1 /* 2 * Copyright (c) 1992 The Regents of the University of California. 3 * 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 * %sccs.include.redist.c% 10 * 11 * @(#)pte.h 7.1 (Berkeley) 07/13/92 12 * 13 * from: $Header: pte.h,v 1.4 92/06/17 06:10:25 torek Exp $ 14 */ 15 16 /* 17 * Sun-4 (sort of) and 4c (SparcStation) Page Table Entries 18 * (Sun call them `Page Map Entries'). 19 */ 20 21 #ifndef LOCORE 22 /* 23 * Segment maps contain `pmeg' (Page Map Entry Group) numbers. 24 * A PMEG is simply an index that names a group of 32 (sun4) or 25 * 64 (sun4c) PTEs. 26 */ 27 #ifdef SUN4 28 typedef u_short pmeg_t; /* 9 bits needed per Sun-4 segmap entry */ 29 #else 30 typedef u_char pmeg_t; /* 7 bits needed per Sun-4c segmap entry */ 31 #endif 32 #endif 33 34 /* 35 * Address translation works as follows: 36 * 37 * 1. test va<31:29> -- these must be 000 or 111 (or you get a fault) 38 * 2. concatenate context_reg<2:0> and va<29:18> to get a 15 bit number; 39 * use this to index the segment maps, yeilding a 7 or 9 bit value. 40 * (for sun4c) 41 * 3. take the value from (2) above and concatenate va<17:12> to 42 * get a `page map entry' index. This gives a 32-bit PTE. 43 * (for sun4) 44 * 3. take the value from (2) above and concatenate va<17:13> to 45 * get a `page map entry' index. This gives a 32-bit PTE. 46 * 47 * In other words: 48 * 49 * struct sun4_virtual_addr { 50 * u_int :2, (required to be the same as bit 29) 51 * va_seg:12, (virtual segment) 52 * va_pg:5, (virtual page within segment) 53 * va_off:13; (offset within page) 54 * }; 55 * struct sun4c_virtual_addr { 56 * u_int :2, (required to be the same as bit 29) 57 * va_seg:12, (virtual segment) 58 * va_pg:6, (virtual page within segment) 59 * va_off:12; (offset within page) 60 * }; 61 * 62 * Then, given any `va': 63 * 64 * extern pmeg_t segmap[8][1<<12]; ([16][1<<12] for sun4) 65 * extern int ptetable[128][1<<6]; ([512][1<<5] for sun4) 66 * 67 * (the above being in the hardware, accessed as Alternate Address Spaces) 68 * 69 * physseg = segmap[curr_ctx][va.va_seg]; 70 * pte = ptetable[physseg][va.va_pg]; 71 * if (!(pte & PG_V)) TRAP(); 72 * if (writing && !pte.pg_w) TRAP(); 73 * if (usermode && pte.pg_s) TRAP(); 74 * if (pte & PG_NC) DO_NOT_USE_CACHE_FOR_THIS_ACCESS(); 75 * pte |= PG_U; (mark used/accessed) 76 * if (writing) pte |= PG_M; (mark modified) 77 * ptetable[physseg][va.va_pg] = pte; 78 * physadr = ((pte & PG_PFNUM) << PGSHIFT) | va.va_off; 79 */ 80 81 #define NBPSG (1 << 18) /* bytes per segment */ 82 #define SGSHIFT 18 /* log2(NBPSG) */ 83 #define SGOFSET (NBPSG - 1) /* mask for segment offset */ 84 85 /* number of PTEs that map one segment (not number that fit in one segment!) */ 86 #if defined(SUN4) && defined(SUN4C) 87 #define NPTESG nptesg /* (which someone will have to init) */ 88 #else 89 #define NPTESG (NBPSG / NBPG) 90 #endif 91 92 /* virtual address to virtual segment number */ 93 #define VA_VSEG(va) (((int)(va) >> SGSHIFT) & 0xfff) 94 95 /* virtual address to virtual page number, for Sun-4 and Sun-4c */ 96 #define VA_SUN4_VPG(va) (((int)(va) >> 13) & 31) 97 #define VA_SUN4C_VPG(va) (((int)(va) >> 12) & 63) 98 99 /* truncate virtual address to segment base */ 100 #define VA_ROUNDDOWNTOSEG(va) ((int)(va) & ~SGOFSET) 101 102 /* virtual segment to virtual address (must sign extend!) */ 103 #define VSTOVA(vseg) (((int)(vseg) << 20) >> 2) 104 105 #ifdef SUN4 106 #ifdef SUN4C 107 int issun4c; 108 #define VA_VPG(va) (issun4c ? VA_SUN4C_VPG(va) : VA_SUN4_VPG(va)) 109 #else /* sun4 and not sun4c */ 110 #define VA_VPG(va) VA_SUN4_VPG(va) 111 #endif 112 #else /* not sun4; must be 4c */ 113 #define VA_VPG(va) VA_SUN4C_VPG(va) 114 #endif 115 116 /* there is no `struct pte'; we just use `int' */ 117 #define PG_V 0x80000000 118 #define PG_PROT 0x60000000 /* both protection bits */ 119 #define PG_W 0x40000000 /* allowed to write */ 120 #define PG_S 0x20000000 /* supervisor only */ 121 #define PG_NC 0x10000000 /* non-cacheable */ 122 #define PG_TYPE 0x0c000000 /* both type bits */ 123 124 #define PG_OBMEM 0x00000000 /* on board memory */ 125 #define PG_OBIO 0x04000000 /* on board I/O (incl. Sbus on 4c) */ 126 #ifdef SUN4 127 #define PG_VME16 0x08000000 /* 16-bit-data VME space */ 128 #define PG_VME32 0x0c000000 /* 32-bit-data VME space */ 129 #endif 130 131 #define PG_U 0x02000000 132 #define PG_M 0x01000000 133 #define PG_MBZ 0x00f80000 /* unused; must be zero (oh really?) */ 134 #define PG_PFNUM 0x0007ffff /* n.b.: only 16 bits on sun4c */ 135 136 #define PG_TNC_SHIFT 26 /* shift to get PG_TYPE + PG_NC */ 137 #define PG_M_SHIFT 24 /* shift to get PG_M, PG_U */ 138 139 /*efine PG_NOACC 0 ** XXX */ 140 #define PG_KR 0x20000000 141 #define PG_KW 0x60000000 142 #define PG_URKR 0 143 #define PG_UW 0x40000000 144 145 #ifdef KGDB 146 /* but we will define one for gdb anyway */ 147 struct pte { 148 u_int pg_v:1, 149 pg_w:1, 150 pg_s:1, 151 pg_nc:1; 152 enum pgtype { pg_obmem, pg_obio, pg_vme16, pg_vme32 } pg_type:2; 153 u_int pg_u:1, 154 pg_m:1, 155 pg_mbz:5, 156 pg_pfnum:19; 157 }; 158 #endif 159 160 /* 161 * These are needed in the register window code 162 * to check the validity of (ostensible) user stack PTEs. 163 */ 164 #define PG_VSHIFT 30 /* (va>>vshift)==0 or -1 => valid */ 165 /* XXX fix this name, it is a va shift not a pte bit shift! */ 166 167 #define PG_PROTSHIFT 29 168 #define PG_PROTUWRITE 6 /* PG_V,PG_W,!PG_S */ 169 #define PG_PROTUREAD 4 /* PG_V,!PG_W,!PG_S */ 170 171 /* static __inline int PG_VALID(void *va) { 172 register int t = va; t >>= PG_VSHIFT; return (t == 0 || t == -1); 173 } */ 174