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)
230 /* Tell the bios to warmboot next time */
233 /* Set up a real frame in case the double return in newboot is executed. */
237 /* Don't trust what the BIOS gives for eflags. */
242 * Don't trust what the BIOS gives for %fs and %gs. Trust the bootstrap
243 * to set %cs, %ds, %es and %ss.
249 call recover_bootinfo
251 /* Get onto a stack that we can trust. */
253 * XXX this step is delayed in case recover_bootinfo needs to return via
254 * the old stack, but it need not be, since recover_bootinfo actually
255 * returns via the old frame.
257 movl $R(HIDENAME(tmpstk)),%esp
260 /* pc98_machine_type & M_EPSON_PC98 */
261 testb $0x02,R(_pc98_system_parameter)+220
263 /* epson_machine_id <= 0x0b */
264 cmpb $0x0b,R(_pc98_system_parameter)+224
267 /* count up memory */
268 movl $0x100000,%eax /* next, talley remaining memory */
269 movl $0xFFF-0x100,%ecx
270 1: movl 0(%eax),%ebx /* save location to check */
271 movl $0xa55a5aa5,0(%eax) /* write test pattern */
272 cmpl $0xa55a5aa5,0(%eax) /* does not check yet for rollover */
274 movl %ebx,0(%eax) /* restore memory */
277 2: subl $0x100000,%eax
279 movb %al,R(_pc98_system_parameter)+1
287 * XXX this should be done a little earlier.
289 * XXX we don't check that there is memory for our bss and page tables
292 * XXX the boot program somewhat bogusly clears the bss. We still have
293 * to do it in case we were unzipped by kzipboot. Then the boot program
294 * only clears kzipboot's bss.
296 * XXX the gdt and idt are still somewhere in the boot program. We
297 * depend on the convention that the boot program is below 1MB and we
298 * are above 1MB to keep the gdt and idt away from the bss and page
299 * tables. The idt is only used if BDE_DEBUGGER is enabled.
309 call create_pagetables
312 * If the CPU has support for VME, turn it on.
314 testl $CPUID_VME, R(_cpu_feature)
323 * Adjust as much as possible for paging before enabling paging so that the
324 * adjustments can be traced.
326 call bdb_prepare_paging
329 /* Now enable paging */
330 movl R(_IdlePTD), %eax
331 movl %eax,%cr3 /* load ptd addr into mmu */
332 movl %cr0,%eax /* get control word */
333 orl $CR0_PE|CR0_PG,%eax /* enable paging */
334 movl %eax,%cr0 /* and let's page NOW! */
338 * Complete the adjustments for paging so that we can keep tracing through
339 * initi386() after the low (physical) addresses for the gdt and idt become
342 call bdb_commit_paging
345 pushl $begin /* jump to high virtualized address */
348 /* now running relocated at KERNBASE where the system is linked to run */
350 /* set up bootstrap stack */
351 movl _proc0paddr,%esp /* location of in-kernel pages */
352 addl $UPAGES*PAGE_SIZE,%esp /* bootstrap stack end location */
353 xorl %eax,%eax /* mark end of frames */
355 movl _proc0paddr,%eax
357 movl %esi,PCB_CR3(%eax)
360 pushl %esi /* value of first for init386(first) */
361 call _init386 /* wire 386 chip for unix operation */
364 .globl __ucodesel,__udatasel
366 pushl $0 /* unused */
367 pushl __udatasel /* ss */
368 pushl $0 /* esp - filled in by execve() */
369 pushl $PSL_USER /* eflags (IOPL 0, int enab) */
370 pushl __ucodesel /* cs */
371 pushl $0 /* eip - filled in by execve() */
372 subl $(13*4),%esp /* space for rest of registers */
374 pushl %esp /* call main with frame pointer */
375 call _mi_startup /* autoconfiguration, mountroot etc */
377 hlt /* never returns to here */
380 * When starting init, call this to configure the process for user
381 * mode. This will be inherited by other processes.
383 NON_GPROF_ENTRY(prepare_usermode)
385 * Now we've run main() and determined what cpu-type we are, we can
386 * enable write protection and alignment checking on i486 cpus and
389 #if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)
390 cmpl $CPUCLASS_386,_cpu_class
392 movl %cr0,%eax /* get control word */
393 orl $CR0_WP|CR0_AM,%eax /* enable i486 features */
394 movl %eax,%cr0 /* and do it */
398 * on return from main(), we are process 1
399 * set up address space and stack so that we can 'return' to user mode
404 #if 0 /* ds/es/fs are in trap frame */
409 movl %cx,%gs /* and ds to gs */
414 * Signal trampoline, copied to top of user stack
416 NON_GPROF_ENTRY(sigcode)
417 call SIGF_HANDLER(%esp) /* call signal handler */
418 lea SIGF_UC(%esp),%eax /* get ucontext_t */
420 movl $SYS_osigreturn,%eax
421 pushl %eax /* junk to fake return addr. */
422 int $0x80 /* enter kernel with args */
432 .long _esigcode-_sigcode
435 /**********************************************************************
437 * Recover the bootinfo passed to us from the boot program
442 * This code is called in different ways depending on what loaded
443 * and started the kernel. This is used to detect how we get the
444 * arguments from the other code and what we do with them.
446 * Old disk boot blocks:
447 * (*btext)(howto, bootdev, cyloffset, esym);
448 * [return address == 0, and can NOT be returned to]
449 * [cyloffset was not supported by the FreeBSD boot code
450 * and always passed in as 0]
451 * [esym is also known as total in the boot code, and
452 * was never properly supported by the FreeBSD boot code]
454 * Old diskless netboot code:
455 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0);
456 * [return address != 0, and can NOT be returned to]
457 * If we are being booted by this code it will NOT work,
458 * so we are just going to halt if we find this case.
460 * New uniform boot code:
461 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo)
462 * [return address != 0, and can be returned to]
464 * There may seem to be a lot of wasted arguments in here, but
465 * that is so the newer boot code can still load very old kernels
466 * and old boot code can load new kernels.
470 * The old style disk boot blocks fake a frame on the stack and
471 * did an lret to get here. The frame on the stack has a return
478 * We have some form of return address, so this is either the
479 * old diskless netboot code, or the new uniform code. That can
480 * be detected by looking at the 5th argument, if it is 0
481 * we are being booted by the new uniform boot code.
487 * Seems we have been loaded by the old diskless boot code, we
488 * don't stand a chance of running as the diskless structure
489 * changed considerably between the two, so just halt.
494 * We have been loaded by the new uniform boot code.
495 * Let's check the bootinfo version, and if we do not understand
496 * it we return to the loader with a status of 1 to indicate this error
499 movl 28(%ebp),%ebx /* &bootinfo.version */
500 movl BI_VERSION(%ebx),%eax
501 cmpl $1,%eax /* We only understand version 1 */
503 movl $1,%eax /* Return status */
506 * XXX this returns to our caller's caller (as is required) since
507 * we didn't set up a frame and our caller did.
513 * If we have a kernelname copy it in
515 movl BI_KERNELNAME(%ebx),%esi
517 je 2f /* No kernelname */
518 movl $MAXPATHLEN,%ecx /* Brute force!!! */
519 movl $R(_kernelname),%edi
520 cmpb $'/',(%esi) /* Make sure it starts with a slash */
532 * Determine the size of the boot loader's copy of the bootinfo
533 * struct. This is impossible to do properly because old versions
534 * of the struct don't contain a size field and there are 2 old
535 * versions with the same version number.
537 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */
538 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */
539 je got_bi_size /* no, sizeless version */
540 movl BI_SIZE(%ebx),%ecx
544 * Copy the common part of the bootinfo struct
547 movl $R(_bootinfo),%edi
548 cmpl $BOOTINFO_SIZE,%ecx
549 jbe got_common_bi_size
550 movl $BOOTINFO_SIZE,%ecx
559 * If we have a nfs_diskless structure copy it in
561 movl BI_NFS_DISKLESS(%ebx),%esi
564 movl $R(_nfs_diskless),%edi
565 movl $NFSDISKLESS_SIZE,%ecx
569 movl $R(_nfs_diskless_valid),%edi
575 * The old style disk boot.
576 * (*btext)(howto, bootdev, cyloffset, esym);
577 * Note that the newer boot code just falls into here to pick
578 * up howto and bootdev, cyloffset and esym are no longer used
582 movl %eax,R(_boothowto)
584 movl %eax,R(_bootdev)
589 /**********************************************************************
591 * Identify the CPU and initialize anything special about it
596 /* Try to toggle alignment check flag; does not exist on 386. */
613 /* NexGen CPU does not have aligment check flag. */
622 movl $CPU_386,R(_cpu)
627 movl $CPU_NX586,R(_cpu)
628 movl $0x4778654e,R(_cpu_vendor) # store vendor string
629 movl $0x72446e65,R(_cpu_vendor+4)
630 movl $0x6e657669,R(_cpu_vendor+8)
631 movl $0,R(_cpu_vendor+12)
634 try486: /* Try to toggle identification flag; does not exist on early 486s. */
650 movl $CPU_486,R(_cpu)
654 * Cyrix CPUs do not change the undefined flags following
655 * execution of the divide instruction which divides 5 by 2.
657 * Note: CPUID is enabled on M2, so it passes another way.
667 jmp 3f /* You may use Intel CPU. */
672 * IBM Bluelighting CPU also doesn't change the undefined flags.
673 * Because IBM doesn't disclose the information for Bluelighting
674 * CPU, we couldn't distinguish it from Cyrix's (including IBM
675 * brand of Cyrix CPUs).
677 movl $0x69727943,R(_cpu_vendor) # store vendor string
678 movl $0x736e4978,R(_cpu_vendor+4)
679 movl $0x64616574,R(_cpu_vendor+8)
682 trycpuid: /* Use the `cpuid' instruction. */
684 .byte 0x0f,0xa2 # cpuid 0
685 movl %eax,R(_cpu_high) # highest capability
686 movl %ebx,R(_cpu_vendor) # store vendor string
687 movl %edx,R(_cpu_vendor+4)
688 movl %ecx,R(_cpu_vendor+8)
689 movb $0,R(_cpu_vendor+12)
692 .byte 0x0f,0xa2 # cpuid 1
693 movl %eax,R(_cpu_id) # store cpu_id
694 movl %edx,R(_cpu_feature) # store cpu_feature
695 rorl $8,%eax # extract family type
700 /* less than Pentium; must be 486 */
701 movl $CPU_486,R(_cpu)
707 movl $CPU_586,R(_cpu)
710 /* Greater than Pentium...call it a Pentium Pro */
711 movl $CPU_686,R(_cpu)
716 /**********************************************************************
718 * Create the first page directory and its page tables.
724 testl $CPUID_PGE, R(_cpu_feature)
731 /* Find end of kernel image (rounded up to a page boundary). */
734 /* include symbols if loaded and useful */
736 movl R(_bootinfo+BI_ESYMTAB),%edi
741 addl %edi,R(_bootinfo+BI_SYMTAB)
742 addl %edi,R(_bootinfo+BI_ESYMTAB)
746 /* If we are told where the end of the kernel space is, believe it. */
747 movl R(_bootinfo+BI_KERNEND),%edi
754 andl $~PAGE_MASK,%esi
755 movl %esi,R(_KERNend) /* save end of kernel */
756 movl %esi,R(physfree) /* next free page is at end of kernel */
758 /* Allocate Kernel Page Tables */
760 movl %esi,R(_KPTphys)
762 /* Allocate Page Table Directory */
764 movl %esi,R(_IdlePTD)
766 /* Allocate UPAGES */
770 movl %esi, R(_proc0paddr)
772 ALLOCPAGES(1) /* vm86/bios stack */
773 movl %esi,R(vm86phystk)
775 ALLOCPAGES(3) /* pgtable + ext + IOPAGES */
778 movl %esi, R(_vm86paddr)
781 /* Allocate cpu0's private data page */
785 movl %esi, R(_cpu0prvpage) /* relocated to KVM space */
787 /* Allocate SMP page table page */
791 movl %esi, R(_SMPpt) /* relocated to KVM space */
794 /* Map read-only from zero to the end of the kernel text section */
797 /* If the debugger is present, actually map everything read-write. */
798 cmpl $0,R(_bdb_exists)
804 testl $CPUID_PGE, R(_cpu_feature)
809 2: movl $R(_etext),%ecx
811 shrl $PAGE_SHIFT,%ecx
814 /* Map read-write, data, bss and symbols */
816 addl $PAGE_MASK, %eax
817 andl $~PAGE_MASK, %eax
821 testl $CPUID_PGE, R(_cpu_feature)
826 1: movl R(_KERNend),%ecx
828 shrl $PAGE_SHIFT,%ecx
831 /* Map page directory. */
832 movl R(_IdlePTD), %eax
836 /* Map proc0's UPAGES in the physical way ... */
842 movl $ISA_HOLE_START, %eax
843 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
846 /* Map space for the vm86 region */
847 movl R(vm86phystk), %eax
851 /* Map page 0 into the vm86 page table */
855 fillkpt(R(_vm86pa), $PG_RW|PG_U)
857 /* ...likewise for the ISA hole */
858 movl $ISA_HOLE_START, %eax
859 movl $ISA_HOLE_START>>PAGE_SHIFT, %ebx
860 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
861 fillkpt(R(_vm86pa), $PG_RW|PG_U)
864 /* Map cpu0's private page into global kmem (4K @ cpu0prvpage) */
869 /* Map SMP page table page into global kmem FWIW */
870 movl R(SMPptpa), %eax
874 /* Map the private page into the SMP page table */
876 movl $0, %ebx /* pte offset = 0 */
877 movl $1, %ecx /* one private page coming right up */
878 fillkpt(R(SMPptpa), $PG_RW)
880 /* ... and put the page table table in the pde. */
881 movl R(SMPptpa), %eax
884 fillkpt(R(_IdlePTD), $PG_RW)
886 /* Fakeup VA for the local apic to allow early traps. */
889 movl $(NPTEPG-1), %ebx /* pte offset = NTEPG-1 */
890 movl $1, %ecx /* one private pt coming right up */
891 fillkpt(R(SMPptpa), $PG_RW)
893 /* Initialize mp lock to allow early traps */
897 /* install a pde for temporary double map of bottom of VA */
898 movl R(_KPTphys), %eax
901 fillkpt(R(_IdlePTD), $PG_RW)
903 /* install pde's for pt's */
904 movl R(_KPTphys), %eax
907 fillkpt(R(_IdlePTD), $PG_RW)
909 /* install a pde recursively mapping page directory as a page table */
910 movl R(_IdlePTD), %eax
913 fillkpt(R(_IdlePTD), $PG_RW)
919 cmpl $0,R(_bdb_exists)
920 je bdb_prepare_paging_exit
925 * Copy and convert debugger entries from the bootstrap gdt and idt
926 * to the kernel gdt and idt. Everything is still in low memory.
927 * Tracing continues to work after paging is enabled because the
928 * low memory addresses remain valid until everything is relocated.
929 * However, tracing through the setidt() that initializes the trace
933 movl 2(%esp),%esi /* base address of bootstrap gdt */
935 movl %edi,2(%esp) /* prepare to load kernel gdt */
940 movl $R(_gdt),-8+2(%edi) /* adjust gdt self-ptr */
941 movb $0x92,-8+5(%edi)
945 movl 2(%esp),%esi /* base address of current idt */
946 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */
948 movl %eax,R(bdb_dbg_ljmp+1) /* ... immediate offset ... */
950 movw %ax,R(bdb_dbg_ljmp+5) /* ... and selector for ljmp */
951 movl 24+4(%esi),%eax /* same for bpt descriptor */
953 movl %eax,R(bdb_bpt_ljmp+1)
955 movw %ax,R(bdb_bpt_ljmp+5)
957 movl %edi,2(%esp) /* prepare to load kernel idt */
966 bdb_prepare_paging_exit:
969 /* Relocate debugger gdt entries and gdt and idt pointers. */
972 je bdb_commit_paging_exit
974 movl $_gdt+8*9,%eax /* adjust slots 9-17 */
977 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */
978 addl $8,%eax /* now KERNBASE>>24 */
983 addl $KERNBASE,2(%esp)
986 addl $KERNBASE,2(%esp)
992 bdb_commit_paging_exit:
995 #endif /* BDE_DEBUGGER */