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 * @(#)pmap.h 8.1 (Berkeley) 06/11/93 17 * 18 * from: $Header: pmap.h,v 1.11 93/05/25 10:36:09 torek Exp $ 19 */ 20 21 #ifndef _SPARC_PMAP_H_ 22 #define _SPARC_PMAP_H_ 23 24 #include <machine/pte.h> 25 26 /* 27 * Pmap structure. 28 * 29 * The pmap structure really comes in two variants, one---a single 30 * instance---for kernel virtual memory and the other---up to nproc 31 * instances---for user virtual memory. Unfortunately, we have to mash 32 * both into the same structure. Fortunately, they are almost the same. 33 * 34 * The kernel begins at 0xf8000000 and runs to 0xffffffff (although 35 * some of this is not actually used). Kernel space, including DVMA 36 * space (for now?), is mapped identically into all user contexts. 37 * There is no point in duplicating this mapping in each user process 38 * so they do not appear in the user structures. 39 * 40 * User space begins at 0x00000000 and runs through 0x1fffffff, 41 * then has a `hole', then resumes at 0xe0000000 and runs until it 42 * hits the kernel space at 0xf8000000. This can be mapped 43 * contiguously by ignorning the top two bits and pretending the 44 * space goes from 0 to 37ffffff. Typically the lower range is 45 * used for text+data and the upper for stack, but the code here 46 * makes no such distinction. 47 * 48 * Since each virtual segment covers 256 kbytes, the user space 49 * requires 3584 segments, while the kernel (including DVMA) requires 50 * only 512 segments. 51 * 52 * The segment map entry for virtual segment vseg is offset in 53 * pmap->pm_rsegmap by 0 if pmap is not the kernel pmap, or by 54 * NUSEG if it is. We keep a pointer called pmap->pm_segmap 55 * pre-offset by this value. pmap->pm_segmap thus contains the 56 * values to be loaded into the user portion of the hardware segment 57 * map so as to reach the proper PMEGs within the MMU. The kernel 58 * mappings are `set early' and are always valid in every context 59 * (every change is always propagated immediately). 60 * 61 * The PMEGs within the MMU are loaded `on demand'; when a PMEG is 62 * taken away from context `c', the pmap for context c has its 63 * corresponding pm_segmap[vseg] entry marked invalid (the MMU segment 64 * map entry is also made invalid at the same time). Thus 65 * pm_segmap[vseg] is the `invalid pmeg' number (127 or 511) whenever 66 * the corresponding PTEs are not actually in the MMU. On the other 67 * hand, pm_pte[vseg] is NULL only if no pages in that virtual segment 68 * are in core; otherwise it points to a copy of the 32 or 64 PTEs that 69 * must be loaded in the MMU in order to reach those pages. 70 * pm_npte[vseg] counts the number of valid pages in each vseg. 71 * 72 * XXX performance: faster to count valid bits? 73 * 74 * The kernel pmap cannot malloc() PTEs since malloc() will sometimes 75 * allocate a new virtual segment. Since kernel mappings are never 76 * `stolen' out of the the MMU, we just keep all its PTEs there, and 77 * have no software copies. Its mmu entries are nonetheless kept on lists 78 * so that the code that fiddles with mmu lists has something to fiddle. 79 */ 80 #define NKSEG ((int)((-(unsigned)KERNBASE) / NBPSG)) /* i.e., 512 */ 81 #define NUSEG (4096 - NKSEG) /* i.e., 3584 */ 82 83 /* data appearing in both user and kernel pmaps */ 84 struct pmap_common { 85 union ctxinfo *pmc_ctx; /* current context, if any */ 86 int pmc_ctxnum; /* current context's number */ 87 #if NCPUS > 1 88 simple_lock_data_t pmc_lock; /* spinlock */ 89 #endif 90 int pmc_refcount; /* just what it says */ 91 struct mmuentry *pmc_mmuforw; /* pmap pmeg chain */ 92 struct mmuentry **pmc_mmuback; /* (two way street) */ 93 pmeg_t *pmc_segmap; /* points to pm_rsegmap per above */ 94 u_char *pmc_npte; /* points to pm_rnpte */ 95 int **pmc_pte; /* points to pm_rpte */ 96 }; 97 98 /* data appearing only in user pmaps */ 99 struct pmap { 100 struct pmap_common pmc; 101 pmeg_t pm_rsegmap[NUSEG]; /* segment map */ 102 u_char pm_rnpte[NUSEG]; /* number of valid PTEs per seg */ 103 int *pm_rpte[NUSEG]; /* points to PTEs for valid segments */ 104 }; 105 106 /* data appearing only in the kernel pmap */ 107 struct kpmap { 108 struct pmap_common pmc; 109 pmeg_t pm_rsegmap[NKSEG]; /* segment map */ 110 u_char pm_rnpte[NKSEG]; /* number of valid PTEs per kseg */ 111 int *pm_rpte[NKSEG]; /* always NULL */ 112 }; 113 114 #define pm_ctx pmc.pmc_ctx 115 #define pm_ctxnum pmc.pmc_ctxnum 116 #define pm_lock pmc.pmc_lock 117 #define pm_refcount pmc.pmc_refcount 118 #define pm_mmuforw pmc.pmc_mmuforw 119 #define pm_mmuback pmc.pmc_mmuback 120 #define pm_segmap pmc.pmc_segmap 121 #define pm_npte pmc.pmc_npte 122 #define pm_pte pmc.pmc_pte 123 124 #ifdef KERNEL 125 126 typedef struct pmap *pmap_t; 127 #define PMAP_NULL ((pmap_t)0) 128 129 extern struct kpmap kernel_pmap_store; 130 #define kernel_pmap ((struct pmap *)(&kernel_pmap_store)) 131 132 #define PMAP_ACTIVATE(pmap, pcb, iscurproc) 133 #define PMAP_DEACTIVATE(pmap, pcb) 134 135 /* 136 * Since PTEs also contain type bits, we have to have some way 137 * to tell pmap_enter `this is an IO page' or `this is not to 138 * be cached'. Since physical addresses are always aligned, we 139 * can do this with the low order bits. 140 * 141 * The ordering below is important: PMAP_PGTYPE << PG_TNC must give 142 * exactly the PG_NC and PG_TYPE bits. 143 */ 144 #define PMAP_OBIO 1 /* tells pmap_enter to use PG_OBIO */ 145 #define PMAP_VME16 2 /* etc */ 146 #define PMAP_VME32 3 /* etc */ 147 #define PMAP_NC 4 /* tells pmap_enter to set PG_NC */ 148 #define PMAP_TNC 7 /* mask to get PG_TYPE & PG_NC */ 149 150 #endif /* KERNEL */ 151 152 #endif /* _SPARC_PMAP_H_ */ 153