/* $NetBSD: locore.s,v 1.25 1995/02/11 21:08:44 gwr Exp $ */ /* * Copyright (c) 1994 Gordon W. Ross * Copyright (c) 1993 Adam Glass * All rights reserved. * * 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 Adam Glass. * 4. The name of the authors may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 AUTHORS 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. */ #include "assym.s" #include #include #include | remember this is a fun project :) | Define some addresses, mostly so DDB can print useful info. .set _kernbase,KERNBASE .globl _kernbase .set _dvma_base,DVMA_SPACE_START .globl _dvma_base .set _prom_start,MONSTART .globl _prom_start .set _prom_base,PROM_BASE .globl _prom_base | This is where the UPAGES get mapped. .set _kstack,UADDR .globl _kstack | 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 .globl _kernel_text _kernel_text: | This is the entry point, as well as the end of the temporary stack | used during process switch (one 8K page ending at start) .globl tmpstk tmpstk: .globl start start: | First we need to set it up so we can access the sun MMU, and be otherwise | undisturbed. Until otherwise noted, all code must be position independent | as the boot loader put us low in memory, but we are linked high. movw #PSL_HIGHIPL, sr | no interrupts moveq #FC_CONTROL, d0 | make movs access "control" movc d0, sfc | space where the sun3 designers movc d0, dfc | put all the "useful" stuff | Set context zero and stay there until pmap_bootstrap. moveq #0, d0 movsb d0, CONTEXT_REG | In order to "move" the kernel to high memory, we are going to copy the | first 4 Mb of pmegs such that we will be mapped at the linked address. | This is all done by copying in the segment map (top-level MMU table). | We will unscramble which PMEGs we actually need later. movl #(SEGMAP_BASE+0), a0 | src movl #(SEGMAP_BASE+KERNBASE), a1 | dst movl #(0x400000/NBSG), d0 | count L_per_pmeg: movsb a0@, d1 | copy segmap entry movsb d1, a1@ addl #NBSG, a0 | increment pointers addl #NBSG, a1 subql #1, d0 | decrement count bgt L_per_pmeg | Kernel is now double mapped at zero and KERNBASE. | Force a long jump to the relocated code (high VA). movl #IC_CLEAR, d0 | Flush the I-cache movc d0, cacr jmp L_high_code:l | long jump L_high_code: | We are now running in the correctly relocated kernel, so | we are no longer restricted to position-independent code. lea tmpstk, sp | switch to tmpstack jsr _sun3_bootstrap | init everything but calling main() lea _kstack, a1 | proc0 kernel stack (low end) lea a1@(UPAGES*NBPG-4),sp | set stack pointer to last word pea _kstack_fall_off | push something to fall back on :) movl #USRSTACK-4, a2 movl a2, usp | set user stack movl _proc0paddr,a1 | get proc0 pcb addr movl a1,_curpcb | proc0 is running clrw a1@(PCB_FLAGS) | clear flags clrl a1@(PCB_FPCTX) | ensure null FP context | Will do fpu initialization during autoconfig (see fpu.c) /* Interrupts remain disabled until after autoconfig is done. */ moveq #FC_USERD, d0 | make movs access "user data" movc d0, sfc | space for copyin/copyout movc d0, dfc /* * Final preparation for calling main: * * Create a fake exception frame that returns to user mode, * make space for the rest of a fake saved register set, and * pass the first available RAM and a pointer to the register * set to "main()". "main()" will call "icode()", which fakes * an "execve()" system call, which is why we need to do that * ("main()" sets "u.u_ar0" to point to the register set). * When "main()" returns, we're running in process 1 and have * successfully faked the "execve()". We load up the registers from * that set; the "rte" loads the PC and PSR, which jumps to "init". */ clrw sp@- | vector offset/frame type clrl sp@- | PC - filled in by "execve" movw #PSL_USER,sp@- | in user mode clrl sp@- | stack adjust count and padding lea sp@(-64),sp | construct space for D0-D7/A0-A7 pea sp@ | addr of space for D0 jbsr _main | main(firstaddr, r0) addql #4,sp | pop args movl sp@(FR_SP),a0 | grab and load movl a0,usp | user SP moveml sp@+,#0x7FFF | load most registers (all but SSP) addql #8,sp | pop SSP and align word rte #include "lib.s" #include "m68k.s" #include "signal.s" #include "process.s" #include "softint.s" #include "interrupt.s" #include "trap.s" #include "delay.s"