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
37 * $FreeBSD: src/sys/i386/i386/locore.s,v 1.132.2.10 2003/02/03 20:54:49 jhb Exp $
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"
47 #include "opt_nfsroot.h"
49 #include <sys/syscall.h>
50 #include <sys/reboot.h>
52 #include <machine/asmacros.h>
53 #include <machine/cputypes.h>
54 #include <machine/psl.h>
55 #include <machine/pmap.h>
56 #include <machine/specialreg.h>
63 * Note: This version greatly munged to avoid various assembler errors
64 * that may be fixed in newer versions of gas. Perhaps newer versions
65 * will have more pleasant appearance.
69 * PTmap is recursive pagemap at top of virtual address space.
70 * Within PTmap, the page directory can be found (third indirection).
72 .globl _PTmap,_PTD,_PTDpde
73 .set _PTmap,(PTDPTDI << PDRSHIFT)
74 .set _PTD,_PTmap + (PTDPTDI * PAGE_SIZE)
75 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE)
78 * APTmap, APTD is the alternate recursive pagemap.
79 * It's used when modifying another process's page tables.
81 .globl _APTmap,_APTD,_APTDpde
82 .set _APTmap,APTDPTDI << PDRSHIFT
83 .set _APTD,_APTmap + (APTDPTDI * PAGE_SIZE)
84 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE)
87 * Compiled KERNBASE location
90 .set _kernbase,KERNBASE
96 ALIGN_DATA /* just to be sure */
98 .globl HIDENAME(tmpstk)
99 .space 0x2000 /* space for tmpstk - temporary stack */
102 .globl _boothowto,_bootdev
104 .globl _cpu,_cpu_vendor,_cpu_id,_bootinfo
105 .globl _cpu_high, _cpu_feature, _cpu_procinfo
107 _cpu: .long 0 /* are we 386, 386sx, or 486 */
108 _cpu_id: .long 0 /* stepping ID */
109 _cpu_high: .long 0 /* highest arg to CPUID */
110 _cpu_feature: .long 0 /* features */
111 _cpu_procinfo: .long 0 /* brand index / HTT info */
112 _cpu_vendor: .space 20 /* CPU origin code */
113 _bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */
115 _KERNend: .long 0 /* phys addr end of kernel (just after bss) */
116 physfree: .long 0 /* phys addr of next free page */
120 cpu0pp: .long 0 /* phys addr cpu0 private pg */
121 _cpu0prvpage: .long 0 /* relocated version */
124 SMPptpa: .long 0 /* phys addr SMP page table */
125 _SMPpt: .long 0 /* relocated version */
129 _IdlePTD: .long 0 /* phys addr of kernel PTD */
134 _KPTphys: .long 0 /* phys addr of kernel page tables */
137 _proc0paddr: .long 0 /* address of proc 0 address space */
138 p0upa: .long 0 /* phys addr of proc0's UPAGES */
140 vm86phystk: .long 0 /* PA of vm86/bios stack */
142 .globl _vm86paddr, _vm86pa
143 _vm86paddr: .long 0 /* address of vm86 region */
144 _vm86pa: .long 0 /* phys addr of vm86 region */
147 .globl _bdb_exists /* flag to indicate BDE debugger is present */
152 .globl _pc98_system_parameter
153 _pc98_system_parameter:
157 /**********************************************************************
163 #define R(foo) ((foo)-KERNBASE)
165 #define ALLOCPAGES(foo) \
166 movl R(physfree), %esi ; \
167 movl $((foo)*PAGE_SIZE), %eax ; \
169 movl %eax, R(physfree) ; \
171 movl $((foo)*PAGE_SIZE),%ecx ; \
179 * eax = page frame address
180 * ebx = index into page table
181 * ecx = how many pages to map
182 * base = base address of page dir/table
183 * prot = protection bits
185 #define fillkpt(base, prot) \
190 1: movl %eax,(%ebx) ; \
191 addl $PAGE_SIZE,%eax ; /* increment physical address */ \
192 addl $4,%ebx ; /* next pte */ \
197 * eax = physical address
198 * ecx = how many pages to map
199 * prot = protection bits
201 #define fillkptphys(prot) \
203 shrl $PAGE_SHIFT, %ebx ; \
204 fillkpt(R(_KPTphys), prot)
207 /**********************************************************************
209 * This is where the bootblocks start us, set the ball rolling...
212 NON_GPROF_ENTRY(btext)
215 /* save SYSTEM PARAMETER for resume (NS/T or other) */
217 movl $R(_pc98_system_parameter),%edi
224 #ifdef BIOS_STEALS_3K
225 cmpl $0x0375c339,0x95504
227 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */
230 movb $1,R(_bdb_exists)
233 /* Tell the bios to warmboot next time */
237 /* Set up a real frame in case the double return in newboot is executed. */
241 /* Don't trust what the BIOS gives for eflags. */
246 * Don't trust what the BIOS gives for %fs and %gs. Trust the bootstrap
247 * to set %cs, %ds, %es and %ss.
253 call recover_bootinfo
255 /* Get onto a stack that we can trust. */
257 * XXX this step is delayed in case recover_bootinfo needs to return via
258 * the old stack, but it need not be, since recover_bootinfo actually
259 * returns via the old frame.
261 movl $R(HIDENAME(tmpstk)),%esp
264 /* pc98_machine_type & M_EPSON_PC98 */
265 testb $0x02,R(_pc98_system_parameter)+220
267 /* epson_machine_id <= 0x0b */
268 cmpb $0x0b,R(_pc98_system_parameter)+224
271 /* count up memory */
272 movl $0x100000,%eax /* next, talley remaining memory */
273 movl $0xFFF-0x100,%ecx
274 1: movl 0(%eax),%ebx /* save location to check */
275 movl $0xa55a5aa5,0(%eax) /* write test pattern */
276 cmpl $0xa55a5aa5,0(%eax) /* does not check yet for rollover */
278 movl %ebx,0(%eax) /* restore memory */
281 2: subl $0x100000,%eax
283 movb %al,R(_pc98_system_parameter)+1
286 movw R(_pc98_system_parameter+0x86),%ax
294 * XXX this should be done a little earlier.
296 * XXX we don't check that there is memory for our bss and page tables
299 * XXX the boot program somewhat bogusly clears the bss. We still have
300 * to do it in case we were unzipped by kzipboot. Then the boot program
301 * only clears kzipboot's bss.
303 * XXX the gdt and idt are still somewhere in the boot program. We
304 * depend on the convention that the boot program is below 1MB and we
305 * are above 1MB to keep the gdt and idt away from the bss and page
306 * tables. The idt is only used if BDE_DEBUGGER is enabled.
316 call create_pagetables
319 * If the CPU has support for VME, turn it on.
321 testl $CPUID_VME, R(_cpu_feature)
330 * Adjust as much as possible for paging before enabling paging so that the
331 * adjustments can be traced.
333 call bdb_prepare_paging
336 /* Now enable paging */
337 movl R(_IdlePTD), %eax
338 movl %eax,%cr3 /* load ptd addr into mmu */
339 movl %cr0,%eax /* get control word */
340 orl $CR0_PE|CR0_PG,%eax /* enable paging */
341 movl %eax,%cr0 /* and let's page NOW! */
345 * Complete the adjustments for paging so that we can keep tracing through
346 * initi386() after the low (physical) addresses for the gdt and idt become
349 call bdb_commit_paging
352 pushl $begin /* jump to high virtualized address */
355 /* now running relocated at KERNBASE where the system is linked to run */
357 /* set up bootstrap stack */
358 movl _proc0paddr,%esp /* location of in-kernel pages */
359 addl $UPAGES*PAGE_SIZE,%esp /* bootstrap stack end location */
360 xorl %eax,%eax /* mark end of frames */
362 movl _proc0paddr,%eax
364 movl %esi,PCB_CR3(%eax)
366 testl $CPUID_PGE, R(_cpu_feature)
374 pushl %esi /* value of first for init386(first) */
375 call _init386 /* wire 386 chip for unix operation */
378 call _mi_startup /* autoconfiguration, mountroot etc */
380 hlt /* never returns to here */
383 * Signal trampoline, copied to top of user stack
385 NON_GPROF_ENTRY(sigcode)
386 call *SIGF_HANDLER(%esp) /* call signal handler */
387 lea SIGF_UC(%esp),%eax /* get ucontext_t */
389 testl $PSL_VM,UC_EFLAGS(%eax)
391 movl UC_GS(%eax),%gs /* restore %gs */
393 movl $SYS_sigreturn,%eax
394 pushl %eax /* junk to fake return addr. */
395 int $0x80 /* enter kernel with args */
400 call *SIGF_HANDLER(%esp) /* call signal handler */
401 lea SIGF_SC(%esp),%eax /* get sigcontext */
403 testl $PSL_VM,SC_PS(%eax)
405 movl SC_GS(%eax),%gs /* restore %gs */
407 movl $0x01d516,SC_TRAPNO(%eax) /* magic: 0ldSiG */
408 movl $SYS_sigreturn,%eax
409 pushl %eax /* junk to fake return addr. */
410 int $0x80 /* enter kernel with args */
417 .globl _szsigcode, _szosigcode
419 .long _esigcode-_sigcode
421 .long _esigcode-_osigcode
424 /**********************************************************************
426 * Recover the bootinfo passed to us from the boot program
431 * This code is called in different ways depending on what loaded
432 * and started the kernel. This is used to detect how we get the
433 * arguments from the other code and what we do with them.
435 * Old disk boot blocks:
436 * (*btext)(howto, bootdev, cyloffset, esym);
437 * [return address == 0, and can NOT be returned to]
438 * [cyloffset was not supported by the FreeBSD boot code
439 * and always passed in as 0]
440 * [esym is also known as total in the boot code, and
441 * was never properly supported by the FreeBSD boot code]
443 * Old diskless netboot code:
444 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0);
445 * [return address != 0, and can NOT be returned to]
446 * If we are being booted by this code it will NOT work,
447 * so we are just going to halt if we find this case.
449 * New uniform boot code:
450 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo)
451 * [return address != 0, and can be returned to]
453 * There may seem to be a lot of wasted arguments in here, but
454 * that is so the newer boot code can still load very old kernels
455 * and old boot code can load new kernels.
459 * The old style disk boot blocks fake a frame on the stack and
460 * did an lret to get here. The frame on the stack has a return
467 * We have some form of return address, so this is either the
468 * old diskless netboot code, or the new uniform code. That can
469 * be detected by looking at the 5th argument, if it is 0
470 * we are being booted by the new uniform boot code.
476 * Seems we have been loaded by the old diskless boot code, we
477 * don't stand a chance of running as the diskless structure
478 * changed considerably between the two, so just halt.
483 * We have been loaded by the new uniform boot code.
484 * Let's check the bootinfo version, and if we do not understand
485 * it we return to the loader with a status of 1 to indicate this error
488 movl 28(%ebp),%ebx /* &bootinfo.version */
489 movl BI_VERSION(%ebx),%eax
490 cmpl $1,%eax /* We only understand version 1 */
492 movl $1,%eax /* Return status */
495 * XXX this returns to our caller's caller (as is required) since
496 * we didn't set up a frame and our caller did.
502 * If we have a kernelname copy it in
504 movl BI_KERNELNAME(%ebx),%esi
506 je 2f /* No kernelname */
507 movl $MAXPATHLEN,%ecx /* Brute force!!! */
508 movl $R(_kernelname),%edi
509 cmpb $'/',(%esi) /* Make sure it starts with a slash */
521 * Determine the size of the boot loader's copy of the bootinfo
522 * struct. This is impossible to do properly because old versions
523 * of the struct don't contain a size field and there are 2 old
524 * versions with the same version number.
526 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */
527 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */
528 je got_bi_size /* no, sizeless version */
529 movl BI_SIZE(%ebx),%ecx
533 * Copy the common part of the bootinfo struct
536 movl $R(_bootinfo),%edi
537 cmpl $BOOTINFO_SIZE,%ecx
538 jbe got_common_bi_size
539 movl $BOOTINFO_SIZE,%ecx
548 * If we have a nfs_diskless structure copy it in
550 movl BI_NFS_DISKLESS(%ebx),%esi
553 movl $R(_nfs_diskless),%edi
554 movl $NFSDISKLESS_SIZE,%ecx
558 movl $R(_nfs_diskless_valid),%edi
564 * The old style disk boot.
565 * (*btext)(howto, bootdev, cyloffset, esym);
566 * Note that the newer boot code just falls into here to pick
567 * up howto and bootdev, cyloffset and esym are no longer used
571 movl %eax,R(_boothowto)
573 movl %eax,R(_bootdev)
578 /**********************************************************************
580 * Identify the CPU and initialize anything special about it
585 /* Try to toggle alignment check flag; does not exist on 386. */
602 /* NexGen CPU does not have aligment check flag. */
611 movl $CPU_386,R(_cpu)
616 movl $CPU_NX586,R(_cpu)
617 movl $0x4778654e,R(_cpu_vendor) # store vendor string
618 movl $0x72446e65,R(_cpu_vendor+4)
619 movl $0x6e657669,R(_cpu_vendor+8)
620 movl $0,R(_cpu_vendor+12)
623 try486: /* Try to toggle identification flag; does not exist on early 486s. */
639 movl $CPU_486,R(_cpu)
643 * Cyrix CPUs do not change the undefined flags following
644 * execution of the divide instruction which divides 5 by 2.
646 * Note: CPUID is enabled on M2, so it passes another way.
656 jmp 3f /* You may use Intel CPU. */
661 * IBM Bluelighting CPU also doesn't change the undefined flags.
662 * Because IBM doesn't disclose the information for Bluelighting
663 * CPU, we couldn't distinguish it from Cyrix's (including IBM
664 * brand of Cyrix CPUs).
666 movl $0x69727943,R(_cpu_vendor) # store vendor string
667 movl $0x736e4978,R(_cpu_vendor+4)
668 movl $0x64616574,R(_cpu_vendor+8)
671 trycpuid: /* Use the `cpuid' instruction. */
674 movl %eax,R(_cpu_high) # highest capability
675 movl %ebx,R(_cpu_vendor) # store vendor string
676 movl %edx,R(_cpu_vendor+4)
677 movl %ecx,R(_cpu_vendor+8)
678 movb $0,R(_cpu_vendor+12)
682 movl %eax,R(_cpu_id) # store cpu_id
683 movl %ebx,R(_cpu_procinfo) # store cpu_procinfo
684 movl %edx,R(_cpu_feature) # store cpu_feature
685 rorl $8,%eax # extract family type
690 /* less than Pentium; must be 486 */
691 movl $CPU_486,R(_cpu)
697 movl $CPU_586,R(_cpu)
700 /* Greater than Pentium...call it a Pentium Pro */
701 movl $CPU_686,R(_cpu)
706 /**********************************************************************
708 * Create the first page directory and its page tables.
714 /* Find end of kernel image (rounded up to a page boundary). */
717 /* Include symbols, if any. */
718 movl R(_bootinfo+BI_ESYMTAB),%edi
723 addl %edi,R(_bootinfo+BI_SYMTAB)
724 addl %edi,R(_bootinfo+BI_ESYMTAB)
727 /* If we are told where the end of the kernel space is, believe it. */
728 movl R(_bootinfo+BI_KERNEND),%edi
735 andl $~PAGE_MASK,%esi
736 movl %esi,R(_KERNend) /* save end of kernel */
737 movl %esi,R(physfree) /* next free page is at end of kernel */
739 /* Allocate Kernel Page Tables */
741 movl %esi,R(_KPTphys)
743 /* Allocate Page Table Directory */
745 movl %esi,R(_IdlePTD)
747 /* Allocate UPAGES */
751 movl %esi, R(_proc0paddr)
753 ALLOCPAGES(1) /* vm86/bios stack */
754 movl %esi,R(vm86phystk)
756 ALLOCPAGES(3) /* pgtable + ext + IOPAGES */
759 movl %esi, R(_vm86paddr)
762 /* Allocate cpu0's private data page */
766 movl %esi, R(_cpu0prvpage) /* relocated to KVM space */
768 /* Allocate SMP page table page */
772 movl %esi, R(_SMPpt) /* relocated to KVM space */
775 /* Map read-only from zero to the end of the kernel text section */
778 /* If the debugger is present, actually map everything read-write. */
779 cmpl $0,R(_bdb_exists)
785 testl $CPUID_PGE, R(_cpu_feature)
790 2: movl $R(_etext),%ecx
792 shrl $PAGE_SHIFT,%ecx
795 /* Map read-write, data, bss and symbols */
797 addl $PAGE_MASK, %eax
798 andl $~PAGE_MASK, %eax
802 testl $CPUID_PGE, R(_cpu_feature)
807 1: movl R(_KERNend),%ecx
809 shrl $PAGE_SHIFT,%ecx
812 /* Map page directory. */
813 movl R(_IdlePTD), %eax
817 /* Map proc0's UPAGES in the physical way ... */
823 movl $ISA_HOLE_START, %eax
824 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
827 /* Map space for the vm86 region */
828 movl R(vm86phystk), %eax
832 /* Map page 0 into the vm86 page table */
836 fillkpt(R(_vm86pa), $PG_RW|PG_U)
838 /* ...likewise for the ISA hole */
839 movl $ISA_HOLE_START, %eax
840 movl $ISA_HOLE_START>>PAGE_SHIFT, %ebx
841 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
842 fillkpt(R(_vm86pa), $PG_RW|PG_U)
845 /* Map cpu0's private page into global kmem (4K @ cpu0prvpage) */
850 /* Map SMP page table page into global kmem FWIW */
851 movl R(SMPptpa), %eax
855 /* Map the private page into the SMP page table */
857 movl $0, %ebx /* pte offset = 0 */
858 movl $1, %ecx /* one private page coming right up */
859 fillkpt(R(SMPptpa), $PG_RW)
861 /* ... and put the page table table in the pde. */
862 movl R(SMPptpa), %eax
865 fillkpt(R(_IdlePTD), $PG_RW)
867 /* Fakeup VA for the local apic to allow early traps. */
870 movl $(NPTEPG-1), %ebx /* pte offset = NTEPG-1 */
871 movl $1, %ecx /* one private pt coming right up */
872 fillkpt(R(SMPptpa), $PG_RW)
874 /* Initialize mp lock to allow early traps */
878 /* install a pde for temporary double map of bottom of VA */
879 movl R(_KPTphys), %eax
882 fillkpt(R(_IdlePTD), $PG_RW)
884 /* install pde's for pt's */
885 movl R(_KPTphys), %eax
888 fillkpt(R(_IdlePTD), $PG_RW)
890 /* install a pde recursively mapping page directory as a page table */
891 movl R(_IdlePTD), %eax
894 fillkpt(R(_IdlePTD), $PG_RW)
900 cmpl $0,R(_bdb_exists)
901 je bdb_prepare_paging_exit
906 * Copy and convert debugger entries from the bootstrap gdt and idt
907 * to the kernel gdt and idt. Everything is still in low memory.
908 * Tracing continues to work after paging is enabled because the
909 * low memory addresses remain valid until everything is relocated.
910 * However, tracing through the setidt() that initializes the trace
914 movl 2(%esp),%esi /* base address of bootstrap gdt */
916 movl %edi,2(%esp) /* prepare to load kernel gdt */
921 movl $R(_gdt),-8+2(%edi) /* adjust gdt self-ptr */
922 movb $0x92,-8+5(%edi)
926 movl 2(%esp),%esi /* base address of current idt */
927 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */
929 movl %eax,R(bdb_dbg_ljmp+1) /* ... immediate offset ... */
931 movw %ax,R(bdb_dbg_ljmp+5) /* ... and selector for ljmp */
932 movl 24+4(%esi),%eax /* same for bpt descriptor */
934 movl %eax,R(bdb_bpt_ljmp+1)
936 movw %ax,R(bdb_bpt_ljmp+5)
938 movl %edi,2(%esp) /* prepare to load kernel idt */
947 bdb_prepare_paging_exit:
950 /* Relocate debugger gdt entries and gdt and idt pointers. */
953 je bdb_commit_paging_exit
955 movl $_gdt+8*9,%eax /* adjust slots 9-17 */
958 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */
959 addl $8,%eax /* now KERNBASE>>24 */
964 addl $KERNBASE,2(%esp)
967 addl $KERNBASE,2(%esp)
973 bdb_commit_paging_exit:
976 #endif /* BDE_DEBUGGER */