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 * 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.
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
36 * from: @(#)locore.s 7.3 (Berkeley) 5/13/91
39 * originally from: locore.s, by William F. Jolitz
41 * Substantially rewritten by David Greenman, Rod Grimes,
42 * Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp
46 #include "opt_bootp.h"
48 #include "opt_nfsroot.h"
49 #include "opt_userconfig.h"
51 #include <sys/syscall.h>
52 #include <sys/reboot.h>
54 #include <machine/asmacros.h>
55 #include <machine/cputypes.h>
56 #include <machine/psl.h>
57 #include <machine/pmap.h>
58 #include <machine/specialreg.h>
65 * Note: This version greatly munged to avoid various assembler errors
66 * that may be fixed in newer versions of gas. Perhaps newer versions
67 * will have more pleasant appearance.
71 * PTmap is recursive pagemap at top of virtual address space.
72 * Within PTmap, the page directory can be found (third indirection).
74 .globl _PTmap,_PTD,_PTDpde
75 .set _PTmap,(PTDPTDI << PDRSHIFT)
76 .set _PTD,_PTmap + (PTDPTDI * PAGE_SIZE)
77 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE)
80 * APTmap, APTD is the alternate recursive pagemap.
81 * It's used when modifying another process's page tables.
83 .globl _APTmap,_APTD,_APTDpde
84 .set _APTmap,APTDPTDI << PDRSHIFT
85 .set _APTD,_APTmap + (APTDPTDI * PAGE_SIZE)
86 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE)
92 ALIGN_DATA /* just to be sure */
94 .globl HIDENAME(tmpstk)
95 .space 0x2000 /* space for tmpstk - temporary stack */
98 .globl _boothowto,_bootdev
100 .globl _cpu,_cpu_vendor,_cpu_id,_bootinfo
101 .globl _cpu_high, _cpu_feature
103 _cpu: .long 0 /* are we 386, 386sx, or 486 */
104 _cpu_id: .long 0 /* stepping ID */
105 _cpu_high: .long 0 /* highest arg to CPUID */
106 _cpu_feature: .long 0 /* features */
107 _cpu_vendor: .space 20 /* CPU origin code */
108 _bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */
110 _KERNend: .long 0 /* phys addr end of kernel (just after bss) */
111 physfree: .long 0 /* phys addr of next free page */
115 cpu0pp: .long 0 /* phys addr cpu0 private pg */
116 _cpu0prvpage: .long 0 /* relocated version */
119 SMPptpa: .long 0 /* phys addr SMP page table */
120 _SMPpt: .long 0 /* relocated version */
124 _IdlePTD: .long 0 /* phys addr of kernel PTD */
129 _KPTphys: .long 0 /* phys addr of kernel page tables */
132 _proc0paddr: .long 0 /* address of proc 0 address space */
133 p0upa: .long 0 /* phys addr of proc0's UPAGES */
135 vm86phystk: .long 0 /* PA of vm86/bios stack */
137 .globl _vm86paddr, _vm86pa
138 _vm86paddr: .long 0 /* address of vm86 region */
139 _vm86pa: .long 0 /* phys addr of vm86 region */
142 .globl _bdb_exists /* flag to indicate BDE debugger is present */
147 .globl _pc98_system_parameter
148 _pc98_system_parameter:
152 /**********************************************************************
158 #define R(foo) ((foo)-KERNBASE)
160 #define ALLOCPAGES(foo) \
161 movl R(physfree), %esi ; \
162 movl $((foo)*PAGE_SIZE), %eax ; \
164 movl %eax, R(physfree) ; \
166 movl $((foo)*PAGE_SIZE),%ecx ; \
174 * eax = page frame address
175 * ebx = index into page table
176 * ecx = how many pages to map
177 * base = base address of page dir/table
178 * prot = protection bits
180 #define fillkpt(base, prot) \
185 1: movl %eax,(%ebx) ; \
186 addl $PAGE_SIZE,%eax ; /* increment physical address */ \
187 addl $4,%ebx ; /* next pte */ \
192 * eax = physical address
193 * ecx = how many pages to map
194 * prot = protection bits
196 #define fillkptphys(prot) \
198 shrl $PAGE_SHIFT, %ebx ; \
199 fillkpt(R(_KPTphys), prot)
202 /**********************************************************************
204 * This is where the bootblocks start us, set the ball rolling...
207 NON_GPROF_ENTRY(btext)
210 /* save SYSTEM PARAMETER for resume (NS/T or other) */
212 movl $R(_pc98_system_parameter),%edi
219 #ifdef BIOS_STEALS_3K
220 cmpl $0x0375c339,0x95504
222 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */
225 movb $1,R(_bdb_exists)
228 /* Tell the bios to warmboot next time */
232 /* Set up a real frame in case the double return in newboot is executed. */
236 /* Don't trust what the BIOS gives for eflags. */
241 * Don't trust what the BIOS gives for %fs and %gs. Trust the bootstrap
242 * to set %cs, %ds, %es and %ss.
248 call recover_bootinfo
250 /* Get onto a stack that we can trust. */
252 * XXX this step is delayed in case recover_bootinfo needs to return via
253 * the old stack, but it need not be, since recover_bootinfo actually
254 * returns via the old frame.
256 movl $R(HIDENAME(tmpstk)),%esp
259 /* pc98_machine_type & M_EPSON_PC98 */
260 testb $0x02,R(_pc98_system_parameter)+220
262 /* epson_machine_id <= 0x0b */
263 cmpb $0x0b,R(_pc98_system_parameter)+224
266 /* count up memory */
267 movl $0x100000,%eax /* next, talley remaining memory */
268 movl $0xFFF-0x100,%ecx
269 1: movl 0(%eax),%ebx /* save location to check */
270 movl $0xa55a5aa5,0(%eax) /* write test pattern */
271 cmpl $0xa55a5aa5,0(%eax) /* does not check yet for rollover */
273 movl %ebx,0(%eax) /* restore memory */
276 2: subl $0x100000,%eax
278 movb %al,R(_pc98_system_parameter)+1
286 * XXX this should be done a little earlier.
288 * XXX we don't check that there is memory for our bss and page tables
291 * XXX the boot program somewhat bogusly clears the bss. We still have
292 * to do it in case we were unzipped by kzipboot. Then the boot program
293 * only clears kzipboot's bss.
295 * XXX the gdt and idt are still somewhere in the boot program. We
296 * depend on the convention that the boot program is below 1MB and we
297 * are above 1MB to keep the gdt and idt away from the bss and page
298 * tables. The idt is only used if BDE_DEBUGGER is enabled.
308 call create_pagetables
311 * If the CPU has support for VME, turn it on.
313 testl $CPUID_VME, R(_cpu_feature)
322 * Adjust as much as possible for paging before enabling paging so that the
323 * adjustments can be traced.
325 call bdb_prepare_paging
328 /* Now enable paging */
329 movl R(_IdlePTD), %eax
330 movl %eax,%cr3 /* load ptd addr into mmu */
331 movl %cr0,%eax /* get control word */
332 orl $CR0_PE|CR0_PG,%eax /* enable paging */
333 movl %eax,%cr0 /* and let's page NOW! */
337 * Complete the adjustments for paging so that we can keep tracing through
338 * initi386() after the low (physical) addresses for the gdt and idt become
341 call bdb_commit_paging
344 pushl $begin /* jump to high virtualized address */
347 /* now running relocated at KERNBASE where the system is linked to run */
349 /* set up bootstrap stack */
350 movl _proc0paddr,%esp /* location of in-kernel pages */
351 addl $UPAGES*PAGE_SIZE,%esp /* bootstrap stack end location */
352 xorl %eax,%eax /* mark end of frames */
354 movl _proc0paddr,%eax
356 movl %esi,PCB_CR3(%eax)
359 pushl %esi /* value of first for init386(first) */
360 call _init386 /* wire 386 chip for unix operation */
363 .globl __ucodesel,__udatasel
365 pushl $0 /* unused */
366 pushl __udatasel /* ss */
367 pushl $0 /* esp - filled in by execve() */
368 pushl $PSL_USER /* eflags (IOPL 0, int enab) */
369 pushl __ucodesel /* cs */
370 pushl $0 /* eip - filled in by execve() */
371 subl $(13*4),%esp /* space for rest of registers */
373 pushl %esp /* call main with frame pointer */
374 call _mi_startup /* autoconfiguration, mountroot etc */
376 hlt /* never returns to here */
379 * When starting init, call this to configure the process for user
380 * mode. This will be inherited by other processes.
382 NON_GPROF_ENTRY(prepare_usermode)
384 * Now we've run main() and determined what cpu-type we are, we can
385 * enable write protection and alignment checking on i486 cpus and
388 #if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)
389 cmpl $CPUCLASS_386,_cpu_class
391 movl %cr0,%eax /* get control word */
392 orl $CR0_WP|CR0_AM,%eax /* enable i486 features */
393 movl %eax,%cr0 /* and do it */
397 * on return from main(), we are process 1
398 * set up address space and stack so that we can 'return' to user mode
403 #if 0 /* ds/es/fs are in trap frame */
408 movl %cx,%gs /* and ds to gs */
413 * Signal trampoline, copied to top of user stack
415 NON_GPROF_ENTRY(sigcode)
416 call SIGF_HANDLER(%esp) /* call signal handler */
417 lea SIGF_UC(%esp),%eax /* get ucontext_t */
419 testl $PSL_VM,UC_EFLAGS(%eax)
421 movl UC_GS(%eax),%gs /* restore %gs */
423 movl $SYS_sigreturn,%eax
424 pushl %eax /* junk to fake return addr. */
425 int $0x80 /* enter kernel with args */
430 call SIGF_HANDLER(%esp) /* call signal handler */
431 lea SIGF_SC(%esp),%eax /* get sigcontext */
433 testl $PSL_VM,SC_PS(%eax)
435 movl SC_GS(%eax),%gs /* restore %gs */
437 movl $0x01d516,SC_TRAPNO(%eax) /* magic: 0ldSiG */
438 movl $SYS_sigreturn,%eax
439 pushl %eax /* junk to fake return addr. */
440 int $0x80 /* enter kernel with args */
447 .globl _szsigcode, _szosigcode
449 .long _esigcode-_sigcode
451 .long _esigcode-_osigcode
454 /**********************************************************************
456 * Recover the bootinfo passed to us from the boot program
461 * This code is called in different ways depending on what loaded
462 * and started the kernel. This is used to detect how we get the
463 * arguments from the other code and what we do with them.
465 * Old disk boot blocks:
466 * (*btext)(howto, bootdev, cyloffset, esym);
467 * [return address == 0, and can NOT be returned to]
468 * [cyloffset was not supported by the FreeBSD boot code
469 * and always passed in as 0]
470 * [esym is also known as total in the boot code, and
471 * was never properly supported by the FreeBSD boot code]
473 * Old diskless netboot code:
474 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0);
475 * [return address != 0, and can NOT be returned to]
476 * If we are being booted by this code it will NOT work,
477 * so we are just going to halt if we find this case.
479 * New uniform boot code:
480 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo)
481 * [return address != 0, and can be returned to]
483 * There may seem to be a lot of wasted arguments in here, but
484 * that is so the newer boot code can still load very old kernels
485 * and old boot code can load new kernels.
489 * The old style disk boot blocks fake a frame on the stack and
490 * did an lret to get here. The frame on the stack has a return
497 * We have some form of return address, so this is either the
498 * old diskless netboot code, or the new uniform code. That can
499 * be detected by looking at the 5th argument, if it is 0
500 * we are being booted by the new uniform boot code.
506 * Seems we have been loaded by the old diskless boot code, we
507 * don't stand a chance of running as the diskless structure
508 * changed considerably between the two, so just halt.
513 * We have been loaded by the new uniform boot code.
514 * Let's check the bootinfo version, and if we do not understand
515 * it we return to the loader with a status of 1 to indicate this error
518 movl 28(%ebp),%ebx /* &bootinfo.version */
519 movl BI_VERSION(%ebx),%eax
520 cmpl $1,%eax /* We only understand version 1 */
522 movl $1,%eax /* Return status */
525 * XXX this returns to our caller's caller (as is required) since
526 * we didn't set up a frame and our caller did.
532 * If we have a kernelname copy it in
534 movl BI_KERNELNAME(%ebx),%esi
536 je 2f /* No kernelname */
537 movl $MAXPATHLEN,%ecx /* Brute force!!! */
538 movl $R(_kernelname),%edi
539 cmpb $'/',(%esi) /* Make sure it starts with a slash */
551 * Determine the size of the boot loader's copy of the bootinfo
552 * struct. This is impossible to do properly because old versions
553 * of the struct don't contain a size field and there are 2 old
554 * versions with the same version number.
556 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */
557 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */
558 je got_bi_size /* no, sizeless version */
559 movl BI_SIZE(%ebx),%ecx
563 * Copy the common part of the bootinfo struct
566 movl $R(_bootinfo),%edi
567 cmpl $BOOTINFO_SIZE,%ecx
568 jbe got_common_bi_size
569 movl $BOOTINFO_SIZE,%ecx
578 * If we have a nfs_diskless structure copy it in
580 movl BI_NFS_DISKLESS(%ebx),%esi
583 movl $R(_nfs_diskless),%edi
584 movl $NFSDISKLESS_SIZE,%ecx
588 movl $R(_nfs_diskless_valid),%edi
594 * The old style disk boot.
595 * (*btext)(howto, bootdev, cyloffset, esym);
596 * Note that the newer boot code just falls into here to pick
597 * up howto and bootdev, cyloffset and esym are no longer used
601 movl %eax,R(_boothowto)
603 movl %eax,R(_bootdev)
608 /**********************************************************************
610 * Identify the CPU and initialize anything special about it
615 /* Try to toggle alignment check flag; does not exist on 386. */
632 /* NexGen CPU does not have aligment check flag. */
641 movl $CPU_386,R(_cpu)
646 movl $CPU_NX586,R(_cpu)
647 movl $0x4778654e,R(_cpu_vendor) # store vendor string
648 movl $0x72446e65,R(_cpu_vendor+4)
649 movl $0x6e657669,R(_cpu_vendor+8)
650 movl $0,R(_cpu_vendor+12)
653 try486: /* Try to toggle identification flag; does not exist on early 486s. */
669 movl $CPU_486,R(_cpu)
673 * Cyrix CPUs do not change the undefined flags following
674 * execution of the divide instruction which divides 5 by 2.
676 * Note: CPUID is enabled on M2, so it passes another way.
686 jmp 3f /* You may use Intel CPU. */
691 * IBM Bluelighting CPU also doesn't change the undefined flags.
692 * Because IBM doesn't disclose the information for Bluelighting
693 * CPU, we couldn't distinguish it from Cyrix's (including IBM
694 * brand of Cyrix CPUs).
696 movl $0x69727943,R(_cpu_vendor) # store vendor string
697 movl $0x736e4978,R(_cpu_vendor+4)
698 movl $0x64616574,R(_cpu_vendor+8)
701 trycpuid: /* Use the `cpuid' instruction. */
703 .byte 0x0f,0xa2 # cpuid 0
704 movl %eax,R(_cpu_high) # highest capability
705 movl %ebx,R(_cpu_vendor) # store vendor string
706 movl %edx,R(_cpu_vendor+4)
707 movl %ecx,R(_cpu_vendor+8)
708 movb $0,R(_cpu_vendor+12)
711 .byte 0x0f,0xa2 # cpuid 1
712 movl %eax,R(_cpu_id) # store cpu_id
713 movl %edx,R(_cpu_feature) # store cpu_feature
714 rorl $8,%eax # extract family type
719 /* less than Pentium; must be 486 */
720 movl $CPU_486,R(_cpu)
726 movl $CPU_586,R(_cpu)
729 /* Greater than Pentium...call it a Pentium Pro */
730 movl $CPU_686,R(_cpu)
735 /**********************************************************************
737 * Create the first page directory and its page tables.
743 testl $CPUID_PGE, R(_cpu_feature)
750 /* Find end of kernel image (rounded up to a page boundary). */
753 /* include symbols if loaded and useful */
755 movl R(_bootinfo+BI_ESYMTAB),%edi
760 addl %edi,R(_bootinfo+BI_SYMTAB)
761 addl %edi,R(_bootinfo+BI_ESYMTAB)
765 /* If we are told where the end of the kernel space is, believe it. */
766 movl R(_bootinfo+BI_KERNEND),%edi
773 andl $~PAGE_MASK,%esi
774 movl %esi,R(_KERNend) /* save end of kernel */
775 movl %esi,R(physfree) /* next free page is at end of kernel */
777 /* Allocate Kernel Page Tables */
779 movl %esi,R(_KPTphys)
781 /* Allocate Page Table Directory */
783 movl %esi,R(_IdlePTD)
785 /* Allocate UPAGES */
789 movl %esi, R(_proc0paddr)
791 ALLOCPAGES(1) /* vm86/bios stack */
792 movl %esi,R(vm86phystk)
794 ALLOCPAGES(3) /* pgtable + ext + IOPAGES */
797 movl %esi, R(_vm86paddr)
800 /* Allocate cpu0's private data page */
804 movl %esi, R(_cpu0prvpage) /* relocated to KVM space */
806 /* Allocate SMP page table page */
810 movl %esi, R(_SMPpt) /* relocated to KVM space */
813 /* Map read-only from zero to the end of the kernel text section */
816 /* If the debugger is present, actually map everything read-write. */
817 cmpl $0,R(_bdb_exists)
823 testl $CPUID_PGE, R(_cpu_feature)
828 2: movl $R(_etext),%ecx
830 shrl $PAGE_SHIFT,%ecx
833 /* Map read-write, data, bss and symbols */
835 addl $PAGE_MASK, %eax
836 andl $~PAGE_MASK, %eax
840 testl $CPUID_PGE, R(_cpu_feature)
845 1: movl R(_KERNend),%ecx
847 shrl $PAGE_SHIFT,%ecx
850 /* Map page directory. */
851 movl R(_IdlePTD), %eax
855 /* Map proc0's UPAGES in the physical way ... */
861 movl $ISA_HOLE_START, %eax
862 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
865 /* Map space for the vm86 region */
866 movl R(vm86phystk), %eax
870 /* Map page 0 into the vm86 page table */
874 fillkpt(R(_vm86pa), $PG_RW|PG_U)
876 /* ...likewise for the ISA hole */
877 movl $ISA_HOLE_START, %eax
878 movl $ISA_HOLE_START>>PAGE_SHIFT, %ebx
879 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
880 fillkpt(R(_vm86pa), $PG_RW|PG_U)
883 /* Map cpu0's private page into global kmem (4K @ cpu0prvpage) */
888 /* Map SMP page table page into global kmem FWIW */
889 movl R(SMPptpa), %eax
893 /* Map the private page into the SMP page table */
895 movl $0, %ebx /* pte offset = 0 */
896 movl $1, %ecx /* one private page coming right up */
897 fillkpt(R(SMPptpa), $PG_RW)
899 /* ... and put the page table table in the pde. */
900 movl R(SMPptpa), %eax
903 fillkpt(R(_IdlePTD), $PG_RW)
905 /* Fakeup VA for the local apic to allow early traps. */
908 movl $(NPTEPG-1), %ebx /* pte offset = NTEPG-1 */
909 movl $1, %ecx /* one private pt coming right up */
910 fillkpt(R(SMPptpa), $PG_RW)
912 /* Initialize mp lock to allow early traps */
916 /* install a pde for temporary double map of bottom of VA */
917 movl R(_KPTphys), %eax
920 fillkpt(R(_IdlePTD), $PG_RW)
922 /* install pde's for pt's */
923 movl R(_KPTphys), %eax
926 fillkpt(R(_IdlePTD), $PG_RW)
928 /* install a pde recursively mapping page directory as a page table */
929 movl R(_IdlePTD), %eax
932 fillkpt(R(_IdlePTD), $PG_RW)
938 cmpl $0,R(_bdb_exists)
939 je bdb_prepare_paging_exit
944 * Copy and convert debugger entries from the bootstrap gdt and idt
945 * to the kernel gdt and idt. Everything is still in low memory.
946 * Tracing continues to work after paging is enabled because the
947 * low memory addresses remain valid until everything is relocated.
948 * However, tracing through the setidt() that initializes the trace
952 movl 2(%esp),%esi /* base address of bootstrap gdt */
954 movl %edi,2(%esp) /* prepare to load kernel gdt */
959 movl $R(_gdt),-8+2(%edi) /* adjust gdt self-ptr */
960 movb $0x92,-8+5(%edi)
964 movl 2(%esp),%esi /* base address of current idt */
965 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */
967 movl %eax,R(bdb_dbg_ljmp+1) /* ... immediate offset ... */
969 movw %ax,R(bdb_dbg_ljmp+5) /* ... and selector for ljmp */
970 movl 24+4(%esi),%eax /* same for bpt descriptor */
972 movl %eax,R(bdb_bpt_ljmp+1)
974 movw %ax,R(bdb_bpt_ljmp+5)
976 movl %edi,2(%esp) /* prepare to load kernel idt */
985 bdb_prepare_paging_exit:
988 /* Relocate debugger gdt entries and gdt and idt pointers. */
991 je bdb_commit_paging_exit
993 movl $_gdt+8*9,%eax /* adjust slots 9-17 */
996 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */
997 addl $8,%eax /* now KERNBASE>>24 */
1002 addl $KERNBASE,2(%esp)
1005 addl $KERNBASE,2(%esp)
1011 bdb_commit_paging_exit:
1014 #endif /* BDE_DEBUGGER */