rep /* copy idt */ 693 movsl 694 695 lgdt (%esp) 696 lidt 6(%esp) 697 698 addl $2*6,%esp 699 popal 700#endif /* BDE_DEBUGGER */ 701 702 /* load base of page directory and enable mapping */ 703 movl %esi,%eax /* phys address of ptd in proc 0 */ 704 movl %eax,%cr3 /* load ptd addr into mmu */ 705 movl %cr0,%eax /* get control word */ 706 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 707 movl %eax,%cr0 /* and let's page NOW! */ 708 709 pushl $begin /* jump to high mem */ 710 ret 711 712begin: /* now running relocated at KERNBASE where the system is linked to run */ 713 movl _atdevphys,%edx /* get pte PA */ 714 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 715 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 716 addl $KERNBASE,%edx /* add virtual base */ 717 movl %edx,_atdevbase 718 719 /* set up bootstrap stack */ 720 movl $_kstack+UPAGES*NBPG,%esp /* bootstrap stack end location */ 721 xorl %eax,%eax /* mark end of frames */ 722 movl %eax,%ebp 723 movl _proc0paddr,%eax 724 movl %esi,PCB_CR3(%eax) 725 726#ifdef BDE_DEBUGGER 727 /* relocate debugger gdt entries */ 728 729 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 730 movl $9,%ecx 731reloc_gdt: 732 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 733 addl $8,%eax /* now KERNBASE>>24 */ 734 loop reloc_gdt 735 736 cmpl $0,_bdb_exists 737 je 1f 738 int $3 7391: 740#endif /* BDE_DEBUGGER */ 741 742 /* 743 * Prepare "first" - physical address of first available page 744 * after the kernel+pdir+upages+p0stack+page tables 745 */ 746 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 747 748 pushl %esi /* value of first for init386(first) */ 749 call _init386 /* wire 386 chip for unix operation */ 750 popl %esi 751 752 .globl __ucodesel,__udatasel 753 754 pushl $0 /* unused */ 755 pushl __udatasel /* ss */ 756 pushl $0 /* esp - filled in by execve() */ 757 pushl $PSL_USER /* eflags (IOPL 0, int enab) */ 758 pushl __ucodesel /* cs */ 759 pushl $0 /* eip - filled in by execve() */ 760 subl $(12*4),%esp /* space for rest of registers */ 761 762 pushl %esp /* call main with frame pointer */ 763 call _main /* autoconfiguration, mountroot etc */ 764 765 addl $(13*4),%esp /* back to a frame we can return with */ 766 767 /* 768 * now we've run main() and determined what cpu-type we are, we can 769 * enable write protection and alignment checking on i486 cpus and 770 * above. 771 */ 772#if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU) 773 cmpl $CPUCLASS_386,_cpu_class 774 je 1f 775 movl %cr0,%eax /* get control word */ 776 orl $CR0_WP|CR0_AM,%eax /* enable i486 features */ 777 movl %eax,%cr0 /* and do it */ 778#endif 779 /* 780 * on return from main(), we are process 1 781 * set up address space and stack so that we can 'return' to user mode 782 */ 7831: 784 movl __ucodesel,%eax 785 movl __udatasel,%ecx 786 787 movl %cx,%ds 788 movl %cx,%es 789 movl %ax,%fs /* double map cs to fs */ 790 movl %cx,%gs /* and ds to gs */ 791 iret /* goto user! */ 792 793#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 794 795NON_GPROF_ENTRY(sigcode) 796 call SIGF_HANDLER(%esp) 797 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 798 /* copy at 8(%esp)) */ 799 pushl %eax 800 pushl %eax /* junk to fake return address */ 801 movl $103,%eax /* XXX sigreturn() */ 802 LCALL(0x7,0) /* enter kernel with args on stack */ 803 hlt /* never gets here */ 804 805 .globl _szsigcode 806_szsigcode: 807 .long _szsigcode-_sigcode 808