locore.s revision 3861
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 1.39 1994/10/25 07:25:55 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 "apm.h" 57#if NAPM > 0 58#define ASM 59#include <machine/apm_bios.h> 60#include <machine/apm_segments.h> 61#endif /* NAPM */ 62 63/* 64 * XXX 65 * 66 * Note: This version greatly munged to avoid various assembler errors 67 * that may be fixed in newer versions of gas. Perhaps newer versions 68 * will have more pleasant appearance. 69 */ 70 71/* 72 * PTmap is recursive pagemap at top of virtual address space. 73 * Within PTmap, the page directory can be found (third indirection). 74 */ 75 .globl _PTmap,_PTD,_PTDpde 76 .set _PTmap,PTDPTDI << PDRSHIFT 77 .set _PTD,_PTmap + (PTDPTDI * NBPG) 78 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE) 79 80/* 81 * Sysmap is the base address of the kernel page tables. 82 * It is a bogus interface for kgdb and isn't used by the kernel itself. 83 */ 84 .set _Sysmap,_PTmap + (KPTDI * NBPG) 85 86/* 87 * APTmap, APTD is the alternate recursive pagemap. 88 * It's used when modifying another process's page tables. 89 */ 90 .globl _APTmap,_APTD,_APTDpde 91 .set _APTmap,APTDPTDI << PDRSHIFT 92 .set _APTD,_APTmap + (APTDPTDI * NBPG) 93 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE) 94 95/* 96 * Access to each processes kernel stack is via a region of 97 * per-process address space (at the beginning), immediatly above 98 * the user process stack. 99 */ 100 .set _kstack,USRSTACK 101 .globl _kstack 102 103/* 104 * Globals 105 */ 106 .data 107 108 .globl tmpstk 109 .space 0x1000 /* space for tmpstk - temporary stack */ 110tmpstk: 111 .long 0 /* for debugging tmpstk stack underflow */ 112 113 .globl _boothowto,_bootdev 114 115 .globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id 116 117 .globl _video_mode_ptr 118 119_cpu: .long 0 /* are we 386, 386sx, or 486 */ 120_cpu_id: .long 0 /* stepping ID */ 121_cpu_vendor: .space 20 /* CPU origin code */ 122_video_mode_ptr: .long 0 123_cold: .long 1 /* cold till we are not */ 124_atdevbase: .long 0 /* location of start of iomem in virtual */ 125_atdevphys: .long 0 /* location of device mapping ptes (phys) */ 126 127_KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 128 129 .globl _IdlePTD 130_IdlePTD: .long 0 /* phys addr of kernel PTD */ 131 132_KPTphys: .long 0 /* phys addr of kernel page tables */ 133 134 .globl _proc0paddr 135_proc0paddr: .long 0 /* address of proc 0 address space */ 136 137#ifdef BDE_DEBUGGER 138 .globl _bdb_exists /* flag to indicate BDE debugger is available */ 139_bdb_exists: .long 0 140#endif 141#if NAPM > 0 142 .globl _apm_current_gdt_pdesc /* current GDT pseudo desc. */ 143_apm_current_gdt_pdesc: 144 .word 0, 0, 0 145 146 .globl _bootstrap_gdt 147_bootstrap_gdt: 148 .space SIZEOF_GDT * BOOTSTRAP_GDT_NUM 149#endif /* NAPM */ 150 151/* 152 * System Initialization 153 */ 154 .text 155 156/* 157 * btext: beginning of text section. 158 * Also the entry point (jumped to directly from the boot blocks). 159 */ 160NON_GPROF_ENTRY(btext) 161 movw $0x1234,0x472 /* warm boot */ 162 jmp 1f 163 /* 164 * XXX now that we load at 1MB is this still really used? 165 */ 166 .org 0x500 /* space for BIOS variables */ 167 1681: 169 /* Set up a real frame, some day we will be doing returns */ 170 pushl %ebp 171 movl %esp, %ebp 172 173 /* Don't trust what the BIOS gives for eflags. */ 174 pushl $PSL_MBO 175 popfl 176 177 /* 178 * This code is called in different ways depending on what loaded 179 * and started the kernel. This is used to detect how we get the 180 * arguments from the other code and what we do with them. 181 * 182 * Old disk boot blocks: 183 * (*btext)(howto, bootdev, cyloffset, esym); 184 * [return address == 0, and can NOT be returned to] 185 * [cyloffset was not supported by the FreeBSD boot code 186 * and always passed in as 0] 187 * [esym is also known as total in the boot code, and 188 * was never properly supported by the FreeBSD boot code] 189 * 190 * Old diskless netboot code: 191 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 192 * [return address != 0, and can NOT be returned to] 193 * If we are being booted by this code it will NOT work, 194 * so we are just going to halt if we find this case. 195 * 196 * New uniform boot code: 197 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 198 * [return address != 0, and can be returned to] 199 * 200 * There may seem to be a lot of wasted arguments in here, but 201 * that is so the newer boot code can still load very old kernels 202 * and old boot code can load new kernels. 203 */ 204 205 /* 206 * The old style disk boot blocks fake a frame on the stack and 207 * did an lret to get here. The frame on the stack has a return 208 * address of 0. 209 */ 210 cmpl $0,4(%ebp) 211 je 2f /* olddiskboot: */ 212 213 /* 214 * We have some form of return address, so this is either the 215 * old diskless netboot code, or the new uniform code. That can 216 * be detected by looking at the 5th argument, it if is 0 we 217 * we are being booted by the new unifrom boot code. 218 */ 219 cmpl $0,24(%ebp) 220 je 1f /* newboot: */ 221 222 /* 223 * Seems we have been loaded by the old diskless boot code, we 224 * don't stand a chance of running as the diskless structure 225 * changed considerably between the two, so just halt. 226 */ 227 hlt 228 229 /* 230 * We have been loaded by the new uniform boot code. 231 * Lets check the bootinfo version, and if we do not understand 232 * it we return to the loader with a status of 1 to indicate this error 233 */ 2341: /* newboot: */ 235 movl 28(%ebp),%ebx /* &bootinfo.version */ 236 movl BOOTINFO_VERSION(%ebx),%eax 237 cmpl $1,%eax /* We only understand version 1 */ 238 je 1f 239 movl $1,%eax /* Return status */ 240 leave 241 ret 242 2431: 244 /* 245 * If we have a kernelname copy it in 246 */ 247 movl BOOTINFO_KERNELNAME(%ebx),%esi 248 cmpl $0,%esi 249 je 1f /* No kernelname */ 250 lea _kernelname-KERNBASE,%edi 251 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 252 cld 253 rep 254 movsb 255 2561: 257#ifdef NFS 258 /* 259 * If we have a nfs_diskless structure copy it in 260 */ 261 movl BOOTINFO_NFS_DISKLESS(%ebx),%esi 262 cmpl $0,%esi 263 je 2f 264 lea _nfs_diskless-KERNBASE,%edi 265 movl $NFSDISKLESS_SIZE,%ecx 266 cld 267 rep 268 movsb 269 lea _nfs_diskless_valid-KERNBASE,%edi 270 movl $1,(%edi) 271#endif 272 273 /* 274 * The old style disk boot. 275 * (*btext)(howto, bootdev, cyloffset, esym); 276 * Note that the newer boot code just falls into here to pick 277 * up howto and bootdev, cyloffset and esym are no longer used 278 */ 2792: /* olddiskboot: */ 280 movl 8(%ebp),%eax 281 movl %eax,_boothowto-KERNBASE 282 movl 12(%ebp),%eax 283 movl %eax,_bootdev-KERNBASE 284 285 /* get the BIOS video mode pointer */ 286 movl $0x4a8, %ecx 287 movl (%ecx), %eax 288 movl %eax, %ecx 289 shrl $12, %ecx 290 andl $0xffff0000, %ecx 291 andl $0x0000ffff, %eax 292 orl %ecx, %eax 293 movl (%eax), %eax 294 movl %eax, %ecx 295 shrl $12, %ecx 296 andl $0xffff0000, %ecx 297 andl $0x0000ffff, %eax 298 orl %ecx, %eax 299 addl $KERNBASE, %eax 300 movl %eax, _video_mode_ptr-KERNBASE 301 302#if NAPM > 0 303 /* 304 * Setup APM BIOS: 305 * 306 * APM BIOS initialization should be done from real mode or V86 mode. 307 * 308 * (by HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>) 309 */ 310 311 /* 312 * Copy APM initializer under 1MB boundary: 313 * 314 * APM initializer program must switch the CPU to real mode. 315 * But FreeBSD kernel runs above 1MB boundary. So we must 316 * copy the initializer code to conventional memory. 317 */ 318 movl _apm_init_image_size-KERNBASE, %ecx /* size */ 319 lea _apm_init_image-KERNBASE, %esi /* source */ 320 movl $ APM_OURADDR, %edi /* destination */ 321 cld 322 rep 323 movsb 324 325 /* get GDT base */ 326 sgdt _apm_current_gdt_pdesc-KERNBASE 327 328 /* copy GDT to _bootstrap_gdt */ 329 xorl %ecx, %ecx 330 movw _apm_current_gdt_pdesc-KERNBASE, %cx 331 movl _apm_current_gdt_pdesc-KERNBASE+2, %esi 332 lea _bootstrap_gdt-KERNBASE, %edi 333 cld 334 rep 335 movsb 336 337 /* setup GDT pseudo descriptor */ 338 movw $(SIZEOF_GDT*BOOTSTRAP_GDT_NUM), %ax 339 movw %ax, _apm_current_gdt_pdesc-KERNBASE 340 leal _bootstrap_gdt-KERNBASE, %eax 341 movl %eax, _apm_current_gdt_pdesc-KERNBASE+2 342 343 /* load new GDTR */ 344 lgdt _apm_current_gdt_pdesc-KERNBASE 345 346 /* setup GDT for APM initializer */ 347 lea _bootstrap_gdt-KERNBASE, %ecx 348 movl $(APM_OURADDR), %eax /* use %ax for 15..0 */ 349 movl %eax, %ebx 350 shrl $16, %ebx /* use %bl for 23..16 */ 351 /* use %bh for 31..24 */ 352#define APM_SETUP_GDT(index, attrib) \ 353 movl $(index), %si ; \ 354 lea 0(%ecx,%esi,8), %edx ; \ 355 movw $0xffff, (%edx) ; \ 356 movw %ax, 2(%edx) ; \ 357 movb %bl, 4(%edx) ; \ 358 movw $(attrib), 5(%edx) ; \ 359 movb %bh, 7(%edx) 360 361 APM_SETUP_GDT(APM_INIT_CS_INDEX , CS32_ATTRIB) 362 APM_SETUP_GDT(APM_INIT_DS_INDEX , DS32_ATTRIB) 363 APM_SETUP_GDT(APM_INIT_CS16_INDEX, CS16_ATTRIB) 364 365 /* 366 * Call the initializer: 367 * 368 * direct intersegment call to conventional memory code 369 */ 370 .byte 0x9a /* actually, lcall $APM_INIT_CS_SEL, $0 */ 371 .long 0 372 .word APM_INIT_CS_SEL 373 374 movw %ax, _apm_version-KERNBASE 375 movl %ebx, _apm_cs_entry-KERNBASE 376 movw %cx, _apm_cs32_base-KERNBASE 377 shrl $16, %ecx 378 movw %cx, _apm_cs16_base-KERNBASE 379 movw %dx, _apm_ds_base-KERNBASE 380 movw %si, _apm_cs_limit-KERNBASE 381 shrl $16, %esi 382 movw %si, _apm_ds_limit-KERNBASE 383 movw %di, _apm_flags-KERNBASE 384#endif /* NAPM */ 385 386 /* Find out our CPU type. */ 387 388 /* Try to toggle alignment check flag; does not exist on 386. */ 389 pushfl 390 popl %eax 391 movl %eax,%ecx 392 orl $PSL_AC,%eax 393 pushl %eax 394 popfl 395 pushfl 396 popl %eax 397 xorl %ecx,%eax 398 andl $PSL_AC,%eax 399 pushl %ecx 400 popfl 401 402 testl %eax,%eax 403 jnz 1f 404 movl $CPU_386,_cpu-KERNBASE 405 jmp 2f 406 4071: /* Try to toggle identification flag; does not exist on early 486s. */ 408 pushfl 409 popl %eax 410 movl %eax,%ecx 411 xorl $PSL_ID,%eax 412 pushl %eax 413 popfl 414 pushfl 415 popl %eax 416 xorl %ecx,%eax 417 andl $PSL_ID,%eax 418 pushl %ecx 419 popfl 420 421 testl %eax,%eax 422 jnz 1f 423 movl $CPU_486,_cpu-KERNBASE 424 425 /* check for Cyrix 486DLC -- based on check routine */ 426 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 427 xorw %dx,%dx 428 cmpw %dx,%dx # set flags to known state 429 pushfw 430 popw %cx # store flags in ecx 431 movw $0xffff,%ax 432 movw $0x0004,%bx 433 divw %bx 434 pushfw 435 popw %ax 436 andw $0x08d5,%ax # mask off important bits 437 andw $0x08d5,%cx 438 cmpw %ax,%cx 439 440 jnz 2f # if flags changed, Intel chip 441 442 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 443 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 444 movw $0x0078,_cpu_vendor-KERNBASE+4 445 446 invd # Start with guaranteed clean cache 447 /* Disable caching of the ISA hole only. */ 448 movb $CCR0,%al # Configuration Register index (CCR0) 449 outb %al,$0x22 450 inb $0x23,%al 451 orb $(CCR0_NC1|CCR0_BARB),%al 452 outb %al,$0x23 453 invd 454 jmp 2f 455 4561: /* Use the `cpuid' instruction. */ 457 xorl %eax,%eax 458 .byte 0x0f,0xa2 # cpuid 0 459 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 460 movl %edx,_cpu_vendor+4-KERNBASE 461 movl %ecx,_cpu_vendor+8-KERNBASE 462 movb $0,_cpu_vendor+12-KERNBASE 463 464 movl $1,%eax 465 .byte 0x0f,0xa2 # cpuid 1 466 movl %eax,_cpu_id-KERNBASE # store cpu_id 467 rorl $8,%eax # extract family type 468 andl $15,%eax 469 cmpl $5,%eax 470 jae 1f 471 472 /* less than Pentium; must be 486 */ 473 movl $CPU_486,_cpu-KERNBASE 474 jmp 2f 475 4761: movl $CPU_586,_cpu-KERNBASE 4772: 478 479 /* 480 * Finished with old stack; load new %esp now instead of later so 481 * we can trace this code without having to worry about the trace 482 * trap clobbering the memory test or the zeroing of the bss+bootstrap 483 * page tables. 484 * 485 * XXX - wdboot clears the bss after testing that this is safe. 486 * This is too wasteful - memory below 640K is scarce. The boot 487 * program should check: 488 * text+data <= &stack_variable - more_space_for_stack 489 * text+data+bss+pad+space_for_page_tables <= end_of_memory 490 * Oops, the gdt is in the carcass of the boot program so clearing 491 * the rest of memory is still not possible. 492 */ 493 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 494 495/* 496 * Virtual address space of kernel: 497 * 498 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 499 * pages: 1 UPAGES (2) 1 NKPT (7) 500 */ 501 502/* find end of kernel image */ 503 movl $_end-KERNBASE,%ecx 504 addl $NBPG-1,%ecx /* page align up */ 505 andl $~(NBPG-1),%ecx 506 movl %ecx,%esi /* esi = start of free memory */ 507 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 508 509/* clear bss */ 510 movl $_edata-KERNBASE,%edi 511 subl %edi,%ecx /* get amount to clear */ 512 xorl %eax,%eax /* specify zero fill */ 513 cld 514 rep 515 stosb 516 517/* 518 * The value in esi is both the end of the kernel bss and a pointer to 519 * the kernel page directory, and is used by the rest of locore to build 520 * the tables. 521 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 522 * page table pages) is then passed on the stack to init386(first) as 523 * the value first. esi should ALWAYS be page aligned!! 524 */ 525 movl %esi,%ecx /* Get current first availiable address */ 526 527/* clear pagetables, page directory, stack, etc... */ 528 movl %esi,%edi /* base (page directory) */ 529 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 530 xorl %eax,%eax /* specify zero fill */ 531 cld 532 rep 533 stosb 534 535/* physical address of Idle proc/kernel page directory */ 536 movl %esi,_IdlePTD-KERNBASE 537 538/* 539 * fillkpt 540 * eax = (page frame address | control | status) == pte 541 * ebx = address of page table 542 * ecx = how many pages to map 543 */ 544#define fillkpt \ 5451: movl %eax,(%ebx) ; \ 546 addl $NBPG,%eax ; /* increment physical address */ \ 547 addl $4,%ebx ; /* next pte */ \ 548 loop 1b ; 549 550/* 551 * Map Kernel 552 * 553 * First step - build page tables 554 */ 555#if defined (KGDB) || defined (BDE_DEBUGGER) 556 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 557 shrl $PGSHIFT,%ecx /* for this many PTEs */ 558#ifdef BDE_DEBUGGER 559 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 560 jae 1f 561 movl $0xa0,%ecx 5621: 563#endif /* BDE_DEBUGGER */ 564 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 565 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 566 movl %ebx,_KPTphys-KERNBASE /* save in global */ 567 fillkpt 568 569#else /* !KGDB && !BDE_DEBUGGER */ 570 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 571 movl $_etext-KERNBASE,%ecx /* get size of text */ 572 addl $NBPG-1,%ecx /* round up to page */ 573 shrl $PGSHIFT,%ecx /* for this many PTEs */ 574 movl $PG_V|PG_KR,%eax /* specify read only */ 575#if 0 576 movl $_etext,%ecx /* get size of text */ 577 subl $_btext,%ecx 578 addl $NBPG-1,%ecx /* round up to page */ 579 shrl $PGSHIFT,%ecx /* for this many PTEs */ 580 movl $_btext-KERNBASE,%eax /* get offset to physical memory */ 581 orl $PG_V|PG_KR,%eax /* specify read only */ 582#endif 583 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 584 movl %ebx,_KPTphys-KERNBASE /* save in global */ 585 fillkpt 586 587 /* data and bss are r/w */ 588 andl $PG_FRAME,%eax /* strip to just addr of bss */ 589 movl _KERNend-KERNBASE,%ecx /* calculate size */ 590 subl %eax,%ecx 591 shrl $PGSHIFT,%ecx 592 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 593 fillkpt 594#endif /* KGDB || BDE_DEBUGGER */ 595 596/* now initialize the page dir, upages, p0stack PT, and page tables */ 597 598 movl $(1+UPAGES+1+NKPT),%ecx /* number of PTEs */ 599 movl %esi,%eax /* phys address of PTD */ 600 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 601 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 602 movl %esi,%ebx /* calculate pte offset to ptd */ 603 shrl $PGSHIFT-2,%ebx 604 addl %esi,%ebx /* address of page directory */ 605 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 606 fillkpt 607 608/* map I/O memory map */ 609 610 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 611 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 612 movl $0x100-0xa0,%ecx /* for this many pte s, */ 613 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 614 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 615 fillkpt 616 617 /* map proc 0's kernel stack into user page table page */ 618 619 movl $UPAGES,%ecx /* for this many pte s, */ 620 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 621 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 622 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 623 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 624 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 625 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 626 fillkpt 627 628/* 629 * Initialize kernel page table directory 630 */ 631 /* install a pde for temporary double map of bottom of VA */ 632 movl _KPTphys-KERNBASE,%eax 633 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 634 movl %eax,(%esi) /* which is where temp maps! */ 635 636 /* initialize kernel pde's */ 637 movl $(NKPT),%ecx /* for this many PDEs */ 638 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 639 fillkpt 640 641 /* install a pde recursively mapping page directory as a page table! */ 642 movl %esi,%eax /* phys address of ptd in proc 0 */ 643 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 644 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 645 646 /* install a pde to map kernel stack for proc 0 */ 647 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 648 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 649 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 650 651#ifdef BDE_DEBUGGER 652 /* copy and convert stuff from old gdt and idt for debugger */ 653 654 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 655 jne 1f 656 movb $1,_bdb_exists-KERNBASE 6571: 658 pushal 659 subl $2*6,%esp 660 661 sgdt (%esp) 662 movl 2(%esp),%esi /* base address of current gdt */ 663 movl $_gdt-KERNBASE,%edi 664 movl %edi,2(%esp) 665 movl $8*18/4,%ecx 666 cld 667 rep /* copy gdt */ 668 movsl 669 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 670 movb $0x92,-8+5(%edi) 671 672 sidt 6(%esp) 673 movl 6+2(%esp),%esi /* base address of current idt */ 674 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 675 movw 8(%esi),%ax 676 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 677 movl 8+2(%esi),%eax 678 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 679 movl 24+4(%esi),%eax /* same for bpt descriptor */ 680 movw 24(%esi),%ax 681 movl %eax,bdb_bpt_ljmp+1-KERNBASE 682 movl 24+2(%esi),%eax 683 movw %ax,bdb_bpt_ljmp+5-KERNBASE 684 685 movl $_idt-KERNBASE,%edi 686 movl %edi,6+2(%esp) 687 movl $8*4/4,%ecx 688 cld 689 rep /* copy idt */ 690 movsl 691 692 lgdt (%esp) 693 lidt 6(%esp) 694 695 addl $2*6,%esp 696 popal 697#endif /* BDE_DEBUGGER */ 698 699 /* load base of page directory and enable mapping */ 700 movl %esi,%eax /* phys address of ptd in proc 0 */ 701 movl %eax,%cr3 /* load ptd addr into mmu */ 702 movl %cr0,%eax /* get control word */ 703 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 704 movl %eax,%cr0 /* and let's page NOW! */ 705 706 pushl $begin /* jump to high mem */ 707 ret 708 709begin: /* now running relocated at KERNBASE where the system is linked to run */ 710 movl _atdevphys,%edx /* get pte PA */ 711 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 712 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 713 addl $KERNBASE,%edx /* add virtual base */ 714 movl %edx,_atdevbase 715 716#include "sc.h" 717#if NSC > 0 718 /* XXX: can't scinit relocate Crtat relative to atdevbase itself? */ 719 .globl _Crtat /* XXX - locore should not know about */ 720 movl _Crtat,%eax /* variables of device drivers (pccons)! */ 721 subl $(KERNBASE+0xA0000),%eax 722 addl %eax,%edx 723 movl %edx,_Crtat 724#endif 725 726 /* set up bootstrap stack - 48 bytes */ 727 movl $_kstack+UPAGES*NBPG-4*12,%esp /* bootstrap stack end location */ 728 xorl %eax,%eax /* mark end of frames */ 729 movl %eax,%ebp 730 movl _proc0paddr,%eax 731 movl %esi,PCB_CR3(%eax) 732 733#ifdef BDE_DEBUGGER 734 /* relocate debugger gdt entries */ 735 736 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 737 movl $9,%ecx 738reloc_gdt: 739 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 740 addl $8,%eax /* now KERNBASE>>24 */ 741 loop reloc_gdt 742 743 cmpl $0,_bdb_exists 744 je 1f 745 int $3 7461: 747#endif /* BDE_DEBUGGER */ 748 749 /* 750 * Skip over the page tables and the kernel stack 751 */ 752 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 753 754 pushl %esi /* value of first for init386(first) */ 755 call _init386 /* wire 386 chip for unix operation */ 756 popl %esi 757 758 .globl __ucodesel,__udatasel 759 760 pushl $0 /* unused */ 761 pushl __udatasel /* ss */ 762 pushl $0 /* esp - filled in by execve() */ 763 pushl $PSL_USERSET /* eflags (ring 0, int enab) */ 764 pushl __ucodesel /* cs */ 765 pushl $0 /* eip - filled in by execve() */ 766 subl $(12*4),%esp /* space for rest of registers */ 767 768 pushl %esp /* call main with frame pointer */ 769 call _main /* autoconfiguration, mountroot etc */ 770 771 addl $(13*4),%esp /* back to a frame we can return with */ 772 773 /* 774 * now we've run main() and determined what cpu-type we are, we can 775 * enable WP mode on i486 cpus and above. 776 */ 777#if defined(I486_CPU) || defined(I586_CPU) 778 cmpl $CPUCLASS_386,_cpu_class 779 je 1f 780 movl %cr0,%eax /* get control word */ 781 orl $CR0_WP,%eax /* enable write protect for all modes */ 782 movl %eax,%cr0 /* and do it */ 783#endif 784 /* 785 * on return from main(), we are process 1 786 * set up address space and stack so that we can 'return' to user mode 787 */ 7881: 789 movl __ucodesel,%eax 790 movl __udatasel,%ecx 791 792 movl %cx,%ds 793 movl %cx,%es 794 movl %ax,%fs /* double map cs to fs */ 795 movl %cx,%gs /* and ds to gs */ 796 iret /* goto user! */ 797 798#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 799 800NON_GPROF_ENTRY(sigcode) 801 call SIGF_HANDLER(%esp) 802 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 803 /* copy at 8(%esp)) */ 804 pushl %eax 805 pushl %eax /* junk to fake return address */ 806 movl $103,%eax /* XXX sigreturn() */ 807 LCALL(0x7,0) /* enter kernel with args on stack */ 808 hlt /* never gets here */ 809 810 .globl _szsigcode 811_szsigcode: 812 .long _szsigcode-_sigcode 813