1 /* $NetBSD: control.c,v 1.6 2008/04/28 20:23:37 martin 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: control.c,v 1.6 2008/04/28 20:23:37 martin Exp $"); 34 35 #include <sys/param.h> 36 37 #include <machine/pte.h> 38 #include <sun2/sun2/control.h> 39 40 int 41 get_context(void) 42 { 43 return (get_control_byte(CONTEXT_REG) & CONTEXT_MASK); 44 } 45 46 void 47 set_context(int c) 48 { 49 set_control_byte(CONTEXT_REG, (c & CONTEXT_MASK)); 50 } 51 52 u_int 53 get_pte(vaddr_t va) 54 { 55 u_int pte; 56 57 pte = get_control_word(CONTROL_ADDR_BUILD(PGMAP_BASE, va)); 58 if (pte & PG_VALID) { 59 /* 60 * This clears bit 30 (the kernel readable bit, which 61 * should always be set), bit 28 (which should always 62 * be set), bit 26 (the user writable bit, which we 63 * always have tracking the kernel writable bit), and 64 * bit 25 (the fill-on-demand bit, which should always 65 * be set). In the protection, this leaves bit 29 66 * (the kernel writable bit) and bit 27 (the user 67 * readable bit). See pte.h for more about this 68 * hack. 69 */ 70 pte &= ~(0x56000000); 71 /* 72 * Flip bit 27 (the user readable bit) to become bit 73 * 27 (the PG_SYSTEM bit). 74 */ 75 pte ^= (PG_SYSTEM); 76 } 77 return (pte); 78 } 79 80 void 81 set_pte(vaddr_t va, u_int pte) 82 { 83 if (pte & PG_VALID) { 84 /* Clear bit 26 (the user writable bit). */ 85 pte &= (~0x04000000); 86 /* 87 * Flip bit 27 (the PG_SYSTEM bit) to become bit 27 88 * (the user readable bit). 89 */ 90 pte ^= (PG_SYSTEM); 91 /* 92 * Always set bits 30 (the kernel readable bit), bit 93 * 28, and bit 25 (the fill-on-demand bit), and set 94 * bit 26 (the user writable bit) iff bit 29 (the 95 * kernel writable bit) is set *and* bit 27 (the user 96 * readable bit) is set. This latter bit of logic is 97 * expressed in the bizarre second term below, chosen 98 * because it needs no branches. 99 */ 100 #if (PG_WRITE >> 2) != PG_SYSTEM 101 #error "PG_WRITE and PG_SYSTEM definitions don't match!" 102 #endif 103 pte |= 0x52000000 104 | ((((pte & PG_WRITE) >> 2) & pte) >> 1); 105 } 106 set_control_word(CONTROL_ADDR_BUILD(PGMAP_BASE, va), pte); 107 } 108 109 int 110 get_segmap(vaddr_t va) 111 { 112 return (get_control_byte(CONTROL_ADDR_BUILD(SEGMAP_BASE, va))); 113 } 114 115 void 116 set_segmap(vaddr_t va, int sme) 117 { 118 set_control_byte(CONTROL_ADDR_BUILD(SEGMAP_BASE, va), sme); 119 } 120