1 /* $NetBSD: control.c,v 1.2 2001/11/30 18:06:55 fredette Exp $ */ 2 3 /*- 4 * Copyright (c) 1996 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Adam Glass, Gordon W. Ross, and Matthew Fredette. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/param.h> 40 41 #include <machine/pte.h> 42 #include <sun2/sun2/control.h> 43 44 int 45 get_context() 46 { 47 return (get_control_byte(CONTEXT_REG) & CONTEXT_MASK); 48 } 49 50 void 51 set_context(c) 52 int c; 53 { 54 set_control_byte(CONTEXT_REG, (c & CONTEXT_MASK)); 55 } 56 57 u_int 58 get_pte(va) 59 vaddr_t va; 60 { 61 u_int pte; 62 63 pte = get_control_word(CONTROL_ADDR_BUILD(PGMAP_BASE, va)); 64 if (pte & PG_VALID) { 65 /* 66 * This clears bit 30 (the kernel readable bit, which 67 * should always be set), bit 28 (which should always 68 * be set), bit 26 (the user writable bit, which we 69 * always have tracking the kernel writable bit), and 70 * bit 25 (the fill-on-demand bit, which should always 71 * be set). In the protection, this leaves bit 29 72 * (the kernel writable bit) and bit 27 (the user 73 * readable bit). See pte.h for more about this 74 * hack. 75 */ 76 pte &= ~(0x56000000); 77 /* 78 * Flip bit 27 (the user readable bit) to become bit 79 * 27 (the PG_SYSTEM bit). 80 */ 81 pte ^= (PG_SYSTEM); 82 } 83 return (pte); 84 } 85 86 void 87 set_pte(va, pte) 88 vaddr_t va; 89 u_int pte; 90 { 91 if (pte & PG_VALID) { 92 /* Clear bit 26 (the user writable bit). */ 93 pte &= (~0x04000000); 94 /* 95 * Flip bit 27 (the PG_SYSTEM bit) to become bit 27 96 * (the user readable bit). 97 */ 98 pte ^= (PG_SYSTEM); 99 /* 100 * Always set bits 30 (the kernel readable bit), bit 101 * 28, and bit 25 (the fill-on-demand bit), and set 102 * bit 26 (the user writable bit) iff bit 29 (the 103 * kernel writable bit) is set *and* bit 27 (the user 104 * readable bit) is set. This latter bit of logic is 105 * expressed in the bizarre second term below, chosen 106 * because it needs no branches. 107 */ 108 #if (PG_WRITE >> 2) != PG_SYSTEM 109 #error "PG_WRITE and PG_SYSTEM definitions don't match!" 110 #endif 111 pte |= 0x52000000 112 | ((((pte & PG_WRITE) >> 2) & pte) >> 1); 113 } 114 set_control_word(CONTROL_ADDR_BUILD(PGMAP_BASE, va), pte); 115 } 116 117 int 118 get_segmap(va) 119 vaddr_t va; 120 { 121 return (get_control_byte(CONTROL_ADDR_BUILD(SEGMAP_BASE, va))); 122 } 123 124 void 125 set_segmap(va, sme) 126 vaddr_t va; 127 int sme; 128 { 129 set_control_byte(CONTROL_ADDR_BUILD(SEGMAP_BASE, va), sme); 130 } 131