locore.s revision 4217
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 1.43 1994/10/31 17:20:15 joerg 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/* 112 * Dummy frame at top of tmpstk to help debuggers print a nice stack trace. 113 */ 114 .long tmpstk+8 /* caller's %ebp */ 115 .long _cpu_switch /* caller */ 116 .long 0 /* %ebp == 0 should terminate trace */ 117 .long _mvesp /* in case %ebp == 0 doesn't work ... */ 118 .long 0x11111111, 0x22222222, 0x33333333, 0x44444444, 0x55555555 119 120 .globl _boothowto,_bootdev 121 122 .globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id 123 124_cpu: .long 0 /* are we 386, 386sx, or 486 */ 125_cpu_id: .long 0 /* stepping ID */ 126_cpu_vendor: .space 20 /* CPU origin code */ 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#if NAPM > 0 146 .globl _apm_current_gdt_pdesc /* current GDT pseudo desc. */ 147_apm_current_gdt_pdesc: 148 .word 0, 0, 0 149 150 .globl _bootstrap_gdt 151_bootstrap_gdt: 152 .space SIZEOF_GDT * BOOTSTRAP_GDT_NUM 153#endif /* NAPM */ 154 155/* 156 * System Initialization 157 */ 158 .text 159 160/* 161 * btext: beginning of text section. 162 * Also the entry point (jumped to directly from the boot blocks). 163 */ 164NON_GPROF_ENTRY(btext) 165 movw $0x1234,0x472 /* warm boot */ 166 jmp 1f 167 /* 168 * XXX now that we load at 1MB is this still really used? 169 */ 170 .org 0x500 /* space for BIOS variables */ 171 1721: 173 /* Set up a real frame, some day we will be doing returns */ 174 pushl %ebp 175 movl %esp, %ebp 176 177 /* Don't trust what the BIOS gives for eflags. */ 178 pushl $PSL_MBO 179 popfl 180 181 /* Don't trust what the BIOS gives for %fs and %gs. */ 182 mov %ds, %ax 183 mov %ax, %fs 184 mov %ax, %gs 185 186 /* 187 * This code is called in different ways depending on what loaded 188 * and started the kernel. This is used to detect how we get the 189 * arguments from the other code and what we do with them. 190 * 191 * Old disk boot blocks: 192 * (*btext)(howto, bootdev, cyloffset, esym); 193 * [return address == 0, and can NOT be returned to] 194 * [cyloffset was not supported by the FreeBSD boot code 195 * and always passed in as 0] 196 * [esym is also known as total in the boot code, and 197 * was never properly supported by the FreeBSD boot code] 198 * 199 * Old diskless netboot code: 200 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 201 * [return address != 0, and can NOT be returned to] 202 * If we are being booted by this code it will NOT work, 203 * so we are just going to halt if we find this case. 204 * 205 * New uniform boot code: 206 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 207 * [return address != 0, and can be returned to] 208 * 209 * There may seem to be a lot of wasted arguments in here, but 210 * that is so the newer boot code can still load very old kernels 211 * and old boot code can load new kernels. 212 */ 213 214 /* 215 * The old style disk boot blocks fake a frame on the stack and 216 * did an lret to get here. The frame on the stack has a return 217 * address of 0. 218 */ 219 cmpl $0,4(%ebp) 220 je 2f /* olddiskboot: */ 221 222 /* 223 * We have some form of return address, so this is either the 224 * old diskless netboot code, or the new uniform code. That can 225 * be detected by looking at the 5th argument, it if is 0 we 226 * we are being booted by the new unifrom boot code. 227 */ 228 cmpl $0,24(%ebp) 229 je 1f /* newboot: */ 230 231 /* 232 * Seems we have been loaded by the old diskless boot code, we 233 * don't stand a chance of running as the diskless structure 234 * changed considerably between the two, so just halt. 235 */ 236 hlt 237 238 /* 239 * We have been loaded by the new uniform boot code. 240 * Lets check the bootinfo version, and if we do not understand 241 * it we return to the loader with a status of 1 to indicate this error 242 */ 2431: /* newboot: */ 244 movl 28(%ebp),%ebx /* &bootinfo.version */ 245 movl BOOTINFO_VERSION(%ebx),%eax 246 cmpl $1,%eax /* We only understand version 1 */ 247 je 1f 248 movl $1,%eax /* Return status */ 249 leave 250 ret 251 2521: 253 /* 254 * If we have a kernelname copy it in 255 */ 256 movl BOOTINFO_KERNELNAME(%ebx),%esi 257 cmpl $0,%esi 258 je 1f /* No kernelname */ 259 lea _kernelname-KERNBASE,%edi 260 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 261 cld 262 rep 263 movsb 264 2651: 266#ifdef NFS 267 /* 268 * If we have a nfs_diskless structure copy it in 269 */ 270 movl BOOTINFO_NFS_DISKLESS(%ebx),%esi 271 cmpl $0,%esi 272 je 2f 273 lea _nfs_diskless-KERNBASE,%edi 274 movl $NFSDISKLESS_SIZE,%ecx 275 cld 276 rep 277 movsb 278 lea _nfs_diskless_valid-KERNBASE,%edi 279 movl $1,(%edi) 280#endif 281 282 /* 283 * The old style disk boot. 284 * (*btext)(howto, bootdev, cyloffset, esym); 285 * Note that the newer boot code just falls into here to pick 286 * up howto and bootdev, cyloffset and esym are no longer used 287 */ 2882: /* olddiskboot: */ 289 movl 8(%ebp),%eax 290 movl %eax,_boothowto-KERNBASE 291 movl 12(%ebp),%eax 292 movl %eax,_bootdev-KERNBASE 293 294#if NAPM > 0 295 /* 296 * Setup APM BIOS: 297 * 298 * APM BIOS initialization should be done from real mode or V86 mode. 299 * 300 * (by HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>) 301 */ 302 303 /* 304 * Copy APM initializer under 1MB boundary: 305 * 306 * APM initializer program must switch the CPU to real mode. 307 * But FreeBSD kernel runs above 1MB boundary. So we must 308 * copy the initializer code to conventional memory. 309 */ 310 movl _apm_init_image_size-KERNBASE, %ecx /* size */ 311 lea _apm_init_image-KERNBASE, %esi /* source */ 312 movl $ APM_OURADDR, %edi /* destination */ 313 cld 314 rep 315 movsb 316 317 /* get GDT base */ 318 sgdt _apm_current_gdt_pdesc-KERNBASE 319 320 /* copy GDT to _bootstrap_gdt */ 321 xorl %ecx, %ecx 322 movw _apm_current_gdt_pdesc-KERNBASE, %cx 323 movl _apm_current_gdt_pdesc-KERNBASE+2, %esi 324 lea _bootstrap_gdt-KERNBASE, %edi 325 cld 326 rep 327 movsb 328 329 /* setup GDT pseudo descriptor */ 330 movw $(SIZEOF_GDT*BOOTSTRAP_GDT_NUM), %ax 331 movw %ax, _apm_current_gdt_pdesc-KERNBASE 332 leal _bootstrap_gdt-KERNBASE, %eax 333 movl %eax, _apm_current_gdt_pdesc-KERNBASE+2 334 335 /* load new GDTR */ 336 lgdt _apm_current_gdt_pdesc-KERNBASE 337 338 /* setup GDT for APM initializer */ 339 lea _bootstrap_gdt-KERNBASE, %ecx 340 movl $(APM_OURADDR), %eax /* use %ax for 15..0 */ 341 movl %eax, %ebx 342 shrl $16, %ebx /* use %bl for 23..16 */ 343 /* use %bh for 31..24 */ 344#define APM_SETUP_GDT(index, attrib) \ 345 movl $(index), %si ; \ 346 lea 0(%ecx,%esi,8), %edx ; \ 347 movw $0xffff, (%edx) ; \ 348 movw %ax, 2(%edx) ; \ 349 movb %bl, 4(%edx) ; \ 350 movw $(attrib), 5(%edx) ; \ 351 movb %bh, 7(%edx) 352 353 APM_SETUP_GDT(APM_INIT_CS_INDEX , CS32_ATTRIB) 354 APM_SETUP_GDT(APM_INIT_DS_INDEX , DS32_ATTRIB) 355 APM_SETUP_GDT(APM_INIT_CS16_INDEX, CS16_ATTRIB) 356 357 /* 358 * Call the initializer: 359 * 360 * direct intersegment call to conventional memory code 361 */ 362 .byte 0x9a /* actually, lcall $APM_INIT_CS_SEL, $0 */ 363 .long 0 364 .word APM_INIT_CS_SEL 365 366 movw %ax, _apm_version-KERNBASE 367 movl %ebx, _apm_cs_entry-KERNBASE 368 movw %cx, _apm_cs32_base-KERNBASE 369 shrl $16, %ecx 370 movw %cx, _apm_cs16_base-KERNBASE 371 movw %dx, _apm_ds_base-KERNBASE 372 movw %si, _apm_cs_limit-KERNBASE 373 shrl $16, %esi 374 movw %si, _apm_ds_limit-KERNBASE 375 movw %di, _apm_flags-KERNBASE 376#endif /* NAPM */ 377 378 /* Find out our CPU type. */ 379 380 /* Try to toggle alignment check flag; does not exist on 386. */ 381 pushfl 382 popl %eax 383 movl %eax,%ecx 384 orl $PSL_AC,%eax 385 pushl %eax 386 popfl 387 pushfl 388 popl %eax 389 xorl %ecx,%eax 390 andl $PSL_AC,%eax 391 pushl %ecx 392 popfl 393 394 testl %eax,%eax 395 jnz 1f 396 movl $CPU_386,_cpu-KERNBASE 397 jmp 2f 398 3991: /* Try to toggle identification flag; does not exist on early 486s. */ 400 pushfl 401 popl %eax 402 movl %eax,%ecx 403 xorl $PSL_ID,%eax 404 pushl %eax 405 popfl 406 pushfl 407 popl %eax 408 xorl %ecx,%eax 409 andl $PSL_ID,%eax 410 pushl %ecx 411 popfl 412 413 testl %eax,%eax 414 jnz 1f 415 movl $CPU_486,_cpu-KERNBASE 416 417 /* check for Cyrix 486DLC -- based on check routine */ 418 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 419 xorw %dx,%dx 420 cmpw %dx,%dx # set flags to known state 421 pushfw 422 popw %cx # store flags in ecx 423 movw $0xffff,%ax 424 movw $0x0004,%bx 425 divw %bx 426 pushfw 427 popw %ax 428 andw $0x08d5,%ax # mask off important bits 429 andw $0x08d5,%cx 430 cmpw %ax,%cx 431 432 jnz 2f # if flags changed, Intel chip 433 434 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 435 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 436 movw $0x0078,_cpu_vendor-KERNBASE+4 437 438 invd # Start with guaranteed clean cache 439 /* Disable caching of the ISA hole only. */ 440 movb $CCR0,%al # Configuration Register index (CCR0) 441 outb %al,$0x22 442 inb $0x23,%al 443 orb $(CCR0_NC1|CCR0_BARB),%al 444 outb %al,$0x23 445 invd 446 jmp 2f 447 4481: /* Use the `cpuid' instruction. */ 449 xorl %eax,%eax 450 .byte 0x0f,0xa2 # cpuid 0 451 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 452 movl %edx,_cpu_vendor+4-KERNBASE 453 movl %ecx,_cpu_vendor+8-KERNBASE 454 movb $0,_cpu_vendor+12-KERNBASE 455 456 movl $1,%eax 457 .byte 0x0f,0xa2 # cpuid 1 458 movl %eax,_cpu_id-KERNBASE # store cpu_id 459 rorl $8,%eax # extract family type 460 andl $15,%eax 461 cmpl $5,%eax 462 jae 1f 463 464 /* less than Pentium; must be 486 */ 465 movl $CPU_486,_cpu-KERNBASE 466 jmp 2f 467 4681: movl $CPU_586,_cpu-KERNBASE 4692: 470 471 /* 472 * Finished with old stack; load new %esp now instead of later so 473 * we can trace this code without having to worry about the trace 474 * trap clobbering the memory test or the zeroing of the bss+bootstrap 475 * page tables. 476 * 477 * XXX - wdboot clears the bss after testing that this is safe. 478 * This is too wasteful - memory below 640K is scarce. The boot 479 * program should check: 480 * text+data <= &stack_variable - more_space_for_stack 481 * text+data+bss+pad+space_for_page_tables <= end_of_memory 482 * Oops, the gdt is in the carcass of the boot program so clearing 483 * the rest of memory is still not possible. 484 */ 485 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 486 487/* 488 * Virtual address space of kernel: 489 * 490 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 491 * pages: 1 UPAGES (2) 1 NKPT (7) 492 */ 493 494/* find end of kernel image */ 495 movl $_end-KERNBASE,%ecx 496 addl $NBPG-1,%ecx /* page align up */ 497 andl $~(NBPG-1),%ecx 498 movl %ecx,%esi /* esi = start of free memory */ 499 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 500 501/* clear bss */ 502 movl $_edata-KERNBASE,%edi 503 subl %edi,%ecx /* get amount to clear */ 504 xorl %eax,%eax /* specify zero fill */ 505 cld 506 rep 507 stosb 508 509/* 510 * The value in esi is both the end of the kernel bss and a pointer to 511 * the kernel page directory, and is used by the rest of locore to build 512 * the tables. 513 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 514 * page table pages) is then passed on the stack to init386(first) as 515 * the value first. esi should ALWAYS be page aligned!! 516 */ 517 movl %esi,%ecx /* Get current first availiable address */ 518 519/* clear pagetables, page directory, stack, etc... */ 520 movl %esi,%edi /* base (page directory) */ 521 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 522 xorl %eax,%eax /* specify zero fill */ 523 cld 524 rep 525 stosb 526 527/* physical address of Idle proc/kernel page directory */ 528 movl %esi,_IdlePTD-KERNBASE 529 530/* 531 * fillkpt 532 * eax = (page frame address | control | status) == pte 533 * ebx = address of page table 534 * ecx = how many pages to map 535 */ 536#define fillkpt \ 5371: movl %eax,(%ebx) ; \ 538 addl $NBPG,%eax ; /* increment physical address */ \ 539 addl $4,%ebx ; /* next pte */ \ 540 loop 1b ; 541 542/* 543 * Map Kernel 544 * 545 * First step - build page tables 546 */ 547#if defined (KGDB) || defined (BDE_DEBUGGER) 548 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 549 shrl $PGSHIFT,%ecx /* for this many PTEs */ 550#ifdef BDE_DEBUGGER 551 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 552 jae 1f 553 movl $0xa0,%ecx 5541: 555#endif /* BDE_DEBUGGER */ 556 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 557 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 558 movl %ebx,_KPTphys-KERNBASE /* save in global */ 559 fillkpt 560 561#else /* !KGDB && !BDE_DEBUGGER */ 562 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 563 movl $_etext-KERNBASE,%ecx /* get size of text */ 564 addl $NBPG-1,%ecx /* round up to page */ 565 shrl $PGSHIFT,%ecx /* for this many PTEs */ 566 movl $PG_V|PG_KR,%eax /* specify read only */ 567#if 0 568 movl $_etext,%ecx /* get size of text */ 569 subl $_btext,%ecx 570 addl $NBPG-1,%ecx /* round up to page */ 571 shrl $PGSHIFT,%ecx /* for this many PTEs */ 572 movl $_btext-KERNBASE,%eax /* get offset to physical memory */ 573 orl $PG_V|PG_KR,%eax /* specify read only */ 574#endif 575 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 576 movl %ebx,_KPTphys-KERNBASE /* save in global */ 577 fillkpt 578 579 /* data and bss are r/w */ 580 andl $PG_FRAME,%eax /* strip to just addr of bss */ 581 movl _KERNend-KERNBASE,%ecx /* calculate size */ 582 subl %eax,%ecx 583 shrl $PGSHIFT,%ecx 584 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 585 fillkpt 586#endif /* KGDB || BDE_DEBUGGER */ 587 588/* now initialize the page dir, upages, p0stack PT, and page tables */ 589 590 movl $(1+UPAGES+1+NKPT),%ecx /* number of PTEs */ 591 movl %esi,%eax /* phys address of PTD */ 592 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 593 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 594 movl %esi,%ebx /* calculate pte offset to ptd */ 595 shrl $PGSHIFT-2,%ebx 596 addl %esi,%ebx /* address of page directory */ 597 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 598 fillkpt 599 600/* map I/O memory map */ 601 602 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 603 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 604 movl $0x100-0xa0,%ecx /* for this many pte s, */ 605 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 606 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 607 fillkpt 608 609 /* map proc 0's kernel stack into user page table page */ 610 611 movl $UPAGES,%ecx /* for this many pte s, */ 612 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 613 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 614 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 615 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 616 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 617 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 618 fillkpt 619 620/* 621 * Initialize kernel page table directory 622 */ 623 /* install a pde for temporary double map of bottom of VA */ 624 movl _KPTphys-KERNBASE,%eax 625 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 626 movl %eax,(%esi) /* which is where temp maps! */ 627 628 /* initialize kernel pde's */ 629 movl $(NKPT),%ecx /* for this many PDEs */ 630 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 631 fillkpt 632 633 /* install a pde recursively mapping page directory as a page table! */ 634 movl %esi,%eax /* phys address of ptd in proc 0 */ 635 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 636 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 637 638 /* install a pde to map kernel stack for proc 0 */ 639 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 640 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 641 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 642 643#ifdef BDE_DEBUGGER 644 /* copy and convert stuff from old gdt and idt for debugger */ 645 646 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 647 jne 1f 648 movb $1,_bdb_exists-KERNBASE 6491: 650 pushal 651 subl $2*6,%esp 652 653 sgdt (%esp) 654 movl 2(%esp),%esi /* base address of current gdt */ 655 movl $_gdt-KERNBASE,%edi 656 movl %edi,2(%esp) 657 movl $8*18/4,%ecx 658 cld 659 rep /* copy gdt */ 660 movsl 661 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 662 movb $0x92,-8+5(%edi) 663 664 sidt 6(%esp) 665 movl 6+2(%esp),%esi /* base address of current idt */ 666 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 667 movw 8(%esi),%ax 668 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 669 movl 8+2(%esi),%eax 670 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 671 movl 24+4(%esi),%eax /* same for bpt descriptor */ 672 movw 24(%esi),%ax 673 movl %eax,bdb_bpt_ljmp+1-KERNBASE 674 movl 24+2(%esi),%eax 675 movw %ax,bdb_bpt_ljmp+5-KERNBASE 676 677 movl $_idt-KERNBASE,%edi 678 movl %edi,6+2(%esp) 679 movl $8*4/4,%ecx 680 cld 681 rep /* copy idt */ 682 movsl 683 684 lgdt (%esp) 685 lidt 6(%esp) 686 687 addl $2*6,%esp 688 popal 689#endif /* BDE_DEBUGGER */ 690 691 /* load base of page directory and enable mapping */ 692 movl %esi,%eax /* phys address of ptd in proc 0 */ 693 movl %eax,%cr3 /* load ptd addr into mmu */ 694 movl %cr0,%eax /* get control word */ 695 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 696 movl %eax,%cr0 /* and let's page NOW! */ 697 698 pushl $begin /* jump to high mem */ 699 ret 700 701begin: /* now running relocated at KERNBASE where the system is linked to run */ 702 movl _atdevphys,%edx /* get pte PA */ 703 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 704 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 705 addl $KERNBASE,%edx /* add virtual base */ 706 movl %edx,_atdevbase 707 708#include "sc.h" 709#include "vt.h" 710#if NSC > 0 || NVT > 0 711 /* XXX: can't scinit relocate Crtat relative to atdevbase itself? */ 712 .globl _Crtat /* XXX - locore should not know about */ 713 movl _Crtat,%eax /* variables of device drivers (pccons)! */ 714 subl $(KERNBASE+0xA0000),%eax 715 addl %eax,%edx 716 movl %edx,_Crtat 717#endif 718 719 /* set up bootstrap stack - 48 bytes */ 720 movl $_kstack+UPAGES*NBPG-4*12,%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 * Skip over the page tables and the kernel stack 744 */ 745 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 746 747 pushl %esi /* value of first for init386(first) */ 748 call _init386 /* wire 386 chip for unix operation */ 749 popl %esi 750 751 .globl __ucodesel,__udatasel 752 753 pushl $0 /* unused */ 754 pushl __udatasel /* ss */ 755 pushl $0 /* esp - filled in by execve() */ 756 pushl $PSL_USERSET /* eflags (ring 0, int enab) */ 757 pushl __ucodesel /* cs */ 758 pushl $0 /* eip - filled in by execve() */ 759 subl $(12*4),%esp /* space for rest of registers */ 760 761 pushl %esp /* call main with frame pointer */ 762 call _main /* autoconfiguration, mountroot etc */ 763 764 addl $(13*4),%esp /* back to a frame we can return with */ 765 766 /* 767 * now we've run main() and determined what cpu-type we are, we can 768 * enable WP mode on i486 cpus and above. 769 */ 770#if defined(I486_CPU) || defined(I586_CPU) 771 cmpl $CPUCLASS_386,_cpu_class 772 je 1f 773 movl %cr0,%eax /* get control word */ 774 orl $CR0_WP,%eax /* enable write protect for all modes */ 775 movl %eax,%cr0 /* and do it */ 776#endif 777 /* 778 * on return from main(), we are process 1 779 * set up address space and stack so that we can 'return' to user mode 780 */ 7811: 782 movl __ucodesel,%eax 783 movl __udatasel,%ecx 784 785 movl %cx,%ds 786 movl %cx,%es 787 movl %ax,%fs /* double map cs to fs */ 788 movl %cx,%gs /* and ds to gs */ 789 iret /* goto user! */ 790 791#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 792 793NON_GPROF_ENTRY(sigcode) 794 call SIGF_HANDLER(%esp) 795 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 796 /* copy at 8(%esp)) */ 797 pushl %eax 798 pushl %eax /* junk to fake return address */ 799 movl $103,%eax /* XXX sigreturn() */ 800 LCALL(0x7,0) /* enter kernel with args on stack */ 801 hlt /* never gets here */ 802 803 .globl _szsigcode 804_szsigcode: 805 .long _szsigcode-_sigcode 806