/* $NetBSD: locore.s,v 1.50 2026/04/04 00:55:45 thorpej Exp $ */ /* * Copyright (c) 1988 University of Utah. * Copyright (c) 1980, 1990, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department. * * 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. 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: Utah $Hdr: locore.s 1.66 92/12/22$ * * @(#)locore.s 8.6 (Berkeley) 5/27/94 */ #include "opt_compat_netbsd.h" #include "opt_compat_sunos.h" #include "opt_fpsp.h" #include "opt_ddb.h" #include "opt_kgdb.h" #include "opt_lockdebug.h" #include "opt_m68k_arch.h" #include "assym.h" #include <machine/asm.h> #include <machine/trap.h> #include "ksyms.h" /* * Memory starts at 0x0000.0000, and we have linked the kernel * at 0x0000.2000 to ensure that VA==0 is unmapped once we turn * on the MMU. We arrive here running VA==PA and with the MMU * disabled. * * This first 8KB of RAM at PA==0 won't go to waste, though; we * will use it for the kernel message buffer. */ /* * Temporary stack for a variety of purposes. * Try and make this the first thing is the data segment so it * is page aligned. Note that if we overflow here, we run into * our text segment. */ .data .space PAGE_SIZE ASGLOBAL(tmpstk) /* * Macro to relocate a symbol, used before MMU is enabled. */ #define IMMEDIATE # #define _RELOC(var, ar) \ movl IMMEDIATE var,ar; \ addl %a5,ar #define RELOC(var, ar) _RELOC(_C_LABEL(var), ar) #define ASRELOC(var, ar) _RELOC(_ASM_LABEL(var), ar) BSS(esym,4) .globl _C_LABEL(edata) .globl _C_LABEL(etext),_C_LABEL(end) /* * This is for kvm_mkdb, and should be the address of the beginning * of the kernel text segment (not necessarily the same as kernbase). */ .text GLOBAL(kernel_text) /* * start of kernel and .text! */ ASENTRY_NOPROFILE(start) movw #PSL_HIGHIPL,%sr | no interrupts movl #CACHE_OFF,%d0 movc %d0,%cacr | clear and disable on-chip cache(s) /* * Determine our relocation offset. We need this to manually * translate the virtual addresses of global references to the * physical addresses we need to use before the MMU is enabled. */ lea %pc@(_ASM_LABEL(start)), %a5 movl %a5,%d0 | %d0 = phys address of start subl #_ASM_LABEL(start), %d0 | %d0 -= virt address of start movl %d0, %a5 | %a5 = relocation offset /* * NOTE: %a5 cannot be used until after the MMU is enabled; it * is used by the RELOC() macro. */ ASRELOC(tmpstk, %a0) movl %a0,%sp | give ourselves a temporary stack RELOC(edata,%a0) | clear out BSS movl #_C_LABEL(end) - 4, %d0 | (must be <= 256 kB) subl #_C_LABEL(edata), %d0 lsrl #2,%d0 1: clrl %a0@+ dbra %d0,1b /* * Qemu does not pass us the symbols, so leave esym alone. * The bootinfo immediately follows the kernel. Go parse * it to get CPU/FPU/MMU information and figure out where * the end of the loaded image really is. */ movl #_C_LABEL(end),%a4 | end of static kernel text/data addl %a5,%a4 | convert to PA pea %a5@ | reloff pea %a4@ | endpa RELOC(bootinfo_startup1,%a0) jbsr %a0@ | bootinfo_startup1(endpa, reloff) addql #8,%sp /* * End of boot info returned in %d0. That represents the * end of the loaded image. */ pea %a5@ | reloff movl %d0,%sp@- | nextpa RELOC(pmap_bootstrap1,%a0) jbsr %a0@ | pmap_bootstrap1(nextpa, reloff) addql #8,%sp /* * Updated nextpa returned in %d0. We need to squirrel * that away in a callee-saved register to use later, * after the MMU is enabled. */ movl %d0, %d7 /* NOTE: %d7 is now off-limits!! */ /* * Enable the MMU. * Since the kernel is mapped logical == physical, there is no prep * work to do. */ #include <m68k/m68k/mmu_enable.s> /* * Should be running mapped from this point on */ Lmmuenabled: lea _ASM_LABEL(tmpstk),%sp | re-load the temporary stack jbsr _C_LABEL(vec_init) | initialize the vector table /* phase 2 of pmap setup, returns lwp0 SP in %a0 */ jbsr _C_LABEL(pmap_bootstrap2) movl %a0,%sp | now running on lwp0's stack movl #0,%a6 | terminate the stack back trace movl %d7,%sp@- | push nextpa saved above jbsr _C_LABEL(machine_init) | additional pre-main initialization addql #4,%sp jra _C_LABEL(main) | main() (never returns) ENTRY(paravirt_membar_sync) /* * Store-before-load ordering with respect to matching logic * on the hypervisor side. * * This is the same as membar_sync, but guaranteed never to be * conditionalized or hotpatched away even on uniprocessor * builds and boots -- because under virtualization, we still * have to coordinate with a `device' backed by a hypervisor * that is potentially on another physical CPU even if we * observe only one virtual CPU as the guest. * * I don't see an obvious ordering-only instruction in the m68k * instruction set, but qemu implements CAS with * store-before-load ordering, so this should work for virtio. */ moveq #0,%d0 casl %d0,%d0,%sp@ rts END(paravirt_membar_sync) /* * Misc. global variables. */ .data GLOBAL(mmutype) .long MMU_68040 | default to MMU_68040 GLOBAL(cputype) .long CPU_68040 | default to CPU_68040
