1/*- 2 * Copyright (C) 2009-2011 Nathan Whitehorn 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 18 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 20 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 21 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 22 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 23 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 * 25 * $FreeBSD$ 26 */ 27 28#include <sys/syscall.h> 29 30#include <machine/trap.h> 31#include <machine/param.h> 32#include <machine/spr.h> 33#include <machine/asm.h> 34 35#define OFWSTKSZ 4096 /* 4K Open Firmware stack */ 36 37/* 38 * Globals 39 */ 40 .data 41GLOBAL(ofmsr) 42 .long 0, 0, 0, 0, 0 /* msr/sprg0-3 used in Open Firmware */ 43GLOBAL(rtasmsr) 44 .long 0 45GLOBAL(openfirmware_entry) 46 .long 0 /* Open Firmware entry point */ 47GLOBAL(rtas_entry) 48 .long 0 /* RTAS entry point */ 49 50 .align 4 51ofwstk: 52 .space OFWSTKSZ 53rtas_regsave: 54 .space 4 55 56/* 57 * Open Firmware Entry Point. May need to enter real mode. 58 * 59 * C prototype: int ofwcall(void *callbuffer); 60 */ 61 62ASENTRY(ofwcall) 63 mflr %r0 64 stw %r0,4(%r1) 65 66 /* Record the old MSR */ 67 mfmsr %r6 68 69 /* GOT pointer in r7 */ 70 bl _GLOBAL_OFFSET_TABLE_@local-4 71 mflr %r7 72 73 /* read client interface handler */ 74 lwz %r4,openfirmware_entry@got(%r7) 75 lwz %r4,0(%r4) 76 77 /* 78 * Set the MSR to the OF value. This has the side effect of disabling 79 * exceptions, which prevents preemption later. 80 */ 81 82 lwz %r5,ofmsr@got(%r7) 83 lwz %r5,0(%r5) 84 mtmsr %r5 85 isync 86 87 /* 88 * Set up OF stack. This needs to be potentially accessible in real mode 89 * The pointer to the current kernel stack is placed at the very 90 * top of the stack along with the old MSR so we can get them back 91 * later. 92 */ 93 mr %r5,%r1 94 lwz %r1,ofwstk@got(%r7) 95 addi %r1,%r1,(OFWSTKSZ-32) 96 stw %r5,20(%r1) /* Save real stack pointer */ 97 stw %r2,24(%r1) /* Save curthread */ 98 stw %r6,28(%r1) /* Save old MSR */ 99 li %r5,0 100 stw %r5,4(%r1) 101 stw %r5,0(%r1) 102 103 /* Finally, branch to OF */ 104 mtctr %r4 105 bctrl 106 107 /* Reload stack pointer and MSR from the OFW stack */ 108 lwz %r6,28(%r1) 109 lwz %r2,24(%r1) 110 lwz %r1,20(%r1) 111 112 /* Now set the real MSR */ 113 mtmsr %r6 114 isync 115 116 /* Return */ 117 lwz %r0,4(%r1) 118 mtlr %r0 119 blr 120 121/* 122 * RTAS Entry Point. Similar to the OF one, but simpler (no separate stack) 123 * 124 * C prototype: int rtascall(void *callbuffer, void *rtas_privdat); 125 */ 126 127ASENTRY(rtascall) 128 mflr %r0 129 stw %r0,4(%r1) 130 131 /* GOT pointer in r7 */ 132 bl _GLOBAL_OFFSET_TABLE_@local-4 133 mflr %r7 134 135 /* Record the old MSR to real-mode-accessible area */ 136 mfmsr %r0 137 lwz %r5,rtas_regsave@got(%r7) 138 stw %r0,0(%r5) 139 140 /* read client interface handler */ 141 lwz %r5,rtas_entry@got(%r7) 142 lwz %r5,0(%r5) 143 144 /* Set the MSR to the RTAS value */ 145 lwz %r6,rtasmsr@got(%r7) 146 lwz %r6,0(%r6) 147 mtmsr %r6 148 isync 149 150 /* Branch to RTAS */ 151 mtctr %r5 152 bctrl 153 154 /* GOT pointer in r7 */ 155 bl _GLOBAL_OFFSET_TABLE_@local-4 156 mflr %r7 157 158 /* Now set the MSR back */ 159 lwz %r6,rtas_regsave@got(%r7) 160 lwz %r6,0(%r6) 161 mtmsr %r6 162 isync 163 164 /* And return */ 165 lwz %r0,4(%r1) 166 mtlr %r0 167 blr 168 169