/*- * 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 * $FreeBSD: src/sys/i386/i386/locore.s,v 1.132.2.10 2003/02/03 20:54:49 jhb Exp $ * $DragonFly: src/sys/i386/i386/Attic/locore.s,v 1.11 2005/11/07 20:05:51 dillon Exp $ * * originally from: locore.s, by William F. Jolitz * * Substantially rewritten by David Greenman, Rod Grimes, * Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp * and many others. */ #include "opt_bootp.h" #include "opt_nfsroot.h" #include #include #include #include #include #include #include #include "assym.s" /* * 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 .set PTmap,(PTDPTDI << PDRSHIFT) .set PTD,PTmap + (PTDPTDI * PAGE_SIZE) .set PTDpde,PTD + (PTDPTDI * PDESIZE) /* * 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 * PAGE_SIZE) .set APTDpde,PTD + (APTDPTDI * PDESIZE) /* * Compiled KERNBASE location */ .globl kernbase .set kernbase,KERNBASE /* * Globals */ .data ALIGN_DATA /* just to be sure */ .globl .tmpstk .space 0x2000 /* space for tmpstk - temporary stack */ .tmpstk: .globl boothowto,bootdev .globl cpu,cpu_vendor,cpu_id,bootinfo .globl cpu_high, cpu_feature, cpu_procinfo cpu: .long 0 /* are we 386, 386sx, or 486 */ cpu_id: .long 0 /* stepping ID */ cpu_high: .long 0 /* highest arg to CPUID */ cpu_feature: .long 0 /* features */ cpu_procinfo: .long 0 /* brand index / HTT info */ cpu_vendor: .space 20 /* CPU origin code */ bootinfo: .space BOOTINFO_SIZE /* bootinfo buffer space */ KERNend: .long 0 /* phys addr end of kernel (just after bss) */ physfree: .long 0 /* phys addr of next free page */ #if 0 .globl cpu0prvpage cpu0prvpage: .long 0 /* relocated version */ #endif cpu0pp: .long 0 /* phys addr cpu0 private pg */ cpu0idlestk: .long 0 /* stack for the idle thread */ .globl SMPpt SMPptpa: .long 0 /* phys addr SMP page table */ SMPpt: .long 0 /* relocated version */ .globl IdlePTD IdlePTD: .long 0 /* phys addr of kernel PTD */ .globl KPTphys KPTphys: .long 0 /* PA of kernel page tables */ .globl proc0paddr proc0paddr: .long 0 /* VA of proc 0 address space */ p0upa: .long 0 /* PA of proc0's UPAGES */ vm86phystk: .long 0 /* PA of vm86/bios stack */ .globl vm86paddr, vm86pa vm86paddr: .long 0 /* address of vm86 region */ vm86pa: .long 0 /* phys addr of vm86 region */ #ifdef BDE_DEBUGGER .globl bdb_exists /* BDE debugger is present */ bdb_exists: .long 0 #endif /********************************************************************** * * Some handy macros * */ #define R(foo) ((foo)-KERNBASE) #define ALLOCPAGES(foo) \ movl R(physfree), %esi ; \ movl $((foo)*PAGE_SIZE), %eax ; \ addl %esi, %eax ; \ movl %eax, R(physfree) ; \ movl %esi, %edi ; \ movl $((foo)*PAGE_SIZE),%ecx ; \ xorl %eax,%eax ; \ cld ; \ rep ; \ stosb /* * fillkpt * eax = page frame address * ebx = index into page table * ecx = how many pages to map * base = base address of page dir/table * prot = protection bits */ #define fillkpt(base, prot) \ shll $2,%ebx ; \ addl base,%ebx ; \ orl $PG_V,%eax ; \ orl prot,%eax ; \ 1: movl %eax,(%ebx) ; \ addl $PAGE_SIZE,%eax ; /* increment physical address */ \ addl $4,%ebx ; /* next pte */ \ loop 1b /* * fillkptphys(prot) * eax = physical address * ecx = how many pages to map * prot = protection bits */ #define fillkptphys(prot) \ movl %eax, %ebx ; \ shrl $PAGE_SHIFT, %ebx ; \ fillkpt(R(KPTphys), prot) .text /********************************************************************** * * This is where the bootblocks start us, set the ball rolling... * */ NON_GPROF_ENTRY(btext) #ifdef BDE_DEBUGGER #ifdef BIOS_STEALS_3K cmpl $0x0375c339,0x95504 #else cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ #endif jne 1f movb $1,R(bdb_exists) 1: #endif /* Tell the bios to warmboot next time */ movw $0x1234,0x472 /* Set up a real frame in case the double return in newboot is executed. */ pushl %ebp movl %esp, %ebp /* Don't trust what the BIOS gives for eflags. */ pushl $PSL_KERNEL popfl /* * Don't trust what the BIOS gives for %fs and %gs. Trust the bootstrap * to set %cs, %ds, %es and %ss. */ mov %ds, %ax mov %ax, %fs mov %ax, %gs /* * Clear the bss. Not all boot programs do it, and it is our job anyway. * * XXX we don't check that there is memory for our bss and page tables * before using it. * * Note: we must be careful to not overwrite an active gdt or idt. They * inactive from now until we switch to new ones, since we don't load any * more segment registers or permit interrupts until after the switch. */ movl $R(_end),%ecx movl $R(_edata),%edi subl %edi,%ecx xorl %eax,%eax cld rep stosb call recover_bootinfo /* Get onto a stack that we can trust. */ /* * XXX this step is delayed in case recover_bootinfo needs to return via * the old stack, but it need not be, since recover_bootinfo actually * returns via the old frame. */ movl $R(.tmpstk),%esp call identify_cpu call create_pagetables /* * If the CPU has support for VME, turn it on. */ testl $CPUID_VME, R(cpu_feature) jz 1f movl %cr4, %eax orl $CR4_VME, %eax movl %eax, %cr4 1: #ifdef BDE_DEBUGGER /* * Adjust as much as possible for paging before enabling paging so that the * adjustments can be traced. */ call bdb_prepare_paging #endif /* Now enable paging */ movl R(IdlePTD), %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! */ #ifdef BDE_DEBUGGER /* * Complete the adjustments for paging so that we can keep tracing through * initi386() after the low (physical) addresses for the gdt and idt become * invalid. */ call bdb_commit_paging #endif pushl $begin /* jump to high virtualized address */ ret /* now running relocated at KERNBASE where the system is linked to run */ begin: /* * set up the bootstrap stack. The pcb sits at the end of the * bootstrap stack. */ /* set up bootstrap stack */ movl proc0paddr,%esp /* location of in-kernel pages */ addl $UPAGES*PAGE_SIZE-PCB_SIZE,%esp xorl %eax,%eax /* mark end of frames */ movl %eax,%ebp /*movl proc0paddr,%eax*/ movl IdlePTD, %esi movl %esi,PCB_CR3(%esp) testl $CPUID_PGE, R(cpu_feature) jz 1f movl %cr4, %eax orl $CR4_PGE, %eax movl %eax, %cr4 1: movl physfree, %esi pushl %esi /* value of first for init386(first) */ call init386 /* wire 386 chip for unix operation */ popl %esi call mi_startup /* autoconfiguration, mountroot etc */ hlt /* never returns to here */ /* * Signal trampoline, copied to top of user stack */ NON_GPROF_ENTRY(sigcode) call *SIGF_HANDLER(%esp) /* call signal handler */ lea SIGF_UC(%esp),%eax /* get ucontext_t */ pushl %eax testl $PSL_VM,UC_EFLAGS(%eax) jne 9f movl UC_GS(%eax),%gs /* restore %gs */ 9: movl $SYS_sigreturn,%eax pushl %eax /* junk to fake return addr. */ int $0x80 /* enter kernel with args */ 0: jmp 0b ALIGN_TEXT esigcode: .data .globl szsigcode szsigcode: .long esigcode - sigcode .text /********************************************************************** * * Recover the bootinfo passed to us from the boot program * */ recover_bootinfo: /* * This code is called in different ways depending on what loaded * and started the kernel. This is used to detect how we get the * arguments from the other code and what we do with them. * * Old disk boot blocks: * (*btext)(howto, bootdev, cyloffset, esym); * [return address == 0, and can NOT be returned to] * [cyloffset was not supported by the FreeBSD boot code * and always passed in as 0] * [esym is also known as total in the boot code, and * was never properly supported by the FreeBSD boot code] * * Old diskless netboot code: * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); * [return address != 0, and can NOT be returned to] * If we are being booted by this code it will NOT work, * so we are just going to halt if we find this case. * * New uniform boot code: * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) * [return address != 0, and can be returned to] * * There may seem to be a lot of wasted arguments in here, but * that is so the newer boot code can still load very old kernels * and old boot code can load new kernels. */ /* * The old style disk boot blocks fake a frame on the stack and * did an lret to get here. The frame on the stack has a return * address of 0. */ cmpl $0,4(%ebp) je olddiskboot /* * We have some form of return address, so this is either the * old diskless netboot code, or the new uniform code. That can * be detected by looking at the 5th argument, if it is 0 * we are being booted by the new uniform boot code. */ cmpl $0,24(%ebp) je newboot /* * Seems we have been loaded by the old diskless boot code, we * don't stand a chance of running as the diskless structure * changed considerably between the two, so just halt. */ hlt /* * We have been loaded by the new uniform boot code. * Let's check the bootinfo version, and if we do not understand * it we return to the loader with a status of 1 to indicate this error */ newboot: movl 28(%ebp),%ebx /* &bootinfo.version */ movl BI_VERSION(%ebx),%eax cmpl $1,%eax /* We only understand version 1 */ je 1f movl $1,%eax /* Return status */ leave /* * XXX this returns to our caller's caller (as is required) since * we didn't set up a frame and our caller did. */ ret 1: /* * If we have a kernelname copy it in */ movl BI_KERNELNAME(%ebx),%esi cmpl $0,%esi je 2f /* No kernelname */ movl $MAXPATHLEN,%ecx /* Brute force!!! */ movl $R(kernelname),%edi cmpb $'/',(%esi) /* Make sure it starts with a slash */ je 1f movb $'/',(%edi) incl %edi decl %ecx 1: cld rep movsb 2: /* * Determine the size of the boot loader's copy of the bootinfo * struct. This is impossible to do properly because old versions * of the struct don't contain a size field and there are 2 old * versions with the same version number. */ movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */ testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */ je got_bi_size /* no, sizeless version */ movl BI_SIZE(%ebx),%ecx got_bi_size: /* * Copy the common part of the bootinfo struct */ movl %ebx,%esi movl $R(bootinfo),%edi cmpl $BOOTINFO_SIZE,%ecx jbe got_common_bi_size movl $BOOTINFO_SIZE,%ecx got_common_bi_size: cld rep movsb #ifdef NFS_ROOT #ifndef BOOTP_NFSV3 /* * If we have a nfs_diskless structure copy it in */ movl BI_NFS_DISKLESS(%ebx),%esi cmpl $0,%esi je olddiskboot movl $R(nfs_diskless),%edi movl $NFSDISKLESS_SIZE,%ecx cld rep movsb movl $R(nfs_diskless_valid),%edi movl $1,(%edi) #endif #endif /* * The old style disk boot. * (*btext)(howto, bootdev, cyloffset, esym); * Note that the newer boot code just falls into here to pick * up howto and bootdev, cyloffset and esym are no longer used */ olddiskboot: movl 8(%ebp),%eax movl %eax,R(boothowto) movl 12(%ebp),%eax movl %eax,R(bootdev) ret /********************************************************************** * * Identify the CPU and initialize anything special about it * */ identify_cpu: /* 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 try486 /* NexGen CPU does not have aligment check flag. */ pushfl movl $0x5555, %eax xorl %edx, %edx movl $2, %ecx clc divl %ecx jz trynexgen popfl movl $CPU_386,R(cpu) jmp 3f trynexgen: popfl movl $CPU_NX586,R(cpu) movl $0x4778654e,R(cpu_vendor) # store vendor string movl $0x72446e65,R(cpu_vendor+4) movl $0x6e657669,R(cpu_vendor+8) movl $0,R(cpu_vendor+12) jmp 3f try486: /* 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 trycpuid movl $CPU_486,R(cpu) /* * Check Cyrix CPU * Cyrix CPUs do not change the undefined flags following * execution of the divide instruction which divides 5 by 2. * * Note: CPUID is enabled on M2, so it passes another way. */ pushfl movl $0x5555, %eax xorl %edx, %edx movl $2, %ecx clc divl %ecx jnc trycyrix popfl jmp 3f /* You may use Intel CPU. */ trycyrix: popfl /* * IBM Bluelighting CPU also doesn't change the undefined flags. * Because IBM doesn't disclose the information for Bluelighting * CPU, we couldn't distinguish it from Cyrix's (including IBM * brand of Cyrix CPUs). */ movl $0x69727943,R(cpu_vendor) # store vendor string movl $0x736e4978,R(cpu_vendor+4) movl $0x64616574,R(cpu_vendor+8) jmp 3f trycpuid: /* Use the `cpuid' instruction. */ xorl %eax,%eax cpuid # cpuid 0 movl %eax,R(cpu_high) # highest capability movl %ebx,R(cpu_vendor) # store vendor string movl %edx,R(cpu_vendor+4) movl %ecx,R(cpu_vendor+8) movb $0,R(cpu_vendor+12) movl $1,%eax cpuid # cpuid 1 movl %eax,R(cpu_id) # store cpu_id movl %ebx,R(cpu_procinfo) # store cpu_procinfo movl %edx,R(cpu_feature) # store cpu_feature rorl $8,%eax # extract family type andl $15,%eax cmpl $5,%eax jae 1f /* less than Pentium; must be 486 */ movl $CPU_486,R(cpu) jmp 3f 1: /* a Pentium? */ cmpl $5,%eax jne 2f movl $CPU_586,R(cpu) jmp 3f 2: /* Greater than Pentium...call it a Pentium Pro */ movl $CPU_686,R(cpu) 3: ret /********************************************************************** * * Create the first page directory and its page tables. * */ create_pagetables: /* Find end of kernel image (rounded up to a page boundary). */ movl $R(end),%esi /* Include symbols, if any. */ movl R(bootinfo+BI_ESYMTAB),%edi testl %edi,%edi je over_symalloc movl %edi,%esi movl $KERNBASE,%edi addl %edi,R(bootinfo+BI_SYMTAB) addl %edi,R(bootinfo+BI_ESYMTAB) over_symalloc: /* If we are told where the end of the kernel space is, believe it. */ movl R(bootinfo+BI_KERNEND),%edi testl %edi,%edi je no_kernend movl %edi,%esi no_kernend: addl $PAGE_MASK,%esi andl $~PAGE_MASK,%esi movl %esi,R(KERNend) /* save end of kernel */ movl %esi,R(physfree) /* next free page is at end of kernel */ /* Allocate Kernel Page Tables */ ALLOCPAGES(NKPT) movl %esi,R(KPTphys) /* Allocate Page Table Directory */ ALLOCPAGES(1) movl %esi,R(IdlePTD) /* Allocate UPAGES */ ALLOCPAGES(UPAGES) movl %esi,R(p0upa) addl $KERNBASE, %esi movl %esi, R(proc0paddr) ALLOCPAGES(1) /* vm86/bios stack */ movl %esi,R(vm86phystk) ALLOCPAGES(3) /* pgtable + ext + IOPAGES */ movl %esi,R(vm86pa) addl $KERNBASE, %esi movl %esi, R(vm86paddr) /* Allocate cpu0's mdglobaldata */ ALLOCPAGES(MDGLOBALDATA_BASEALLOC_PAGES) movl %esi,R(cpu0pp) #if 0 addl $KERNBASE, %esi movl %esi, R(cpu0prvpage) /* relocated to KVM space */ #endif /* Allocate cpu0's idle stack */ ALLOCPAGES(UPAGES) movl %esi,R(cpu0idlestk) /* Allocate SMP page table page */ ALLOCPAGES(1) movl %esi,R(SMPptpa) addl $KERNBASE, %esi movl %esi, R(SMPpt) /* relocated to KVM space */ /* Map read-only from zero to the end of the kernel text section */ xorl %eax, %eax #ifdef BDE_DEBUGGER /* If the debugger is present, actually map everything read-write. */ cmpl $0,R(bdb_exists) jne map_read_write #endif xorl %edx,%edx #if !defined(SMP) testl $CPUID_PGE, R(cpu_feature) jz 2f orl $PG_G,%edx #endif 2: movl $R(etext),%ecx addl $PAGE_MASK,%ecx shrl $PAGE_SHIFT,%ecx fillkptphys(%edx) /* Map read-write, data, bss and symbols */ movl $R(etext),%eax addl $PAGE_MASK, %eax andl $~PAGE_MASK, %eax map_read_write: movl $PG_RW,%edx #if !defined(SMP) testl $CPUID_PGE, R(cpu_feature) jz 1f orl $PG_G,%edx #endif 1: movl R(KERNend),%ecx subl %eax,%ecx shrl $PAGE_SHIFT,%ecx fillkptphys(%edx) /* Map page directory. */ movl R(IdlePTD), %eax movl $1, %ecx fillkptphys($PG_RW) /* Map proc0's UPAGES in the physical way ... */ movl R(p0upa), %eax movl $UPAGES, %ecx fillkptphys($PG_RW) /* Map ISA hole */ movl $ISA_HOLE_START, %eax movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx fillkptphys($PG_RW) /* Map space for the vm86 region */ movl R(vm86phystk), %eax movl $4, %ecx fillkptphys($PG_RW) /* Map page 0 into the vm86 page table */ movl $0, %eax movl $0, %ebx movl $1, %ecx fillkpt(R(vm86pa), $PG_RW|PG_U) /* ...likewise for the ISA hole */ movl $ISA_HOLE_START, %eax movl $ISA_HOLE_START>>PAGE_SHIFT, %ebx movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx fillkpt(R(vm86pa), $PG_RW|PG_U) #if 0 /* Map cpu0's mdglobaldata into global kmem (N pages @ cpu0pp) */ movl R(cpu0pp), %eax movl $MDGLOBALDATA_BASEALLOC_PAGES, %ecx fillkptphys($PG_RW) #endif /* Map SMP page table page into global kmem FWIW */ movl R(SMPptpa), %eax movl $1, %ecx fillkptphys($PG_RW) /* Map the private page into the SMP page table */ movl R(cpu0pp), %eax movl $0, %ebx /* pte offset = 0 */ /* N private pages coming right up */ movl $MDGLOBALDATA_BASEALLOC_PAGES, %ecx fillkpt(R(SMPptpa), $PG_RW) /* Map the cpu0's idle thread stack */ movl R(cpu0idlestk), %eax movl $PS_IDLESTACK_PAGE, %ebx movl $UPAGES, %ecx fillkpt(R(SMPptpa), $PG_RW) /* ... and put the page table table in the pde. */ movl R(SMPptpa), %eax movl $MPPTDI, %ebx movl $1, %ecx fillkpt(R(IdlePTD), $PG_RW) /* Fakeup VA for the local apic to allow early traps. */ ALLOCPAGES(1) movl %esi, %eax movl $(NPTEPG-1), %ebx /* pte offset = NTEPG-1 */ movl $1, %ecx /* one private pt coming right up */ fillkpt(R(SMPptpa), $PG_RW) #ifdef SMP /* Initialize mp lock to allow early traps */ movl $0, R(mp_lock) #endif /* SMP */ /* install a pde for temporary double map of bottom of VA */ movl R(KPTphys), %eax xorl %ebx, %ebx movl $NKPT, %ecx fillkpt(R(IdlePTD), $PG_RW) /* install pde's for pt's */ movl R(KPTphys), %eax movl $KPTDI, %ebx movl $NKPT, %ecx fillkpt(R(IdlePTD), $PG_RW) /* install a pde recursively mapping page directory as a page table */ movl R(IdlePTD), %eax movl $PTDPTDI, %ebx movl $1,%ecx fillkpt(R(IdlePTD), $PG_RW) ret #ifdef BDE_DEBUGGER bdb_prepare_paging: cmpl $0,R(bdb_exists) je bdb_prepare_paging_exit subl $6,%esp /* * Copy and convert debugger entries from the bootstrap gdt and idt * to the kernel gdt and idt. Everything is still in low memory. * Tracing continues to work after paging is enabled because the * low memory addresses remain valid until everything is relocated. * However, tracing through the setidt() that initializes the trace * trap will crash. */ sgdt (%esp) movl 2(%esp),%esi /* base address of bootstrap gdt */ movl $R(gdt),%edi movl %edi,2(%esp) /* prepare to load kernel gdt */ movl $8*18/4,%ecx cld rep /* copy gdt */ movsl movl $R(gdt),-8+2(%edi) /* adjust gdt self-ptr */ movb $0x92,-8+5(%edi) lgdt (%esp) sidt (%esp) movl 2(%esp),%esi /* base address of current idt */ movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ movw 8(%esi),%ax movl %eax,R(bdb_dbg_ljmp+1) /* ... immediate offset ... */ movl 8+2(%esi),%eax movw %ax,R(bdb_dbg_ljmp+5) /* ... and selector for ljmp */ movl 24+4(%esi),%eax /* same for bpt descriptor */ movw 24(%esi),%ax movl %eax,R(bdb_bpt_ljmp+1) movl 24+2(%esi),%eax movw %ax,R(bdb_bpt_ljmp+5) movl R(idt),%edi movl %edi,2(%esp) /* prepare to load kernel idt */ movl $8*4/4,%ecx cld rep /* copy idt */ movsl lidt (%esp) addl $6,%esp bdb_prepare_paging_exit: ret /* Relocate debugger gdt entries and gdt and idt pointers. */ bdb_commit_paging: cmpl $0,_bdb_exists je bdb_commit_paging_exit 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 subl $6,%esp sgdt (%esp) addl $KERNBASE,2(%esp) lgdt (%esp) sidt (%esp) addl $KERNBASE,2(%esp) lidt (%esp) addl $6,%esp int $3 bdb_commit_paging_exit: ret #endif /* BDE_DEBUGGER */