+/*
+ * Copyright (c) 1992 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This software was developed by the Computer Systems Engineering group
+ * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
+ * contributed to Berkeley.
+ *
+ * %sccs.include.redist.c%
+ *
+ * @(#)pmap.h 7.1 (Berkeley) %G%
+ *
+ * from: $Header: pmap.h,v 1.9 92/06/17 06:10:22 torek Exp $
+ */
+
+#ifndef _SPARC_PMAP_H_
+#define _SPARC_PMAP_H_
+
+#include "machine/pte.h"
+
+/*
+ * Pmap structure.
+ *
+ * The pmap structure really comes in two variants, one---a single
+ * instance---for kernel virtual memory and the other---up to nproc
+ * instances---for user virtual memory. Unfortunately, we have to mash
+ * both into the same structure. Fortunately, they are almost the same.
+ *
+ * The kernel begins at 0xf8000000 and runs to 0xffffffff (although
+ * some of this is not actually used). Kernel space, including DVMA
+ * space (for now?), is mapped identically into all user contexts.
+ * There is no point in duplicating this mapping in each user process
+ * so they do not appear in the user structures.
+ *
+ * User space begins at 0x00000000 and runs through 0x1fffffff,
+ * then has a `hole', then resumes at 0xe0000000 and runs until it
+ * hits the kernel space at 0xf8000000. This can be mapped
+ * contiguously by ignorning the top two bits and pretending the
+ * space goes from 0 to 37ffffff. Typically the lower range is
+ * used for text+data and the upper for stack, but the code here
+ * makes no such distinction.
+ *
+ * Since each virtual segment covers 256 kbytes, the user space
+ * requires 3584 segments, while the kernel (including DVMA) requires
+ * only 512 segments.
+ *
+ * The segment map entry for virtual segment vseg is offset in
+ * pmap->pm_rsegmap by 0 if pmap is not the kernel pmap, or by
+ * NUSEG if it is. We keep a pointer called pmap->pm_segmap
+ * pre-offset by this value. pmap->pm_segmap thus contains the
+ * values to be loaded into the user portion of the hardware segment
+ * map so as to reach the proper PMEGs within the MMU. The kernel
+ * mappings are `set early' and are always valid in every context
+ * (every change is always propagated immediately).
+ *
+ * The PMEGs within the MMU are loaded `on demand'; when a PMEG is
+ * taken away from context `c', the pmap for context c has its
+ * corresponding pm_segmap[vseg] entry marked invalid (the MMU segment
+ * map entry is also made invalid at the same time). Thus
+ * pm_segmap[vseg] is the `invalid pmeg' number (127 or 511) whenever
+ * the corresponding PTEs are not actually in the MMU. On the other
+ * hand, pm_pte[vseg] is NULL only if no pages in that virtual segment
+ * are in core; otherwise it points to a copy of the 32 or 64 PTEs that
+ * must be loaded in the MMU in order to reach those pages.
+ * pm_npte[vseg] counts the number of valid pages in each vseg.
+ *
+ * XXX performance: faster to count valid bits?
+ *
+ * The kernel pmap cannot malloc() PTEs since malloc() will sometimes
+ * allocate a new virtual segment. Since kernel mappings are never
+ * `stolen' out of the the MMU, we just keep all its PTEs there, and
+ * have no software copies. Its mmu entries are nonetheless kept on lists
+ * so that the code that fiddles with mmu lists has something to fiddle.
+ */
+#define NKSEG ((int)((-(unsigned)KERNBASE) / NBPSG)) /* i.e., 512 */
+#define NUSEG (4096 - NKSEG) /* i.e., 3584 */
+
+/* data appearing in both user and kernel pmaps */
+struct pmap_common {
+ union ctxinfo *pmc_ctx; /* current context, if any */
+ int pmc_ctxnum; /* current context's number */
+#if NCPUS > 1
+ simple_lock_data_t pmc_lock; /* spinlock */
+#endif
+ int pmc_refcount; /* just what it says */
+ struct mmuentry *pmc_mmuforw; /* pmap pmeg chain */
+ struct mmuentry **pmc_mmuback; /* (two way street) */
+ pmeg_t *pmc_segmap; /* points to pm_rsegmap per above */
+ u_char *pmc_npte; /* points to pm_rnpte */
+ int **pmc_pte; /* points to pm_rpte */
+};
+
+/* data appearing only in user pmaps */
+struct pmap {
+ struct pmap_common pmc;
+ pmeg_t pm_rsegmap[NUSEG]; /* segment map */
+ u_char pm_rnpte[NUSEG]; /* number of valid PTEs per seg */
+ int *pm_rpte[NUSEG]; /* points to PTEs for valid segments */
+};
+
+/* data appearing only in the kernel pmap */
+struct kpmap {
+ struct pmap_common pmc;
+ pmeg_t pm_rsegmap[NKSEG]; /* segment map */
+ u_char pm_rnpte[NKSEG]; /* number of valid PTEs per kseg */
+ int *pm_rpte[NKSEG]; /* always NULL */
+};
+
+#define pm_ctx pmc.pmc_ctx
+#define pm_ctxnum pmc.pmc_ctxnum
+#define pm_lock pmc.pmc_lock
+#define pm_refcount pmc.pmc_refcount
+#define pm_mmuforw pmc.pmc_mmuforw
+#define pm_mmuback pmc.pmc_mmuback
+#define pm_segmap pmc.pmc_segmap
+#define pm_npte pmc.pmc_npte
+#define pm_pte pmc.pmc_pte
+
+#ifdef KERNEL
+
+typedef struct pmap *pmap_t;
+#define PMAP_NULL ((pmap_t)0)
+
+extern struct kpmap kernel_pmap_store;
+#define kernel_pmap ((struct pmap *)(&kernel_pmap_store))
+
+#define PMAP_ACTIVATE(pmap, pcb, iscurproc)
+#define PMAP_DEACTIVATE(pmap, pcb)
+
+/*
+ * Since PTEs also contain type bits, we have to have some way
+ * to tell pmap_enter `this is an IO page' or `this is not to
+ * be cached'. Since physical addresses are always aligned, we
+ * can do this with the low order bits.
+ *
+ * The ordering below is important: PMAP_PGTYPE << PG_TNC must give
+ * exactly the PG_NC and PG_TYPE bits.
+ */
+#define PMAP_OBIO 1 /* tells pmap_enter to use PG_OBIO */
+#define PMAP_VME16 2 /* etc */
+#define PMAP_VME32 3 /* etc */
+#define PMAP_NC 4 /* tells pmap_enter to set PG_NC */
+#define PMAP_TNC 7 /* mask to get PG_TYPE & PG_NC */
+
+#endif KERNEL
+
+#endif /* _SPARC_PMAP_H_ */
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