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 $
38 * $DragonFly: src/sys/i386/i386/Attic/locore.s,v 1.3 2003/06/18 18:29:55 dillon Exp $
40 * originally from: locore.s, by William F. Jolitz
42 * Substantially rewritten by David Greenman, Rod Grimes,
43 * Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp
47 #include "opt_bootp.h"
48 #include "opt_nfsroot.h"
50 #include <sys/syscall.h>
51 #include <sys/reboot.h>
53 #include <machine/asmacros.h>
54 #include <machine/cputypes.h>
55 #include <machine/psl.h>
56 #include <machine/pmap.h>
57 #include <machine/specialreg.h>
64 * Note: This version greatly munged to avoid various assembler errors
65 * that may be fixed in newer versions of gas. Perhaps newer versions
66 * will have more pleasant appearance.
70 * PTmap is recursive pagemap at top of virtual address space.
71 * Within PTmap, the page directory can be found (third indirection).
73 .globl _PTmap,_PTD,_PTDpde
74 .set _PTmap,(PTDPTDI << PDRSHIFT)
75 .set _PTD,_PTmap + (PTDPTDI * PAGE_SIZE)
76 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE)
79 * APTmap, APTD is the alternate recursive pagemap.
80 * It's used when modifying another process's page tables.
82 .globl _APTmap,_APTD,_APTDpde
83 .set _APTmap,APTDPTDI << PDRSHIFT
84 .set _APTD,_APTmap + (APTDPTDI * PAGE_SIZE)
85 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE)
88 * Compiled KERNBASE location
91 .set _kernbase,KERNBASE
97 ALIGN_DATA /* just to be sure */
99 .globl HIDENAME(tmpstk)
100 .space 0x2000 /* space for tmpstk - temporary stack */
103 .globl _boothowto,_bootdev
105 .globl _cpu,_cpu_vendor,_cpu_id,_bootinfo
106 .globl _cpu_high, _cpu_feature, _cpu_procinfo
108 _cpu: .long 0 /* are we 386, 386sx, or 486 */
109 _cpu_id: .long 0 /* stepping ID */
110 _cpu_high: .long 0 /* highest arg to CPUID */
111 _cpu_feature: .long 0 /* features */
112 _cpu_procinfo: .long 0 /* brand index / HTT info */
113 _cpu_vendor: .space 20 /* CPU origin code */
114 _bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */
116 _KERNend: .long 0 /* phys addr end of kernel (just after bss) */
117 physfree: .long 0 /* phys addr of next free page */
121 cpu0pp: .long 0 /* phys addr cpu0 private pg */
122 _cpu0prvpage: .long 0 /* relocated version */
125 SMPptpa: .long 0 /* phys addr SMP page table */
126 _SMPpt: .long 0 /* relocated version */
130 _IdlePTD: .long 0 /* phys addr of kernel PTD */
135 _KPTphys: .long 0 /* phys addr of kernel page tables */
138 _proc0paddr: .long 0 /* address of proc 0 address space */
139 p0upa: .long 0 /* phys addr of proc0's UPAGES */
141 vm86phystk: .long 0 /* PA of vm86/bios stack */
143 .globl _vm86paddr, _vm86pa
144 _vm86paddr: .long 0 /* address of vm86 region */
145 _vm86pa: .long 0 /* phys addr of vm86 region */
148 .globl _bdb_exists /* flag to indicate BDE debugger is present */
153 .globl _pc98_system_parameter
154 _pc98_system_parameter:
158 /**********************************************************************
164 #define R(foo) ((foo)-KERNBASE)
166 #define ALLOCPAGES(foo) \
167 movl R(physfree), %esi ; \
168 movl $((foo)*PAGE_SIZE), %eax ; \
170 movl %eax, R(physfree) ; \
172 movl $((foo)*PAGE_SIZE),%ecx ; \
180 * eax = page frame address
181 * ebx = index into page table
182 * ecx = how many pages to map
183 * base = base address of page dir/table
184 * prot = protection bits
186 #define fillkpt(base, prot) \
191 1: movl %eax,(%ebx) ; \
192 addl $PAGE_SIZE,%eax ; /* increment physical address */ \
193 addl $4,%ebx ; /* next pte */ \
198 * eax = physical address
199 * ecx = how many pages to map
200 * prot = protection bits
202 #define fillkptphys(prot) \
204 shrl $PAGE_SHIFT, %ebx ; \
205 fillkpt(R(_KPTphys), prot)
208 /**********************************************************************
210 * This is where the bootblocks start us, set the ball rolling...
213 NON_GPROF_ENTRY(btext)
216 /* save SYSTEM PARAMETER for resume (NS/T or other) */
218 movl $R(_pc98_system_parameter),%edi
225 #ifdef BIOS_STEALS_3K
226 cmpl $0x0375c339,0x95504
228 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */
231 movb $1,R(_bdb_exists)
234 /* Tell the bios to warmboot next time */
238 /* Set up a real frame in case the double return in newboot is executed. */
242 /* Don't trust what the BIOS gives for eflags. */
247 * Don't trust what the BIOS gives for %fs and %gs. Trust the bootstrap
248 * to set %cs, %ds, %es and %ss.
254 call recover_bootinfo
256 /* Get onto a stack that we can trust. */
258 * XXX this step is delayed in case recover_bootinfo needs to return via
259 * the old stack, but it need not be, since recover_bootinfo actually
260 * returns via the old frame.
262 movl $R(HIDENAME(tmpstk)),%esp
265 /* pc98_machine_type & M_EPSON_PC98 */
266 testb $0x02,R(_pc98_system_parameter)+220
268 /* epson_machine_id <= 0x0b */
269 cmpb $0x0b,R(_pc98_system_parameter)+224
272 /* count up memory */
273 movl $0x100000,%eax /* next, talley remaining memory */
274 movl $0xFFF-0x100,%ecx
275 1: movl 0(%eax),%ebx /* save location to check */
276 movl $0xa55a5aa5,0(%eax) /* write test pattern */
277 cmpl $0xa55a5aa5,0(%eax) /* does not check yet for rollover */
279 movl %ebx,0(%eax) /* restore memory */
282 2: subl $0x100000,%eax
284 movb %al,R(_pc98_system_parameter)+1
287 movw R(_pc98_system_parameter+0x86),%ax
295 * XXX this should be done a little earlier.
297 * XXX we don't check that there is memory for our bss and page tables
300 * XXX the boot program somewhat bogusly clears the bss. We still have
301 * to do it in case we were unzipped by kzipboot. Then the boot program
302 * only clears kzipboot's bss.
304 * XXX the gdt and idt are still somewhere in the boot program. We
305 * depend on the convention that the boot program is below 1MB and we
306 * are above 1MB to keep the gdt and idt away from the bss and page
307 * tables. The idt is only used if BDE_DEBUGGER is enabled.
317 call create_pagetables
320 * If the CPU has support for VME, turn it on.
322 testl $CPUID_VME, R(_cpu_feature)
331 * Adjust as much as possible for paging before enabling paging so that the
332 * adjustments can be traced.
334 call bdb_prepare_paging
337 /* Now enable paging */
338 movl R(_IdlePTD), %eax
339 movl %eax,%cr3 /* load ptd addr into mmu */
340 movl %cr0,%eax /* get control word */
341 orl $CR0_PE|CR0_PG,%eax /* enable paging */
342 movl %eax,%cr0 /* and let's page NOW! */
346 * Complete the adjustments for paging so that we can keep tracing through
347 * initi386() after the low (physical) addresses for the gdt and idt become
350 call bdb_commit_paging
353 pushl $begin /* jump to high virtualized address */
356 /* now running relocated at KERNBASE where the system is linked to run */
359 * set up the bootstrap stack. The pcb sits at the end of the
362 /* set up bootstrap stack */
363 movl _proc0paddr,%esp /* location of in-kernel pages */
364 addl $UPAGES*PAGE_SIZE-PCB_SIZE,%esp
365 xorl %eax,%eax /* mark end of frames */
367 /*movl _proc0paddr,%eax*/
369 movl %esi,PCB_CR3(%esp)
371 testl $CPUID_PGE, R(_cpu_feature)
379 pushl %esi /* value of first for init386(first) */
380 call _init386 /* wire 386 chip for unix operation */
383 call _mi_startup /* autoconfiguration, mountroot etc */
385 hlt /* never returns to here */
388 * Signal trampoline, copied to top of user stack
390 NON_GPROF_ENTRY(sigcode)
391 call *SIGF_HANDLER(%esp) /* call signal handler */
392 lea SIGF_UC(%esp),%eax /* get ucontext_t */
394 testl $PSL_VM,UC_EFLAGS(%eax)
396 movl UC_GS(%eax),%gs /* restore %gs */
398 movl $SYS_sigreturn,%eax
399 pushl %eax /* junk to fake return addr. */
400 int $0x80 /* enter kernel with args */
405 call *SIGF_HANDLER(%esp) /* call signal handler */
406 lea SIGF_SC(%esp),%eax /* get sigcontext */
408 testl $PSL_VM,SC_PS(%eax)
410 movl SC_GS(%eax),%gs /* restore %gs */
412 movl $0x01d516,SC_TRAPNO(%eax) /* magic: 0ldSiG */
413 movl $SYS_sigreturn,%eax
414 pushl %eax /* junk to fake return addr. */
415 int $0x80 /* enter kernel with args */
422 .globl _szsigcode, _szosigcode
424 .long _esigcode-_sigcode
426 .long _esigcode-_osigcode
429 /**********************************************************************
431 * Recover the bootinfo passed to us from the boot program
436 * This code is called in different ways depending on what loaded
437 * and started the kernel. This is used to detect how we get the
438 * arguments from the other code and what we do with them.
440 * Old disk boot blocks:
441 * (*btext)(howto, bootdev, cyloffset, esym);
442 * [return address == 0, and can NOT be returned to]
443 * [cyloffset was not supported by the FreeBSD boot code
444 * and always passed in as 0]
445 * [esym is also known as total in the boot code, and
446 * was never properly supported by the FreeBSD boot code]
448 * Old diskless netboot code:
449 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0);
450 * [return address != 0, and can NOT be returned to]
451 * If we are being booted by this code it will NOT work,
452 * so we are just going to halt if we find this case.
454 * New uniform boot code:
455 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo)
456 * [return address != 0, and can be returned to]
458 * There may seem to be a lot of wasted arguments in here, but
459 * that is so the newer boot code can still load very old kernels
460 * and old boot code can load new kernels.
464 * The old style disk boot blocks fake a frame on the stack and
465 * did an lret to get here. The frame on the stack has a return
472 * We have some form of return address, so this is either the
473 * old diskless netboot code, or the new uniform code. That can
474 * be detected by looking at the 5th argument, if it is 0
475 * we are being booted by the new uniform boot code.
481 * Seems we have been loaded by the old diskless boot code, we
482 * don't stand a chance of running as the diskless structure
483 * changed considerably between the two, so just halt.
488 * We have been loaded by the new uniform boot code.
489 * Let's check the bootinfo version, and if we do not understand
490 * it we return to the loader with a status of 1 to indicate this error
493 movl 28(%ebp),%ebx /* &bootinfo.version */
494 movl BI_VERSION(%ebx),%eax
495 cmpl $1,%eax /* We only understand version 1 */
497 movl $1,%eax /* Return status */
500 * XXX this returns to our caller's caller (as is required) since
501 * we didn't set up a frame and our caller did.
507 * If we have a kernelname copy it in
509 movl BI_KERNELNAME(%ebx),%esi
511 je 2f /* No kernelname */
512 movl $MAXPATHLEN,%ecx /* Brute force!!! */
513 movl $R(_kernelname),%edi
514 cmpb $'/',(%esi) /* Make sure it starts with a slash */
526 * Determine the size of the boot loader's copy of the bootinfo
527 * struct. This is impossible to do properly because old versions
528 * of the struct don't contain a size field and there are 2 old
529 * versions with the same version number.
531 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */
532 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */
533 je got_bi_size /* no, sizeless version */
534 movl BI_SIZE(%ebx),%ecx
538 * Copy the common part of the bootinfo struct
541 movl $R(_bootinfo),%edi
542 cmpl $BOOTINFO_SIZE,%ecx
543 jbe got_common_bi_size
544 movl $BOOTINFO_SIZE,%ecx
553 * If we have a nfs_diskless structure copy it in
555 movl BI_NFS_DISKLESS(%ebx),%esi
558 movl $R(_nfs_diskless),%edi
559 movl $NFSDISKLESS_SIZE,%ecx
563 movl $R(_nfs_diskless_valid),%edi
569 * The old style disk boot.
570 * (*btext)(howto, bootdev, cyloffset, esym);
571 * Note that the newer boot code just falls into here to pick
572 * up howto and bootdev, cyloffset and esym are no longer used
576 movl %eax,R(_boothowto)
578 movl %eax,R(_bootdev)
583 /**********************************************************************
585 * Identify the CPU and initialize anything special about it
590 /* Try to toggle alignment check flag; does not exist on 386. */
607 /* NexGen CPU does not have aligment check flag. */
616 movl $CPU_386,R(_cpu)
621 movl $CPU_NX586,R(_cpu)
622 movl $0x4778654e,R(_cpu_vendor) # store vendor string
623 movl $0x72446e65,R(_cpu_vendor+4)
624 movl $0x6e657669,R(_cpu_vendor+8)
625 movl $0,R(_cpu_vendor+12)
628 try486: /* Try to toggle identification flag; does not exist on early 486s. */
644 movl $CPU_486,R(_cpu)
648 * Cyrix CPUs do not change the undefined flags following
649 * execution of the divide instruction which divides 5 by 2.
651 * Note: CPUID is enabled on M2, so it passes another way.
661 jmp 3f /* You may use Intel CPU. */
666 * IBM Bluelighting CPU also doesn't change the undefined flags.
667 * Because IBM doesn't disclose the information for Bluelighting
668 * CPU, we couldn't distinguish it from Cyrix's (including IBM
669 * brand of Cyrix CPUs).
671 movl $0x69727943,R(_cpu_vendor) # store vendor string
672 movl $0x736e4978,R(_cpu_vendor+4)
673 movl $0x64616574,R(_cpu_vendor+8)
676 trycpuid: /* Use the `cpuid' instruction. */
679 movl %eax,R(_cpu_high) # highest capability
680 movl %ebx,R(_cpu_vendor) # store vendor string
681 movl %edx,R(_cpu_vendor+4)
682 movl %ecx,R(_cpu_vendor+8)
683 movb $0,R(_cpu_vendor+12)
687 movl %eax,R(_cpu_id) # store cpu_id
688 movl %ebx,R(_cpu_procinfo) # store cpu_procinfo
689 movl %edx,R(_cpu_feature) # store cpu_feature
690 rorl $8,%eax # extract family type
695 /* less than Pentium; must be 486 */
696 movl $CPU_486,R(_cpu)
702 movl $CPU_586,R(_cpu)
705 /* Greater than Pentium...call it a Pentium Pro */
706 movl $CPU_686,R(_cpu)
711 /**********************************************************************
713 * Create the first page directory and its page tables.
719 /* Find end of kernel image (rounded up to a page boundary). */
722 /* Include symbols, if any. */
723 movl R(_bootinfo+BI_ESYMTAB),%edi
728 addl %edi,R(_bootinfo+BI_SYMTAB)
729 addl %edi,R(_bootinfo+BI_ESYMTAB)
732 /* If we are told where the end of the kernel space is, believe it. */
733 movl R(_bootinfo+BI_KERNEND),%edi
740 andl $~PAGE_MASK,%esi
741 movl %esi,R(_KERNend) /* save end of kernel */
742 movl %esi,R(physfree) /* next free page is at end of kernel */
744 /* Allocate Kernel Page Tables */
746 movl %esi,R(_KPTphys)
748 /* Allocate Page Table Directory */
750 movl %esi,R(_IdlePTD)
752 /* Allocate UPAGES */
756 movl %esi, R(_proc0paddr)
758 ALLOCPAGES(1) /* vm86/bios stack */
759 movl %esi,R(vm86phystk)
761 ALLOCPAGES(3) /* pgtable + ext + IOPAGES */
764 movl %esi, R(_vm86paddr)
767 /* Allocate cpu0's private data page */
771 movl %esi, R(_cpu0prvpage) /* relocated to KVM space */
773 /* Allocate SMP page table page */
777 movl %esi, R(_SMPpt) /* relocated to KVM space */
780 /* Map read-only from zero to the end of the kernel text section */
783 /* If the debugger is present, actually map everything read-write. */
784 cmpl $0,R(_bdb_exists)
790 testl $CPUID_PGE, R(_cpu_feature)
795 2: movl $R(_etext),%ecx
797 shrl $PAGE_SHIFT,%ecx
800 /* Map read-write, data, bss and symbols */
802 addl $PAGE_MASK, %eax
803 andl $~PAGE_MASK, %eax
807 testl $CPUID_PGE, R(_cpu_feature)
812 1: movl R(_KERNend),%ecx
814 shrl $PAGE_SHIFT,%ecx
817 /* Map page directory. */
818 movl R(_IdlePTD), %eax
822 /* Map proc0's UPAGES in the physical way ... */
828 movl $ISA_HOLE_START, %eax
829 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
832 /* Map space for the vm86 region */
833 movl R(vm86phystk), %eax
837 /* Map page 0 into the vm86 page table */
841 fillkpt(R(_vm86pa), $PG_RW|PG_U)
843 /* ...likewise for the ISA hole */
844 movl $ISA_HOLE_START, %eax
845 movl $ISA_HOLE_START>>PAGE_SHIFT, %ebx
846 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
847 fillkpt(R(_vm86pa), $PG_RW|PG_U)
850 /* Map cpu0's private page into global kmem (4K @ cpu0prvpage) */
855 /* Map SMP page table page into global kmem FWIW */
856 movl R(SMPptpa), %eax
860 /* Map the private page into the SMP page table */
862 movl $0, %ebx /* pte offset = 0 */
863 movl $1, %ecx /* one private page coming right up */
864 fillkpt(R(SMPptpa), $PG_RW)
866 /* ... and put the page table table in the pde. */
867 movl R(SMPptpa), %eax
870 fillkpt(R(_IdlePTD), $PG_RW)
872 /* Fakeup VA for the local apic to allow early traps. */
875 movl $(NPTEPG-1), %ebx /* pte offset = NTEPG-1 */
876 movl $1, %ecx /* one private pt coming right up */
877 fillkpt(R(SMPptpa), $PG_RW)
879 /* Initialize mp lock to allow early traps */
883 /* install a pde for temporary double map of bottom of VA */
884 movl R(_KPTphys), %eax
887 fillkpt(R(_IdlePTD), $PG_RW)
889 /* install pde's for pt's */
890 movl R(_KPTphys), %eax
893 fillkpt(R(_IdlePTD), $PG_RW)
895 /* install a pde recursively mapping page directory as a page table */
896 movl R(_IdlePTD), %eax
899 fillkpt(R(_IdlePTD), $PG_RW)
905 cmpl $0,R(_bdb_exists)
906 je bdb_prepare_paging_exit
911 * Copy and convert debugger entries from the bootstrap gdt and idt
912 * to the kernel gdt and idt. Everything is still in low memory.
913 * Tracing continues to work after paging is enabled because the
914 * low memory addresses remain valid until everything is relocated.
915 * However, tracing through the setidt() that initializes the trace
919 movl 2(%esp),%esi /* base address of bootstrap gdt */
921 movl %edi,2(%esp) /* prepare to load kernel gdt */
926 movl $R(_gdt),-8+2(%edi) /* adjust gdt self-ptr */
927 movb $0x92,-8+5(%edi)
931 movl 2(%esp),%esi /* base address of current idt */
932 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */
934 movl %eax,R(bdb_dbg_ljmp+1) /* ... immediate offset ... */
936 movw %ax,R(bdb_dbg_ljmp+5) /* ... and selector for ljmp */
937 movl 24+4(%esi),%eax /* same for bpt descriptor */
939 movl %eax,R(bdb_bpt_ljmp+1)
941 movw %ax,R(bdb_bpt_ljmp+5)
943 movl %edi,2(%esp) /* prepare to load kernel idt */
952 bdb_prepare_paging_exit:
955 /* Relocate debugger gdt entries and gdt and idt pointers. */
958 je bdb_commit_paging_exit
960 movl $_gdt+8*9,%eax /* adjust slots 9-17 */
963 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */
964 addl $8,%eax /* now KERNBASE>>24 */
969 addl $KERNBASE,2(%esp)
972 addl $KERNBASE,2(%esp)
978 bdb_commit_paging_exit:
981 #endif /* BDE_DEBUGGER */