locore.s revision 2783
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 1.27 1994/09/12 11:38:06 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 58/* 59 * XXX 60 * 61 * Note: This version greatly munged to avoid various assembler errors 62 * that may be fixed in newer versions of gas. Perhaps newer versions 63 * will have more pleasant appearance. 64 */ 65 66/* 67 * PTmap is recursive pagemap at top of virtual address space. 68 * Within PTmap, the page directory can be found (third indirection). 69 */ 70 .globl _PTmap,_PTD,_PTDpde,_Sysmap 71 .set _PTmap,PTDPTDI << PDRSHIFT 72 .set _PTD,_PTmap + (PTDPTDI * NBPG) 73 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE) 74 75/* Sysmap is the base address of the kernel page tables */ 76 .set _Sysmap,_PTmap + (KPTDI * NBPG) 77 78/* 79 * APTmap, APTD is the alternate recursive pagemap. 80 * It's used when modifying another process's page tables. 81 */ 82 .globl _APTmap,_APTD,_APTDpde 83 .set _APTmap,APTDPTDI << PDRSHIFT 84 .set _APTD,_APTmap + (APTDPTDI * NBPG) 85 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE) 86 87/* 88 * Access to each processes kernel stack is via a region of 89 * per-process address space (at the beginning), immediatly above 90 * the user process stack. 91 */ 92 .set _kstack,USRSTACK 93 .globl _kstack 94 95/* 96 * Globals 97 */ 98 .data 99 .globl _esym 100_esym: .long 0 /* ptr to end of syms */ 101 102 .globl _boothowto,_bootdev,_curpcb 103 104 .globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id 105 106 .globl _video_mode_ptr 107 108_cpu: .long 0 /* are we 386, 386sx, or 486 */ 109_cpu_id: .long 0 /* stepping ID */ 110_cpu_vendor: .space 20 /* CPU origin code */ 111_video_mode_ptr: .long 0 112_cold: .long 1 /* cold till we are not */ 113_atdevbase: .long 0 /* location of start of iomem in virtual */ 114_atdevphys: .long 0 /* location of device mapping ptes (phys) */ 115 116 .globl _KERNend 117_KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 118 119 .globl _IdlePTD,_KPTphys 120_IdlePTD: .long 0 /* phys addr of kernel PTD */ 121_KPTphys: .long 0 /* phys addr of kernel page tables */ 122 123 .globl _cyloffset 124_cyloffset: .long 0 /* cylinder offset from boot blocks */ 125 126 .globl _proc0paddr 127_proc0paddr: .long 0 /* address of proc 0 address space */ 128 129#ifdef BDE_DEBUGGER 130 .globl _bdb_exists /* flag to indicate BDE debugger is available */ 131_bdb_exists: .long 0 132#endif 133 134 .globl tmpstk 135 .space 0x1000 136tmpstk: 137 138 139/* 140 * System Initialization 141 */ 142 .text 143 144/* 145 * btext: beginning of text section. 146 * Also the entry point (jumped to directly from the boot blocks). 147 */ 148NON_GPROF_ENTRY(btext) 149 movw $0x1234,0x472 /* warm boot */ 150 jmp 1f 151 .org 0x500 /* space for BIOS variables */ 152 153 1: 154 /* Don't trust what the BIOS gives for eflags. */ 155 pushl $PSL_MBO 156 popfl 157 158 /* 159 * pass parameters on stack (howto, bootdev, unit, cyloffset, esym) 160 * note: (%esp) is return address of boot 161 * ( if we want to hold onto /boot, it's physical %esp up to _end) 162 */ 163 movl 4(%esp),%eax 164 movl %eax,_boothowto-KERNBASE 165 movl 8(%esp),%eax 166 movl %eax,_bootdev-KERNBASE 167 movl 12(%esp),%eax 168 movl %eax,_cyloffset-KERNBASE 169 movl 16(%esp),%eax 170 addl $KERNBASE,%eax 171 movl %eax,_esym-KERNBASE 172 173 /* get the BIOS video mode pointer */ 174 movl $0x4a8, %ecx 175 movl (%ecx), %eax 176 movl %eax, %ecx 177 shrl $12, %ecx 178 andl $0xffff0000, %ecx 179 andl $0x0000ffff, %eax 180 orl %ecx, %eax 181 movl (%eax), %eax 182 movl %eax, %ecx 183 shrl $12, %ecx 184 andl $0xffff0000, %ecx 185 andl $0x0000ffff, %eax 186 orl %ecx, %eax 187 addl $KERNBASE, %eax 188 movl %eax, _video_mode_ptr-KERNBASE 189 190#ifdef DISKLESS /* Copy diskless structure */ 191 movl _nfs_diskless_size-KERNBASE,%ecx 192 movl 20(%esp),%esi 193 movl $(_nfs_diskless-KERNBASE),%edi 194 cld 195 rep 196 movsb 197#endif 198 199 /* Find out our CPU type. */ 200 201 /* Try to toggle alignment check flag; does not exist on 386. */ 202 pushfl 203 popl %eax 204 movl %eax,%ecx 205 orl $PSL_AC,%eax 206 pushl %eax 207 popfl 208 pushfl 209 popl %eax 210 xorl %ecx,%eax 211 andl $PSL_AC,%eax 212 pushl %ecx 213 popfl 214 215 testl %eax,%eax 216 jnz 1f 217 movl $CPU_386,_cpu-KERNBASE 218 jmp 2f 219 2201: /* Try to toggle identification flag; does not exist on early 486s. */ 221 pushfl 222 popl %eax 223 movl %eax,%ecx 224 xorl $PSL_ID,%eax 225 pushl %eax 226 popfl 227 pushfl 228 popl %eax 229 xorl %ecx,%eax 230 andl $PSL_ID,%eax 231 pushl %ecx 232 popfl 233 234 testl %eax,%eax 235 jnz 1f 236 movl $CPU_486,_cpu-KERNBASE 237 238 /* check for Cyrix 486DLC -- based on check routine */ 239 /* documented in "Cx486SLC/e SMM Programmer's Guide" */ 240 xorw %dx,%dx 241 cmpw %dx,%dx # set flags to known state 242 pushfw 243 popw %cx # store flags in ecx 244 movw $0xffff,%ax 245 movw $0x0004,%bx 246 divw %bx 247 pushfw 248 popw %ax 249 andw $0x08d5,%ax # mask off important bits 250 andw $0x08d5,%cx 251 cmpw %ax,%cx 252 253 jnz 2f # if flags changed, Intel chip 254 255 movl $CPU_486DLC,_cpu-KERNBASE # set CPU value for Cyrix 256 movl $0x69727943,_cpu_vendor-KERNBASE # store vendor string 257 movw $0x0078,_cpu_vendor-KERNBASE+4 258 259 invd # Start with guaranteed clean cache 260 /* Disable caching of the ISA hole only. */ 261 movb $CCR0,%al # Configuration Register index (CCR0) 262 outb %al,$0x22 263 inb $0x23,%al 264 orb $CCR0_NC1,%al 265 outb %al,$0x23 266 invd 267 jmp 2f 268 2691: /* Use the `cpuid' instruction. */ 270 xorl %eax,%eax 271 .byte 0x0f,0xa2 # cpuid 0 272 movl %ebx,_cpu_vendor-KERNBASE # store vendor string 273 movl %edx,_cpu_vendor+4-KERNBASE 274 movl %ecx,_cpu_vendor+8-KERNBASE 275 movb $0,_cpu_vendor+12-KERNBASE 276 277 movl $1,%eax 278 .byte 0x0f,0xa2 # cpuid 1 279 movl %eax,_cpu_id-KERNBASE # store cpu_id 280 rorl $8,%eax # extract family type 281 andl $15,%eax 282 cmpl $5,%eax 283 jae 1f 284 285 /* less than Pentium; must be 486 */ 286 movl $CPU_486,_cpu-KERNBASE 287 jmp 2f 288 2891: movl $CPU_586,_cpu-KERNBASE 2902: 291 292 /* 293 * Finished with old stack; load new %esp now instead of later so 294 * we can trace this code without having to worry about the trace 295 * trap clobbering the memory test or the zeroing of the bss+bootstrap 296 * page tables. 297 * 298 * XXX - wdboot clears the bss after testing that this is safe. 299 * This is too wasteful - memory below 640K is scarce. The boot 300 * program should check: 301 * text+data <= &stack_variable - more_space_for_stack 302 * text+data+bss+pad+space_for_page_tables <= end_of_memory 303 * Oops, the gdt is in the carcass of the boot program so clearing 304 * the rest of memory is still not possible. 305 */ 306 movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */ 307 308/* 309 * Virtual address space of kernel: 310 * 311 * text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap 312 * pages: 1 UPAGES (2) 1 NKPT (7) 313 */ 314 315/* find end of kernel image */ 316 movl $_end-KERNBASE,%ecx 317 addl $NBPG-1,%ecx /* page align up */ 318 andl $~(NBPG-1),%ecx 319 movl %ecx,%esi /* esi = start of free memory */ 320 movl %ecx,_KERNend-KERNBASE /* save end of kernel */ 321 322/* clear bss */ 323 movl $_edata-KERNBASE,%edi 324 subl %edi,%ecx /* get amount to clear */ 325 xorl %eax,%eax /* specify zero fill */ 326 cld 327 rep 328 stosb 329 330/* 331 * The value in esi is both the end of the kernel bss and a pointer to 332 * the kernel page directory, and is used by the rest of locore to build 333 * the tables. 334 * esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel 335 * page table pages) is then passed on the stack to init386(first) as 336 * the value first. esi should ALWAYS be page aligned!! 337 */ 338 movl %esi,%ecx /* Get current first availiable address */ 339 340/* clear pagetables, page directory, stack, etc... */ 341 movl %esi,%edi /* base (page directory) */ 342 movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */ 343 xorl %eax,%eax /* specify zero fill */ 344 cld 345 rep 346 stosb 347 348/* physical address of Idle proc/kernel page directory */ 349 movl %esi,_IdlePTD-KERNBASE 350 351/* 352 * fillkpt 353 * eax = (page frame address | control | status) == pte 354 * ebx = address of page table 355 * ecx = how many pages to map 356 */ 357#define fillkpt \ 3581: movl %eax,(%ebx) ; \ 359 addl $NBPG,%eax ; /* increment physical address */ \ 360 addl $4,%ebx ; /* next pte */ \ 361 loop 1b ; 362 363/* 364 * Map Kernel 365 * 366 * First step - build page tables 367 */ 368#if defined (KGDB) || defined (BDE_DEBUGGER) 369 movl _KERNend-KERNBASE,%ecx /* this much memory, */ 370 shrl $PGSHIFT,%ecx /* for this many PTEs */ 371#ifdef BDE_DEBUGGER 372 cmpl $0xa0,%ecx /* XXX - cover debugger pages */ 373 jae 1f 374 movl $0xa0,%ecx 3751: 376#endif /* BDE_DEBUGGER */ 377 movl $PG_V|PG_KW,%eax /* kernel R/W, valid */ 378 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 379 movl %ebx,_KPTphys-KERNBASE /* save in global */ 380 fillkpt 381 382#else /* !KGDB && !BDE_DEBUGGER */ 383 /* write protect kernel text (doesn't do a thing for 386's - only 486's) */ 384 movl $_etext-KERNBASE,%ecx /* get size of text */ 385 shrl $PGSHIFT,%ecx /* for this many PTEs */ 386 movl $PG_V|PG_KR,%eax /* specify read only */ 387 lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */ 388 movl %ebx,_KPTphys-KERNBASE /* save in global */ 389 fillkpt 390 391 /* data and bss are r/w */ 392 andl $PG_FRAME,%eax /* strip to just addr of bss */ 393 movl _KERNend-KERNBASE,%ecx /* calculate size */ 394 subl %eax,%ecx 395 shrl $PGSHIFT,%ecx 396 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 397 fillkpt 398#endif /* KGDB || BDE_DEBUGGER */ 399 400/* now initialize the page dir, upages, p0stack PT, and page tables */ 401 402 movl $(1+UPAGES+1+NKPT),%ecx /* number of PTEs */ 403 movl %esi,%eax /* phys address of PTD */ 404 andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ 405 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 406 movl %esi,%ebx /* calculate pte offset to ptd */ 407 shrl $PGSHIFT-2,%ebx 408 addl %esi,%ebx /* address of page directory */ 409 addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ 410 fillkpt 411 412/* map I/O memory map */ 413 414 movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */ 415 lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */ 416 movl $0x100-0xa0,%ecx /* for this many pte s, */ 417 movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */ 418 movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */ 419 fillkpt 420 421 /* map proc 0's kernel stack into user page table page */ 422 423 movl $UPAGES,%ecx /* for this many pte s, */ 424 lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */ 425 lea (KERNBASE)(%eax),%edx /* change into virtual addr */ 426 movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */ 427 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 428 lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */ 429 addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */ 430 fillkpt 431 432/* 433 * Initialize kernel page table directory 434 */ 435 /* install a pde for temporary double map of bottom of VA */ 436 movl _KPTphys-KERNBASE,%eax 437 orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ 438 movl %eax,(%esi) /* which is where temp maps! */ 439 440 /* initialize kernel pde's */ 441 movl $(NKPT),%ecx /* for this many PDEs */ 442 lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */ 443 fillkpt 444 445 /* install a pde recursively mapping page directory as a page table! */ 446 movl %esi,%eax /* phys address of ptd in proc 0 */ 447 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 448 movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */ 449 450 /* install a pde to map kernel stack for proc 0 */ 451 lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */ 452 orl $PG_V|PG_KW,%eax /* pde entry is valid */ 453 movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */ 454 455#ifdef BDE_DEBUGGER 456 /* copy and convert stuff from old gdt and idt for debugger */ 457 458 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 459 jne 1f 460 movb $1,_bdb_exists-KERNBASE 4611: 462 pushal 463 subl $2*6,%esp 464 465 sgdt (%esp) 466 movl 2(%esp),%esi /* base address of current gdt */ 467 movl $_gdt-KERNBASE,%edi 468 movl %edi,2(%esp) 469 movl $8*18/4,%ecx 470 cld 471 rep /* copy gdt */ 472 movsl 473 movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */ 474 movb $0x92,-8+5(%edi) 475 476 sidt 6(%esp) 477 movl 6+2(%esp),%esi /* base address of current idt */ 478 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 479 movw 8(%esi),%ax 480 movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */ 481 movl 8+2(%esi),%eax 482 movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */ 483 movl 24+4(%esi),%eax /* same for bpt descriptor */ 484 movw 24(%esi),%ax 485 movl %eax,bdb_bpt_ljmp+1-KERNBASE 486 movl 24+2(%esi),%eax 487 movw %ax,bdb_bpt_ljmp+5-KERNBASE 488 489 movl $_idt-KERNBASE,%edi 490 movl %edi,6+2(%esp) 491 movl $8*4/4,%ecx 492 cld 493 rep /* copy idt */ 494 movsl 495 496 lgdt (%esp) 497 lidt 6(%esp) 498 499 addl $2*6,%esp 500 popal 501#endif /* BDE_DEBUGGER */ 502 503 /* load base of page directory and enable mapping */ 504 movl %esi,%eax /* phys address of ptd in proc 0 */ 505 movl %eax,%cr3 /* load ptd addr into mmu */ 506 movl %cr0,%eax /* get control word */ 507 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 508 movl %eax,%cr0 /* and let's page NOW! */ 509 510 pushl $begin /* jump to high mem */ 511 ret 512 513begin: /* now running relocated at KERNBASE where the system is linked to run */ 514 515 .globl _Crtat /* XXX - locore should not know about */ 516 movl _Crtat,%eax /* variables of device drivers (pccons)! */ 517 subl $(KERNBASE+0xA0000),%eax 518 movl _atdevphys,%edx /* get pte PA */ 519 subl _KPTphys,%edx /* remove base of ptes, now have phys offset */ 520 shll $PGSHIFT-2,%edx /* corresponding to virt offset */ 521 addl $KERNBASE,%edx /* add virtual base */ 522 movl %edx,_atdevbase 523 addl %eax,%edx 524 movl %edx,_Crtat 525 526 /* set up bootstrap stack - 48 bytes */ 527 movl $_kstack+UPAGES*NBPG-4*12,%esp /* bootstrap stack end location */ 528 xorl %eax,%eax /* mark end of frames */ 529 movl %eax,%ebp 530 movl _proc0paddr,%eax 531 movl %esi,PCB_CR3(%eax) 532 533#ifdef BDE_DEBUGGER 534 /* relocate debugger gdt entries */ 535 536 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 537 movl $9,%ecx 538reloc_gdt: 539 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 540 addl $8,%eax /* now KERNBASE>>24 */ 541 loop reloc_gdt 542 543 cmpl $0,_bdb_exists 544 je 1f 545 int $3 5461: 547#endif /* BDE_DEBUGGER */ 548 549 /* 550 * Skip over the page tables and the kernel stack 551 */ 552 lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi 553 554 pushl %esi /* value of first for init386(first) */ 555 call _init386 /* wire 386 chip for unix operation */ 556 popl %esi 557 558 .globl __ucodesel,__udatasel 559 560 pushl $0 /* unused */ 561 pushl __udatasel /* ss */ 562 pushl $0 /* esp - filled in by execve() */ 563 pushl $PSL_USERSET /* eflags (ring 0, int enab) */ 564 pushl __ucodesel /* cs */ 565 pushl $0 /* eip - filled in by execve() */ 566 subl $(12*4),%esp /* space for rest of registers */ 567 568 pushl %esp /* call main with frame pointer */ 569 call _main /* autoconfiguration, mountroot etc */ 570 571 addl $(13*4),%esp /* back to a frame we can return with */ 572 573 /* 574 * now we've run main() and determined what cpu-type we are, we can 575 * enable WP mode on i486 cpus and above. 576 */ 577#if defined(I486_CPU) || defined(I586_CPU) 578 cmpl $CPUCLASS_386,_cpu_class 579 je 1f 580 movl %cr0,%eax /* get control word */ 581 orl $CR0_WP,%eax /* enable write protect for all modes */ 582 movl %eax,%cr0 /* and do it */ 583#endif 584 /* 585 * on return from main(), we are process 1 586 * set up address space and stack so that we can 'return' to user mode 587 */ 5881: 589 movl __ucodesel,%eax 590 movl __udatasel,%ecx 591 592 movl %cx,%ds 593 movl %cx,%es 594 movl %ax,%fs /* double map cs to fs */ 595 movl %cx,%gs /* and ds to gs */ 596 iret /* goto user! */ 597 598#define LCALL(x,y) .byte 0x9a ; .long y ; .word x 599 600NON_GPROF_ENTRY(sigcode) 601 call SIGF_HANDLER(%esp) 602 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 603 /* copy at 8(%esp)) */ 604 pushl %eax 605 pushl %eax /* junk to fake return address */ 606 movl $103,%eax /* XXX sigreturn() */ 607 LCALL(0x7,0) /* enter kernel with args on stack */ 608 hlt /* never gets here */ 609 610 .globl _szsigcode 611_szsigcode: 612 .long _szsigcode-_sigcode 613