Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/locore.s
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
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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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)locore.s 7.3 (Berkeley) 5/13/91 33 * $FreeBSD$ 34 * 35 * originally from: locore.s, by William F. Jolitz 36 * 37 * Substantially rewritten by David Greenman, Rod Grimes, 38 * Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp 39 * and many others. 40 */ 41 42 #include "opt_bootp.h" 43 #include "opt_nfsroot.h" 44 #include "opt_pmap.h" 45 46 #include <sys/reboot.h> 47 48 #include <machine/asmacros.h> 49 #include <machine/cputypes.h> 50 #include <machine/psl.h> 51 #include <machine/pmap.h> 52 #include <machine/specialreg.h> 53 54 #include "assym.inc" 55 56 /* 57 * PTmap is recursive pagemap at top of virtual address space. 58 * Within PTmap, the page directory can be found (third indirection). 59 */ 60 .globl PTmap,PTD,PTDpde 61 .set PTmap,(PTDPTDI << PDRSHIFT) 62 .set PTD,PTmap + (PTDPTDI * PAGE_SIZE) 63 .set PTDpde,PTD + (PTDPTDI * PDESIZE) 64 65 /* 66 * Compiled KERNBASE location and the kernel load address, now identical. 67 */ 68 .globl kernbase 69 .set kernbase,KERNBASE 70 .globl kernload 71 .set kernload,KERNLOAD 72 73 /* 74 * Globals 75 */ 76 .data 77 ALIGN_DATA /* just to be sure */ 78 79 .space 0x2000 /* space for tmpstk - temporary stack */ 80 tmpstk: 81 82 .globl bootinfo 83 bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */ 84 85 .text 86 /********************************************************************** 87 * 88 * This is where the bootblocks start us, set the ball rolling... 89 * 90 */ 91 NON_GPROF_ENTRY(btext) 92 93 /* Tell the bios to warmboot next time */ 94 movw $0x1234,0x472 95 96 /* Set up a real frame in case the double return in newboot is executed. */ 97 xorl %ebp,%ebp 98 pushl %ebp 99 movl %esp, %ebp 100 101 /* Don't trust what the BIOS gives for eflags. */ 102 pushl $PSL_KERNEL 103 popfl 104 105 /* 106 * Don't trust what the BIOS gives for %fs and %gs. Trust the bootstrap 107 * to set %cs, %ds, %es and %ss. 108 */ 109 mov %ds, %ax 110 mov %ax, %fs 111 mov %ax, %gs 112 113 /* 114 * Clear the bss. Not all boot programs do it, and it is our job anyway. 115 * 116 * XXX we don't check that there is memory for our bss and page tables 117 * before using it. 118 * 119 * Note: we must be careful to not overwrite an active gdt or idt. They 120 * inactive from now until we switch to new ones, since we don't load any 121 * more segment registers or permit interrupts until after the switch. 122 */ 123 movl $__bss_end,%ecx 124 movl $__bss_start,%edi 125 subl %edi,%ecx 126 xorl %eax,%eax 127 cld 128 rep 129 stosb 130 131 call recover_bootinfo 132 133 /* Get onto a stack that we can trust. */ 134 /* 135 * XXX this step is delayed in case recover_bootinfo needs to return via 136 * the old stack, but it need not be, since recover_bootinfo actually 137 * returns via the old frame. 138 */ 139 movl $tmpstk,%esp 140 141 call identify_cpu 142 call pmap_cold 143 144 /* set up bootstrap stack */ 145 movl proc0kstack,%eax /* location of in-kernel stack */ 146 147 /* 148 * Only use bottom page for init386(). init386() calculates the 149 * PCB + FPU save area size and returns the true top of stack. 150 */ 151 leal PAGE_SIZE(%eax),%esp 152 153 xorl %ebp,%ebp /* mark end of frames */ 154 155 pushl physfree /* value of first for init386(first) */ 156 call init386 /* wire 386 chip for unix operation */ 157 158 /* 159 * Clean up the stack in a way that db_numargs() understands, so 160 * that backtraces in ddb don't underrun the stack. Traps for 161 * inaccessible memory are more fatal than usual this early. 162 */ 163 addl $4,%esp 164 165 /* Switch to true top of stack. */ 166 movl %eax,%esp 167 168 call mi_startup /* autoconfiguration, mountroot etc */ 169 /* NOTREACHED */ 170 addl $0,%esp /* for db_numargs() again */ 171 172 /********************************************************************** 173 * 174 * Recover the bootinfo passed to us from the boot program 175 * 176 */ 177 recover_bootinfo: 178 /* 179 * This code is called in different ways depending on what loaded 180 * and started the kernel. This is used to detect how we get the 181 * arguments from the other code and what we do with them. 182 * 183 * Old disk boot blocks: 184 * (*btext)(howto, bootdev, cyloffset, esym); 185 * [return address == 0, and can NOT be returned to] 186 * [cyloffset was not supported by the FreeBSD boot code 187 * and always passed in as 0] 188 * [esym is also known as total in the boot code, and 189 * was never properly supported by the FreeBSD boot code] 190 * 191 * Old diskless netboot code: 192 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 193 * [return address != 0, and can NOT be returned to] 194 * If we are being booted by this code it will NOT work, 195 * so we are just going to halt if we find this case. 196 * 197 * New uniform boot code: 198 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 199 * [return address != 0, and can be returned to] 200 * 201 * There may seem to be a lot of wasted arguments in here, but 202 * that is so the newer boot code can still load very old kernels 203 * and old boot code can load new kernels. 204 */ 205 206 /* 207 * The old style disk boot blocks fake a frame on the stack and 208 * did an lret to get here. The frame on the stack has a return 209 * address of 0. 210 */ 211 cmpl $0,4(%ebp) 212 je olddiskboot 213 214 /* 215 * We have some form of return address, so this is either the 216 * old diskless netboot code, or the new uniform code. That can 217 * be detected by looking at the 5th argument, if it is 0 218 * we are being booted by the new uniform boot code. 219 */ 220 cmpl $0,24(%ebp) 221 je newboot 222 223 /* 224 * Seems we have been loaded by the old diskless boot code, we 225 * don't stand a chance of running as the diskless structure 226 * changed considerably between the two, so just halt. 227 */ 228 hlt 229 230 /* 231 * We have been loaded by the new uniform boot code. 232 * Let's check the bootinfo version, and if we do not understand 233 * it we return to the loader with a status of 1 to indicate this error 234 */ 235 newboot: 236 movl 28(%ebp),%ebx /* &bootinfo.version */ 237 movl BI_VERSION(%ebx),%eax 238 cmpl $1,%eax /* We only understand version 1 */ 239 je 1f 240 movl $1,%eax /* Return status */ 241 leave 242 /* 243 * XXX this returns to our caller's caller (as is required) since 244 * we didn't set up a frame and our caller did. 245 */ 246 ret 247 248 1: 249 /* 250 * If we have a kernelname copy it in 251 */ 252 movl BI_KERNELNAME(%ebx),%esi 253 cmpl $0,%esi 254 je 2f /* No kernelname */ 255 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 256 movl $kernelname,%edi 257 cmpb $'/',(%esi) /* Make sure it starts with a slash */ 258 je 1f 259 movb $'/',(%edi) 260 incl %edi 261 decl %ecx 262 1: 263 cld 264 rep 265 movsb 266 267 2: 268 /* 269 * Determine the size of the boot loader's copy of the bootinfo 270 * struct. This is impossible to do properly because old versions 271 * of the struct don't contain a size field and there are 2 old 272 * versions with the same version number. 273 */ 274 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */ 275 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */ 276 je got_bi_size /* no, sizeless version */ 277 movl BI_SIZE(%ebx),%ecx 278 got_bi_size: 279 280 /* 281 * Copy the common part of the bootinfo struct 282 */ 283 movl %ebx,%esi 284 movl $bootinfo,%edi 285 cmpl $BOOTINFO_SIZE,%ecx 286 jbe got_common_bi_size 287 movl $BOOTINFO_SIZE,%ecx 288 got_common_bi_size: 289 cld 290 rep 291 movsb 292 293 #ifdef NFS_ROOT 294 #ifndef BOOTP_NFSV3 295 /* 296 * If we have a nfs_diskless structure copy it in 297 */ 298 movl BI_NFS_DISKLESS(%ebx),%esi 299 cmpl $0,%esi 300 je olddiskboot 301 movl $nfs_diskless,%edi 302 movl $NFSDISKLESS_SIZE,%ecx 303 cld 304 rep 305 movsb 306 movl $nfs_diskless_valid,%edi 307 movl $1,(%edi) 308 #endif 309 #endif 310 311 /* 312 * The old style disk boot. 313 * (*btext)(howto, bootdev, cyloffset, esym); 314 * Note that the newer boot code just falls into here to pick 315 * up howto and bootdev, cyloffset and esym are no longer used 316 */ 317 olddiskboot: 318 movl 8(%ebp),%eax 319 movl %eax,boothowto 320 movl 12(%ebp),%eax 321 movl %eax,bootdev 322 323 ret 324 325 326 /********************************************************************** 327 * 328 * Identify the CPU and initialize anything special about it 329 * 330 */ 331 ENTRY(identify_cpu) 332 333 pushl %ebx 334 335 /* Try to toggle alignment check flag; does not exist on 386. */ 336 pushfl 337 popl %eax 338 movl %eax,%ecx 339 orl $PSL_AC,%eax 340 pushl %eax 341 popfl 342 pushfl 343 popl %eax 344 xorl %ecx,%eax 345 andl $PSL_AC,%eax 346 pushl %ecx 347 popfl 348 349 testl %eax,%eax 350 jnz try486 351 352 /* NexGen CPU does not have alignment check flag. */ 353 pushfl 354 movl $0x5555, %eax 355 xorl %edx, %edx 356 movl $2, %ecx 357 clc 358 divl %ecx 359 jz trynexgen 360 popfl 361 movl $CPU_386,cpu 362 jmp 3f 363 364 trynexgen: 365 popfl 366 movl $CPU_NX586,cpu 367 movl $0x4778654e,cpu_vendor # store vendor string 368 movl $0x72446e65,cpu_vendor+4 369 movl $0x6e657669,cpu_vendor+8 370 movl $0,cpu_vendor+12 371 jmp 3f 372 373 try486: /* Try to toggle identification flag; does not exist on early 486s. */ 374 pushfl 375 popl %eax 376 movl %eax,%ecx 377 xorl $PSL_ID,%eax 378 pushl %eax 379 popfl 380 pushfl 381 popl %eax 382 xorl %ecx,%eax 383 andl $PSL_ID,%eax 384 pushl %ecx 385 popfl 386 387 testl %eax,%eax 388 jnz trycpuid 389 movl $CPU_486,cpu 390 391 /* 392 * Check Cyrix CPU 393 * Cyrix CPUs do not change the undefined flags following 394 * execution of the divide instruction which divides 5 by 2. 395 * 396 * Note: CPUID is enabled on M2, so it passes another way. 397 */ 398 pushfl 399 movl $0x5555, %eax 400 xorl %edx, %edx 401 movl $2, %ecx 402 clc 403 divl %ecx 404 jnc trycyrix 405 popfl 406 jmp 3f /* You may use Intel CPU. */ 407 408 trycyrix: 409 popfl 410 /* 411 * IBM Bluelighting CPU also doesn't change the undefined flags. 412 * Because IBM doesn't disclose the information for Bluelighting 413 * CPU, we couldn't distinguish it from Cyrix's (including IBM 414 * brand of Cyrix CPUs). 415 */ 416 movl $0x69727943,cpu_vendor # store vendor string 417 movl $0x736e4978,cpu_vendor+4 418 movl $0x64616574,cpu_vendor+8 419 jmp 3f 420 421 trycpuid: /* Use the `cpuid' instruction. */ 422 xorl %eax,%eax 423 cpuid # cpuid 0 424 movl %eax,cpu_high # highest capability 425 movl %ebx,cpu_vendor # store vendor string 426 movl %edx,cpu_vendor+4 427 movl %ecx,cpu_vendor+8 428 movb $0,cpu_vendor+12 429 430 movl $1,%eax 431 cpuid # cpuid 1 432 movl %eax,cpu_id # store cpu_id 433 movl %ebx,cpu_procinfo # store cpu_procinfo 434 movl %edx,cpu_feature # store cpu_feature 435 movl %ecx,cpu_feature2 # store cpu_feature2 436 rorl $8,%eax # extract family type 437 andl $15,%eax 438 cmpl $5,%eax 439 jae 1f 440 441 /* less than Pentium; must be 486 */ 442 movl $CPU_486,cpu 443 jmp 3f 444 1: 445 /* a Pentium? */ 446 cmpl $5,%eax 447 jne 2f 448 movl $CPU_586,cpu 449 jmp 3f 450 2: 451 /* Greater than Pentium...call it a Pentium Pro */ 452 movl $CPU_686,cpu 453 3: 454 popl %ebx 455 ret 456 END(identify_cpu) 457 458 #ifdef XENHVM 459 /* Xen Hypercall page */ 460 .text 461 .p2align PAGE_SHIFT, 0x90 /* Hypercall_page needs to be PAGE aligned */ 462 463 NON_GPROF_ENTRY(hypercall_page) 464 .skip 0x1000, 0x90 /* Fill with "nop"s */ 465 #endif
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