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/slab.h>
#include <mm/tlb.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 <adt/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);
        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;
 
    as = (as_t *) malloc(sizeof(as_t), 0);
 
 
 
 
 
 
 
 
 
 
    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), 0);
 
    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 = 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, 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);
    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 814	Rev 822
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/slab.h>	39	#include <mm/slab.h>
40	#include <mm/tlb.h>	40	#include <mm/tlb.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 <adt/list.h>	49	#include <adt/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);
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	as = (as_t *) malloc(sizeof(as_t));	81	as = (as_t *) malloc(sizeof(as_t), 0);
82	if (as) {	-
83	list_initialize(&as->as_with_asid_link);	-
84	spinlock_initialize(&as->lock, "as_lock");	-
85	list_initialize(&as->as_area_head);	-
86		-
87	if (flags & FLAG_AS_KERNEL)	-
88	as->asid = ASID_KERNEL;	-
89	else	-
90	as->asid = ASID_INVALID;	-
91		82
-		83	list_initialize(&as->as_with_asid_link);
-		84	spinlock_initialize(&as->lock, "as_lock");
92	as->page_table = page_table_create(flags);	85	list_initialize(&as->as_area_head);
-		86
-		87	if (flags & FLAG_AS_KERNEL)
-		88	as->asid = ASID_KERNEL;
-		89	else
-		90	as->asid = ASID_INVALID;
93	}	91
-		92	as->page_table = page_table_create(flags);
94		93
95	return as;	94	return as;
96	}	95	}
97		96
98	/** Create address space area of common attributes.	97	/** Create address space area of common attributes.
99	*	98	*
100	* The created address space area is added to the target address space.	99	* The created address space area is added to the target address space.
101	*	100	*
102	* @param as Target address space.	101	* @param as Target address space.
103	* @param type Type of area.	102	* @param type Type of area.
104	* @param size Size of area in multiples of PAGE_SIZE.	103	* @param size Size of area in multiples of PAGE_SIZE.
105	* @param base Base address of area.	104	* @param base Base address of area.
106	*	105	*
107	* @return Address space area on success or NULL on failure.	106	* @return Address space area on success or NULL on failure.
108	*/	107	*/
109	as_area_t as_area_create(as_t as, as_area_type_t type, size_t size, __address base)	108	as_area_t as_area_create(as_t as, as_area_type_t type, size_t size, __address base)
110	{	109	{
111	ipl_t ipl;	110	ipl_t ipl;
112	as_area_t *a;	111	as_area_t *a;
113		112
114	if (base % PAGE_SIZE)	113	if (base % PAGE_SIZE)
115	panic("addr not aligned to a page boundary");	114	panic("addr not aligned to a page boundary");
116		115
117	ipl = interrupts_disable();	116	ipl = interrupts_disable();
118	spinlock_lock(&as->lock);	117	spinlock_lock(&as->lock);
119		118
120	/*	119	/*
121	* TODO: test as_area which is to be created doesn't overlap with an existing one.	120	* TODO: test as_area which is to be created doesn't overlap with an existing one.
122	*/	121	*/
123		122
124	a = (as_area_t *) malloc(sizeof(as_area_t));	123	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
125	if (a) {	124
126	spinlock_initialize(&a->lock, "as_area_lock");	125	spinlock_initialize(&a->lock, "as_area_lock");
127		126
128	link_initialize(&a->link);	127	link_initialize(&a->link);
129	a->type = type;	128	a->type = type;
130	a->size = size;	129	a->size = size;
131	a->base = base;	130	a->base = base;
132		131
133	list_append(&a->link, &as->as_area_head);	132	list_append(&a->link, &as->as_area_head);
134	}	-
135		133
136	spinlock_unlock(&as->lock);	134	spinlock_unlock(&as->lock);
137	interrupts_restore(ipl);	135	interrupts_restore(ipl);
138		136
139	return a;	137	return a;
140	}	138	}
141		139
142	/** Initialize mapping for one page of address space.	140	/** Initialize mapping for one page of address space.
143	*	141	*
144	* This functions maps 'page' to 'frame' according	142	* This functions maps 'page' to 'frame' according
145	* to attributes of the address space area to	143	* to attributes of the address space area to
146	* wich 'page' belongs.	144	* wich 'page' belongs.
147	*	145	*
148	* @param a Target address space.	146	* @param a Target address space.
149	* @param page Virtual page within the area.	147	* @param page Virtual page within the area.
150	* @param frame Physical frame to which page will be mapped.	148	* @param frame Physical frame to which page will be mapped.
151	*/	149	*/
152	void as_set_mapping(as_t *as, __address page, __address frame)	150	void as_set_mapping(as_t *as, __address page, __address frame)
153	{	151	{
154	as_area_t a, area = NULL;	152	as_area_t a, area = NULL;
155	link_t *cur;	153	link_t *cur;
156	ipl_t ipl;	154	ipl_t ipl;
157		155
158	ipl = interrupts_disable();	156	ipl = interrupts_disable();
159	spinlock_lock(&as->lock);	157	spinlock_lock(&as->lock);
160		158
161	/*	159	/*
162	* First, try locate an area.	160	* First, try locate an area.
163	*/	161	*/
164	for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {	162	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);	163	a = list_get_instance(cur, as_area_t, link);
166	spinlock_lock(&a->lock);	164	spinlock_lock(&a->lock);
167		165
168	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {	166	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
169	area = a;	167	area = a;
170	break;	168	break;
171	}	169	}
172		170
173	spinlock_unlock(&a->lock);	171	spinlock_unlock(&a->lock);
174	}	172	}
175		173
176	if (!area) {	174	if (!area) {
177	panic("page not part of any as_area\n");	175	panic("page not part of any as_area\n");
178	}	176	}
179		177
180	/*	178	/*
181	* Note: area->lock is held.	179	* Note: area->lock is held.
182	*/	180	*/
183		181
184	page_mapping_insert(as, page, frame, get_area_flags(area));	182	page_mapping_insert(as, page, frame, get_area_flags(area));
185		183
186	spinlock_unlock(&area->lock);	184	spinlock_unlock(&area->lock);
187	spinlock_unlock(&as->lock);	185	spinlock_unlock(&as->lock);
188	interrupts_restore(ipl);	186	interrupts_restore(ipl);
189	}	187	}
190		188
191	/** Handle page fault within the current address space.	189	/** Handle page fault within the current address space.
192	*	190	*
193	* This is the high-level page fault handler.	191	* This is the high-level page fault handler.
194	* Interrupts are assumed disabled.	192	* Interrupts are assumed disabled.
195	*	193	*
196	* @param page Faulting page.	194	* @param page Faulting page.
197	*	195	*
198	* @return 0 on page fault, 1 on success.	196	* @return 0 on page fault, 1 on success.
199	*/	197	*/
200	int as_page_fault(__address page)	198	int as_page_fault(__address page)
201	{	199	{
202	link_t *cur;	200	link_t *cur;
203	as_area_t a, area = NULL;	201	as_area_t a, area = NULL;
204	__address frame;	202	__address frame;
205		203
206	ASSERT(AS);	204	ASSERT(AS);
207	spinlock_lock(&AS->lock);	205	spinlock_lock(&AS->lock);
208		206
209	/*	207	/*
210	* Search this areas of this address space for presence of 'page'.	208	* Search this areas of this address space for presence of 'page'.
211	*/	209	*/
212	for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {	210	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);	211	a = list_get_instance(cur, as_area_t, link);
214	spinlock_lock(&a->lock);	212	spinlock_lock(&a->lock);
215		213
216	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {	214	if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
217		215
218	/*	216	/*
219	* We found the area containing 'page'.	217	* We found the area containing 'page'.
220	* TODO: access checking	218	* TODO: access checking
221	*/	219	*/
222	area = a;	220	area = a;
223	break;	221	break;
224	}	222	}
225		223
226	spinlock_unlock(&a->lock);	224	spinlock_unlock(&a->lock);
227	}	225	}
228		226
229	if (!area) {	227	if (!area) {
230	/*	228	/*
231	* No area contained mapping for 'page'.	229	* No area contained mapping for 'page'.
232	* Signal page fault to low-level handler.	230	* Signal page fault to low-level handler.
233	*/	231	*/
234	spinlock_unlock(&AS->lock);	232	spinlock_unlock(&AS->lock);
235	return 0;	233	return 0;
236	}	234	}
237		235
238	/*	236	/*
239	* Note: area->lock is held.	237	* Note: area->lock is held.
240	*/	238	*/
241		239
242	/*	240	/*
243	* In general, there can be several reasons that	241	* In general, there can be several reasons that
244	* can have caused this fault.	242	* can have caused this fault.
245	*	243	*
246	* - non-existent mapping: the area is a scratch	244	* - non-existent mapping: the area is a scratch
247	* area (e.g. stack) and so far has not been	245	* area (e.g. stack) and so far has not been
248	* allocated a frame for the faulting page	246	* allocated a frame for the faulting page
249	*	247	*
250	* - non-present mapping: another possibility,	248	* - non-present mapping: another possibility,
251	* currently not implemented, would be frame	249	* currently not implemented, would be frame
252	* reuse; when this becomes a possibility,	250	* reuse; when this becomes a possibility,
253	* do not forget to distinguish between	251	* do not forget to distinguish between
254	* the different causes	252	* the different causes
255	*/	253	*/
256	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	254	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
257	memsetb(PA2KA(frame), FRAME_SIZE, 0);	255	memsetb(PA2KA(frame), FRAME_SIZE, 0);
258		256
259	/*	257	/*
260	* Map 'page' to 'frame'.	258	* Map 'page' to 'frame'.
261	* Note that TLB shootdown is not attempted as only new information is being	259	* Note that TLB shootdown is not attempted as only new information is being
262	* inserted into page tables.	260	* inserted into page tables.
263	*/	261	*/
264	page_mapping_insert(AS, page, frame, get_area_flags(area));	262	page_mapping_insert(AS, page, frame, get_area_flags(area));
265		263
266	spinlock_unlock(&area->lock);	264	spinlock_unlock(&area->lock);
267	spinlock_unlock(&AS->lock);	265	spinlock_unlock(&AS->lock);
268		266
269	return 1;	267	return 1;
270	}	268	}
271		269
272	/** Install address space on CPU.	270	/** Install address space on CPU.
273	*	271	*
274	* @param as Address space.	272	* @param as Address space.
275	*/	273	*/
276	void as_install(as_t *as)	274	void as_install(as_t *as)
277	{	275	{
278	ipl_t ipl;	276	ipl_t ipl;
279		277
280	asid_install(as);	278	asid_install(as);
281		279
282	ipl = interrupts_disable();	280	ipl = interrupts_disable();
283	spinlock_lock(&as->lock);	281	spinlock_lock(&as->lock);
284	SET_PTL0_ADDRESS(as->page_table);	282	SET_PTL0_ADDRESS(as->page_table);
285	spinlock_unlock(&as->lock);	283	spinlock_unlock(&as->lock);
286	interrupts_restore(ipl);	284	interrupts_restore(ipl);
287		285
288	/*	286	/*
289	* Perform architecture-specific steps.	287	* Perform architecture-specific steps.
290	* (e.g. write ASID to hardware register etc.)	288	* (e.g. write ASID to hardware register etc.)
291	*/	289	*/
292	as_install_arch(as);	290	as_install_arch(as);
293		291
294	AS = as;	292	AS = as;
295	}	293	}
296		294
297	/** Compute flags for virtual address translation subsytem.	295	/** Compute flags for virtual address translation subsytem.
298	*	296	*
299	* The address space area must be locked.	297	* The address space area must be locked.
300	* Interrupts must be disabled.	298	* Interrupts must be disabled.
301	*	299	*
302	* @param a Address space area.	300	* @param a Address space area.
303	*	301	*
304	* @return Flags to be used in page_mapping_insert().	302	* @return Flags to be used in page_mapping_insert().
305	*/	303	*/
306	int get_area_flags(as_area_t *a)	304	int get_area_flags(as_area_t *a)
307	{	305	{
308	int flags;	306	int flags;
309		307
310	switch (a->type) {	308	switch (a->type) {
311	case AS_AREA_TEXT:	309	case AS_AREA_TEXT:
312	flags = PAGE_EXEC \| PAGE_READ \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	310	flags = PAGE_EXEC \| PAGE_READ \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
313	break;	311	break;
314	case AS_AREA_DATA:	312	case AS_AREA_DATA:
315	case AS_AREA_STACK:	313	case AS_AREA_STACK:
316	flags = PAGE_READ \| PAGE_WRITE \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	314	flags = PAGE_READ \| PAGE_WRITE \| PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
317	break;	315	break;
318	default:	316	default:
319	panic("unexpected as_area_type_t %d", a->type);	317	panic("unexpected as_area_type_t %d", a->type);
320	}	318	}
321		319
322	return flags;	320	return flags;
323	}	321	}
324		322
325	/** Create page table.	323	/** Create page table.
326	*	324	*
327	* Depending on architecture, create either address space	325	* Depending on architecture, create either address space
328	* private or global page table.	326	* private or global page table.
329	*	327	*
330	* @param flags Flags saying whether the page table is for kernel address space.	328	* @param flags Flags saying whether the page table is for kernel address space.
331	*	329	*
332	* @return First entry of the page table.	330	* @return First entry of the page table.
333	*/	331	*/
334	pte_t *page_table_create(int flags)	332	pte_t *page_table_create(int flags)
335	{	333	{
336	ASSERT(as_operations);	334	ASSERT(as_operations);
337	ASSERT(as_operations->page_table_create);	335	ASSERT(as_operations->page_table_create);
338		336
339	return as_operations->page_table_create(flags);	337	return as_operations->page_table_create(flags);
340	}	338	}
341		339

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(root)/kernel/trunk/generic/src/mm/as.c – Rev 814 → 822