2 * Copyright (c) 1990 The Regents of the University of California.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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 * 4. 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.
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
32 * from: @(#)locore.s 7.3 (Berkeley) 5/13/91
35 * originally from: locore.s, by William F. Jolitz
37 * Substantially rewritten by David Greenman, Rod Grimes,
38 * Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp
42 #include "opt_bootp.h"
43 #include "opt_compat.h"
44 #include "opt_nfsroot.h"
47 #include <sys/syscall.h>
48 #include <sys/reboot.h>
50 #include <machine/asmacros.h>
51 #include <machine/cputypes.h>
52 #include <machine/psl.h>
53 #include <machine/pmap.h>
54 #include <machine/specialreg.h>
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.
67 * PTmap is recursive pagemap at top of virtual address space.
68 * Within PTmap, the page directory can be found (third indirection).
70 .globl PTmap,PTD,PTDpde
71 .set PTmap,(PTDPTDI << PDRSHIFT)
72 .set PTD,PTmap + (PTDPTDI * PAGE_SIZE)
73 .set PTDpde,PTD + (PTDPTDI * PDESIZE)
76 * Compiled KERNBASE location and the kernel load address
79 .set kernbase,KERNBASE
81 .set kernload,KERNLOAD
87 ALIGN_DATA /* just to be sure */
89 .space 0x2000 /* space for tmpstk - temporary stack */
93 bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */
96 KERNend: .long 0 /* phys addr end of kernel (just after bss) */
97 physfree: .long 0 /* phys addr of next free page */
100 IdlePTD: .long 0 /* phys addr of kernel PTD */
104 IdlePDPT: .long 0 /* phys addr of kernel PDPT */
108 KPTmap: .long 0 /* address of kernel page tables */
111 KPTphys: .long 0 /* phys addr of kernel page tables */
114 proc0kstack: .long 0 /* address of proc 0 kstack space */
115 p0kpa: .long 0 /* phys addr of proc0's STACK */
117 vm86phystk: .long 0 /* PA of vm86/bios stack */
119 .globl vm86paddr, vm86pa
120 vm86paddr: .long 0 /* address of vm86 region */
121 vm86pa: .long 0 /* phys addr of vm86 region */
124 .globl pc98_system_parameter
125 pc98_system_parameter:
129 /**********************************************************************
135 #define R(foo) ((foo)-KERNBASE)
137 #define ALLOCPAGES(foo) \
138 movl R(physfree), %esi ; \
139 movl $((foo)*PAGE_SIZE), %eax ; \
141 movl %eax, R(physfree) ; \
143 movl $((foo)*PAGE_SIZE),%ecx ; \
151 * eax = page frame address
152 * ebx = index into page table
153 * ecx = how many pages to map
154 * base = base address of page dir/table
155 * prot = protection bits
157 #define fillkpt(base, prot) \
158 shll $PTESHIFT,%ebx ; \
162 1: movl %eax,(%ebx) ; \
163 addl $PAGE_SIZE,%eax ; /* increment physical address */ \
164 addl $PTESIZE,%ebx ; /* next pte */ \
169 * eax = physical address
170 * ecx = how many pages to map
171 * prot = protection bits
173 #define fillkptphys(prot) \
175 shrl $PAGE_SHIFT, %ebx ; \
176 fillkpt(R(KPTphys), prot)
179 /**********************************************************************
181 * This is where the bootblocks start us, set the ball rolling...
184 NON_GPROF_ENTRY(btext)
187 /* save SYSTEM PARAMETER for resume (NS/T or other) */
189 movl $R(pc98_system_parameter),%edi
195 /* Tell the bios to warmboot next time */
199 /* Set up a real frame in case the double return in newboot is executed. */
203 /* Don't trust what the BIOS gives for eflags. */
208 * Don't trust what the BIOS gives for %fs and %gs. Trust the bootstrap
209 * to set %cs, %ds, %es and %ss.
216 * Clear the bss. Not all boot programs do it, and it is our job anyway.
218 * XXX we don't check that there is memory for our bss and page tables
221 * Note: we must be careful to not overwrite an active gdt or idt. They
222 * inactive from now until we switch to new ones, since we don't load any
223 * more segment registers or permit interrupts until after the switch.
233 call recover_bootinfo
235 /* Get onto a stack that we can trust. */
237 * XXX this step is delayed in case recover_bootinfo needs to return via
238 * the old stack, but it need not be, since recover_bootinfo actually
239 * returns via the old frame.
244 /* pc98_machine_type & M_EPSON_PC98 */
245 testb $0x02,R(pc98_system_parameter)+220
247 /* epson_machine_id <= 0x0b */
248 cmpb $0x0b,R(pc98_system_parameter)+224
251 /* count up memory */
252 movl $0x100000,%eax /* next, talley remaining memory */
253 movl $0xFFF-0x100,%ecx
254 1: movl 0(%eax),%ebx /* save location to check */
255 movl $0xa55a5aa5,0(%eax) /* write test pattern */
256 cmpl $0xa55a5aa5,0(%eax) /* does not check yet for rollover */
258 movl %ebx,0(%eax) /* restore memory */
261 2: subl $0x100000,%eax
263 movb %al,R(pc98_system_parameter)+1
266 movw R(pc98_system_parameter+0x86),%ax
271 call create_pagetables
274 * If the CPU has support for VME, turn it on.
276 testl $CPUID_VME, R(cpu_feature)
283 /* Now enable paging */
285 movl R(IdlePDPT), %eax
291 movl R(IdlePTD), %eax
292 movl %eax,%cr3 /* load ptd addr into mmu */
294 movl %cr0,%eax /* get control word */
295 orl $CR0_PE|CR0_PG,%eax /* enable paging */
296 movl %eax,%cr0 /* and let's page NOW! */
298 pushl $begin /* jump to high virtualized address */
301 /* now running relocated at KERNBASE where the system is linked to run */
303 /* set up bootstrap stack */
304 movl proc0kstack,%eax /* location of in-kernel stack */
305 /* bootstrap stack end location */
306 leal (KSTACK_PAGES*PAGE_SIZE-PCB_SIZE)(%eax),%esp
308 xorl %ebp,%ebp /* mark end of frames */
315 movl %esi,(KSTACK_PAGES*PAGE_SIZE-PCB_SIZE+PCB_CR3)(%eax)
317 pushl physfree /* value of first for init386(first) */
318 call init386 /* wire 386 chip for unix operation */
321 * Clean up the stack in a way that db_numargs() understands, so
322 * that backtraces in ddb don't underrun the stack. Traps for
323 * inaccessible memory are more fatal than usual this early.
327 call mi_startup /* autoconfiguration, mountroot etc */
329 addl $0,%esp /* for db_numargs() again */
332 * Signal trampoline, copied to top of user stack
334 NON_GPROF_ENTRY(sigcode)
335 calll *SIGF_HANDLER(%esp)
336 leal SIGF_UC(%esp),%eax /* get ucontext */
338 testl $PSL_VM,UC_EFLAGS(%eax)
340 mov UC_GS(%eax),%gs /* restore %gs */
342 movl $SYS_sigreturn,%eax
343 pushl %eax /* junk to fake return addr. */
344 int $0x80 /* enter kernel with args */
349 #ifdef COMPAT_FREEBSD4
352 calll *SIGF_HANDLER(%esp)
353 leal SIGF_UC4(%esp),%eax /* get ucontext */
355 testl $PSL_VM,UC4_EFLAGS(%eax)
357 mov UC4_GS(%eax),%gs /* restore %gs */
359 movl $344,%eax /* 4.x SYS_sigreturn */
360 pushl %eax /* junk to fake return addr. */
361 int $0x80 /* enter kernel with args */
370 call *SIGF_HANDLER(%esp) /* call signal handler */
371 lea SIGF_SC(%esp),%eax /* get sigcontext */
373 testl $PSL_VM,SC_PS(%eax)
375 mov SC_GS(%eax),%gs /* restore %gs */
377 movl $103,%eax /* 3.x SYS_sigreturn */
378 pushl %eax /* junk to fake return addr. */
379 int $0x80 /* enter kernel with args */
381 #endif /* COMPAT_43 */
389 .long esigcode-sigcode
390 #ifdef COMPAT_FREEBSD4
391 .globl szfreebsd4_sigcode
393 .long esigcode-freebsd4_sigcode
398 .long esigcode-osigcode
402 /**********************************************************************
404 * Recover the bootinfo passed to us from the boot program
409 * This code is called in different ways depending on what loaded
410 * and started the kernel. This is used to detect how we get the
411 * arguments from the other code and what we do with them.
413 * Old disk boot blocks:
414 * (*btext)(howto, bootdev, cyloffset, esym);
415 * [return address == 0, and can NOT be returned to]
416 * [cyloffset was not supported by the FreeBSD boot code
417 * and always passed in as 0]
418 * [esym is also known as total in the boot code, and
419 * was never properly supported by the FreeBSD boot code]
421 * Old diskless netboot code:
422 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0);
423 * [return address != 0, and can NOT be returned to]
424 * If we are being booted by this code it will NOT work,
425 * so we are just going to halt if we find this case.
427 * New uniform boot code:
428 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo)
429 * [return address != 0, and can be returned to]
431 * There may seem to be a lot of wasted arguments in here, but
432 * that is so the newer boot code can still load very old kernels
433 * and old boot code can load new kernels.
437 * The old style disk boot blocks fake a frame on the stack and
438 * did an lret to get here. The frame on the stack has a return
445 * We have some form of return address, so this is either the
446 * old diskless netboot code, or the new uniform code. That can
447 * be detected by looking at the 5th argument, if it is 0
448 * we are being booted by the new uniform boot code.
454 * Seems we have been loaded by the old diskless boot code, we
455 * don't stand a chance of running as the diskless structure
456 * changed considerably between the two, so just halt.
461 * We have been loaded by the new uniform boot code.
462 * Let's check the bootinfo version, and if we do not understand
463 * it we return to the loader with a status of 1 to indicate this error
466 movl 28(%ebp),%ebx /* &bootinfo.version */
467 movl BI_VERSION(%ebx),%eax
468 cmpl $1,%eax /* We only understand version 1 */
470 movl $1,%eax /* Return status */
473 * XXX this returns to our caller's caller (as is required) since
474 * we didn't set up a frame and our caller did.
480 * If we have a kernelname copy it in
482 movl BI_KERNELNAME(%ebx),%esi
484 je 2f /* No kernelname */
485 movl $MAXPATHLEN,%ecx /* Brute force!!! */
486 movl $R(kernelname),%edi
487 cmpb $'/',(%esi) /* Make sure it starts with a slash */
499 * Determine the size of the boot loader's copy of the bootinfo
500 * struct. This is impossible to do properly because old versions
501 * of the struct don't contain a size field and there are 2 old
502 * versions with the same version number.
504 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */
505 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */
506 je got_bi_size /* no, sizeless version */
507 movl BI_SIZE(%ebx),%ecx
511 * Copy the common part of the bootinfo struct
514 movl $R(bootinfo),%edi
515 cmpl $BOOTINFO_SIZE,%ecx
516 jbe got_common_bi_size
517 movl $BOOTINFO_SIZE,%ecx
526 * If we have a nfs_diskless structure copy it in
528 movl BI_NFS_DISKLESS(%ebx),%esi
531 movl $R(nfs_diskless),%edi
532 movl $NFSDISKLESS_SIZE,%ecx
536 movl $R(nfs_diskless_valid),%edi
542 * The old style disk boot.
543 * (*btext)(howto, bootdev, cyloffset, esym);
544 * Note that the newer boot code just falls into here to pick
545 * up howto and bootdev, cyloffset and esym are no longer used
549 movl %eax,R(boothowto)
556 /**********************************************************************
558 * Identify the CPU and initialize anything special about it
563 /* Try to toggle alignment check flag; does not exist on 386. */
580 /* NexGen CPU does not have aligment check flag. */
594 movl $CPU_NX586,R(cpu)
595 movl $0x4778654e,R(cpu_vendor) # store vendor string
596 movl $0x72446e65,R(cpu_vendor+4)
597 movl $0x6e657669,R(cpu_vendor+8)
598 movl $0,R(cpu_vendor+12)
601 try486: /* Try to toggle identification flag; does not exist on early 486s. */
621 * Cyrix CPUs do not change the undefined flags following
622 * execution of the divide instruction which divides 5 by 2.
624 * Note: CPUID is enabled on M2, so it passes another way.
634 jmp 3f /* You may use Intel CPU. */
639 * IBM Bluelighting CPU also doesn't change the undefined flags.
640 * Because IBM doesn't disclose the information for Bluelighting
641 * CPU, we couldn't distinguish it from Cyrix's (including IBM
642 * brand of Cyrix CPUs).
644 movl $0x69727943,R(cpu_vendor) # store vendor string
645 movl $0x736e4978,R(cpu_vendor+4)
646 movl $0x64616574,R(cpu_vendor+8)
649 trycpuid: /* Use the `cpuid' instruction. */
652 movl %eax,R(cpu_high) # highest capability
653 movl %ebx,R(cpu_vendor) # store vendor string
654 movl %edx,R(cpu_vendor+4)
655 movl %ecx,R(cpu_vendor+8)
656 movb $0,R(cpu_vendor+12)
660 movl %eax,R(cpu_id) # store cpu_id
661 movl %ebx,R(cpu_procinfo) # store cpu_procinfo
662 movl %edx,R(cpu_feature) # store cpu_feature
663 movl %ecx,R(cpu_feature2) # store cpu_feature2
664 rorl $8,%eax # extract family type
669 /* less than Pentium; must be 486 */
679 /* Greater than Pentium...call it a Pentium Pro */
685 /**********************************************************************
687 * Create the first page directory and its page tables.
693 /* Find end of kernel image (rounded up to a page boundary). */
696 /* Include symbols, if any. */
697 movl R(bootinfo+BI_ESYMTAB),%edi
702 addl %edi,R(bootinfo+BI_SYMTAB)
703 addl %edi,R(bootinfo+BI_ESYMTAB)
706 /* If we are told where the end of the kernel space is, believe it. */
707 movl R(bootinfo+BI_KERNEND),%edi
713 addl $PDRMASK,%esi /* Play conservative for now, and */
714 andl $~PDRMASK,%esi /* ... wrap to next 4M. */
715 movl %esi,R(KERNend) /* save end of kernel */
716 movl %esi,R(physfree) /* next free page is at end of kernel */
718 /* Allocate Kernel Page Tables */
721 addl $(KERNBASE-(KPTDI<<(PDRSHIFT-PAGE_SHIFT+PTESHIFT))),%esi
724 /* Allocate Page Table Directory */
726 /* XXX only need 32 bytes (easier for now) */
728 movl %esi,R(IdlePDPT)
733 /* Allocate KSTACK */
734 ALLOCPAGES(KSTACK_PAGES)
737 movl %esi, R(proc0kstack)
739 ALLOCPAGES(1) /* vm86/bios stack */
740 movl %esi,R(vm86phystk)
742 ALLOCPAGES(3) /* pgtable + ext + IOPAGES */
745 movl %esi, R(vm86paddr)
748 * Enable PSE and PGE.
751 testl $CPUID_PSE, R(cpu_feature)
753 movl $PG_PS, R(pseflag)
760 testl $CPUID_PGE, R(cpu_feature)
762 movl $PG_G, R(pgeflag)
770 * Initialize page table pages mapping physical address zero through the
771 * end of the kernel. All of the page table entries allow read and write
772 * access. Write access to the first physical page is required by bios32
773 * calls, and write access to the first 1 MB of physical memory is required
774 * by ACPI for implementing suspend and resume. We do this even
775 * if we've enabled PSE above, we'll just switch the corresponding kernel
776 * PDEs before we turn on paging.
778 * XXX: We waste some pages here in the PSE case!
782 shrl $PAGE_SHIFT,%ecx
785 /* Map page table pages. */
790 /* Map page directory. */
792 movl R(IdlePDPT), %eax
797 movl R(IdlePTD), %eax
801 /* Map proc0's KSTACK in the physical way ... */
803 movl $(KSTACK_PAGES), %ecx
807 movl $ISA_HOLE_START, %eax
808 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
811 /* Map space for the vm86 region */
812 movl R(vm86phystk), %eax
816 /* Map page 0 into the vm86 page table */
820 fillkpt(R(vm86pa), $PG_RW|PG_U)
822 /* ...likewise for the ISA hole */
823 movl $ISA_HOLE_START, %eax
824 movl $ISA_HOLE_START>>PAGE_SHIFT, %ebx
825 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
826 fillkpt(R(vm86pa), $PG_RW|PG_U)
829 * Create an identity mapping for low physical memory, including the kernel.
830 * The part of this mapping that covers the first 1 MB of physical memory
831 * becomes a permanent part of the kernel's address space. The rest of this
832 * mapping is destroyed in pmap_bootstrap(). Ordinarily, the same page table
833 * pages are shared by the identity mapping and the kernel's native mapping.
834 * However, the permanent identity mapping cannot contain PG_G mappings.
835 * Thus, if the kernel is loaded within the permanent identity mapping, that
836 * page table page must be duplicated and not shared.
838 * N.B. Due to errata concerning large pages and physical address zero,
839 * a PG_PS mapping is not used.
841 movl R(KPTphys), %eax
844 fillkpt(R(IdlePTD), $PG_RW)
845 #if KERNLOAD < (1 << PDRSHIFT)
846 testl $PG_G, R(pgeflag)
850 movl R(IdlePTD), %eax
853 movl $PAGE_SIZE, %ecx
861 * For the non-PSE case, install PDEs for PTs covering the KVA.
862 * For the PSE case, do the same, but clobber the ones corresponding
863 * to the kernel (from btext to KERNend) with 4M (2M for PAE) ('PS')
864 * PDEs immediately after.
866 movl R(KPTphys), %eax
869 fillkpt(R(IdlePTD), $PG_RW)
873 movl R(KERNend), %ecx
877 movl $(KPTDI+(KERNLOAD/(1 << PDRSHIFT))), %ebx
879 addl R(IdlePTD), %ebx
880 orl $(PG_V|PG_RW|PG_PS), %eax
882 addl $(1 << PDRSHIFT), %eax
887 /* install a pde recursively mapping page directory as a page table */
888 movl R(IdlePTD), %eax
891 fillkpt(R(IdlePTD), $PG_RW)
894 movl R(IdlePTD), %eax
897 fillkpt(R(IdlePDPT), $0x0)