locore.s revision 4600
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 1.44 1994/11/06 22:18:45 phk 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,_bootinfo 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_bootinfo: .space BOOTINFO_SIZE /* the bootstrapper knew it! */ 128_cold: .long 1 /* cold till we are not */ 129_atdevbase: .long 0 /* location of start of iomem in virtual */ 130_atdevphys: .long 0 /* location of device mapping ptes (phys) */ 131 132_KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 133 134 .globl _IdlePTD 135_IdlePTD: .long 0 /* phys addr of kernel PTD */ 136 137_KPTphys: .long 0 /* phys addr of kernel page tables */ 138 139 .globl _proc0paddr 140_proc0paddr: .long 0 /* address of proc 0 address space */ 141 142#ifdef BDE_DEBUGGER 143 .globl _bdb_exists /* flag to indicate BDE debugger is available */ 144_bdb_exists: .long 0 145#endif 146#if NAPM > 0 147 .globl _apm_current_gdt_pdesc /* current GDT pseudo desc. */ 148_apm_current_gdt_pdesc: 149 .word 0, 0, 0 150 151 .globl _bootstrap_gdt 152_bootstrap_gdt: 153 .space SIZEOF_GDT * BOOTSTRAP_GDT_NUM 154#endif /* NAPM */ 155 156/* 157 * System Initialization 158 */ 159 .text 160 161/* 162 * btext: beginning of text section. 163 * Also the entry point (jumped to directly from the boot blocks). 164 */ 165NON_GPROF_ENTRY(btext) 166 movw $0x1234,0x472 /* warm boot */ 167 jmp 1f 168 /* 169 * XXX now that we load at 1MB is this still really used? 170 */ 171 .org 0x500 /* space for BIOS variables */ 172 1731: 174 /* Set up a real frame, some day we will be doing returns */ 175 pushl %ebp 176 movl %esp, %ebp 177 178 /* Don't trust what the BIOS gives for eflags. */ 179 pushl $PSL_MBO 180 popfl 181 182 /* Don't trust what the BIOS gives for %fs and %gs. */ 183 mov %ds, %ax 184 mov %ax, %fs 185 mov %ax, %gs 186 187 /* 188 * This code is called in different ways depending on what loaded 189 * and started the kernel. This is used to detect how we get the 190 * arguments from the other code and what we do with them. 191 * 192 * Old disk boot blocks: 193 * (*btext)(howto, bootdev, cyloffset, esym); 194 * [return address == 0, and can NOT be returned to] 195 * [cyloffset was not supported by the FreeBSD boot code 196 * and always passed in as 0] 197 * [esym is also known as total in the boot code, and 198 * was never properly supported by the FreeBSD boot code] 199 * 200 * Old diskless netboot code: 201 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 202 * [return address != 0, and can NOT be returned to] 203 * If we are being booted by this code it will NOT work, 204 * so we are just going to halt if we find this case. 205 * 206 * New uniform boot code: 207 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 208 * [return address != 0, and can be returned to] 209 * 210 * There may seem to be a lot of wasted arguments in here, but 211 * that is so the newer boot code can still load very old kernels 212 * and old boot code can load new kernels. 213 */ 214 215 /* 216 * The old style disk boot blocks fake a frame on the stack and 217 * did an lret to get here. The frame on the stack has a return 218 * address of 0. 219 */ 220 cmpl $0,4(%ebp) 221 je 2f /* olddiskboot: */ 222 223 /* 224 * We have some form of return address, so this is either the 225 * old diskless netboot code, or the new uniform code. That can 226 * be detected by looking at the 5th argument, it if is 0 we 227 * we are being booted by the new unifrom boot code. 228 */ 229 cmpl $0,24(%ebp) 230 je 1f /* newboot: */ 231 232 /* 233 * Seems we have been loaded by the old diskless boot code, we 234 * don't stand a chance of running as the diskless structure 235 * changed considerably between the two, so just halt. 236 */ 237 hlt 238 239 /* 240 * We have been loaded by the new uniform boot code. 241 * Lets check the bootinfo version, and if we do not understand 242 * it we return to the loader with a status of 1 to indicate this error 243 */ 2441: /* newboot: */ 245 movl 28(%ebp),%ebx /* &bootinfo.version */ 246 movl BOOTINFO_VERSION(%ebx),%eax 247 cmpl $1,%eax /* We only understand version 1 */ 248 je 1f 249 movl $1,%eax /* Return status */ 250 leave 251 ret 252 2531: 254 /* 255 * If we have a kernelname copy it in 256 */ 257 movl BOOTINFO_KERNELNAME(%ebx),%esi 258 cmpl $0,%esi 259 je 1f /* No kernelname */ 260 lea _kernelname-KERNBASE,%edi 261 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 262 cld 263 rep 264 movsb 265 2661: 267 /* 268 * Copy the bootinfo structure 269 */ 270 movl %ebx,%esi 271 lea _bootinfo-KERNBASE,%edi 272 movl $BOOTINFO_SIZE,%ecx 273 cld 274 rep 275 movsb 276 277#ifdef NFS 278 /* 279 * If we have a nfs_diskless structure copy it in 280 */ 281 movl BOOTINFO_NFS_DISKLESS(%ebx),%esi 282 cmpl $0,%esi 283 je 2f 284 lea _nfs_diskless-KERNBASE,%edi 285 movl $NFSDISKLESS_SIZE,%ecx 286 cld 287 rep 288 movsb 289 lea _nfs_diskless_valid-KERNBASE,%edi 290 movl $1,(%edi) 291#endif 292 293 /* 294 * The old style disk boot. 295 * (*btext)(howto, bootdev, cyloffset, esym); 296 * Note that the newer boot code just falls into here to pick 297 * up howto and bootdev, cyloffset and esym are no longer used 298 */ 2992: /* olddiskboot: */ 300 movl 8(%ebp),%eax 301 movl %eax,_boothowto-KERNBASE 302 movl 12(%ebp),%eax 303 movl %eax,_bootdev-KERNBASE 304 305#if NAPM > 0 306 /* 307 * Setup APM BIOS: 308 * 309 * APM BIOS initialization should be done from real mode or V86 mode. 310 * 311 * (by HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>) 312 */ 313 314 /* 315 * Copy APM initializer under 1MB boundary: 316 * 317 * APM initializer program must switch the CPU to real mode. 318 * But FreeBSD kernel runs above 1MB boundary. So we must 319 * copy the initializer code to conventional memory. 320 */ 321 movl _apm_init_image_size-KERNBASE, %ecx /* size */ 322 lea _apm_init_image-KERNBASE, %esi /* source */ 323 movl $ APM_OURADDR, %edi /* destination */ 324 cld 325 rep 326 movsb 327 328 /* get GDT base */ 329 sgdt _apm_current_gdt_pdesc-KERNBASE 330 331 /* copy GDT to _bootstrap_gdt */ 332 xorl %ecx, %ecx 333 movw _apm_current_gdt_pdesc-KERNBASE, %cx 334 movl _apm_current_gdt_pdesc-KERNBASE+2, %esi 335 lea _bootstrap_gdt-KERNBASE, %edi 336 cld 337 rep 338 movsb 339 340 /* setup GDT pseudo descriptor */ 341 movw $(SIZEOF_GDT*BOOTSTRAP_GDT_NUM), %ax 342 movw %ax, _apm_current_gdt_pdesc-KERNBASE 343 leal _bootstrap_gdt-KERNBASE, %eax 344 movl %eax, _apm_current_gdt_pdesc-KERNBASE+2 345 346 /* load new GDTR */ 347 lgdt _apm_current_gdt_pdesc-KERNBASE 348 349 /* setup GDT for APM initializer */ 350 lea _bootstrap_gdt-KERNBASE, %ecx 351 movl $(APM_OURADDR), %eax /* use %ax for 15..0 */ 352 movl %eax, %ebx 353 shrl $16, %ebx /* use %bl for 23..16 */ 354 /* use %bh for 31..24 */ 355#define APM_SETUP_GDT(index, attrib) \ 356 movl $(index), %si ; \ 357 lea 0(%ecx,%esi,8), %edx ; \ 358 movw $0xffff, (%edx) ; \ 359 movw %ax, 2(%edx) ; \ 360 movb %bl, 4(%edx) ; \ 361 movw $(attrib), 5(%edx) ; \ 362 movb %bh, 7(%edx) 363 364 APM_SETUP_GDT(APM_INIT_CS_INDEX , CS32_ATTRIB) 365 APM_SETUP_GDT(APM_INIT_DS_INDEX , DS32_ATTRIB) 366 APM_SETUP_GDT(APM_INIT_CS16_INDEX, CS16_ATTRIB) 367 368 /* 369 * Call the initializer: 370 * 371 * direct intersegment call to conventional memory code 372 */ 373 .byte 0x9a /* actually, lcall $APM_INIT_CS_SEL, $0 */ 374 .long 0 375 .word APM_INIT_CS_SEL 376 377 movw %ax, _apm_version-KERNBASE 378 movl %ebx, _apm_cs_entry-KERNBASE 379 movw %cx, _apm_cs32_base-KERNBASE 380 shrl $16, %ecx 381 movw %cx, _apm_cs16_base-KERNBASE 382 movw %dx, _apm_ds_base-KERNBASE 383 movw %si, _apm_cs_limit-KERNBASE 384 shrl $16, %esi 385 movw %si, _apm_ds_limit-KERNBASE 386 movw %di, _apm_flags-KERNBASE 387#endif /* NAPM */ 388 389 /* Find out our CPU type. */ 390 391 /* Try to toggle alignment check flag; does not exist on 386. */ 392 pushfl 393 popl %eax 394 movl %eax,%ecx 395 orl $PSL_AC,%eax 396 pushl %eax 397 popfl 398 pushfl 399 popl %eax 400 xorl %ecx,%eax 401 andl $PSL_AC,%eax 402 pushl %ecx 403 popfl 404 405 testl %eax,%eax 406 jnz 1f 407 movl $CPU_386,_cpu-KERNBASE 408 jmp 2f 409 4101: /* Try to toggle identification flag; does not exist on early 486s. */ 411 pushfl 412 popl %eax 413 movl %eax,%ecx 414 xorl $PSL_ID,%eax 415 pushl %eax 416 popfl 417 pushfl 418 popl %eax 419 xorl %ecx,%eax 420 andl $PSL_ID,%eax 421 pushl %ecx 422 popfl 423 424 testl %eax,%eax 425 jnz 1f 426 movl $CPU_486,_cpu-KERNBASE 427 428 /* check for Cyrix 486DLC -- based on check routine */ 429 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 430 xorw %dx,%dx 431 cmpw %dx,%dx # set flags to known state 432 pushfw 433 popw %cx # store flags in ecx 434 movw $0xffff,%ax 435 movw $0x0004,%bx 436 divw %bx 437 pushfw 438 popw %ax 439 andw $0x08d5,%ax # mask off important bits 440 andw $0x08d5,%cx 441 cmpw %ax,%cx 442 443 jnz 2f # if flags changed, Intel chip 444 445 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 446 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 447 movw $0x0078,_cpu_vendor-KERNBASE+4 448 449 invd # Start with guaranteed clean cache 450 /* Disable caching of the ISA hole only. */ 451 movb $CCR0,%al # Configuration Register index (CCR0) 452 outb %al,$0x22 453 inb $0x23,%al 454 orb $(CCR0_NC1|CCR0_BARB),%al 455 outb %al,$0x23 456 invd 457 jmp 2f 458 4591: /* Use the `cpuid' instruction. */ 460 xorl %eax,%eax 461 .byte 0x0f,0xa2 # cpuid 0 462 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 463 movl %edx,_cpu_vendor+4-KERNBASE 464 movl %ecx,_cpu_vendor+8-KERNBASE 465 movb $0,_cpu_vendor+12-KERNBASE 466 467 movl $1,%eax 468 .byte 0x0f,0xa2 # cpuid 1 469 movl %eax,_cpu_id-KERNBASE # store cpu_id 470 rorl $8,%eax # extract family type 471 andl $15,%eax 472 cmpl $5,%eax 473 jae 1f 474 475 /* less than Pentium; must be 486 */ 476 movl $CPU_486,_cpu-KERNBASE 477 jmp 2f 478 4791: movl $CPU_586,_cpu-KERNBASE 4802: 481 482 /* 483 * Finished with old stack; load new %esp now instead of later so 484 * we can trace this code without having to worry about the trace 485 * trap clobbering the memory test or the zeroing of the bss+bootstrap 486 * page tables. 487 * 488 * XXX - wdboot clears the bss after testing that this is safe. 489 * This is too wasteful - memory below 640K is scarce. The boot 490 * program should check: 491 * text+data <= &stack_variable - more_space_for_stack 492 * text+data+bss+pad+space_for_page_tables <= end_of_memory 493 * Oops, the gdt is in the carcass of the boot program so clearing 494 * the rest of memory is still not possible. 495 */ 496 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 497 498/* 499 * Virtual address space of kernel: 500 * 501 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 502 * pages: 1 UPAGES (2) 1 NKPT (7) 503 */ 504 505/* find end of kernel image */ 506 movl $_end-KERNBASE,%ecx 507 addl $NBPG-1,%ecx /* page align up */ 508 andl $~(NBPG-1),%ecx 509 movl %ecx,%esi /* esi = start of free memory */ 510 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 511 512/* clear bss */ 513 movl $_edata-KERNBASE,%edi 514 subl %edi,%ecx /* get amount to clear */ 515 xorl %eax,%eax /* specify zero fill */ 516 cld 517 rep 518 stosb 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, p0stack PT, and page tables */ 600 601 movl $(1+UPAGES+1+NKPT),%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#include "sc.h" 720#include "vt.h" 721#if NSC > 0 || NVT > 0 722 /* XXX: can't scinit relocate Crtat relative to atdevbase itself? */ 723 .globl _Crtat /* XXX - locore should not know about */ 724 movl _Crtat,%eax /* variables of device drivers (pccons)! */ 725 subl $(KERNBASE+0xA0000),%eax 726 addl %eax,%edx 727 movl %edx,_Crtat 728#endif 729 730 /* set up bootstrap stack - 48 bytes */ 731 movl $_kstack+UPAGES*NBPG-4*12,%esp /* bootstrap stack end location */ 732 xorl %eax,%eax /* mark end of frames */ 733 movl %eax,%ebp 734 movl _proc0paddr,%eax 735 movl %esi,PCB_CR3(%eax) 736 737#ifdef BDE_DEBUGGER 738 /* relocate debugger gdt entries */ 739 740 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 741 movl $9,%ecx 742reloc_gdt: 743 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 744 addl $8,%eax /* now KERNBASE>>24 */ 745 loop reloc_gdt 746 747 cmpl $0,_bdb_exists 748 je 1f 749 int $3 7501: 751#endif /* BDE_DEBUGGER */ 752 753 /* 754 * Skip over the page tables and the kernel stack 755 */ 756 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 757 758 pushl %esi /* value of first for init386(first) */ 759 call _init386 /* wire 386 chip for unix operation */ 760 popl %esi 761 762 .globl __ucodesel,__udatasel 763 764 pushl $0 /* unused */ 765 pushl __udatasel /* ss */ 766 pushl $0 /* esp - filled in by execve() */ 767 pushl $PSL_USERSET /* eflags (ring 0, int enab) */ 768 pushl __ucodesel /* cs */ 769 pushl $0 /* eip - filled in by execve() */ 770 subl $(12*4),%esp /* space for rest of registers */ 771 772 pushl %esp /* call main with frame pointer */ 773 call _main /* autoconfiguration, mountroot etc */ 774 775 addl $(13*4),%esp /* back to a frame we can return with */ 776 777 /* 778 * now we've run main() and determined what cpu-type we are, we can 779 * enable WP mode on i486 cpus and above. 780 */ 781#if defined(I486_CPU) || defined(I586_CPU) 782 cmpl $CPUCLASS_386,_cpu_class 783 je 1f 784 movl %cr0,%eax /* get control word */ 785 orl $CR0_WP,%eax /* enable write protect for all modes */ 786 movl %eax,%cr0 /* and do it */ 787#endif 788 /* 789 * on return from main(), we are process 1 790 * set up address space and stack so that we can 'return' to user mode 791 */ 7921: 793 movl __ucodesel,%eax 794 movl __udatasel,%ecx 795 796 movl %cx,%ds 797 movl %cx,%es 798 movl %ax,%fs /* double map cs to fs */ 799 movl %cx,%gs /* and ds to gs */ 800 iret /* goto user! */ 801 802#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 803 804NON_GPROF_ENTRY(sigcode) 805 call SIGF_HANDLER(%esp) 806 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 807 /* copy at 8(%esp)) */ 808 pushl %eax 809 pushl %eax /* junk to fake return address */ 810 movl $103,%eax /* XXX sigreturn() */ 811 LCALL(0x7,0) /* enter kernel with args on stack */ 812 hlt /* never gets here */ 813 814 .globl _szsigcode 815_szsigcode: 816 .long _szsigcode-_sigcode 817