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/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)locore.s 7.3 (Berkeley) 5/13/91
* $Id: locore.s,v 1.19 1994/08/10 03:51:05 wollman Exp $
*/
/*
* locore.s: FreeBSD machine support for the Intel 386
* originally from: locore.s, by William F. Jolitz
*
* Substantially rewritten by David Greenman, Rod Grimes,
* Bruce Evans, Wolfgang Solfrank, and many others.
*/
#include "npx.h" /* for NNPX */
#include "assym.s" /* system definitions */
#include <machine/psl.h> /* processor status longword defs */
#include <machine/pte.h> /* page table entry definitions */
#include <sys/errno.h> /* error return codes */
#include <machine/specialreg.h> /* x86 special registers */
#include <machine/cputypes.h> /* x86 cpu type definitions */
#include <sys/syscall.h> /* system call numbers */
#include <machine/asmacros.h> /* miscellaneous asm macros */
/*
* XXX
*
* Note: This version greatly munged to avoid various assembler errors
* that may be fixed in newer versions of gas. Perhaps newer versions
* will have more pleasant appearance.
*/
/*
* PTmap is recursive pagemap at top of virtual address space.
* Within PTmap, the page directory can be found (third indirection).
*/
.globl _PTmap,_PTD,_PTDpde,_Sysmap
.set _PTmap,PTDPTDI << PDRSHIFT
.set _PTD,_PTmap + (PTDPTDI * NBPG)
.set _PTDpde,_PTD + (PTDPTDI * PDESIZE)
/* Sysmap is the base address of the kernel page tables */
.set _Sysmap,_PTmap + (KPTDI * NBPG)
/*
* APTmap, APTD is the alternate recursive pagemap.
* It's used when modifying another process's page tables.
*/
.globl _APTmap,_APTD,_APTDpde
.set _APTmap,APTDPTDI << PDRSHIFT
.set _APTD,_APTmap + (APTDPTDI * NBPG)
.set _APTDpde,_PTD + (APTDPTDI * PDESIZE)
/*
* Access to each processes kernel stack is via a region of
* per-process address space (at the beginning), immediatly above
* the user process stack.
*/
.set _kstack,USRSTACK
.globl _kstack
/*
* Globals
*/
.data
.globl _esym
_esym: .long 0 /* ptr to end of syms */
.globl _boothowto,_bootdev,_curpcb
.globl _cpu,_cold,_atdevbase,_cpu_vendor,_cpu_id
_cpu: .long 0 /* are we 386, 386sx, or 486 */
_cpu_id: .long 0 /* stepping ID */
_cpu_vendor: .space 17 /* CPU origin code */
_cold: .long 1 /* cold till we are not */
_atdevbase: .long 0 /* location of start of iomem in virtual */
_atdevphys: .long 0 /* location of device mapping ptes (phys) */
.globl _KERNend
_KERNend: .long 0 /* phys addr end of kernel (just after bss) */
.globl _IdlePTD,_KPTphys
_IdlePTD: .long 0 /* phys addr of kernel PTD */
_KPTphys: .long 0 /* phys addr of kernel page tables */
.globl _cyloffset
_cyloffset: .long 0 /* cylinder offset from boot blocks */
.globl _proc0paddr
_proc0paddr: .long 0 /* address of proc 0 address space */
#ifdef BDE_DEBUGGER
.globl _bdb_exists /* flag to indicate BDE debugger is available */
_bdb_exists: .long 0
#endif
.globl tmpstk
.space 0x1000
tmpstk:
/*
* System Initialization
*/
.text
/*
* btext: beginning of text section.
* Also the entry point (jumped to directly from the boot blocks).
*/
NON_GPROF_ENTRY(btext)
movw $0x1234,0x472 /* warm boot */
jmp 1f
.org 0x500 /* space for BIOS variables */
/*
* pass parameters on stack (howto, bootdev, unit, cyloffset, esym)
* note: (%esp) is return address of boot
* ( if we want to hold onto /boot, it's physical %esp up to _end)
*/
1: movl 4(%esp),%eax
movl %eax,_boothowto-KERNBASE
movl 8(%esp),%eax
movl %eax,_bootdev-KERNBASE
movl 12(%esp),%eax
movl %eax,_cyloffset-KERNBASE
movl 16(%esp),%eax
addl $KERNBASE,%eax
movl %eax,_esym-KERNBASE
#ifdef DISKLESS /* Copy diskless structure */
movl _nfs_diskless_size-KERNBASE,%ecx
movl 20(%esp),%esi
movl $(_nfs_diskless-KERNBASE),%edi
cld
rep
movsb
#endif
/* Find out our CPU type. */
/* Try to toggle alignment check flag; does not exist on 386. */
pushfl
popl %eax
movl %eax,%ecx
orl $PSL_AC,%eax
pushl %eax
popfl
pushfl
popl %eax
xorl %ecx,%eax
andl $PSL_AC,%eax
pushl %ecx
popfl
testl %eax,%eax
jnz 1f
movl $CPU_386,_cpu-KERNBASE
jmp 2f
1: /* Try to toggle identification flag; does not exist on early 486s. */
pushfl
popl %eax
movl %eax,%ecx
xorl $PSL_ID,%eax
pushl %eax
popfl
pushfl
popl %eax
xorl %ecx,%eax
andl $PSL_ID,%eax
pushl %ecx
popfl
testl %eax,%eax
jnz 1f
movl $CPU_486,_cpu-KERNBASE
jmp 2f
1: /* Use the `cpuid' instruction. */
xorl %eax,%eax
.byte 0x0f,0xa2 # cpuid 0
movl %ebx,_cpu_vendor-KERNBASE # store vendor string
movl %edx,_cpu_vendor+4-KERNBASE
movl %ecx,_cpu_vendor+8-KERNBASE
movb $0,_cpu_vendor+12-KERNBASE
movl $1,%eax
.byte 0x0f,0xa2 # cpuid 1
movl %eax,_cpu_id-KERNBASE # store cpu_id
rorl $8,%eax # extract family type
andl $15,%eax
cmpl $5,%eax
jae 1f
/* less than Pentium; must be 486 */
movl $CPU_486,_cpu-KERNBASE
jmp 2f
1: movl $CPU_586,_cpu-KERNBASE
2:
/*
* Finished with old stack; load new %esp now instead of later so
* we can trace this code without having to worry about the trace
* trap clobbering the memory test or the zeroing of the bss+bootstrap
* page tables.
*
* XXX - wdboot clears the bss after testing that this is safe.
* This is too wasteful - memory below 640K is scarce. The boot
* program should check:
* text+data <= &stack_variable - more_space_for_stack
* text+data+bss+pad+space_for_page_tables <= end_of_memory
* Oops, the gdt is in the carcass of the boot program so clearing
* the rest of memory is still not possible.
*/
movl $tmpstk-KERNBASE,%esp /* bootstrap stack end location */
/*
* Virtual address space of kernel:
*
* text | data | bss | [syms] | page dir | proc0 kernel stack | usr stk map | Sysmap
* pages: 1 UPAGES (2) 1 NKPT (7)
*/
/* find end of kernel image */
movl $_end-KERNBASE,%ecx
addl $NBPG-1,%ecx /* page align up */
andl $~(NBPG-1),%ecx
movl %ecx,%esi /* esi = start of free memory */
movl %ecx,_KERNend-KERNBASE /* save end of kernel */
/* clear bss */
movl $_edata-KERNBASE,%edi
subl %edi,%ecx /* get amount to clear */
xorl %eax,%eax /* specify zero fill */
cld
rep
stosb
/*
* The value in esi is both the end of the kernel bss and a pointer to
* the kernel page directory, and is used by the rest of locore to build
* the tables.
* esi + 1(page dir) + 2(UPAGES) + 1(p0stack) + NKPT(number of kernel
* page table pages) is then passed on the stack to init386(first) as
* the value first. esi should ALWAYS be page aligned!!
*/
movl %esi,%ecx /* Get current first availiable address */
/* clear pagetables, page directory, stack, etc... */
movl %esi,%edi /* base (page directory) */
movl $((1+UPAGES+1+NKPT)*NBPG),%ecx /* amount to clear */
xorl %eax,%eax /* specify zero fill */
cld
rep
stosb
/* physical address of Idle proc/kernel page directory */
movl %esi,_IdlePTD-KERNBASE
/*
* fillkpt
* eax = (page frame address | control | status) == pte
* ebx = address of page table
* ecx = how many pages to map
*/
#define fillkpt \
1: movl %eax,(%ebx) ; \
addl $NBPG,%eax ; /* increment physical address */ \
addl $4,%ebx ; /* next pte */ \
loop 1b ;
/*
* Map Kernel
*
* First step - build page tables
*/
#if defined (KGDB) || defined (BDE_DEBUGGER)
movl _KERNend-KERNBASE,%ecx /* this much memory, */
shrl $PGSHIFT,%ecx /* for this many PTEs */
#ifdef BDE_DEBUGGER
cmpl $0xa0,%ecx /* XXX - cover debugger pages */
jae 1f
movl $0xa0,%ecx
1:
#endif /* BDE_DEBUGGER */
movl $PG_V|PG_KW|PG_NC_PWT,%eax /* kernel R/W, valid, cache write-through */
lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */
movl %ebx,_KPTphys-KERNBASE /* save in global */
fillkpt
#else /* !KGDB && !BDE_DEBUGGER */
/* write protect kernel text (doesn't do a thing for 386's - only 486's) */
movl $_etext-KERNBASE,%ecx /* get size of text */
shrl $PGSHIFT,%ecx /* for this many PTEs */
movl $PG_V|PG_KR,%eax /* specify read only */
lea ((1+UPAGES+1)*NBPG)(%esi),%ebx /* phys addr of kernel PT base */
movl %ebx,_KPTphys-KERNBASE /* save in global */
fillkpt
/* data and bss are r/w */
andl $PG_FRAME,%eax /* strip to just addr of bss */
movl _KERNend-KERNBASE,%ecx /* calculate size */
subl %eax,%ecx
shrl $PGSHIFT,%ecx
orl $PG_V|PG_KW,%eax /* valid, kernel read/write */
fillkpt
#endif /* KGDB || BDE_DEBUGGER */
/* now initialize the page dir, upages, p0stack PT, and page tables */
movl $(1+UPAGES+1+NKPT),%ecx /* number of PTEs */
movl %esi,%eax /* phys address of PTD */
andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */
orl $PG_V|PG_KW|PG_NC_PWT,%eax /* valid, kernel read/write, cache write-though */
movl %esi,%ebx /* calculate pte offset to ptd */
shrl $PGSHIFT-2,%ebx
addl %esi,%ebx /* address of page directory */
addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */
fillkpt
/* map I/O memory map */
movl _KPTphys-KERNBASE,%ebx /* base of kernel page tables */
lea (0xa0 * PTESIZE)(%ebx),%ebx /* hardwire ISA hole at KERNBASE + 0xa0000 */
movl $0x100-0xa0,%ecx /* for this many pte s, */
movl $(0xa0000|PG_V|PG_KW|PG_N),%eax /* valid, kernel read/write, non-cacheable */
movl %ebx,_atdevphys-KERNBASE /* save phys addr of ptes */
fillkpt
/* map proc 0's kernel stack into user page table page */
movl $UPAGES,%ecx /* for this many pte s, */
lea (1*NBPG)(%esi),%eax /* physical address in proc 0 */
lea (KERNBASE)(%eax),%edx /* change into virtual addr */
movl %edx,_proc0paddr-KERNBASE /* save VA for proc 0 init */
orl $PG_V|PG_KW,%eax /* valid, kernel read/write */
lea ((1+UPAGES)*NBPG)(%esi),%ebx /* addr of stack page table in proc 0 */
addl $(KSTKPTEOFF * PTESIZE),%ebx /* offset to kernel stack PTE */
fillkpt
/*
* Initialize kernel page table directory
*/
/* install a pde for temporary double map of bottom of VA */
movl _KPTphys-KERNBASE,%eax
orl $PG_V|PG_KW,%eax /* valid, kernel read/write */
movl %eax,(%esi) /* which is where temp maps! */
/* initialize kernel pde's */
movl $(NKPT),%ecx /* for this many PDEs */
lea (KPTDI*PDESIZE)(%esi),%ebx /* offset of pde for kernel */
fillkpt
/* install a pde recursively mapping page directory as a page table! */
movl %esi,%eax /* phys address of ptd in proc 0 */
orl $PG_V|PG_KW,%eax /* pde entry is valid */
movl %eax,PTDPTDI*PDESIZE(%esi) /* which is where PTmap maps! */
/* install a pde to map kernel stack for proc 0 */
lea ((1+UPAGES)*NBPG)(%esi),%eax /* physical address of pt in proc 0 */
orl $PG_V|PG_KW,%eax /* pde entry is valid */
movl %eax,KSTKPTDI*PDESIZE(%esi) /* which is where kernel stack maps! */
#ifdef BDE_DEBUGGER
/* copy and convert stuff from old gdt and idt for debugger */
cmpl $0x0375c339,0x96104 /* XXX - debugger signature */
jne 1f
movb $1,_bdb_exists-KERNBASE
1:
pushal
subl $2*6,%esp
sgdt (%esp)
movl 2(%esp),%esi /* base address of current gdt */
movl $_gdt-KERNBASE,%edi
movl %edi,2(%esp)
movl $8*18/4,%ecx
cld
rep /* copy gdt */
movsl
movl $_gdt-KERNBASE,-8+2(%edi) /* adjust gdt self-ptr */
movb $0x92,-8+5(%edi)
sidt 6(%esp)
movl 6+2(%esp),%esi /* base address of current idt */
movl 8+4(%esi),%eax /* convert dbg descriptor to ... */
movw 8(%esi),%ax
movl %eax,bdb_dbg_ljmp+1-KERNBASE /* ... immediate offset ... */
movl 8+2(%esi),%eax
movw %ax,bdb_dbg_ljmp+5-KERNBASE /* ... and selector for ljmp */
movl 24+4(%esi),%eax /* same for bpt descriptor */
movw 24(%esi),%ax
movl %eax,bdb_bpt_ljmp+1-KERNBASE
movl 24+2(%esi),%eax
movw %ax,bdb_bpt_ljmp+5-KERNBASE
movl $_idt-KERNBASE,%edi
movl %edi,6+2(%esp)
movl $8*4/4,%ecx
cld
rep /* copy idt */
movsl
lgdt (%esp)
lidt 6(%esp)
addl $2*6,%esp
popal
#endif /* BDE_DEBUGGER */
/* load base of page directory and enable mapping */
movl %esi,%eax /* phys address of ptd in proc 0 */
orl $I386_CR3PAT,%eax
movl %eax,%cr3 /* load ptd addr into mmu */
movl %cr0,%eax /* get control word */
orl $CR0_PE|CR0_PG,%eax /* enable paging */
movl %eax,%cr0 /* and let's page NOW! */
pushl $begin /* jump to high mem */
ret
begin: /* now running relocated at KERNBASE where the system is linked to run */
.globl _Crtat /* XXX - locore should not know about */
movl _Crtat,%eax /* variables of device drivers (pccons)! */
subl $(KERNBASE+0xA0000),%eax
movl _atdevphys,%edx /* get pte PA */
subl _KPTphys,%edx /* remove base of ptes, now have phys offset */
shll $PGSHIFT-2,%edx /* corresponding to virt offset */
addl $KERNBASE,%edx /* add virtual base */
movl %edx,_atdevbase
addl %eax,%edx
movl %edx,_Crtat
/* set up bootstrap stack - 48 bytes */
movl $_kstack+UPAGES*NBPG-4*12,%esp /* bootstrap stack end location */
xorl %eax,%eax /* mark end of frames */
movl %eax,%ebp
movl _proc0paddr,%eax
movl %esi,PCB_CR3(%eax)
#ifdef BDE_DEBUGGER
/* relocate debugger gdt entries */
movl $_gdt+8*9,%eax /* adjust slots 9-17 */
movl $9,%ecx
reloc_gdt:
movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */
addl $8,%eax /* now KERNBASE>>24 */
loop reloc_gdt
cmpl $0,_bdb_exists
je 1f
int $3
1:
#endif /* BDE_DEBUGGER */
/*
* Skip over the page tables and the kernel stack
*/
lea ((1+UPAGES+1+NKPT)*NBPG)(%esi),%esi
pushl %esi /* value of first for init386(first) */
call _init386 /* wire 386 chip for unix operation */
popl %esi
#if 0
movl $0,_PTD
#endif
.globl __ucodesel,__udatasel
pushl $0 /* unused */
pushl __udatasel /* ss */
pushl $0 /* esp - filled in by execve() */
pushl $0x3200 /* eflags (ring 3, int enab) */
pushl __ucodesel /* cs */
pushl $0 /* eip - filled in by execve() */
subl $(12*4),%esp /* space for rest of registers */
pushl %esp /* call main with frame pointer */
call _main /* autoconfiguration, mountroot etc */
addl $(13*4),%esp /* back to a frame we can return with */
/*
* now we've run main() and determined what cpu-type we are, we can
* enable WP mode on i486 cpus and above.
*/
#if defined(I486_CPU) || defined(I586_CPU)
cmpl $CPUCLASS_386,_cpu_class
je 1f
movl %cr0,%eax /* get control word */
orl $CR0_WP,%eax /* enable write protect for all modes */
movl %eax,%cr0 /* and do it */
#endif
/*
* on return from main(), we are process 1
* set up address space and stack so that we can 'return' to user mode
*/
1:
movl __ucodesel,%eax
movl __udatasel,%ecx
movl %cx,%ds
movl %cx,%es
movl %ax,%fs /* double map cs to fs */
movl %cx,%gs /* and ds to gs */
iret /* goto user! */
#define LCALL(x,y) .byte 0x9a ; .long y ; .word x
NON_GPROF_ENTRY(sigcode)
call SIGF_HANDLER(%esp)
lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */
/* copy at 8(%esp)) */
pushl %eax
pushl %eax /* junk to fake return address */
movl $103,%eax /* XXX sigreturn() */
LCALL(0x7,0) /* enter kernel with args on stack */
hlt /* never gets here */
.globl _szsigcode
_szsigcode:
.long _szsigcode-_sigcode
|