WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/mm/as.c


/*
 * Copyright (C) 2001-2006 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.
 */
 
/*
 * This file contains address space manipulation functions.
 * Roughly speaking, this is a higher-level client of
 * Virtual Address Translation (VAT) subsystem.
 */
 
#include <mm/as.h>
#include <arch/mm/as.h>
#include <mm/page.h>
#include <mm/frame.h>
#include <mm/tlb.h>
#include <mm/heap.h>
#include <arch/mm/page.h>
#include <genarch/mm/page_pt.h>
#include <mm/asid.h>
#include <arch/mm/asid.h>
#include <arch/types.h>
#include <typedefs.h>
#include <synch/spinlock.h>
#include <config.h>
#include <list.h>
#include <panic.h>
#include <arch/asm.h>
#include <debug.h>
#include <memstr.h>
#include <arch.h>
#include <print.h>
 
as_operations_t *as_operations = NULL;
 
/** Kernel address space. */
as_t *AS_KERNEL = NULL;
 
static int get_area_flags(as_area_t *a);
 
/** Initialize address space subsystem. */
void as_init(void)
{
    as_arch_init();
    AS_KERNEL = as_create(FLAG_AS_KERNEL | FLAG_AS_EARLYMALLOC);
        if (!AS_KERNEL)
                panic("can't create kernel address space\n");
}
 
/** Create address space.
 *
 * @param flags Flags that influence way in wich the address space is created.
 */
as_t *as_create(int flags)
{
    as_t *as;
 
    if (flags & FLAG_AS_EARLYMALLOC)
        as = (as_t *) early_malloc(sizeof(as_t));
    else
        as = (as_t *) malloc(sizeof(as_t));
    if (as) {
        list_initialize(&as->as_with_asid_link);
        spinlock_initialize(&as->lock, "as_lock");
        list_initialize(&as->as_area_head);
 
        if (flags & FLAG_AS_KERNEL)
            as->asid = ASID_KERNEL;
        else
            as->asid = ASID_INVALID;
 
        as->page_table = page_table_create(flags);
    }
 
    return as;
}
 
/** Create address space area of common attributes.
 *
 * The created address space area is added to the target address space.
 *
 * @param as Target address space.
 * @param type Type of area.
 * @param size Size of area in multiples of PAGE_SIZE.
 * @param base Base address of area.
 *
 * @return Address space area on success or NULL on failure.
 */
as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base)
{
    ipl_t ipl;
    as_area_t *a;
   
    if (base % PAGE_SIZE)
        panic("addr not aligned to a page boundary");
   
    ipl = interrupts_disable();
    spinlock_lock(&as->lock);
   
    /*
     * TODO: test as_area which is to be created doesn't overlap with an existing one.
     */
   
    a = (as_area_t *) malloc(sizeof(as_area_t));
    if (a) {   
        spinlock_initialize(&a->lock, "as_area_lock");
           
        link_initialize(&a->link);         
        a->type = type;
        a->size = size;
        a->base = base;
       
        list_append(&a->link, &as->as_area_head);
    }
 
    spinlock_unlock(&as->lock);
    interrupts_restore(ipl);
 
    return a;
}
 
/** Initialize mapping for one page of address space.
 *
 * This functions maps 'page' to 'frame' according
 * to attributes of the address space area to
 * wich 'page' belongs.
 *
 * @param a Target address space.
 * @param page Virtual page within the area.
 * @param frame Physical frame to which page will be mapped.
 */
void as_set_mapping(as_t *as, __address page, __address frame)
{
    as_area_t *a, *area = NULL;
    link_t *cur;
    ipl_t ipl;
   
    ipl = interrupts_disable();
    spinlock_lock(&as->lock);
   
    /*
     * First, try locate an area.
     */
    for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
        a = list_get_instance(cur, as_area_t, link);
        spinlock_lock(&a->lock);
 
        if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
            area = a;
            break;
        }
       
        spinlock_unlock(&a->lock);
    }
   
    if (!area) {
        panic("page not part of any as_area\n");
    }
 
    /*
     * Note: area->lock is held.
     */
   
    page_mapping_insert(as, page, frame, get_area_flags(area));
   
    spinlock_unlock(&area->lock);
    spinlock_unlock(&as->lock);
    interrupts_restore(ipl);
}
 
/** Handle page fault within the current address space.
 *
 * This is the high-level page fault handler.
 * Interrupts are assumed disabled.
 *
 * @param page Faulting page.
 *
 * @return 0 on page fault, 1 on success.
 */
int as_page_fault(__address page)
{
    link_t *cur;
    as_area_t *a, *area = NULL;
    __address frame;
   
    ASSERT(AS);
    spinlock_lock(&AS->lock);
   
    /*
     * Search this areas of this address space for presence of 'page'.
     */
    for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
        a = list_get_instance(cur, as_area_t, link);
        spinlock_lock(&a->lock);
 
        if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
 
            /*
             * We found the area containing 'page'.
             * TODO: access checking
             */
            area = a;
            break;
        }
       
        spinlock_unlock(&a->lock);
    }
   
    if (!area) {
        /*
         * No area contained mapping for 'page'.
         * Signal page fault to low-level handler.
         */
        spinlock_unlock(&AS->lock);
        return 0;
    }
 
    /*
     * Note: area->lock is held.
     */
   
    /*
     * In general, there can be several reasons that
     * can have caused this fault.
     *
     * - non-existent mapping: the area is a scratch
     *   area (e.g. 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 = frame_alloc(0, ONE_FRAME, NULL, NULL);
    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, page, frame, get_area_flags(area));
   
    spinlock_unlock(&area->lock);
    spinlock_unlock(&AS->lock);
 
    return 1;
}
 
/** Install address space on CPU.
 *
 * @param as Address space.
 */
void as_install(as_t *as)
{
    ipl_t ipl;
   
    asid_install(as);
   
    ipl = interrupts_disable();
    spinlock_lock(&as->lock);
    ASSERT(as->page_table);
    SET_PTL0_ADDRESS(as->page_table);
    spinlock_unlock(&as->lock);
    interrupts_restore(ipl);
 
    /*
     * Perform architecture-specific steps.
     * (e.g. write ASID to hardware register etc.)
     */
    as_install_arch(as);
   
    AS = as;
}
 
/** Compute flags for virtual address translation subsytem.
 *
 * The address space area must be locked.
 * Interrupts must be disabled.
 *
 * @param a Address space area.
 *
 * @return Flags to be used in page_mapping_insert().
 */
int get_area_flags(as_area_t *a)
{
    int flags;
 
    switch (a->type) {
        case AS_AREA_TEXT:
            flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
            break;
        case AS_AREA_DATA:
        case AS_AREA_STACK:
            flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
            break;
        default:
            panic("unexpected as_area_type_t %d", a->type);
    }
   
    return flags;
}
 
/** Create page table.
 *
 * Depending on architecture, create either address space
 * private or global page table.
 *
 * @param flags Flags saying whether the page table is for kernel address space.
 *
 * @return First entry of the page table.
 */
pte_t *page_table_create(int flags)
{
        ASSERT(as_operations);
        ASSERT(as_operations->page_table_create);
 
        return as_operations->page_table_create(flags);
}
 

Rev 771	Rev 778
1	/*	1	/*
2	* Copyright (C) 2001-2006 Jakub Jermar	2	* Copyright (C) 2001-2006 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	* This file contains address space manipulation functions.	30	* This file contains address space manipulation functions.
31	* Roughly speaking, this is a higher-level client of	31	* Roughly speaking, this is a higher-level client of
32	* Virtual Address Translation (VAT) subsystem.	32	* Virtual Address Translation (VAT) subsystem.
33	*/	33	*/
34		34
35	#include <mm/as.h>	35	#include <mm/as.h>
36	#include <arch/mm/as.h>	36	#include <arch/mm/as.h>
37	#include <mm/page.h>	37	#include <mm/page.h>
38	#include <mm/frame.h>	38	#include <mm/frame.h>
39	#include <mm/tlb.h>	39	#include <mm/tlb.h>
40	#include <mm/heap.h>	40	#include <mm/heap.h>
41	#include <arch/mm/page.h>	41	#include <arch/mm/page.h>
42	#include <genarch/mm/page_pt.h>	42	#include <genarch/mm/page_pt.h>
43	#include <mm/asid.h>	43	#include <mm/asid.h>
44	#include <arch/mm/asid.h>	44	#include <arch/mm/asid.h>
45	#include <arch/types.h>	45	#include <arch/types.h>
46	#include <typedefs.h>	46	#include <typedefs.h>
47	#include <synch/spinlock.h>	47	#include <synch/spinlock.h>
48	#include <config.h>	48	#include <config.h>
49	#include <list.h>	49	#include <list.h>
50	#include <panic.h>	50	#include <panic.h>
51	#include <arch/asm.h>	51	#include <arch/asm.h>
52	#include <debug.h>	52	#include <debug.h>
53	#include <memstr.h>	53	#include <memstr.h>
54	#include <arch.h>	54	#include <arch.h>
55	#include <print.h>	55	#include <print.h>
56		56
57	as_operations_t *as_operations = NULL;	57	as_operations_t *as_operations = NULL;
58		58
59	/** Kernel address space. */	59	/** Kernel address space. */
60	as_t *AS_KERNEL = NULL;	60	as_t *AS_KERNEL = NULL;
61		61
62	static int get_area_flags(as_area_t *a);	62	static int get_area_flags(as_area_t *a);
63		63
64	/** Initialize address space subsystem. */	64	/** Initialize address space subsystem. */
65	void as_init(void)	65	void as_init(void)
66	{	66	{
67	as_arch_init();	67	as_arch_init();
68	AS_KERNEL = as_create(FLAG_AS_KERNEL);	68	AS_KERNEL = as_create(FLAG_AS_KERNEL \| FLAG_AS_EARLYMALLOC);
69	if (!AS_KERNEL)	69	if (!AS_KERNEL)
70	panic("can't create kernel address space\n");	70	panic("can't create kernel address space\n");
71	}	71	}
72		72
73	/** Create address space.	73	/** Create address space.
74	*	74	*
75	* @param flags Flags that influence way in wich the address space is created.	75	* @param flags Flags that influence way in wich the address space is created.
76	*/	76	*/
77	as_t *as_create(int flags)	77	as_t *as_create(int flags)
78	{	78	{
79	as_t *as;	79	as_t *as;
80		80
-		81	if (flags & FLAG_AS_EARLYMALLOC)
81	as = (as_t *) early_malloc(sizeof(as_t));	82	as = (as_t *) early_malloc(sizeof(as_t));
-		83	else
-		84	as = (as_t *) malloc(sizeof(as_t));
82	if (as) {	85	if (as) {
83	list_initialize(&as->as_with_asid_link);	86	list_initialize(&as->as_with_asid_link);
84	spinlock_initialize(&as->lock, "as_lock");	87	spinlock_initialize(&as->lock, "as_lock");
85	list_initialize(&as->as_area_head);	88	list_initialize(&as->as_area_head);
86		89
87	if (flags & FLAG_AS_KERNEL)	90	if (flags & FLAG_AS_KERNEL)
88	as->asid = ASID_KERNEL;	91	as->asid = ASID_KERNEL;
89	else	92	else
90	as->asid = ASID_INVALID;	93	as->asid = ASID_INVALID;
91		94
92	as->page_table = page_table_create(flags);	95	as->page_table = page_table_create(flags);
93	}	96	}
94		97
95	return as;	98	return as;
96	}	99	}
97		100
98	/** Create address space area of common attributes.	101	/** Create address space area of common attributes.
99	*	102	*
100	* The created address space area is added to the target address space.	103	* The created address space area is added to the target address space.
101	*	104	*
102	* @param as Target address space.	105	* @param as Target address space.
103	* @param type Type of area.	106	* @param type Type of area.
104	* @param size Size of area in multiples of PAGE_SIZE.	107	* @param size Size of area in multiples of PAGE_SIZE.
105	* @param base Base address of area.	108	* @param base Base address of area.
106	*	109	*
107	* @return Address space area on success or NULL on failure.	110	* @return Address space area on success or NULL on failure.
108	*/	111	*/
109	as_area_t as_area_create(as_t as, as_area_type_t type, size_t size, __address base)	112	as_area_t as_area_create(as_t as, as_area_type_t type, size_t size, __address base)
110	{	113	{
111	ipl_t ipl;	114	ipl_t ipl;
112	as_area_t *a;	115	as_area_t *a;
113		116
114	if (base % PAGE_SIZE)	117	if (base % PAGE_SIZE)
115	panic("addr not aligned to a page boundary");	118	panic("addr not aligned to a page boundary");
116		119
117	ipl = interrupts_disable();	120	ipl = interrupts_disable();
118	spinlock_lock(&as->lock);	121	spinlock_lock(&as->lock);
119		122
120	/*	123	/*
121	* TODO: test as_area which is to be created doesn't overlap with an existing one.	124	* TODO: test as_area which is to be created doesn't overlap with an existing one.
122	*/	125	*/
123		126
124	a = (as_area_t *) malloc(sizeof(as_area_t));	127	a = (as_area_t *) malloc(sizeof(as_area_t));
125	if (a) {	128	if (a) {
126	spinlock_initialize(&a->lock, "as_area_lock");	129	spinlock_initialize(&a->lock, "as_area_lock");
127		130
128	link_initialize(&a->link);	131	link_initialize(&a->link);
129	a->type = type;	132	a->type = type;
130	a->size = size;	133	a->size = size;
131	a->base = base;	134	a->base = base;
132		135
133	list_append(&a->link, &as->as_area_head);	136	list_append(&a->link, &as->as_area_head);
134	}	137	}
135		138
136	spinlock_unlock(&as->lock);	139	spinlock_unlock(&as->lock);
137	interrupts_restore(ipl);	140	interrupts_restore(ipl);
138		141
139	return a;	142	return a;
140	}	143	}
141		144
142	/** Initialize mapping for one page of address space.	145	/** Initialize mapping for one page of address space.
143	*	146	*
144	* This functions maps 'page' to 'frame' according	147	* This functions maps 'page' to 'frame' according
145	* to attributes of the address space area to	148	* to attributes of the address space area to
146	* wich 'page' belongs.	149	* wich 'page' belongs.
147	*	150	*
148	* @param a Target address space.	151	* @param a Target address space.
149	* @param page Virtual page within the area.	152	* @param page Virtual page within the area.
150	* @param frame Physical frame to which page will be mapped.	153	* @param frame Physical frame to which page will be mapped.
151	*/	154	*/
152	void as_set_mapping(as_t *as, __address page, __address frame)	155	void as_set_mapping(as_t *as, __address page, __address frame)
153	{	156	{
154	as_area_t a, area = NULL;	157	as_area_t a, area = NULL;
155	link_t *cur;	158	link_t *cur;
156	ipl_t ipl;	159	ipl_t ipl;
157		160
158	ipl = interrupts_disable();	161	ipl = interrupts_disable();
159	spinlock_lock(&as->lock);	162	spinlock_lock(&as->lock);
160		163
161	/*	164	/*
162	* First, try locate an area.	165	* First, try locate an area.
163	*/	166	*/
164	for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {	167	for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
165	a = list_get_instance(cur, as_area_t, link);	168	a = list_get_instance(cur, as_area_t, link);
166	spinlock_lock(&a->lock);	169	spinlock_lock(&a->lock);
167		170
168	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {	171	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
169	area = a;	172	area = a;
170	break;	173	break;
171	}	174	}
172		175
173	spinlock_unlock(&a->lock);	176	spinlock_unlock(&a->lock);
174	}	177	}
175		178
176	if (!area) {	179	if (!area) {
177	panic("page not part of any as_area\n");	180	panic("page not part of any as_area\n");
178	}	181	}
179		182
180	/*	183	/*
181	* Note: area->lock is held.	184	* Note: area->lock is held.
182	*/	185	*/
183		186
184	page_mapping_insert(as, page, frame, get_area_flags(area));	187	page_mapping_insert(as, page, frame, get_area_flags(area));
185		188
186	spinlock_unlock(&area->lock);	189	spinlock_unlock(&area->lock);
187	spinlock_unlock(&as->lock);	190	spinlock_unlock(&as->lock);
188	interrupts_restore(ipl);	191	interrupts_restore(ipl);
189	}	192	}
190		193
191	/** Handle page fault within the current address space.	194	/** Handle page fault within the current address space.
192	*	195	*
193	* This is the high-level page fault handler.	196	* This is the high-level page fault handler.
194	* Interrupts are assumed disabled.	197	* Interrupts are assumed disabled.
195	*	198	*
196	* @param page Faulting page.	199	* @param page Faulting page.
197	*	200	*
198	* @return 0 on page fault, 1 on success.	201	* @return 0 on page fault, 1 on success.
199	*/	202	*/
200	int as_page_fault(__address page)	203	int as_page_fault(__address page)
201	{	204	{
202	link_t *cur;	205	link_t *cur;
203	as_area_t a, area = NULL;	206	as_area_t a, area = NULL;
204	__address frame;	207	__address frame;
205		208
206	ASSERT(AS);	209	ASSERT(AS);
207	spinlock_lock(&AS->lock);	210	spinlock_lock(&AS->lock);
208		211
209	/*	212	/*
210	* Search this areas of this address space for presence of 'page'.	213	* Search this areas of this address space for presence of 'page'.
211	*/	214	*/
212	for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {	215	for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
213	a = list_get_instance(cur, as_area_t, link);	216	a = list_get_instance(cur, as_area_t, link);
214	spinlock_lock(&a->lock);	217	spinlock_lock(&a->lock);
215		218
216	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {	219	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
217		220
218	/*	221	/*
219	* We found the area containing 'page'.	222	* We found the area containing 'page'.
220	* TODO: access checking	223	* TODO: access checking
221	*/	224	*/
222	area = a;	225	area = a;
223	break;	226	break;
224	}	227	}
225		228
226	spinlock_unlock(&a->lock);	229	spinlock_unlock(&a->lock);
227	}	230	}
228		231
229	if (!area) {	232	if (!area) {
230	/*	233	/*
231	* No area contained mapping for 'page'.	234	* No area contained mapping for 'page'.
232	* Signal page fault to low-level handler.	235	* Signal page fault to low-level handler.
233	*/	236	*/
234	spinlock_unlock(&AS->lock);	237	spinlock_unlock(&AS->lock);
235	return 0;	238	return 0;
236	}	239	}
237		240
238	/*	241	/*
239	* Note: area->lock is held.	242	* Note: area->lock is held.
240	*/	243	*/
241		244
242	/*	245	/*
243	* In general, there can be several reasons that	246	* In general, there can be several reasons that
244	* can have caused this fault.	247	* can have caused this fault.
245	*	248	*
246	* - non-existent mapping: the area is a scratch	249	* - non-existent mapping: the area is a scratch
247	* area (e.g. stack) and so far has not been	250	* area (e.g. stack) and so far has not been
248	* allocated a frame for the faulting page	251	* allocated a frame for the faulting page
249	*	252	*
250	* - non-present mapping: another possibility,	253	* - non-present mapping: another possibility,
251	* currently not implemented, would be frame	254	* currently not implemented, would be frame
252	* reuse; when this becomes a possibility,	255	* reuse; when this becomes a possibility,
253	* do not forget to distinguish between	256	* do not forget to distinguish between
254	* the different causes	257	* the different causes
255	*/	258	*/
256	frame = frame_alloc(0, ONE_FRAME, NULL, NULL);	259	frame = frame_alloc(0, ONE_FRAME, NULL, NULL);
257	memsetb(PA2KA(frame), FRAME_SIZE, 0);	260	memsetb(PA2KA(frame), FRAME_SIZE, 0);
258		261
259	/*	262	/*
260	* Map 'page' to 'frame'.	263	* Map 'page' to 'frame'.
261	* Note that TLB shootdown is not attempted as only new information is being	264	* Note that TLB shootdown is not attempted as only new information is being
262	* inserted into page tables.	265	* inserted into page tables.
263	*/	266	*/
264	page_mapping_insert(AS, page, frame, get_area_flags(area));	267	page_mapping_insert(AS, page, frame, get_area_flags(area));
265		268
266	spinlock_unlock(&area->lock);	269	spinlock_unlock(&area->lock);
267	spinlock_unlock(&AS->lock);	270	spinlock_unlock(&AS->lock);
268		271
269	return 1;	272	return 1;
270	}	273	}
271		274
272	/** Install address space on CPU.	275	/** Install address space on CPU.
273	*	276	*
274	* @param as Address space.	277	* @param as Address space.
275	*/	278	*/
276	void as_install(as_t *as)	279	void as_install(as_t *as)
277	{	280	{
278	ipl_t ipl;	281	ipl_t ipl;
279		282
280	asid_install(as);	283	asid_install(as);
281		284
282	ipl = interrupts_disable();	285	ipl = interrupts_disable();
283	spinlock_lock(&as->lock);	286	spinlock_lock(&as->lock);
284	ASSERT(as->page_table);	287	ASSERT(as->page_table);
285	SET_PTL0_ADDRESS(as->page_table);	288	SET_PTL0_ADDRESS(as->page_table);
286	spinlock_unlock(&as->lock);	289	spinlock_unlock(&as->lock);
287	interrupts_restore(ipl);	290	interrupts_restore(ipl);
288		291
289	/*	292	/*
290	* Perform architecture-specific steps.	293	* Perform architecture-specific steps.
291	* (e.g. write ASID to hardware register etc.)	294	* (e.g. write ASID to hardware register etc.)
292	*/	295	*/
293	as_install_arch(as);	296	as_install_arch(as);
294		297
295	AS = as;	298	AS = as;
296	}	299	}
297		300
298	/** Compute flags for virtual address translation subsytem.	301	/** Compute flags for virtual address translation subsytem.
299	*	302	*
300	* The address space area must be locked.	303	* The address space area must be locked.
301	* Interrupts must be disabled.	304	* Interrupts must be disabled.
302	*	305	*
303	* @param a Address space area.	306	* @param a Address space area.
304	*	307	*
305	* @return Flags to be used in page_mapping_insert().	308	* @return Flags to be used in page_mapping_insert().
306	*/	309	*/
307	int get_area_flags(as_area_t *a)	310	int get_area_flags(as_area_t *a)
308	{	311	{
309	int flags;	312	int flags;
310		313
311	switch (a->type) {	314	switch (a->type) {
312	case AS_AREA_TEXT:	315	case AS_AREA_TEXT:
313	flags = PAGE_EXEC \| PAGE_READ \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	316	flags = PAGE_EXEC \| PAGE_READ \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
314	break;	317	break;
315	case AS_AREA_DATA:	318	case AS_AREA_DATA:
316	case AS_AREA_STACK:	319	case AS_AREA_STACK:
317	flags = PAGE_READ \| PAGE_WRITE \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	320	flags = PAGE_READ \| PAGE_WRITE \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
318	break;	321	break;
319	default:	322	default:
320	panic("unexpected as_area_type_t %d", a->type);	323	panic("unexpected as_area_type_t %d", a->type);
321	}	324	}
322		325
323	return flags;	326	return flags;
324	}	327	}
325		328
326	/** Create page table.	329	/** Create page table.
327	*	330	*
328	* Depending on architecture, create either address space	331	* Depending on architecture, create either address space
329	* private or global page table.	332	* private or global page table.
330	*	333	*
331	* @param flags Flags saying whether the page table is for kernel address space.	334	* @param flags Flags saying whether the page table is for kernel address space.
332	*	335	*
333	* @return First entry of the page table.	336	* @return First entry of the page table.
334	*/	337	*/
335	pte_t *page_table_create(int flags)	338	pte_t *page_table_create(int flags)
336	{	339	{
337	ASSERT(as_operations);	340	ASSERT(as_operations);
338	ASSERT(as_operations->page_table_create);	341	ASSERT(as_operations->page_table_create);
339		342
340	return as_operations->page_table_create(flags);	343	return as_operations->page_table_create(flags);
341	}	344	}
342		345

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(root)/kernel/trunk/generic/src/mm/as.c – Rev 771 → 778