locore.s revision 4031
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 1.42 1994/10/30 20:09:12 bde 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 /* 182 * This code is called in different ways depending on what loaded 183 * and started the kernel. This is used to detect how we get the 184 * arguments from the other code and what we do with them. 185 * 186 * Old disk boot blocks: 187 * (*btext)(howto, bootdev, cyloffset, esym); 188 * [return address == 0, and can NOT be returned to] 189 * [cyloffset was not supported by the FreeBSD boot code 190 * and always passed in as 0] 191 * [esym is also known as total in the boot code, and 192 * was never properly supported by the FreeBSD boot code] 193 * 194 * Old diskless netboot code: 195 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 196 * [return address != 0, and can NOT be returned to] 197 * If we are being booted by this code it will NOT work, 198 * so we are just going to halt if we find this case. 199 * 200 * New uniform boot code: 201 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 202 * [return address != 0, and can be returned to] 203 * 204 * There may seem to be a lot of wasted arguments in here, but 205 * that is so the newer boot code can still load very old kernels 206 * and old boot code can load new kernels. 207 */ 208 209 /* 210 * The old style disk boot blocks fake a frame on the stack and 211 * did an lret to get here. The frame on the stack has a return 212 * address of 0. 213 */ 214 cmpl $0,4(%ebp) 215 je 2f /* olddiskboot: */ 216 217 /* 218 * We have some form of return address, so this is either the 219 * old diskless netboot code, or the new uniform code. That can 220 * be detected by looking at the 5th argument, it if is 0 we 221 * we are being booted by the new unifrom boot code. 222 */ 223 cmpl $0,24(%ebp) 224 je 1f /* newboot: */ 225 226 /* 227 * Seems we have been loaded by the old diskless boot code, we 228 * don't stand a chance of running as the diskless structure 229 * changed considerably between the two, so just halt. 230 */ 231 hlt 232 233 /* 234 * We have been loaded by the new uniform boot code. 235 * Lets check the bootinfo version, and if we do not understand 236 * it we return to the loader with a status of 1 to indicate this error 237 */ 2381: /* newboot: */ 239 movl 28(%ebp),%ebx /* &bootinfo.version */ 240 movl BOOTINFO_VERSION(%ebx),%eax 241 cmpl $1,%eax /* We only understand version 1 */ 242 je 1f 243 movl $1,%eax /* Return status */ 244 leave 245 ret 246 2471: 248 /* 249 * If we have a kernelname copy it in 250 */ 251 movl BOOTINFO_KERNELNAME(%ebx),%esi 252 cmpl $0,%esi 253 je 1f /* No kernelname */ 254 lea _kernelname-KERNBASE,%edi 255 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 256 cld 257 rep 258 movsb 259 2601: 261#ifdef NFS 262 /* 263 * If we have a nfs_diskless structure copy it in 264 */ 265 movl BOOTINFO_NFS_DISKLESS(%ebx),%esi 266 cmpl $0,%esi 267 je 2f 268 lea _nfs_diskless-KERNBASE,%edi 269 movl $NFSDISKLESS_SIZE,%ecx 270 cld 271 rep 272 movsb 273 lea _nfs_diskless_valid-KERNBASE,%edi 274 movl $1,(%edi) 275#endif 276 277 /* 278 * The old style disk boot. 279 * (*btext)(howto, bootdev, cyloffset, esym); 280 * Note that the newer boot code just falls into here to pick 281 * up howto and bootdev, cyloffset and esym are no longer used 282 */ 2832: /* olddiskboot: */ 284 movl 8(%ebp),%eax 285 movl %eax,_boothowto-KERNBASE 286 movl 12(%ebp),%eax 287 movl %eax,_bootdev-KERNBASE 288 289#if NAPM > 0 290 /* 291 * Setup APM BIOS: 292 * 293 * APM BIOS initialization should be done from real mode or V86 mode. 294 * 295 * (by HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>) 296 */ 297 298 /* 299 * Copy APM initializer under 1MB boundary: 300 * 301 * APM initializer program must switch the CPU to real mode. 302 * But FreeBSD kernel runs above 1MB boundary. So we must 303 * copy the initializer code to conventional memory. 304 */ 305 movl _apm_init_image_size-KERNBASE, %ecx /* size */ 306 lea _apm_init_image-KERNBASE, %esi /* source */ 307 movl $ APM_OURADDR, %edi /* destination */ 308 cld 309 rep 310 movsb 311 312 /* get GDT base */ 313 sgdt _apm_current_gdt_pdesc-KERNBASE 314 315 /* copy GDT to _bootstrap_gdt */ 316 xorl %ecx, %ecx 317 movw _apm_current_gdt_pdesc-KERNBASE, %cx 318 movl _apm_current_gdt_pdesc-KERNBASE+2, %esi 319 lea _bootstrap_gdt-KERNBASE, %edi 320 cld 321 rep 322 movsb 323 324 /* setup GDT pseudo descriptor */ 325 movw $(SIZEOF_GDT*BOOTSTRAP_GDT_NUM), %ax 326 movw %ax, _apm_current_gdt_pdesc-KERNBASE 327 leal _bootstrap_gdt-KERNBASE, %eax 328 movl %eax, _apm_current_gdt_pdesc-KERNBASE+2 329 330 /* load new GDTR */ 331 lgdt _apm_current_gdt_pdesc-KERNBASE 332 333 /* setup GDT for APM initializer */ 334 lea _bootstrap_gdt-KERNBASE, %ecx 335 movl $(APM_OURADDR), %eax /* use %ax for 15..0 */ 336 movl %eax, %ebx 337 shrl $16, %ebx /* use %bl for 23..16 */ 338 /* use %bh for 31..24 */ 339#define APM_SETUP_GDT(index, attrib) \ 340 movl $(index), %si ; \ 341 lea 0(%ecx,%esi,8), %edx ; \ 342 movw $0xffff, (%edx) ; \ 343 movw %ax, 2(%edx) ; \ 344 movb %bl, 4(%edx) ; \ 345 movw $(attrib), 5(%edx) ; \ 346 movb %bh, 7(%edx) 347 348 APM_SETUP_GDT(APM_INIT_CS_INDEX , CS32_ATTRIB) 349 APM_SETUP_GDT(APM_INIT_DS_INDEX , DS32_ATTRIB) 350 APM_SETUP_GDT(APM_INIT_CS16_INDEX, CS16_ATTRIB) 351 352 /* 353 * Call the initializer: 354 * 355 * direct intersegment call to conventional memory code 356 */ 357 .byte 0x9a /* actually, lcall $APM_INIT_CS_SEL, $0 */ 358 .long 0 359 .word APM_INIT_CS_SEL 360 361 movw %ax, _apm_version-KERNBASE 362 movl %ebx, _apm_cs_entry-KERNBASE 363 movw %cx, _apm_cs32_base-KERNBASE 364 shrl $16, %ecx 365 movw %cx, _apm_cs16_base-KERNBASE 366 movw %dx, _apm_ds_base-KERNBASE 367 movw %si, _apm_cs_limit-KERNBASE 368 shrl $16, %esi 369 movw %si, _apm_ds_limit-KERNBASE 370 movw %di, _apm_flags-KERNBASE 371#endif /* NAPM */ 372 373 /* Find out our CPU type. */ 374 375 /* Try to toggle alignment check flag; does not exist on 386. */ 376 pushfl 377 popl %eax 378 movl %eax,%ecx 379 orl $PSL_AC,%eax 380 pushl %eax 381 popfl 382 pushfl 383 popl %eax 384 xorl %ecx,%eax 385 andl $PSL_AC,%eax 386 pushl %ecx 387 popfl 388 389 testl %eax,%eax 390 jnz 1f 391 movl $CPU_386,_cpu-KERNBASE 392 jmp 2f 393 3941: /* Try to toggle identification flag; does not exist on early 486s. */ 395 pushfl 396 popl %eax 397 movl %eax,%ecx 398 xorl $PSL_ID,%eax 399 pushl %eax 400 popfl 401 pushfl 402 popl %eax 403 xorl %ecx,%eax 404 andl $PSL_ID,%eax 405 pushl %ecx 406 popfl 407 408 testl %eax,%eax 409 jnz 1f 410 movl $CPU_486,_cpu-KERNBASE 411 412 /* check for Cyrix 486DLC -- based on check routine */ 413 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 414 xorw %dx,%dx 415 cmpw %dx,%dx # set flags to known state 416 pushfw 417 popw %cx # store flags in ecx 418 movw $0xffff,%ax 419 movw $0x0004,%bx 420 divw %bx 421 pushfw 422 popw %ax 423 andw $0x08d5,%ax # mask off important bits 424 andw $0x08d5,%cx 425 cmpw %ax,%cx 426 427 jnz 2f # if flags changed, Intel chip 428 429 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 430 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 431 movw $0x0078,_cpu_vendor-KERNBASE+4 432 433 invd # Start with guaranteed clean cache 434 /* Disable caching of the ISA hole only. */ 435 movb $CCR0,%al # Configuration Register index (CCR0) 436 outb %al,$0x22 437 inb $0x23,%al 438 orb $(CCR0_NC1|CCR0_BARB),%al 439 outb %al,$0x23 440 invd 441 jmp 2f 442 4431: /* Use the `cpuid' instruction. */ 444 xorl %eax,%eax 445 .byte 0x0f,0xa2 # cpuid 0 446 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 447 movl %edx,_cpu_vendor+4-KERNBASE 448 movl %ecx,_cpu_vendor+8-KERNBASE 449 movb $0,_cpu_vendor+12-KERNBASE 450 451 movl $1,%eax 452 .byte 0x0f,0xa2 # cpuid 1 453 movl %eax,_cpu_id-KERNBASE # store cpu_id 454 rorl $8,%eax # extract family type 455 andl $15,%eax 456 cmpl $5,%eax 457 jae 1f 458 459 /* less than Pentium; must be 486 */ 460 movl $CPU_486,_cpu-KERNBASE 461 jmp 2f 462 4631: movl $CPU_586,_cpu-KERNBASE 4642: 465 466 /* 467 * Finished with old stack; load new %esp now instead of later so 468 * we can trace this code without having to worry about the trace 469 * trap clobbering the memory test or the zeroing of the bss+bootstrap 470 * page tables. 471 * 472 * XXX - wdboot clears the bss after testing that this is safe. 473 * This is too wasteful - memory below 640K is scarce. The boot 474 * program should check: 475 * text+data <= &stack_variable - more_space_for_stack 476 * text+data+bss+pad+space_for_page_tables <= end_of_memory 477 * Oops, the gdt is in the carcass of the boot program so clearing 478 * the rest of memory is still not possible. 479 */ 480 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 481 482/* 483 * Virtual address space of kernel: 484 * 485 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 486 * pages: 1 UPAGES (2) 1 NKPT (7) 487 */ 488 489/* find end of kernel image */ 490 movl $_end-KERNBASE,%ecx 491 addl $NBPG-1,%ecx /* page align up */ 492 andl $~(NBPG-1),%ecx 493 movl %ecx,%esi /* esi = start of free memory */ 494 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 495 496/* clear bss */ 497 movl $_edata-KERNBASE,%edi 498 subl %edi,%ecx /* get amount to clear */ 499 xorl %eax,%eax /* specify zero fill */ 500 cld 501 rep 502 stosb 503 504/* 505 * The value in esi is both the end of the kernel bss and a pointer to 506 * the kernel page directory, and is used by the rest of locore to build 507 * the tables. 508 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 509 * page table pages) is then passed on the stack to init386(first) as 510 * the value first. esi should ALWAYS be page aligned!! 511 */ 512 movl %esi,%ecx /* Get current first availiable address */ 513 514/* clear pagetables, page directory, stack, etc... */ 515 movl %esi,%edi /* base (page directory) */ 516 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 517 xorl %eax,%eax /* specify zero fill */ 518 cld 519 rep 520 stosb 521 522/* physical address of Idle proc/kernel page directory */ 523 movl %esi,_IdlePTD-KERNBASE 524 525/* 526 * fillkpt 527 * eax = (page frame address | control | status) == pte 528 * ebx = address of page table 529 * ecx = how many pages to map 530 */ 531#define fillkpt \ 5321: movl %eax,(%ebx) ; \ 533 addl $NBPG,%eax ; /* increment physical address */ \ 534 addl $4,%ebx ; /* next pte */ \ 535 loop 1b ; 536 537/* 538 * Map Kernel 539 * 540 * First step - build page tables 541 */ 542#if defined (KGDB) || defined (BDE_DEBUGGER) 543 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 544 shrl $PGSHIFT,%ecx /* for this many PTEs */ 545#ifdef BDE_DEBUGGER 546 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 547 jae 1f 548 movl $0xa0,%ecx 5491: 550#endif /* BDE_DEBUGGER */ 551 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 552 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 553 movl %ebx,_KPTphys-KERNBASE /* save in global */ 554 fillkpt 555 556#else /* !KGDB && !BDE_DEBUGGER */ 557 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 558 movl $_etext-KERNBASE,%ecx /* get size of text */ 559 addl $NBPG-1,%ecx /* round up to page */ 560 shrl $PGSHIFT,%ecx /* for this many PTEs */ 561 movl $PG_V|PG_KR,%eax /* specify read only */ 562#if 0 563 movl $_etext,%ecx /* get size of text */ 564 subl $_btext,%ecx 565 addl $NBPG-1,%ecx /* round up to page */ 566 shrl $PGSHIFT,%ecx /* for this many PTEs */ 567 movl $_btext-KERNBASE,%eax /* get offset to physical memory */ 568 orl $PG_V|PG_KR,%eax /* specify read only */ 569#endif 570 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 571 movl %ebx,_KPTphys-KERNBASE /* save in global */ 572 fillkpt 573 574 /* data and bss are r/w */ 575 andl $PG_FRAME,%eax /* strip to just addr of bss */ 576 movl _KERNend-KERNBASE,%ecx /* calculate size */ 577 subl %eax,%ecx 578 shrl $PGSHIFT,%ecx 579 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 580 fillkpt 581#endif /* KGDB || BDE_DEBUGGER */ 582 583/* now initialize the page dir, upages, p0stack PT, and page tables */ 584 585 movl $(1+UPAGES+1+NKPT),%ecx /* number of PTEs */ 586 movl %esi,%eax /* phys address of PTD */ 587 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 588 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 589 movl %esi,%ebx /* calculate pte offset to ptd */ 590 shrl $PGSHIFT-2,%ebx 591 addl %esi,%ebx /* address of page directory */ 592 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 593 fillkpt 594 595/* map I/O memory map */ 596 597 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 598 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 599 movl $0x100-0xa0,%ecx /* for this many pte s, */ 600 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 601 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 602 fillkpt 603 604 /* map proc 0's kernel stack into user page table page */ 605 606 movl $UPAGES,%ecx /* for this many pte s, */ 607 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 608 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 609 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 610 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 611 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 612 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 613 fillkpt 614 615/* 616 * Initialize kernel page table directory 617 */ 618 /* install a pde for temporary double map of bottom of VA */ 619 movl _KPTphys-KERNBASE,%eax 620 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 621 movl %eax,(%esi) /* which is where temp maps! */ 622 623 /* initialize kernel pde's */ 624 movl $(NKPT),%ecx /* for this many PDEs */ 625 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 626 fillkpt 627 628 /* install a pde recursively mapping page directory as a page table! */ 629 movl %esi,%eax /* phys address of ptd in proc 0 */ 630 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 631 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 632 633 /* install a pde to map kernel stack for proc 0 */ 634 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 635 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 636 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 637 638#ifdef BDE_DEBUGGER 639 /* copy and convert stuff from old gdt and idt for debugger */ 640 641 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 642 jne 1f 643 movb $1,_bdb_exists-KERNBASE 6441: 645 pushal 646 subl $2*6,%esp 647 648 sgdt (%esp) 649 movl 2(%esp),%esi /* base address of current gdt */ 650 movl $_gdt-KERNBASE,%edi 651 movl %edi,2(%esp) 652 movl $8*18/4,%ecx 653 cld 654 rep /* copy gdt */ 655 movsl 656 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 657 movb $0x92,-8+5(%edi) 658 659 sidt 6(%esp) 660 movl 6+2(%esp),%esi /* base address of current idt */ 661 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 662 movw 8(%esi),%ax 663 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 664 movl 8+2(%esi),%eax 665 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 666 movl 24+4(%esi),%eax /* same for bpt descriptor */ 667 movw 24(%esi),%ax 668 movl %eax,bdb_bpt_ljmp+1-KERNBASE 669 movl 24+2(%esi),%eax 670 movw %ax,bdb_bpt_ljmp+5-KERNBASE 671 672 movl $_idt-KERNBASE,%edi 673 movl %edi,6+2(%esp) 674 movl $8*4/4,%ecx 675 cld 676 rep /* copy idt */ 677 movsl 678 679 lgdt (%esp) 680 lidt 6(%esp) 681 682 addl $2*6,%esp 683 popal 684#endif /* BDE_DEBUGGER */ 685 686 /* load base of page directory and enable mapping */ 687 movl %esi,%eax /* phys address of ptd in proc 0 */ 688 movl %eax,%cr3 /* load ptd addr into mmu */ 689 movl %cr0,%eax /* get control word */ 690 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 691 movl %eax,%cr0 /* and let's page NOW! */ 692 693 pushl $begin /* jump to high mem */ 694 ret 695 696begin: /* now running relocated at KERNBASE where the system is linked to run */ 697 movl _atdevphys,%edx /* get pte PA */ 698 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 699 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 700 addl $KERNBASE,%edx /* add virtual base */ 701 movl %edx,_atdevbase 702 703#include "sc.h" 704#include "vt.h" 705#if NSC > 0 || NVT > 0 706 /* XXX: can't scinit relocate Crtat relative to atdevbase itself? */ 707 .globl _Crtat /* XXX - locore should not know about */ 708 movl _Crtat,%eax /* variables of device drivers (pccons)! */ 709 subl $(KERNBASE+0xA0000),%eax 710 addl %eax,%edx 711 movl %edx,_Crtat 712#endif 713 714 /* set up bootstrap stack - 48 bytes */ 715 movl $_kstack+UPAGES*NBPG-4*12,%esp /* bootstrap stack end location */ 716 xorl %eax,%eax /* mark end of frames */ 717 movl %eax,%ebp 718 movl _proc0paddr,%eax 719 movl %esi,PCB_CR3(%eax) 720 721#ifdef BDE_DEBUGGER 722 /* relocate debugger gdt entries */ 723 724 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 725 movl $9,%ecx 726reloc_gdt: 727 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 728 addl $8,%eax /* now KERNBASE>>24 */ 729 loop reloc_gdt 730 731 cmpl $0,_bdb_exists 732 je 1f 733 int $3 7341: 735#endif /* BDE_DEBUGGER */ 736 737 /* 738 * Skip over the page tables and the kernel stack 739 */ 740 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 741 742 pushl %esi /* value of first for init386(first) */ 743 call _init386 /* wire 386 chip for unix operation */ 744 popl %esi 745 746 .globl __ucodesel,__udatasel 747 748 pushl $0 /* unused */ 749 pushl __udatasel /* ss */ 750 pushl $0 /* esp - filled in by execve() */ 751 pushl $PSL_USERSET /* eflags (ring 0, int enab) */ 752 pushl __ucodesel /* cs */ 753 pushl $0 /* eip - filled in by execve() */ 754 subl $(12*4),%esp /* space for rest of registers */ 755 756 pushl %esp /* call main with frame pointer */ 757 call _main /* autoconfiguration, mountroot etc */ 758 759 addl $(13*4),%esp /* back to a frame we can return with */ 760 761 /* 762 * now we've run main() and determined what cpu-type we are, we can 763 * enable WP mode on i486 cpus and above. 764 */ 765#if defined(I486_CPU) || defined(I586_CPU) 766 cmpl $CPUCLASS_386,_cpu_class 767 je 1f 768 movl %cr0,%eax /* get control word */ 769 orl $CR0_WP,%eax /* enable write protect for all modes */ 770 movl %eax,%cr0 /* and do it */ 771#endif 772 /* 773 * on return from main(), we are process 1 774 * set up address space and stack so that we can 'return' to user mode 775 */ 7761: 777 movl __ucodesel,%eax 778 movl __udatasel,%ecx 779 780 movl %cx,%ds 781 movl %cx,%es 782 movl %ax,%fs /* double map cs to fs */ 783 movl %cx,%gs /* and ds to gs */ 784 iret /* goto user! */ 785 786#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 787 788NON_GPROF_ENTRY(sigcode) 789 call SIGF_HANDLER(%esp) 790 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 791 /* copy at 8(%esp)) */ 792 pushl %eax 793 pushl %eax /* junk to fake return address */ 794 movl $103,%eax /* XXX sigreturn() */ 795 LCALL(0x7,0) /* enter kernel with args on stack */ 796 hlt /* never gets here */ 797 798 .globl _szsigcode 799_szsigcode: 800 .long _szsigcode-_sigcode 801