5c845fde2e
executables. The goal here, not yet accomplished, is to let the e500 kernel run under QEMU by setting KERNBASE to something that fits in low memory and then having the kernel relocate itself at runtime.
169 lines
3.8 KiB
ArmAsm
169 lines
3.8 KiB
ArmAsm
/*-
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* Copyright (C) 2009-2011 Nathan Whitehorn
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/syscall.h>
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#include <machine/trap.h>
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#include <machine/param.h>
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#include <machine/spr.h>
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#include <machine/asm.h>
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#define OFWSTKSZ 4096 /* 4K Open Firmware stack */
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/*
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* Globals
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*/
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.data
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GLOBAL(ofmsr)
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.long 0, 0, 0, 0, 0 /* msr/sprg0-3 used in Open Firmware */
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GLOBAL(rtasmsr)
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.long 0
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GLOBAL(openfirmware_entry)
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.long 0 /* Open Firmware entry point */
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GLOBAL(rtas_entry)
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.long 0 /* RTAS entry point */
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.align 4
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ofwstk:
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.space OFWSTKSZ
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rtas_regsave:
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.space 4
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/*
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* Open Firmware Entry Point. May need to enter real mode.
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*
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* C prototype: int ofwcall(void *callbuffer);
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*/
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ASENTRY(ofwcall)
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mflr %r0
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stw %r0,4(%r1)
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/* Record the old MSR */
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mfmsr %r6
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/* GOT pointer in r7 */
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bl _GLOBAL_OFFSET_TABLE_@local-4
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mflr %r7
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/* read client interface handler */
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lwz %r4,openfirmware_entry@got(%r7)
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lwz %r4,0(%r4)
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/*
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* Set the MSR to the OF value. This has the side effect of disabling
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* exceptions, which prevents preemption later.
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*/
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lwz %r5,ofmsr@got(%r7)
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lwz %r5,0(%r5)
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mtmsr %r5
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isync
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/*
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* Set up OF stack. This needs to be potentially accessible in real mode
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* The pointer to the current kernel stack is placed at the very
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* top of the stack along with the old MSR so we can get them back
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* later.
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*/
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mr %r5,%r1
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lwz %r1,ofwstk@got(%r7)
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addi %r1,%r1,(OFWSTKSZ-32)
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stw %r5,20(%r1) /* Save real stack pointer */
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stw %r2,24(%r1) /* Save curthread */
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stw %r6,28(%r1) /* Save old MSR */
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li %r5,0
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stw %r5,4(%r1)
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stw %r5,0(%r1)
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/* Finally, branch to OF */
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mtctr %r4
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bctrl
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/* Reload stack pointer and MSR from the OFW stack */
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lwz %r6,28(%r1)
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lwz %r2,24(%r1)
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lwz %r1,20(%r1)
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/* Now set the real MSR */
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mtmsr %r6
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isync
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/* Return */
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lwz %r0,4(%r1)
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mtlr %r0
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blr
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/*
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* RTAS Entry Point. Similar to the OF one, but simpler (no separate stack)
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*
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* C prototype: int rtascall(void *callbuffer, void *rtas_privdat);
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*/
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ASENTRY(rtascall)
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mflr %r0
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stw %r0,4(%r1)
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/* GOT pointer in r7 */
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bl _GLOBAL_OFFSET_TABLE_@local-4
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mflr %r7
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/* Record the old MSR to real-mode-accessible area */
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mfmsr %r0
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lwz %r5,rtas_regsave@got(%r7)
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stw %r0,0(%r5)
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/* read client interface handler */
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lwz %r5,rtas_entry@got(%r7)
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lwz %r5,0(%r5)
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/* Set the MSR to the RTAS value */
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lwz %r6,rtasmsr@got(%r7)
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lwz %r6,0(%r6)
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mtmsr %r6
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isync
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/* Branch to RTAS */
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mtctr %r5
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bctrl
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/* GOT pointer in r7 */
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bl _GLOBAL_OFFSET_TABLE_@local-4
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mflr %r7
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/* Now set the MSR back */
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lwz %r6,rtas_regsave@got(%r7)
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lwz %r6,0(%r6)
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mtmsr %r6
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isync
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/* And return */
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lwz %r0,4(%r1)
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mtlr %r0
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blr
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