locore.s revision 3284
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 1.30 1994/10/01 02:56:01 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 "npx.h" /* for NNPX */ 49#include "assym.s" /* system definitions */ 50#include <machine/psl.h> /* processor status longword defs */ 51#include <machine/pte.h> /* page table entry definitions */ 52#include <sys/errno.h> /* error return codes */ 53#include <machine/specialreg.h> /* x86 special registers */ 54#include <machine/cputypes.h> /* x86 cpu type definitions */ 55#include <sys/syscall.h> /* system call numbers */ 56#include <machine/asmacros.h> /* miscellaneous asm macros */ 57#ifdef APM 58#define ASM 59#include <machine/apm_bios.h> 60#include <machine/apm_segments.h> 61#endif 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,_Sysmap 76 .set _PTmap,PTDPTDI << PDRSHIFT 77 .set _PTD,_PTmap + (PTDPTDI * NBPG) 78 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE) 79 80/* Sysmap is the base address of the kernel page tables */ 81 .set _Sysmap,_PTmap + (KPTDI * NBPG) 82 83/* 84 * APTmap, APTD is the alternate recursive pagemap. 85 * It's used when modifying another process's page tables. 86 */ 87 .globl _APTmap,_APTD,_APTDpde 88 .set _APTmap,APTDPTDI << PDRSHIFT 89 .set _APTD,_APTmap + (APTDPTDI * NBPG) 90 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE) 91 92/* 93 * Access to each processes kernel stack is via a region of 94 * per-process address space (at the beginning), immediatly above 95 * the user process stack. 96 */ 97 .set _kstack,USRSTACK 98 .globl _kstack 99 100/* 101 * Globals 102 */ 103 .data 104 .globl _esym 105_esym: .long 0 /* ptr to end of syms */ 106 107 .globl _boothowto,_bootdev,_curpcb 108 109 .globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id 110 111 .globl _video_mode_ptr 112 113_cpu: .long 0 /* are we 386, 386sx, or 486 */ 114_cpu_id: .long 0 /* stepping ID */ 115_cpu_vendor: .space 20 /* CPU origin code */ 116_video_mode_ptr: .long 0 117_cold: .long 1 /* cold till we are not */ 118_atdevbase: .long 0 /* location of start of iomem in virtual */ 119_atdevphys: .long 0 /* location of device mapping ptes (phys) */ 120 121 .globl _KERNend 122_KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 123 124 .globl _IdlePTD,_KPTphys 125_IdlePTD: .long 0 /* phys addr of kernel PTD */ 126_KPTphys: .long 0 /* phys addr of kernel page tables */ 127 128 .globl _proc0paddr 129_proc0paddr: .long 0 /* address of proc 0 address space */ 130 131#ifdef BDE_DEBUGGER 132 .globl _bdb_exists /* flag to indicate BDE debugger is available */ 133_bdb_exists: .long 0 134#endif 135#ifdef APM 136 .globl _apm_current_gdt_pdesc /* current GDT pseudo desc. */ 137_apm_current_gdt_pdesc: 138 .byte 0, 0, 0 139 140 .globl _bootstrap_gdt 141_bootstrap_gdt: 142 .space SIZEOF_GDT * BOOTSTRAP_GDT_NUM 143#endif /* APM */ 144 .globl tmpstk 145 .space 0x1000 146tmpstk: 147 148 149/* 150 * System Initialization 151 */ 152 .text 153 154/* 155 * btext: beginning of text section. 156 * Also the entry point (jumped to directly from the boot blocks). 157 */ 158NON_GPROF_ENTRY(btext) 159 movw $0x1234,0x472 /* warm boot */ 160 jmp 1f 161 /* 162 * XXX now that we load at 1MB is this still really used? 163 */ 164 .org 0x500 /* space for BIOS variables */ 165 1661: 167 /* Don't trust what the BIOS gives for eflags. */ 168 pushl $PSL_MBO 169 popfl 170 171 /* 172 * This code is called in different ways depending on what loaded 173 * and started the kernel. This is used to detect how we get the 174 * arguments from the other code and what we do with them. 175 * 176 * Old disk boot blocks: 177 * (*btext)(howto, bootdev, cyloffset, esym); 178 * [return address == 0, and can NOT be returned to] 179 * [cyloffset was not supported by the FreeBSD boot code 180 * and always passed in as 0] 181 * [esym is also known as total in the boot code, and 182 * was never properly supported by the FreeBSD boot code] 183 * 184 * Old diskless netboot code: 185 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 186 * [return address != 0, and can NOT be returned to] 187 * If we are being booted by this code it will NOT work, 188 * so we are just going to halt if we find this case. 189 * 190 * New uniform boot code: 191 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 192 * [return address != 0, and can be returned to] 193 * 194 * There may seem to be a lot of wasted arguments in here, but 195 * that is so the newer boot code can still load very old kernels. 196 */ 197 198 /* 199 * The old style disk boot blocks fake a frame on the stack and 200 * did an lret to get here. The frame on the stack has a return 201 * address of 0. 202 */ 203 cmpl $0,0x00(%esp) 204 je 2f /* olddiskboot: */ 205 206 /* 207 * We have some form of return address, so this is either the 208 * old diskless netboot code, or the new uniform code. That can 209 * be detected by looking at the 5th argument, it if is 0 we 210 * we are being booted by the new unifrom boot code. 211 */ 212 cmpl $0,0x14(%esp) 213 je 1f /* newboot: */ 214 215 /* 216 * Seems we have been loaded by the old diskless boot code, we 217 * don't stand a chance of running as the diskless structure 218 * changed considerably between the two, so just halt. 219 */ 220 hlt 221 222 /* 223 * We have been loaded by the new uniform boot code, this kernel 224 * is not yet ready to handle that, so for now fix up the stack 225 * like a real subroutine and then return to the boot loader with 226 * a status of 1 to indicate this error. 227 */ 2281: /* newboot: */ 229 pushl %ebp 230 movl %esp,%ebp 231 movl $1,%eax 232 leave 233 ret 234 235 /* 236 * The old style disk boot. 237 * (*btext)(howto, bootdev, cyloffset, esym); 238 * cyloffset is no longer copied 239 * XXX Is esym still used for the end of the kernel some place??? 240 * for now make sure we keep a correct value in it until I 241 * can deterimine that. 242 */ 2432: /* olddiskboot: */ 244 movl 4(%esp),%eax 245 movl %eax,_boothowto-KERNBASE 246 movl 8(%esp),%eax 247 movl %eax,_bootdev-KERNBASE 248 movl 16(%esp),%eax 249 addl $KERNBASE,%eax 250 movl %eax,_esym-KERNBASE 251 252 /* get the BIOS video mode pointer */ 253 movl $0x4a8, %ecx 254 movl (%ecx), %eax 255 movl %eax, %ecx 256 shrl $12, %ecx 257 andl $0xffff0000, %ecx 258 andl $0x0000ffff, %eax 259 orl %ecx, %eax 260 movl (%eax), %eax 261 movl %eax, %ecx 262 shrl $12, %ecx 263 andl $0xffff0000, %ecx 264 andl $0x0000ffff, %eax 265 orl %ecx, %eax 266 addl $KERNBASE, %eax 267 movl %eax, _video_mode_ptr-KERNBASE 268 269#ifdef APM 270 /* 271 * Setup APM BIOS: 272 * 273 * APM BIOS initialization should be done from real mode or V86 mode. 274 * 275 * (by HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>) 276 */ 277 278 /* 279 * Copy APM initializer under 1MB boundary: 280 * 281 * APM initializer program must switch the CPU to real mode. 282 * But FreeBSD kernel runs above 1MB boundary. So we must 283 * copy the initializer code to conventional memory. 284 */ 285 movl _apm_init_image_size-KERNBASE, %ecx /* size */ 286 lea _apm_init_image-KERNBASE, %esi /* source */ 287 movl $ APM_OURADDR, %edi /* destination */ 288 cld 289 rep 290 movsb 291 292 /* get GDT base */ 293 sgdt _apm_current_gdt_pdesc-KERNBASE 294 295 /* copy GDT to _bootstrap_gdt */ 296 xorl %ecx, %ecx 297 movw _apm_current_gdt_pdesc-KERNBASE, %cx 298 movl _apm_current_gdt_pdesc-KERNBASE+2, %esi 299 lea _bootstrap_gdt-KERNBASE, %edi 300 cld 301 rep 302 movsb 303 304 /* setup GDT pseudo descriptor */ 305 movw $(SIZEOF_GDT*BOOTSTRAP_GDT_NUM), %ax 306 movw %ax, _apm_current_gdt_pdesc-KERNBASE 307 leal _bootstrap_gdt-KERNBASE, %eax 308 movl %eax, _apm_current_gdt_pdesc-KERNBASE+2 309 310 /* load new GDTR */ 311 lgdt _apm_current_gdt_pdesc-KERNBASE 312 313 /* setup GDT for APM initializer */ 314 lea _bootstrap_gdt-KERNBASE, %ecx 315 movl $(APM_OURADDR), %eax /* use %ax for 15..0 */ 316 movl %eax, %ebx 317 shrl $16, %ebx /* use %bl for 23..16 */ 318 /* use %bh for 31..24 */ 319#define APM_SETUP_GDT(index, attrib) \ 320 movl $(index), %si ; \ 321 lea 0(%ecx,%esi,8), %edx ; \ 322 movw $0xffff, (%edx) ; \ 323 movw %ax, 2(%edx) ; \ 324 movb %bl, 4(%edx) ; \ 325 movw $(attrib), 5(%edx) ; \ 326 movb %bh, 7(%edx) 327 328 APM_SETUP_GDT(APM_INIT_CS_INDEX , CS32_ATTRIB) 329 APM_SETUP_GDT(APM_INIT_DS_INDEX , DS32_ATTRIB) 330 APM_SETUP_GDT(APM_INIT_CS16_INDEX, CS16_ATTRIB) 331 332 /* 333 * Call the initializer: 334 * 335 * direct intersegment call to conventional memory code 336 */ 337 .byte 0x9a /* actually, lcall $APM_INIT_CS_SEL, $0 */ 338 .long 0 339 .word APM_INIT_CS_SEL 340 341 movw %ax, _apm_version-KERNBASE 342 movl %ebx, _apm_cs_entry-KERNBASE 343 movw %cx, _apm_cs32_base-KERNBASE 344 shrl $16, %ecx 345 movw %cx, _apm_cs16_base-KERNBASE 346 movw %dx, _apm_ds_base-KERNBASE 347 movw %si, _apm_cs_limit-KERNBASE 348 shrl $16, %esi 349 movw %si, _apm_ds_limit-KERNBASE 350 movw %di, _apm_flags-KERNBASE 351#endif /* APM */ 352 353 /* Find out our CPU type. */ 354 355 /* Try to toggle alignment check flag; does not exist on 386. */ 356 pushfl 357 popl %eax 358 movl %eax,%ecx 359 orl $PSL_AC,%eax 360 pushl %eax 361 popfl 362 pushfl 363 popl %eax 364 xorl %ecx,%eax 365 andl $PSL_AC,%eax 366 pushl %ecx 367 popfl 368 369 testl %eax,%eax 370 jnz 1f 371 movl $CPU_386,_cpu-KERNBASE 372 jmp 2f 373 3741: /* Try to toggle identification flag; does not exist on early 486s. */ 375 pushfl 376 popl %eax 377 movl %eax,%ecx 378 xorl $PSL_ID,%eax 379 pushl %eax 380 popfl 381 pushfl 382 popl %eax 383 xorl %ecx,%eax 384 andl $PSL_ID,%eax 385 pushl %ecx 386 popfl 387 388 testl %eax,%eax 389 jnz 1f 390 movl $CPU_486,_cpu-KERNBASE 391 392 /* check for Cyrix 486DLC -- based on check routine */ 393 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 394 xorw %dx,%dx 395 cmpw %dx,%dx # set flags to known state 396 pushfw 397 popw %cx # store flags in ecx 398 movw $0xffff,%ax 399 movw $0x0004,%bx 400 divw %bx 401 pushfw 402 popw %ax 403 andw $0x08d5,%ax # mask off important bits 404 andw $0x08d5,%cx 405 cmpw %ax,%cx 406 407 jnz 2f # if flags changed, Intel chip 408 409 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 410 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 411 movw $0x0078,_cpu_vendor-KERNBASE+4 412 413 invd # Start with guaranteed clean cache 414 /* Disable caching of the ISA hole only. */ 415 movb $CCR0,%al # Configuration Register index (CCR0) 416 outb %al,$0x22 417 inb $0x23,%al 418 orb $(CCR0_NC1|CCR0_BARB),%al 419 outb %al,$0x23 420 invd 421 jmp 2f 422 4231: /* Use the `cpuid' instruction. */ 424 xorl %eax,%eax 425 .byte 0x0f,0xa2 # cpuid 0 426 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 427 movl %edx,_cpu_vendor+4-KERNBASE 428 movl %ecx,_cpu_vendor+8-KERNBASE 429 movb $0,_cpu_vendor+12-KERNBASE 430 431 movl $1,%eax 432 .byte 0x0f,0xa2 # cpuid 1 433 movl %eax,_cpu_id-KERNBASE # store cpu_id 434 rorl $8,%eax # extract family type 435 andl $15,%eax 436 cmpl $5,%eax 437 jae 1f 438 439 /* less than Pentium; must be 486 */ 440 movl $CPU_486,_cpu-KERNBASE 441 jmp 2f 442 4431: movl $CPU_586,_cpu-KERNBASE 4442: 445 446 /* 447 * Finished with old stack; load new %esp now instead of later so 448 * we can trace this code without having to worry about the trace 449 * trap clobbering the memory test or the zeroing of the bss+bootstrap 450 * page tables. 451 * 452 * XXX - wdboot clears the bss after testing that this is safe. 453 * This is too wasteful - memory below 640K is scarce. The boot 454 * program should check: 455 * text+data <= &stack_variable - more_space_for_stack 456 * text+data+bss+pad+space_for_page_tables <= end_of_memory 457 * Oops, the gdt is in the carcass of the boot program so clearing 458 * the rest of memory is still not possible. 459 */ 460 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 461 462/* 463 * Virtual address space of kernel: 464 * 465 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 466 * pages: 1 UPAGES (2) 1 NKPT (7) 467 */ 468 469/* find end of kernel image */ 470 movl $_end-KERNBASE,%ecx 471 addl $NBPG-1,%ecx /* page align up */ 472 andl $~(NBPG-1),%ecx 473 movl %ecx,%esi /* esi = start of free memory */ 474 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 475 476/* clear bss */ 477 movl $_edata-KERNBASE,%edi 478 subl %edi,%ecx /* get amount to clear */ 479 xorl %eax,%eax /* specify zero fill */ 480 cld 481 rep 482 stosb 483 484/* 485 * The value in esi is both the end of the kernel bss and a pointer to 486 * the kernel page directory, and is used by the rest of locore to build 487 * the tables. 488 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 489 * page table pages) is then passed on the stack to init386(first) as 490 * the value first. esi should ALWAYS be page aligned!! 491 */ 492 movl %esi,%ecx /* Get current first availiable address */ 493 494/* clear pagetables, page directory, stack, etc... */ 495 movl %esi,%edi /* base (page directory) */ 496 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 497 xorl %eax,%eax /* specify zero fill */ 498 cld 499 rep 500 stosb 501 502/* physical address of Idle proc/kernel page directory */ 503 movl %esi,_IdlePTD-KERNBASE 504 505/* 506 * fillkpt 507 * eax = (page frame address | control | status) == pte 508 * ebx = address of page table 509 * ecx = how many pages to map 510 */ 511#define fillkpt \ 5121: movl %eax,(%ebx) ; \ 513 addl $NBPG,%eax ; /* increment physical address */ \ 514 addl $4,%ebx ; /* next pte */ \ 515 loop 1b ; 516 517/* 518 * Map Kernel 519 * 520 * First step - build page tables 521 */ 522#if defined (KGDB) || defined (BDE_DEBUGGER) 523 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 524 shrl $PGSHIFT,%ecx /* for this many PTEs */ 525#ifdef BDE_DEBUGGER 526 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 527 jae 1f 528 movl $0xa0,%ecx 5291: 530#endif /* BDE_DEBUGGER */ 531 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 532 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 533 movl %ebx,_KPTphys-KERNBASE /* save in global */ 534 fillkpt 535 536#else /* !KGDB && !BDE_DEBUGGER */ 537 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 538 movl $_etext-KERNBASE,%ecx /* get size of text */ 539 shrl $PGSHIFT,%ecx /* for this many PTEs */ 540 movl $PG_V|PG_KR,%eax /* specify read only */ 541 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 542 movl %ebx,_KPTphys-KERNBASE /* save in global */ 543 fillkpt 544 545 /* data and bss are r/w */ 546 andl $PG_FRAME,%eax /* strip to just addr of bss */ 547 movl _KERNend-KERNBASE,%ecx /* calculate size */ 548 subl %eax,%ecx 549 shrl $PGSHIFT,%ecx 550 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 551 fillkpt 552#endif /* KGDB || BDE_DEBUGGER */ 553 554/* now initialize the page dir, upages, p0stack PT, and page tables */ 555 556 movl $(1+UPAGES+1+NKPT),%ecx /* number of PTEs */ 557 movl %esi,%eax /* phys address of PTD */ 558 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 559 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 560 movl %esi,%ebx /* calculate pte offset to ptd */ 561 shrl $PGSHIFT-2,%ebx 562 addl %esi,%ebx /* address of page directory */ 563 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 564 fillkpt 565 566/* map I/O memory map */ 567 568 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 569 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 570 movl $0x100-0xa0,%ecx /* for this many pte s, */ 571 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 572 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 573 fillkpt 574 575 /* map proc 0's kernel stack into user page table page */ 576 577 movl $UPAGES,%ecx /* for this many pte s, */ 578 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 579 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 580 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 581 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 582 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 583 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 584 fillkpt 585 586/* 587 * Initialize kernel page table directory 588 */ 589 /* install a pde for temporary double map of bottom of VA */ 590 movl _KPTphys-KERNBASE,%eax 591 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 592 movl %eax,(%esi) /* which is where temp maps! */ 593 594 /* initialize kernel pde's */ 595 movl $(NKPT),%ecx /* for this many PDEs */ 596 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 597 fillkpt 598 599 /* install a pde recursively mapping page directory as a page table! */ 600 movl %esi,%eax /* phys address of ptd in proc 0 */ 601 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 602 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 603 604 /* install a pde to map kernel stack for proc 0 */ 605 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 606 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 607 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 608 609#ifdef BDE_DEBUGGER 610 /* copy and convert stuff from old gdt and idt for debugger */ 611 612 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 613 jne 1f 614 movb $1,_bdb_exists-KERNBASE 6151: 616 pushal 617 subl $2*6,%esp 618 619 sgdt (%esp) 620 movl 2(%esp),%esi /* base address of current gdt */ 621 movl $_gdt-KERNBASE,%edi 622 movl %edi,2(%esp) 623 movl $8*18/4,%ecx 624 cld 625 rep /* copy gdt */ 626 movsl 627 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 628 movb $0x92,-8+5(%edi) 629 630 sidt 6(%esp) 631 movl 6+2(%esp),%esi /* base address of current idt */ 632 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 633 movw 8(%esi),%ax 634 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 635 movl 8+2(%esi),%eax 636 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 637 movl 24+4(%esi),%eax /* same for bpt descriptor */ 638 movw 24(%esi),%ax 639 movl %eax,bdb_bpt_ljmp+1-KERNBASE 640 movl 24+2(%esi),%eax 641 movw %ax,bdb_bpt_ljmp+5-KERNBASE 642 643 movl $_idt-KERNBASE,%edi 644 movl %edi,6+2(%esp) 645 movl $8*4/4,%ecx 646 cld 647 rep /* copy idt */ 648 movsl 649 650 lgdt (%esp) 651 lidt 6(%esp) 652 653 addl $2*6,%esp 654 popal 655#endif /* BDE_DEBUGGER */ 656 657 /* load base of page directory and enable mapping */ 658 movl %esi,%eax /* phys address of ptd in proc 0 */ 659 movl %eax,%cr3 /* load ptd addr into mmu */ 660 movl %cr0,%eax /* get control word */ 661 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 662 movl %eax,%cr0 /* and let's page NOW! */ 663 664 pushl $begin /* jump to high mem */ 665 ret 666 667begin: /* now running relocated at KERNBASE where the system is linked to run */ 668 669 .globl _Crtat /* XXX - locore should not know about */ 670 movl _Crtat,%eax /* variables of device drivers (pccons)! */ 671 subl $(KERNBASE+0xA0000),%eax 672 movl _atdevphys,%edx /* get pte PA */ 673 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 674 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 675 addl $KERNBASE,%edx /* add virtual base */ 676 movl %edx,_atdevbase 677 addl %eax,%edx 678 movl %edx,_Crtat 679 680 /* set up bootstrap stack - 48 bytes */ 681 movl $_kstack+UPAGES*NBPG-4*12,%esp /* bootstrap stack end location */ 682 xorl %eax,%eax /* mark end of frames */ 683 movl %eax,%ebp 684 movl _proc0paddr,%eax 685 movl %esi,PCB_CR3(%eax) 686 687#ifdef BDE_DEBUGGER 688 /* relocate debugger gdt entries */ 689 690 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 691 movl $9,%ecx 692reloc_gdt: 693 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 694 addl $8,%eax /* now KERNBASE>>24 */ 695 loop reloc_gdt 696 697 cmpl $0,_bdb_exists 698 je 1f 699 int $3 7001: 701#endif /* BDE_DEBUGGER */ 702 703 /* 704 * Skip over the page tables and the kernel stack 705 */ 706 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 707 708 pushl %esi /* value of first for init386(first) */ 709 call _init386 /* wire 386 chip for unix operation */ 710 popl %esi 711 712 .globl __ucodesel,__udatasel 713 714 pushl $0 /* unused */ 715 pushl __udatasel /* ss */ 716 pushl $0 /* esp - filled in by execve() */ 717 pushl $PSL_USERSET /* eflags (ring 0, int enab) */ 718 pushl __ucodesel /* cs */ 719 pushl $0 /* eip - filled in by execve() */ 720 subl $(12*4),%esp /* space for rest of registers */ 721 722 pushl %esp /* call main with frame pointer */ 723 call _main /* autoconfiguration, mountroot etc */ 724 725 addl $(13*4),%esp /* back to a frame we can return with */ 726 727 /* 728 * now we've run main() and determined what cpu-type we are, we can 729 * enable WP mode on i486 cpus and above. 730 */ 731#if defined(I486_CPU) || defined(I586_CPU) 732 cmpl $CPUCLASS_386,_cpu_class 733 je 1f 734 movl %cr0,%eax /* get control word */ 735 orl $CR0_WP,%eax /* enable write protect for all modes */ 736 movl %eax,%cr0 /* and do it */ 737#endif 738 /* 739 * on return from main(), we are process 1 740 * set up address space and stack so that we can 'return' to user mode 741 */ 7421: 743 movl __ucodesel,%eax 744 movl __udatasel,%ecx 745 746 movl %cx,%ds 747 movl %cx,%es 748 movl %ax,%fs /* double map cs to fs */ 749 movl %cx,%gs /* and ds to gs */ 750 iret /* goto user! */ 751 752#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 753 754NON_GPROF_ENTRY(sigcode) 755 call SIGF_HANDLER(%esp) 756 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 757 /* copy at 8(%esp)) */ 758 pushl %eax 759 pushl %eax /* junk to fake return address */ 760 movl $103,%eax /* XXX sigreturn() */ 761 LCALL(0x7,0) /* enter kernel with args on stack */ 762 hlt /* never gets here */ 763 764 .globl _szsigcode 765_szsigcode: 766 .long _szsigcode-_sigcode 767