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/*-
* Copyright (C) 2009-2011 Nathan Whitehorn
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 TOOLS GMBH 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.
*
* $FreeBSD$
*/
#include <sys/syscall.h>
#include <machine/trap.h>
#include <machine/param.h>
#include <machine/spr.h>
#include <machine/asm.h>
#define OFWSTKSZ 4096 /* 4K Open Firmware stack */
/*
* Globals
*/
.data
GLOBAL(ofmsr)
.long 0, 0, 0, 0, 0 /* msr/sprg0-3 used in Open Firmware */
GLOBAL(rtasmsr)
.long 0
GLOBAL(openfirmware_entry)
.long 0 /* Open Firmware entry point */
GLOBAL(rtas_entry)
.long 0 /* RTAS entry point */
.align 4
ofwstk:
.space OFWSTKSZ
rtas_regsave:
.space 4
/*
* Open Firmware Entry Point. May need to enter real mode.
*
* C prototype: int ofwcall(void *callbuffer);
*/
ASENTRY(ofwcall)
mflr %r0
stw %r0,4(%r1)
/* Record the old MSR */
mfmsr %r6
/* GOT pointer in r7 */
bl _GLOBAL_OFFSET_TABLE_@local-4
mflr %r7
/* read client interface handler */
lwz %r4,openfirmware_entry@got(%r7)
lwz %r4,0(%r4)
/*
* Set the MSR to the OF value. This has the side effect of disabling
* exceptions, which prevents preemption later.
*/
lwz %r5,ofmsr@got(%r7)
lwz %r5,0(%r5)
mtmsr %r5
isync
/*
* Set up OF stack. This needs to be potentially accessible in real mode
* The pointer to the current kernel stack is placed at the very
* top of the stack along with the old MSR so we can get them back
* later.
*/
mr %r5,%r1
lwz %r1,ofwstk@got(%r7)
addi %r1,%r1,(OFWSTKSZ-32)
stw %r5,20(%r1) /* Save real stack pointer */
stw %r2,24(%r1) /* Save curthread */
stw %r6,28(%r1) /* Save old MSR */
li %r5,0
stw %r5,4(%r1)
stw %r5,0(%r1)
/* Finally, branch to OF */
mtctr %r4
bctrl
/* Reload stack pointer and MSR from the OFW stack */
lwz %r6,28(%r1)
lwz %r2,24(%r1)
lwz %r1,20(%r1)
/* Now set the real MSR */
mtmsr %r6
isync
/* Return */
lwz %r0,4(%r1)
mtlr %r0
blr
/*
* RTAS Entry Point. Similar to the OF one, but simpler (no separate stack)
*
* C prototype: int rtascall(void *callbuffer, void *rtas_privdat);
*/
ASENTRY(rtascall)
mflr %r0
stw %r0,4(%r1)
/* GOT pointer in r7 */
bl _GLOBAL_OFFSET_TABLE_@local-4
mflr %r7
/* Record the old MSR to real-mode-accessible area */
mfmsr %r0
lwz %r5,rtas_regsave@got(%r7)
stw %r0,0(%r5)
/* read client interface handler */
lwz %r5,rtas_entry@got(%r7)
lwz %r5,0(%r5)
/* Set the MSR to the RTAS value */
lwz %r6,rtasmsr@got(%r7)
lwz %r6,0(%r6)
mtmsr %r6
isync
/* Branch to RTAS */
mtctr %r5
bctrl
/* GOT pointer in r7 */
bl _GLOBAL_OFFSET_TABLE_@local-4
mflr %r7
/* Now set the MSR back */
lwz %r6,rtas_regsave@got(%r7)
lwz %r6,0(%r6)
mtmsr %r6
isync
/* And return */
lwz %r0,4(%r1)
mtlr %r0
blr
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