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 1f 711: 72 mflr %r7 73 addis %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@ha 74 addi %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@l 75 76 /* read client interface handler */ 77 lwz %r4,openfirmware_entry@got(%r7) 78 lwz %r4,0(%r4) 79 80 /* 81 * Set the MSR to the OF value. This has the side effect of disabling 82 * exceptions, which prevents preemption later. 83 */ 84 85 lwz %r5,ofmsr@got(%r7) 86 lwz %r5,0(%r5) 87 mtmsr %r5 88 isync 89 90 /* 91 * Set up OF stack. This needs to be potentially accessible in real mode 92 * The pointer to the current kernel stack is placed at the very 93 * top of the stack along with the old MSR so we can get them back 94 * later. 95 */ 96 mr %r5,%r1 97 lwz %r1,ofwstk@got(%r7) 98 addi %r1,%r1,(OFWSTKSZ-32) 99 stw %r5,20(%r1) /* Save real stack pointer */ 100 stw %r2,24(%r1) /* Save curthread */ 101 stw %r6,28(%r1) /* Save old MSR */ 102 li %r5,0 103 stw %r5,4(%r1) 104 stw %r5,0(%r1) 105 106 /* Finally, branch to OF */ 107 mtctr %r4 108 bctrl 109 110 /* Reload stack pointer and MSR from the OFW stack */ 111 lwz %r6,28(%r1) 112 lwz %r2,24(%r1) 113 lwz %r1,20(%r1) 114 115 /* Now set the real MSR */ 116 mtmsr %r6 117 isync 118 119 /* Return */ 120 lwz %r0,4(%r1) 121 mtlr %r0 122 blr 123 124/* 125 * RTAS Entry Point. Similar to the OF one, but simpler (no separate stack) 126 * 127 * C prototype: int rtascall(void *callbuffer, void *rtas_privdat); 128 */ 129 130ASENTRY(rtascall) 131 mflr %r0 132 stw %r0,4(%r1) 133 134 /* GOT pointer in r7 */ 135 bl 1f 1361: 137 mflr %r7 138 addis %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@ha 139 addi %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@l 140 141 /* Record the old MSR to real-mode-accessible area */ 142 mfmsr %r0 143 lwz %r5,rtas_regsave@got(%r7) 144 stw %r0,0(%r5) 145 146 /* read client interface handler */ 147 lwz %r5,rtas_entry@got(%r7) 148 lwz %r5,0(%r5) 149 150 /* Set the MSR to the RTAS value */ 151 lwz %r6,rtasmsr@got(%r7) 152 lwz %r6,0(%r6) 153 mtmsr %r6 154 isync 155 156 /* Branch to RTAS */ 157 mtctr %r5 158 bctrl 159 160 /* GOT pointer in r7 */ 161 bl 1f 1621: 163 mflr %r7 164 addis %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@ha 165 addi %r7,%r7,(_GLOBAL_OFFSET_TABLE_-1b)@l 166 167 /* Now set the MSR back */ 168 lwz %r6,rtas_regsave@got(%r7) 169 lwz %r6,0(%r6) 170 mtmsr %r6 171 isync 172 173 /* And return */ 174 lwz %r0,4(%r1) 175 mtlr %r0 176 blr 177 178