WebSVN – HelenOS – Diff – /kernel/trunk/generic/src/mm/backend_anon.c


/*
 * Copyright (C) 2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/**
 * @file    backend_anon.c
 * @brief   Backend for anonymous memory address space areas.
 *
 */
 
#include <mm/as.h>
#include <mm/page.h>
#include <genarch/mm/page_pt.h>
#include <genarch/mm/page_ht.h>
#include <mm/frame.h>
#include <mm/slab.h>
#include <synch/mutex.h>
#include <adt/list.h>
#include <adt/btree.h>
#include <errno.h>
#include <arch/types.h>
#include <typedefs.h>
#include <align.h>
#include <arch.h>
 
static int anon_page_fault(as_area_t *area, __address addr, pf_access_t access);
static void anon_frame_free(as_area_t *area, __address page, __address frame);
static void anon_share(as_area_t *area);
 
 
 
 
mem_backend_t anon_backend = {
    .page_fault = anon_page_fault,
    .frame_free = anon_frame_free,
    .share = anon_share
};
 
/** Service a page fault in the anonymous memory address space area.
 *
 * The address space area and page tables must be already locked.
 *
 * @param area Pointer to the address space area.
 * @param addr Faulting virtual address.
 * @param access Access mode that caused the fault (i.e. read/write/exec).
 *
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
 */
int anon_page_fault(as_area_t *area, __address addr, pf_access_t access)
{
    __address frame;
 
    if (!as_area_check_access(area, access))
        return AS_PF_FAULT;
 
    if (area->sh_info) {
        btree_node_t *leaf;
       
        /*
         * The area is shared, chances are that the mapping can be found
         * in the pagemap of the address space area share info structure.
         * In the case that the pagemap does not contain the respective
         * mapping, a new frame is allocated and the mapping is created.
         */
        mutex_lock(&area->sh_info->lock);
        frame = (__address) btree_search(&area->sh_info->pagemap,
            ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
        if (!frame) {
            bool allocate = true;
            int i;
           
            /*
             * Zero can be returned as a valid frame address.
             * Just a small workaround.
             */
            for (i = 0; i < leaf->keys; i++) {
                if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
                    allocate = false;
                    break;
                }
            }
            if (allocate) {
                frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
                memsetb(PA2KA(frame), FRAME_SIZE, 0);
               
                /*
                 * Insert the address of the newly allocated frame to the pagemap.
                 */
                btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base, (void *) frame, leaf);
            }
        }
        mutex_unlock(&area->sh_info->lock);
    } else {
 
        /*
         * In general, there can be several reasons that
         * can have caused this fault.
         *
         * - non-existent mapping: the area is an anonymous
         *   area (e.g. heap or stack) and so far has not been
         *   allocated a frame for the faulting page
         *
         * - non-present mapping: another possibility,
         *   currently not implemented, would be frame
         *   reuse; when this becomes a possibility,
         *   do not forget to distinguish between
         *   the different causes
         */
        frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
    }
   
    /*
     * Map 'page' to 'frame'.
     * Note that TLB shootdown is not attempted as only new information is being
     * inserted into page tables.
     */
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
        panic("Could not insert used space.\n");
       
    return AS_PF_OK;
}
 
/** Free a frame that is backed by the anonymous memory backend.
 *
 * The address space area and page tables must be already locked.
 *
 * @param area Ignored.
 * @param page Ignored.
 * @param frame Frame to be released.
 */
void anon_frame_free(as_area_t *area, __address page, __address frame)
{
    frame_free(ADDR2PFN(frame));
}
 
/** Share the anonymous address space area.
 *
 * Sharing of anonymous area is done by duplicating its entire mapping
 * to the pagemap. Page faults will primarily search for frames there.
 *
 * The address space area and page tables must be already locked.
 *
 * @param area Address space area to be shared.
 */
void anon_share(as_area_t *area)
{
    link_t *cur;
 
    /*
     * Copy used portions of the area to sh_info's page map.
     */
    mutex_lock(&area->sh_info->lock);
    for (cur = area->used_space.leaf_head.next; cur != &area->used_space.leaf_head; cur = cur->next) {
        btree_node_t *node;
        int i;
       
        node = list_get_instance(cur, btree_node_t, leaf_link);
        for (i = 0; i < node->keys; i++) {
            __address base = node->key[i];
            count_t count = (count_t) node->value[i];
            int j;
           
            for (j = 0; j < count; j++) {
                pte_t *pte;
           
                page_table_lock(area->as, false);
                pte = page_mapping_find(area->as, base + j*PAGE_SIZE);
                ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
                btree_insert(&area->sh_info->pagemap, (base + j*PAGE_SIZE) - area->base,
                    (void *) PTE_GET_FRAME(pte), NULL);
                page_table_unlock(area->as, false);
            }
               
        }
    }
    mutex_unlock(&area->sh_info->lock);
}
 

Subversion Repositories HelenOS

(root)/kernel/trunk/generic/src/mm/backend_anon.c – Rev 1424 → 1425

Rev 1424		Rev 1425
1	/*	1	/*
2	* Copyright (C) 2006 Jakub Jermar	2	* Copyright (C) 2006 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/**	29	/**
30	* @file backend_anon.c	30	* @file backend_anon.c
31	* @brief Backend for anonymous memory address space areas.	31	* @brief Backend for anonymous memory address space areas.
32	*	32	*
33	*/	33	*/
34		34
35	#include <mm/as.h>	35	#include <mm/as.h>
36	#include <mm/page.h>	36	#include <mm/page.h>
37	#include <genarch/mm/page_pt.h>	37	#include <genarch/mm/page_pt.h>
38	#include <genarch/mm/page_ht.h>	38	#include <genarch/mm/page_ht.h>
39	#include <mm/frame.h>	39	#include <mm/frame.h>
40	#include <mm/slab.h>	40	#include <mm/slab.h>
41	#include <synch/mutex.h>	41	#include <synch/mutex.h>
42	#include <adt/list.h>	42	#include <adt/list.h>
43	#include <adt/btree.h>	43	#include <adt/btree.h>
44	#include <errno.h>	44	#include <errno.h>
45	#include <arch/types.h>	45	#include <arch/types.h>
46	#include <typedefs.h>	46	#include <typedefs.h>
47	#include <align.h>	47	#include <align.h>
48	#include <arch.h>	48	#include <arch.h>
49		49
50	static int anon_page_fault(as_area_t *area, __address addr, pf_access_t access);	50	static int anon_page_fault(as_area_t *area, __address addr, pf_access_t access);
51	static void anon_frame_free(as_area_t *area, __address page, __address frame);	51	static void anon_frame_free(as_area_t *area, __address page, __address frame);
52	static void anon_share(as_area_t *area);	52	static void anon_share(as_area_t *area);
53		53
54	/*	-
55	* Anonymous memory backend.	-
56	*/	-
57	mem_backend_t anon_backend = {	54	mem_backend_t anon_backend = {
58	.page_fault = anon_page_fault,	55	.page_fault = anon_page_fault,
59	.frame_free = anon_frame_free,	56	.frame_free = anon_frame_free,
60	.share = anon_share	57	.share = anon_share
61	};	58	};
62		59
63	/** Service a page fault in the anonymous memory address space area.	60	/** Service a page fault in the anonymous memory address space area.
64	*	61	*
65	* The address space area and page tables must be already locked.	62	* The address space area and page tables must be already locked.
66	*	63	*
67	* @param area Pointer to the address space area.	64	* @param area Pointer to the address space area.
68	* @param addr Faulting virtual address.	65	* @param addr Faulting virtual address.
69	* @param access Access mode that caused the fault (i.e. read/write/exec).	66	* @param access Access mode that caused the fault (i.e. read/write/exec).
70	*	67	*
71	* @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).	68	* @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
72	*/	69	*/
73	int anon_page_fault(as_area_t *area, __address addr, pf_access_t access)	70	int anon_page_fault(as_area_t *area, __address addr, pf_access_t access)
74	{	71	{
75	__address frame;	72	__address frame;
76		73
77	if (!as_area_check_access(area, access))	74	if (!as_area_check_access(area, access))
78	return AS_PF_FAULT;	75	return AS_PF_FAULT;
79		76
80	if (area->sh_info) {	77	if (area->sh_info) {
81	btree_node_t *leaf;	78	btree_node_t *leaf;
82		79
83	/*	80	/*
84	* The area is shared, chances are that the mapping can be found	81	* The area is shared, chances are that the mapping can be found
85	* in the pagemap of the address space area share info structure.	82	* in the pagemap of the address space area share info structure.
86	* In the case that the pagemap does not contain the respective	83	* In the case that the pagemap does not contain the respective
87	* mapping, a new frame is allocated and the mapping is created.	84	* mapping, a new frame is allocated and the mapping is created.
88	*/	85	*/
89	mutex_lock(&area->sh_info->lock);	86	mutex_lock(&area->sh_info->lock);
90	frame = (__address) btree_search(&area->sh_info->pagemap,	87	frame = (__address) btree_search(&area->sh_info->pagemap,
91	ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);	88	ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
92	if (!frame) {	89	if (!frame) {
93	bool allocate = true;	90	bool allocate = true;
94	int i;	91	int i;
95		92
96	/*	93	/*
97	* Zero can be returned as a valid frame address.	94	* Zero can be returned as a valid frame address.
98	* Just a small workaround.	95	* Just a small workaround.
99	*/	96	*/
100	for (i = 0; i < leaf->keys; i++) {	97	for (i = 0; i < leaf->keys; i++) {
101	if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {	98	if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
102	allocate = false;	99	allocate = false;
103	break;	100	break;
104	}	101	}
105	}	102	}
106	if (allocate) {	103	if (allocate) {
107	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	104	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
108	memsetb(PA2KA(frame), FRAME_SIZE, 0);	105	memsetb(PA2KA(frame), FRAME_SIZE, 0);
109		106
110	/*	107	/*
111	* Insert the address of the newly allocated frame to the pagemap.	108	* Insert the address of the newly allocated frame to the pagemap.
112	*/	109	*/
113	btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base, (void *) frame, leaf);	110	btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base, (void *) frame, leaf);
114	}	111	}
115	}	112	}
116	mutex_unlock(&area->sh_info->lock);	113	mutex_unlock(&area->sh_info->lock);
117	} else {	114	} else {
118		115
119	/*	116	/*
120	* In general, there can be several reasons that	117	* In general, there can be several reasons that
121	* can have caused this fault.	118	* can have caused this fault.
122	*	119	*
123	* - non-existent mapping: the area is an anonymous	120	* - non-existent mapping: the area is an anonymous
124	* area (e.g. heap or stack) and so far has not been	121	* area (e.g. heap or stack) and so far has not been
125	* allocated a frame for the faulting page	122	* allocated a frame for the faulting page
126	*	123	*
127	* - non-present mapping: another possibility,	124	* - non-present mapping: another possibility,
128	* currently not implemented, would be frame	125	* currently not implemented, would be frame
129	* reuse; when this becomes a possibility,	126	* reuse; when this becomes a possibility,
130	* do not forget to distinguish between	127	* do not forget to distinguish between
131	* the different causes	128	* the different causes
132	*/	129	*/
133	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	130	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
134	memsetb(PA2KA(frame), FRAME_SIZE, 0);	131	memsetb(PA2KA(frame), FRAME_SIZE, 0);
135	}	132	}
136		133
137	/*	134	/*
138	* Map 'page' to 'frame'.	135	* Map 'page' to 'frame'.
139	* Note that TLB shootdown is not attempted as only new information is being	136	* Note that TLB shootdown is not attempted as only new information is being
140	* inserted into page tables.	137	* inserted into page tables.
141	*/	138	*/
142	page_mapping_insert(AS, addr, frame, as_area_get_flags(area));	139	page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
143	if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))	140	if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
144	panic("Could not insert used space.\n");	141	panic("Could not insert used space.\n");
145		142
146	return AS_PF_OK;	143	return AS_PF_OK;
147	}	144	}
148		145
149	/** Free a frame that is backed by the anonymous memory backend.	146	/** Free a frame that is backed by the anonymous memory backend.
150	*	147	*
151	* The address space area and page tables must be already locked.	148	* The address space area and page tables must be already locked.
152	*	149	*
153	* @param area Ignored.	150	* @param area Ignored.
154	* @param page Ignored.	151	* @param page Ignored.
155	* @param frame Frame to be released.	152	* @param frame Frame to be released.
156	*/	153	*/
157	void anon_frame_free(as_area_t *area, __address page, __address frame)	154	void anon_frame_free(as_area_t *area, __address page, __address frame)
158	{	155	{
159	frame_free(ADDR2PFN(frame));	156	frame_free(ADDR2PFN(frame));
160	}	157	}
161		158
162	/** Share the anonymous address space area.	159	/** Share the anonymous address space area.
163	*	160	*
164	* Sharing of anonymous area is done by duplicating its entire mapping	161	* Sharing of anonymous area is done by duplicating its entire mapping
165	* to the pagemap. Page faults will primarily search for frames there.	162	* to the pagemap. Page faults will primarily search for frames there.
166	*	163	*
167	* The address space area and page tables must be already locked.	164	* The address space area and page tables must be already locked.
168	*	165	*
169	* @param area Address space area to be shared.	166	* @param area Address space area to be shared.
170	*/	167	*/
171	void anon_share(as_area_t *area)	168	void anon_share(as_area_t *area)
172	{	169	{
173	link_t *cur;	170	link_t *cur;
174		171
175	/*	172	/*
176	* Copy used portions of the area to sh_info's page map.	173	* Copy used portions of the area to sh_info's page map.
177	*/	174	*/
178	mutex_lock(&area->sh_info->lock);	175	mutex_lock(&area->sh_info->lock);
179	for (cur = area->used_space.leaf_head.next; cur != &area->used_space.leaf_head; cur = cur->next) {	176	for (cur = area->used_space.leaf_head.next; cur != &area->used_space.leaf_head; cur = cur->next) {
180	btree_node_t *node;	177	btree_node_t *node;
181	int i;	178	int i;
182		179
183	node = list_get_instance(cur, btree_node_t, leaf_link);	180	node = list_get_instance(cur, btree_node_t, leaf_link);
184	for (i = 0; i < node->keys; i++) {	181	for (i = 0; i < node->keys; i++) {
185	__address base = node->key[i];	182	__address base = node->key[i];
186	count_t count = (count_t) node->value[i];	183	count_t count = (count_t) node->value[i];
187	int j;	184	int j;
188		185
189	for (j = 0; j < count; j++) {	186	for (j = 0; j < count; j++) {
190	pte_t *pte;	187	pte_t *pte;
191		188
192	page_table_lock(area->as, false);	189	page_table_lock(area->as, false);
193	pte = page_mapping_find(area->as, base + j*PAGE_SIZE);	190	pte = page_mapping_find(area->as, base + j*PAGE_SIZE);
194	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));	191	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
195	btree_insert(&area->sh_info->pagemap, (base + j*PAGE_SIZE) - area->base,	192	btree_insert(&area->sh_info->pagemap, (base + j*PAGE_SIZE) - area->base,
196	(void *) PTE_GET_FRAME(pte), NULL);	193	(void *) PTE_GET_FRAME(pte), NULL);
197	page_table_unlock(area->as, false);	194	page_table_unlock(area->as, false);
198	}	195	}
199		196
200	}	197	}
201	}	198	}
202	mutex_unlock(&area->sh_info->lock);	199	mutex_unlock(&area->sh_info->lock);
203	}	200	}
204		201