1 /* 2 * Copyright (c) 1992, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This software was developed by the Computer Systems Engineering group 6 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 7 * contributed to Berkeley. 8 * 9 * All advertising materials mentioning features or use of this software 10 * must display the following acknowledgement: 11 * This product includes software developed by the University of 12 * California, Lawrence Berkeley Laboratory. 13 * 14 * %sccs.include.redist.c% 15 * 16 * @(#)pte.h 8.1 (Berkeley) 06/11/93 17 * 18 * from: $Header: pte.h,v 1.5 92/11/26 02:04:43 torek Exp $ 19 */ 20 21 /* 22 * Sun-4 (sort of) and 4c (SparcStation) Page Table Entries 23 * (Sun call them `Page Map Entries'). 24 */ 25 26 #ifndef LOCORE 27 /* 28 * Segment maps contain `pmeg' (Page Map Entry Group) numbers. 29 * A PMEG is simply an index that names a group of 32 (sun4) or 30 * 64 (sun4c) PTEs. 31 */ 32 #ifdef SUN4 33 typedef u_short pmeg_t; /* 9 bits needed per Sun-4 segmap entry */ 34 #else 35 typedef u_char pmeg_t; /* 7 bits needed per Sun-4c segmap entry */ 36 #endif 37 #endif 38 39 /* 40 * Address translation works as follows: 41 * 42 * 1. test va<31:29> -- these must be 000 or 111 (or you get a fault) 43 * 2. concatenate context_reg<2:0> and va<29:18> to get a 15 bit number; 44 * use this to index the segment maps, yeilding a 7 or 9 bit value. 45 * (for sun4c) 46 * 3. take the value from (2) above and concatenate va<17:12> to 47 * get a `page map entry' index. This gives a 32-bit PTE. 48 * (for sun4) 49 * 3. take the value from (2) above and concatenate va<17:13> to 50 * get a `page map entry' index. This gives a 32-bit PTE. 51 * 52 * In other words: 53 * 54 * struct sun4_virtual_addr { 55 * u_int :2, (required to be the same as bit 29) 56 * va_seg:12, (virtual segment) 57 * va_pg:5, (virtual page within segment) 58 * va_off:13; (offset within page) 59 * }; 60 * struct sun4c_virtual_addr { 61 * u_int :2, (required to be the same as bit 29) 62 * va_seg:12, (virtual segment) 63 * va_pg:6, (virtual page within segment) 64 * va_off:12; (offset within page) 65 * }; 66 * 67 * Then, given any `va': 68 * 69 * extern pmeg_t segmap[8][1<<12]; ([16][1<<12] for sun4) 70 * extern int ptetable[128][1<<6]; ([512][1<<5] for sun4) 71 * 72 * (the above being in the hardware, accessed as Alternate Address Spaces) 73 * 74 * physseg = segmap[curr_ctx][va.va_seg]; 75 * pte = ptetable[physseg][va.va_pg]; 76 * if (!(pte & PG_V)) TRAP(); 77 * if (writing && !pte.pg_w) TRAP(); 78 * if (usermode && pte.pg_s) TRAP(); 79 * if (pte & PG_NC) DO_NOT_USE_CACHE_FOR_THIS_ACCESS(); 80 * pte |= PG_U; (mark used/accessed) 81 * if (writing) pte |= PG_M; (mark modified) 82 * ptetable[physseg][va.va_pg] = pte; 83 * physadr = ((pte & PG_PFNUM) << PGSHIFT) | va.va_off; 84 */ 85 86 #define NBPSG (1 << 18) /* bytes per segment */ 87 #define SGSHIFT 18 /* log2(NBPSG) */ 88 #define SGOFSET (NBPSG - 1) /* mask for segment offset */ 89 90 /* number of PTEs that map one segment (not number that fit in one segment!) */ 91 #if defined(SUN4) && defined(SUN4C) 92 #define NPTESG nptesg /* (which someone will have to init) */ 93 #else 94 #define NPTESG (NBPSG / NBPG) 95 #endif 96 97 /* virtual address to virtual segment number */ 98 #define VA_VSEG(va) (((int)(va) >> SGSHIFT) & 0xfff) 99 100 /* virtual address to virtual page number, for Sun-4 and Sun-4c */ 101 #define VA_SUN4_VPG(va) (((int)(va) >> 13) & 31) 102 #define VA_SUN4C_VPG(va) (((int)(va) >> 12) & 63) 103 104 /* truncate virtual address to segment base */ 105 #define VA_ROUNDDOWNTOSEG(va) ((int)(va) & ~SGOFSET) 106 107 /* virtual segment to virtual address (must sign extend!) */ 108 #define VSTOVA(vseg) (((int)(vseg) << 20) >> 2) 109 110 #ifdef SUN4 111 #ifdef SUN4C 112 int issun4c; 113 #define VA_VPG(va) (issun4c ? VA_SUN4C_VPG(va) : VA_SUN4_VPG(va)) 114 #else /* sun4 and not sun4c */ 115 #define VA_VPG(va) VA_SUN4_VPG(va) 116 #endif 117 #else /* not sun4; must be 4c */ 118 #define VA_VPG(va) VA_SUN4C_VPG(va) 119 #endif 120 121 /* there is no `struct pte'; we just use `int' */ 122 #define PG_V 0x80000000 123 #define PG_PROT 0x60000000 /* both protection bits */ 124 #define PG_W 0x40000000 /* allowed to write */ 125 #define PG_S 0x20000000 /* supervisor only */ 126 #define PG_NC 0x10000000 /* non-cacheable */ 127 #define PG_TYPE 0x0c000000 /* both type bits */ 128 129 #define PG_OBMEM 0x00000000 /* on board memory */ 130 #define PG_OBIO 0x04000000 /* on board I/O (incl. Sbus on 4c) */ 131 #ifdef SUN4 132 #define PG_VME16 0x08000000 /* 16-bit-data VME space */ 133 #define PG_VME32 0x0c000000 /* 32-bit-data VME space */ 134 #endif 135 136 #define PG_U 0x02000000 137 #define PG_M 0x01000000 138 #define PG_MBZ 0x00f80000 /* unused; must be zero (oh really?) */ 139 #define PG_PFNUM 0x0007ffff /* n.b.: only 16 bits on sun4c */ 140 141 #define PG_TNC_SHIFT 26 /* shift to get PG_TYPE + PG_NC */ 142 #define PG_M_SHIFT 24 /* shift to get PG_M, PG_U */ 143 144 /*efine PG_NOACC 0 ** XXX */ 145 #define PG_KR 0x20000000 146 #define PG_KW 0x60000000 147 #define PG_URKR 0 148 #define PG_UW 0x40000000 149 150 #ifdef KGDB 151 /* but we will define one for gdb anyway */ 152 struct pte { 153 u_int pg_v:1, 154 pg_w:1, 155 pg_s:1, 156 pg_nc:1; 157 enum pgtype { pg_obmem, pg_obio, pg_vme16, pg_vme32 } pg_type:2; 158 u_int pg_u:1, 159 pg_m:1, 160 pg_mbz:5, 161 pg_pfnum:19; 162 }; 163 #endif 164 165 /* 166 * These are needed in the register window code 167 * to check the validity of (ostensible) user stack PTEs. 168 */ 169 #define PG_VSHIFT 30 /* (va>>vshift)==0 or -1 => valid */ 170 /* XXX fix this name, it is a va shift not a pte bit shift! */ 171 172 #define PG_PROTSHIFT 29 173 #define PG_PROTUWRITE 6 /* PG_V,PG_W,!PG_S */ 174 #define PG_PROTUREAD 4 /* PG_V,!PG_W,!PG_S */ 175 176 /* static __inline int PG_VALID(void *va) { 177 register int t = va; t >>= PG_VSHIFT; return (t == 0 || t == -1); 178 } */ 179