xref: /illumos-gate/usr/src/uts/common/vm/seg_kp.h (revision 2d6eb4a5e0a47d30189497241345dc5466bb68ab)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #ifndef	_VM_SEG_KP_H
28 #define	_VM_SEG_KP_H
29 
30 /*
31  * segkp (as in kernel pageable) is a segment driver that supports allocation
32  * of page-aligned variable size of vm resources.
33  *
34  * Each vm resource represents a page-aligned range of virtual addresses.
35  * The caller may specify whether the resource should include a redzone,
36  * be locked down, or be zero initialized.
37  */
38 
39 #include <vm/seg.h>
40 #include <sys/vmem.h>
41 
42 #ifdef	__cplusplus
43 extern "C" {
44 #endif
45 
46 #ifdef	_KERNEL
47 
48 /*
49  * Private information per overall segkp segment (as opposed
50  * to per resource within segment). There are as many anon slots
51  * allocated as there there are pages in the segment.
52  */
53 struct segkp_segdata {
54 	struct anon_hdr	*kpsd_anon;	/* anon structs */
55 	vmem_t		*kpsd_arena; 	/* virtual memory descriptor */
56 	struct segkp_data **kpsd_hash;	/* Hash table for lookups */
57 };
58 
59 #define	SEGKP_VMEM(seg)	(((struct segkp_segdata *)(seg)->s_data)->kpsd_arena)
60 
61 /*
62  * A hash table is used to aid in the lookup of a kpd's based on vaddr.
63  * Since the heaviest use of segkp occurs from segkp_*get and segkp_*release,
64  * the hashing is based on the vaddr used by these routines.
65  */
66 #define	SEGKP_HASHSZ		256	/* power of two */
67 #define	SEGKP_HASHMASK		(SEGKP_HASHSZ - 1)
68 #define	SEGKP_HASH(vaddr)	\
69 	((int)(((uintptr_t)vaddr >> PAGESHIFT) & SEGKP_HASHMASK))
70 
71 struct segkp_data {
72 	kmutex_t	kp_lock;	/* per resource lock */
73 	caddr_t		kp_base;	/* starting addr of chunk */
74 	size_t		kp_len;		/* # of bytes */
75 	uint_t		kp_flags;	/* state info */
76 	int		kp_cookie;	/* index into cache array */
77 	ulong_t		kp_anon_idx;	/* index into main anon array */
78 					/* in segkp_segdata */
79 	struct anon_hdr	*kp_anon;	/* anon structs */
80 	struct segkp_data *kp_next;	/* ptr to next in hash chain */
81 };
82 
83 /*
84  * Flag bits
85  *
86  */
87 #define	KPD_ZERO	0x01		/* initialize resource with 0 */
88 #define	KPD_LOCKED	0x02		/* resources locked */
89 #define	KPD_NO_ANON	0x04		/* no swap resources required */
90 #define	KPD_HASREDZONE	0x08		/* include a redzone */
91 #define	KPD_NOWAIT	0x10		/* do not wait for res. if unavail. */
92 #define	KPD_WRITEDIRTY	0x20		/* dirty pages should be flushed */
93 #define	KPD_HASAMP	0x40		/* anon_hdr managed by caller */
94 
95 /*
96  * A cache of segkp elements may be created via segkp_cache_init().
97  * The elements on the freelist all have the same len and flags value.
98  * The cookie passed to the client is an index into the freelist array.
99  */
100 struct segkp_cache  {
101 	int		kpf_max;		/* max # of elements allowed */
102 	int		kpf_count;		/* current no. of elments */
103 	int		kpf_inuse;		/* list inuse */
104 	uint_t		kpf_flags;		/* seg_kp flag value */
105 	size_t		kpf_len;		/* len of resource */
106 	struct seg	*kpf_seg;		/* segment */
107 	struct segkp_data *kpf_list;		/* list of kpd's */
108 };
109 #define	SEGKP_MAX_CACHE		4	/* Number of caches maintained */
110 
111 /*
112  * Define redzone, and stack_to_memory macros.
113  * The redzone is PAGESIZE bytes.
114  */
115 #ifdef	STACK_GROWTH_DOWN
116 #define	KPD_REDZONE(kpd)	(0)
117 #define	stom(v, flags)	(((flags) & KPD_HASREDZONE) ? (v) + PAGESIZE : (v))
118 
119 #else	/* STACK_GROWTH_DOWN */
120 
121 #define	KPD_REDZONE(kpd) (btop(kpd->kp_len) - 1)
122 #define	stom(v)	(v)
123 #endif	/* STACK_GROWTH_DOWN */
124 
125 #define	SEGKP_MAPLEN(len, flags) \
126 	(((flags) & KPD_HASREDZONE) ? (len) - PAGESIZE : (len))
127 
128 extern	struct seg *segkp;
129 /* If segkp becomes more than one seg this test will need changing. */
130 #define	SEG_IS_SEGKP(SEG)	((SEG) == segkp)
131 
132 /*
133  * Public routine declarations not part of the segment ops vector go here.
134  */
135 int	segkp_create(struct seg *seg);
136 caddr_t	segkp_get(struct seg *seg, size_t len, uint_t flags);
137 void	segkp_release(struct seg *seg, caddr_t vaddr);
138 void *  segkp_cache_init(struct seg *seg, int maxsize, size_t len,
139 		uint_t flags);
140 void	segkp_cache_free();
141 caddr_t segkp_cache_get(void *cookie);
142 int	segkp_map_red(void);
143 void	segkp_unmap_red(void);
144 size_t	swapsize(caddr_t v);
145 
146 /* Special currently only used by schedctl. */
147 struct anon_map;	/* Make the compiler happy about the next line. */
148 caddr_t segkp_get_withanonmap(struct seg *, size_t, uint_t, struct anon_map *);
149 
150 /*
151  * We allow explicit calls to segkp_fault, even though it's part
152  * of the segkp ops vector.
153  */
154 faultcode_t segkp_fault(struct hat *hat, struct seg *seg, caddr_t addr,
155 	size_t len, enum fault_type type, enum seg_rw rw);
156 
157 #endif	/* _KERNEL */
158 
159 #ifdef	__cplusplus
160 }
161 #endif
162 
163 #endif	/* _VM_SEG_KP_H */
164