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 /* read client interface handler */ 70 lis %r4,openfirmware_entry@ha 71 lwz %r4,openfirmware_entry@l(%r4) 72 73 /* 74 * Set the MSR to the OF value. This has the side effect of disabling 75 * exceptions, which prevents preemption later. 76 */ 77 78 lis %r5,ofmsr@ha 79 lwz %r5,ofmsr@l(%r5) 80 mtmsr %r5 81 isync 82 83 /* 84 * Set up OF stack. This needs to be potentially accessible in real mode 85 * The pointer to the current kernel stack is placed at the very 86 * top of the stack along with the old MSR so we can get them back 87 * later. 88 */ 89 mr %r5,%r1 90 lis %r1,(ofwstk+OFWSTKSZ-16)@ha 91 addi %r1,%r1,(ofwstk+OFWSTKSZ-16)@l 92 stw %r5,8(%r1) /* Save real stack pointer */ 93 stw %r6,12(%r1) /* Save old MSR */ 94 li %r5,0 95 stw %r5,4(%r1) 96 stw %r5,0(%r1) 97 98 /* Finally, branch to OF */ 99 mtctr %r4 100 bctrl 101 102 /* Reload stack pointer and MSR from the OFW stack */ 103 lwz %r6,12(%r1) 104 lwz %r1,8(%r1) 105 106 /* Now set the real MSR */ 107 mtmsr %r6 108 isync 109 110 /* Return */ 111 lwz %r0,4(%r1) 112 mtlr %r0 113 blr 114 115/* 116 * RTAS Entry Point. Similar to the OF one, but simpler (no separate stack) 117 * 118 * C prototype: int rtascall(void *callbuffer, void *rtas_privdat); 119 */ 120 121ASENTRY(rtascall) 122 mflr %r0 123 stw %r0,4(%r1) 124 125 /* Record the old MSR to real-mode-accessible area */ 126 mfmsr %r0 127 lis %r5,rtas_regsave@ha 128 stw %r0,rtas_regsave@l(%r5) 129 130 /* read client interface handler */ 131 lis %r5,rtas_entry@ha 132 lwz %r5,rtas_entry@l(%r5) 133 134 /* Set the MSR to the RTAS value */ 135 lis %r6,rtasmsr@ha 136 lwz %r6,rtasmsr@l(%r6) 137 mtmsr %r6 138 isync 139 140 /* Branch to RTAS */ 141 mtctr %r5 142 bctrl 143 144 /* Now set the MSR back */ 145 lis %r6,rtas_regsave@ha 146 lwz %r6,rtas_regsave@l(%r6) 147 mtmsr %r6 148 isync 149 150 /* And return */ 151 lwz %r0,4(%r1) 152 mtlr %r0 153 blr 154 155