WebSVN – HelenOS-historic – 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.
 */
 
/** @addtogroup genericmm
 * @{
 */
 
/**
 * @file
 * @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 = (__address) 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);
            }
        }
        frame_reference_add(ADDR2PFN(frame));
        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 = (__address)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(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 and address space area 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);
                frame_reference_add(ADDR2PFN(PTE_GET_FRAME(pte)));
            }
               
        }
    }
    mutex_unlock(&area->sh_info->lock);
}
 
/** @}
 */
 

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/backend_anon.c – Rev 1757 → 1760

Rev 1757		Rev 1760
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	/** @addtogroup genericmm	29	/** @addtogroup genericmm
30	* @{	30	* @{
31	*/	31	*/
32		32
33	/**	33	/**
34	* @file	34	* @file
35	* @brief Backend for anonymous memory address space areas.	35	* @brief Backend for anonymous memory address space areas.
36	*	36	*
37	*/	37	*/
38		38
39	#include <mm/as.h>	39	#include <mm/as.h>
40	#include <mm/page.h>	40	#include <mm/page.h>
41	#include <genarch/mm/page_pt.h>	41	#include <genarch/mm/page_pt.h>
42	#include <genarch/mm/page_ht.h>	42	#include <genarch/mm/page_ht.h>
43	#include <mm/frame.h>	43	#include <mm/frame.h>
44	#include <mm/slab.h>	44	#include <mm/slab.h>
45	#include <synch/mutex.h>	45	#include <synch/mutex.h>
46	#include <adt/list.h>	46	#include <adt/list.h>
47	#include <adt/btree.h>	47	#include <adt/btree.h>
48	#include <errno.h>	48	#include <errno.h>
49	#include <arch/types.h>	49	#include <arch/types.h>
50	#include <typedefs.h>	50	#include <typedefs.h>
51	#include <align.h>	51	#include <align.h>
52	#include <arch.h>	52	#include <arch.h>
53		53
54	static int anon_page_fault(as_area_t *area, __address addr, pf_access_t access);	54	static int anon_page_fault(as_area_t *area, __address addr, pf_access_t access);
55	static void anon_frame_free(as_area_t *area, __address page, __address frame);	55	static void anon_frame_free(as_area_t *area, __address page, __address frame);
56	static void anon_share(as_area_t *area);	56	static void anon_share(as_area_t *area);
57		57
58	mem_backend_t anon_backend = {	58	mem_backend_t anon_backend = {
59	.page_fault = anon_page_fault,	59	.page_fault = anon_page_fault,
60	.frame_free = anon_frame_free,	60	.frame_free = anon_frame_free,
61	.share = anon_share	61	.share = anon_share
62	};	62	};
63		63
64	/** Service a page fault in the anonymous memory address space area.	64	/** Service a page fault in the anonymous memory address space area.
65	*	65	*
66	* The address space area and page tables must be already locked.	66	* The address space area and page tables must be already locked.
67	*	67	*
68	* @param area Pointer to the address space area.	68	* @param area Pointer to the address space area.
69	* @param addr Faulting virtual address.	69	* @param addr Faulting virtual address.
70	* @param access Access mode that caused the fault (i.e. read/write/exec).	70	* @param access Access mode that caused the fault (i.e. read/write/exec).
71	*	71	*
72	* @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).	72	* @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
73	*/	73	*/
74	int anon_page_fault(as_area_t *area, __address addr, pf_access_t access)	74	int anon_page_fault(as_area_t *area, __address addr, pf_access_t access)
75	{	75	{
76	__address frame;	76	__address frame;
77		77
78	if (!as_area_check_access(area, access))	78	if (!as_area_check_access(area, access))
79	return AS_PF_FAULT;	79	return AS_PF_FAULT;
80		80
81	if (area->sh_info) {	81	if (area->sh_info) {
82	btree_node_t *leaf;	82	btree_node_t *leaf;
83		83
84	/*	84	/*
85	* The area is shared, chances are that the mapping can be found	85	* The area is shared, chances are that the mapping can be found
86	* in the pagemap of the address space area share info structure.	86	* in the pagemap of the address space area share info structure.
87	* In the case that the pagemap does not contain the respective	87	* In the case that the pagemap does not contain the respective
88	* mapping, a new frame is allocated and the mapping is created.	88	* mapping, a new frame is allocated and the mapping is created.
89	*/	89	*/
90	mutex_lock(&area->sh_info->lock);	90	mutex_lock(&area->sh_info->lock);
91	frame = (__address) btree_search(&area->sh_info->pagemap,	91	frame = (__address) btree_search(&area->sh_info->pagemap,
92	ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);	92	ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
93	if (!frame) {	93	if (!frame) {
94	bool allocate = true;	94	bool allocate = true;
95	int i;	95	int i;
96		96
97	/*	97	/*
98	* Zero can be returned as a valid frame address.	98	* Zero can be returned as a valid frame address.
99	* Just a small workaround.	99	* Just a small workaround.
100	*/	100	*/
101	for (i = 0; i < leaf->keys; i++) {	101	for (i = 0; i < leaf->keys; i++) {
102	if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {	102	if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
103	allocate = false;	103	allocate = false;
104	break;	104	break;
105	}	105	}
106	}	106	}
107	if (allocate) {	107	if (allocate) {
108	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	108	frame = (__address) frame_alloc(ONE_FRAME, 0);
109	memsetb(PA2KA(frame), FRAME_SIZE, 0);	109	memsetb(PA2KA(frame), FRAME_SIZE, 0);
110		110
111	/*	111	/*
112	* Insert the address of the newly allocated frame to the pagemap.	112	* Insert the address of the newly allocated frame to the pagemap.
113	*/	113	*/
114	btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base, (void *) frame, leaf);	114	btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE) - area->base, (void *) frame, leaf);
115	}	115	}
116	}	116	}
117	frame_reference_add(ADDR2PFN(frame));	117	frame_reference_add(ADDR2PFN(frame));
118	mutex_unlock(&area->sh_info->lock);	118	mutex_unlock(&area->sh_info->lock);
119	} else {	119	} else {
120		120
121	/*	121	/*
122	* In general, there can be several reasons that	122	* In general, there can be several reasons that
123	* can have caused this fault.	123	* can have caused this fault.
124	*	124	*
125	* - non-existent mapping: the area is an anonymous	125	* - non-existent mapping: the area is an anonymous
126	* area (e.g. heap or stack) and so far has not been	126	* area (e.g. heap or stack) and so far has not been
127	* allocated a frame for the faulting page	127	* allocated a frame for the faulting page
128	*	128	*
129	* - non-present mapping: another possibility,	129	* - non-present mapping: another possibility,
130	* currently not implemented, would be frame	130	* currently not implemented, would be frame
131	* reuse; when this becomes a possibility,	131	* reuse; when this becomes a possibility,
132	* do not forget to distinguish between	132	* do not forget to distinguish between
133	* the different causes	133	* the different causes
134	*/	134	*/
135	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	135	frame = (__address)frame_alloc(ONE_FRAME, 0);
136	memsetb(PA2KA(frame), FRAME_SIZE, 0);	136	memsetb(PA2KA(frame), FRAME_SIZE, 0);
137	}	137	}
138		138
139	/*	139	/*
140	* Map 'page' to 'frame'.	140	* Map 'page' to 'frame'.
141	* Note that TLB shootdown is not attempted as only new information is being	141	* Note that TLB shootdown is not attempted as only new information is being
142	* inserted into page tables.	142	* inserted into page tables.
143	*/	143	*/
144	page_mapping_insert(AS, addr, frame, as_area_get_flags(area));	144	page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
145	if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))	145	if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
146	panic("Could not insert used space.\n");	146	panic("Could not insert used space.\n");
147		147
148	return AS_PF_OK;	148	return AS_PF_OK;
149	}	149	}
150		150
151	/** Free a frame that is backed by the anonymous memory backend.	151	/** Free a frame that is backed by the anonymous memory backend.
152	*	152	*
153	* The address space area and page tables must be already locked.	153	* The address space area and page tables must be already locked.
154	*	154	*
155	* @param area Ignored.	155	* @param area Ignored.
156	* @param page Ignored.	156	* @param page Ignored.
157	* @param frame Frame to be released.	157	* @param frame Frame to be released.
158	*/	158	*/
159	void anon_frame_free(as_area_t *area, __address page, __address frame)	159	void anon_frame_free(as_area_t *area, __address page, __address frame)
160	{	160	{
161	frame_free(ADDR2PFN(frame));	161	frame_free(frame);
162	}	162	}
163		163
164	/** Share the anonymous address space area.	164	/** Share the anonymous address space area.
165	*	165	*
166	* Sharing of anonymous area is done by duplicating its entire mapping	166	* Sharing of anonymous area is done by duplicating its entire mapping
167	* to the pagemap. Page faults will primarily search for frames there.	167	* to the pagemap. Page faults will primarily search for frames there.
168	*	168	*
169	* The address space and address space area must be already locked.	169	* The address space and address space area must be already locked.
170	*	170	*
171	* @param area Address space area to be shared.	171	* @param area Address space area to be shared.
172	*/	172	*/
173	void anon_share(as_area_t *area)	173	void anon_share(as_area_t *area)
174	{	174	{
175	link_t *cur;	175	link_t *cur;
176		176
177	/*	177	/*
178	* Copy used portions of the area to sh_info's page map.	178	* Copy used portions of the area to sh_info's page map.
179	*/	179	*/
180	mutex_lock(&area->sh_info->lock);	180	mutex_lock(&area->sh_info->lock);
181	for (cur = area->used_space.leaf_head.next; cur != &area->used_space.leaf_head; cur = cur->next) {	181	for (cur = area->used_space.leaf_head.next; cur != &area->used_space.leaf_head; cur = cur->next) {
182	btree_node_t *node;	182	btree_node_t *node;
183	int i;	183	int i;
184		184
185	node = list_get_instance(cur, btree_node_t, leaf_link);	185	node = list_get_instance(cur, btree_node_t, leaf_link);
186	for (i = 0; i < node->keys; i++) {	186	for (i = 0; i < node->keys; i++) {
187	__address base = node->key[i];	187	__address base = node->key[i];
188	count_t count = (count_t) node->value[i];	188	count_t count = (count_t) node->value[i];
189	int j;	189	int j;
190		190
191	for (j = 0; j < count; j++) {	191	for (j = 0; j < count; j++) {
192	pte_t *pte;	192	pte_t *pte;
193		193
194	page_table_lock(area->as, false);	194	page_table_lock(area->as, false);
195	pte = page_mapping_find(area->as, base + j*PAGE_SIZE);	195	pte = page_mapping_find(area->as, base + j*PAGE_SIZE);
196	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));	196	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
197	btree_insert(&area->sh_info->pagemap, (base + j*PAGE_SIZE) - area->base,	197	btree_insert(&area->sh_info->pagemap, (base + j*PAGE_SIZE) - area->base,
198	(void *) PTE_GET_FRAME(pte), NULL);	198	(void *) PTE_GET_FRAME(pte), NULL);
199	page_table_unlock(area->as, false);	199	page_table_unlock(area->as, false);
200	frame_reference_add(ADDR2PFN(PTE_GET_FRAME(pte)));	200	frame_reference_add(ADDR2PFN(PTE_GET_FRAME(pte)));
201	}	201	}
202		202
203	}	203	}
204	}	204	}
205	mutex_unlock(&area->sh_info->lock);	205	mutex_unlock(&area->sh_info->lock);
206	}	206	}
207		207
208	/** @}	208	/** @}
209	*/	209	*/
210		210