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;
 
/** Address space lock. It protects inactive_as_with_asid_head. */
SPINLOCK_INITIALIZE(as_lock);
 
/**
 * This list contains address spaces that are not active on any
 * processor and that have valid ASID.
 */
LIST_INITIALIZE(inactive_as_with_asid_head);
 
/** Kernel address space. */
as_t *AS_KERNEL = NULL;
 
static int get_area_flags(as_area_t *a);
static as_area_t *find_area_and_lock(as_t *as, __address va);
 
/** 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);
    link_initialize(&as->inactive_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->refcount = 0;
    as->page_table = page_table_create(flags);
 
    return as;
}
 
/** Free Adress space */
void as_free(as_t *as)
{
    ASSERT(as->refcount == 0);
 
    /* TODO: free as_areas and other resources held by as */
    /* TODO: free page table */
    free(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 flags Flags of the 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, int flags, 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->flags = flags;
    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 as 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 *area;
    ipl_t ipl;
   
    ipl = interrupts_disable();
    page_table_lock(as, true);
   
    area = find_area_and_lock(as, page);
    if (!area) {
        panic("page not part of any as_area\n");
    }
 
    page_mapping_insert(as, page, frame, get_area_flags(area));
   
    spinlock_unlock(&area->lock);
    page_table_unlock(as, true);
    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)
{
    pte_t *pte;
    as_area_t *area;
    __address frame;
   
    ASSERT(AS);
 
    spinlock_lock(&AS->lock);
 
    area = find_area_and_lock(AS, page);   
    if (!area) {
        /*
         * No area contained mapping for 'page'.
         * Signal page fault to low-level handler.
         */
        spinlock_unlock(&AS->lock);
        return 0;
    }
 
    page_table_lock(AS, false);
   
    /*
     * To avoid race condition between two page faults
     * on the same address, we need to make sure
     * the mapping has not been already inserted.
     */
    if ((pte = page_mapping_find(AS, page))) {
        if (PTE_PRESENT(pte)) {
            page_table_unlock(AS, false);
            spinlock_unlock(&area->lock);
            spinlock_unlock(&AS->lock);
            return 1;
        }
    }
 
    /*
     * 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));
    page_table_unlock(AS, false);
   
    spinlock_unlock(&area->lock);
    spinlock_unlock(&AS->lock);
 
    return 1;
}
 
/** Switch address spaces.
 *
 * @param old Old address space or NULL.
 * @param new New address space.
 */
void as_switch(as_t *old, as_t *new)
{
    ipl_t ipl;
    bool needs_asid = false;
   
    ipl = interrupts_disable();
    spinlock_lock(&as_lock);
 
    /*
     * First, take care of the old address space.
     */
    if (old) {
        spinlock_lock(&old->lock);
        ASSERT(old->refcount);
        if((--old->refcount == 0) && (old != AS_KERNEL)) {
            /*
             * The old address space is no longer active on
             * any processor. It can be appended to the
             * list of inactive address spaces with assigned
             * ASID.
             */
             ASSERT(old->asid != ASID_INVALID);
             list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
        }
        spinlock_unlock(&old->lock);
    }
 
    /*
     * Second, prepare the new address space.
     */
    spinlock_lock(&new->lock);
    if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
        if (new->asid != ASID_INVALID)
            list_remove(&new->inactive_as_with_asid_link);
        else
            needs_asid = true;  /* defer call to asid_get() until new->lock is released */
    }
    SET_PTL0_ADDRESS(new->page_table);
    spinlock_unlock(&new->lock);
 
    if (needs_asid) {
        /*
         * Allocation of new ASID was deferred
         * until now in order to avoid deadlock.
         */
        asid_t asid;
       
        asid = asid_get();
        spinlock_lock(&new->lock);
        new->asid = asid;
        spinlock_unlock(&new->lock);
    }
    spinlock_unlock(&as_lock);
    interrupts_restore(ipl);
   
    /*
     * Perform architecture-specific steps.
     * (e.g. write ASID to hardware register etc.)
     */
    as_install_arch(new);
   
    AS = new;
}
 
/** 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;
 
    flags = PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
   
    if (a->flags & AS_AREA_READ)
        flags |= PAGE_READ;
       
    if (a->flags & AS_AREA_WRITE)
        flags |= PAGE_WRITE;
   
    if (a->flags & AS_AREA_EXEC)
        flags |= PAGE_EXEC;
   
    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);
}
 
/** Lock page table.
 *
 * This function should be called before any page_mapping_insert(),
 * page_mapping_remove() and page_mapping_find().
 *
 * Locking order is such that address space areas must be locked
 * prior to this call. Address space can be locked prior to this
 * call in which case the lock argument is false.
 *
 * @param as Address space.
 * @param as_locked If false, do not attempt to lock as->lock.
 */
void page_table_lock(as_t *as, bool lock)
{
    ASSERT(as_operations);
    ASSERT(as_operations->page_table_lock);
 
    as_operations->page_table_lock(as, lock);
}
 
/** Unlock page table.
 *
 * @param as Address space.
 * @param as_locked If false, do not attempt to unlock as->lock.
 */
void page_table_unlock(as_t *as, bool unlock)
{
    ASSERT(as_operations);
    ASSERT(as_operations->page_table_unlock);
 
    as_operations->page_table_unlock(as, unlock);
}
 
/** Find address space area and change it.
 *
 * @param as Address space.
 * @param address Virtual address belonging to the area to be changed. Must be page-aligned.
 * @param size New size of the virtual memory block starting at address.
 * @param flags Flags influencing the remap operation. Currently unused.
 *
 * @return address on success, (__address) -1 otherwise.
 */
__address as_remap(as_t *as, __address address, size_t size, int flags)
{
    as_area_t *area = NULL;
    ipl_t ipl;
    size_t pages;
   
    ipl = interrupts_disable();
    spinlock_lock(&as->lock);
   
    /*
     * Locate the area.
     */
    area = find_area_and_lock(as, address);
    if (!area) {
        spinlock_unlock(&as->lock);
        return (__address) -1;
    }
 
    pages = SIZE2FRAMES((address - area->base) + size);
    if (pages < area->size) {
        int i;
 
        /*
         * Shrinking the area.
         */
        for (i = pages; i < area->size; i++) {
            pte_t *pte;
           
            /*
             * Releasing physical memory.
             * This depends on the fact that the memory was allocated using frame_alloc().
             */
            page_table_lock(as, false);
            pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
            if (pte && PTE_VALID(pte)) {
                __address frame;
 
                ASSERT(PTE_PRESENT(pte));
                frame = PTE_GET_FRAME(pte);
                page_mapping_remove(as, area->base + i*PAGE_SIZE);
                page_table_unlock(as, false);
 
                frame_free(ADDR2PFN(frame));
            } else {
                page_table_unlock(as, false);
            }
        }
        /*
         * Invalidate TLB's.
         */
        tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
        tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
        tlb_shootdown_finalize();
    }
 
    area->size = pages;
   
    spinlock_unlock(&area->lock);
    spinlock_unlock(&as->lock);
    interrupts_restore(ipl);
 
    return address;
}
 
/** Find address space area and lock it.
 *
 * The address space must be locked and interrupts must be disabled.
 *
 * @param as Address space.
 * @param va Virtual address.
 *
 * @return Locked address space area containing va on success or NULL on failure.
 */
as_area_t *find_area_and_lock(as_t *as, __address va)
{
    link_t *cur;
    as_area_t *a;
   
    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 ((va >= a->base) && (va < a->base + a->size * PAGE_SIZE))
             return a;
       
        spinlock_unlock(&a->lock);
    }
 
    return NULL;
}
 

Rev 1026	Rev 1044
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	/** Address space lock. It protects inactive_as_with_asid_head. */	59	/** Address space lock. It protects inactive_as_with_asid_head. */
60	SPINLOCK_INITIALIZE(as_lock);	60	SPINLOCK_INITIALIZE(as_lock);
61		61
62	/**	62	/**
63	* This list contains address spaces that are not active on any	63	* This list contains address spaces that are not active on any
64	* processor and that have valid ASID.	64	* processor and that have valid ASID.
65	*/	65	*/
66	LIST_INITIALIZE(inactive_as_with_asid_head);	66	LIST_INITIALIZE(inactive_as_with_asid_head);
67		67
68	/** Kernel address space. */	68	/** Kernel address space. */
69	as_t *AS_KERNEL = NULL;	69	as_t *AS_KERNEL = NULL;
70		70
71	static int get_area_flags(as_area_t *a);	71	static int get_area_flags(as_area_t *a);
72	static as_area_t find_area_and_lock(as_t as, __address va);	72	static as_area_t find_area_and_lock(as_t as, __address va);
73		73
74	/** Initialize address space subsystem. */	74	/** Initialize address space subsystem. */
75	void as_init(void)	75	void as_init(void)
76	{	76	{
77	as_arch_init();	77	as_arch_init();
78	AS_KERNEL = as_create(FLAG_AS_KERNEL);	78	AS_KERNEL = as_create(FLAG_AS_KERNEL);
79	if (!AS_KERNEL)	79	if (!AS_KERNEL)
80	panic("can't create kernel address space\n");	80	panic("can't create kernel address space\n");
81	}	81	}
82		82
83	/** Create address space.	83	/** Create address space.
84	*	84	*
85	* @param flags Flags that influence way in wich the address space is created.	85	* @param flags Flags that influence way in wich the address space is created.
86	*/	86	*/
87	as_t *as_create(int flags)	87	as_t *as_create(int flags)
88	{	88	{
89	as_t *as;	89	as_t *as;
90		90
91	as = (as_t *) malloc(sizeof(as_t), 0);	91	as = (as_t *) malloc(sizeof(as_t), 0);
92	link_initialize(&as->inactive_as_with_asid_link);	92	link_initialize(&as->inactive_as_with_asid_link);
93	spinlock_initialize(&as->lock, "as_lock");	93	spinlock_initialize(&as->lock, "as_lock");
94	list_initialize(&as->as_area_head);	94	list_initialize(&as->as_area_head);
95		95
96	if (flags & FLAG_AS_KERNEL)	96	if (flags & FLAG_AS_KERNEL)
97	as->asid = ASID_KERNEL;	97	as->asid = ASID_KERNEL;
98	else	98	else
99	as->asid = ASID_INVALID;	99	as->asid = ASID_INVALID;
100		100
101	as->refcount = 0;	101	as->refcount = 0;
102	as->page_table = page_table_create(flags);	102	as->page_table = page_table_create(flags);
103		103
104	return as;	104	return as;
105	}	105	}
106		106
107	/** Free Adress space */	107	/** Free Adress space */
108	void as_free(as_t *as)	108	void as_free(as_t *as)
109	{	109	{
110	ASSERT(as->refcount == 0);	110	ASSERT(as->refcount == 0);
111		111
112	/* TODO: free as_areas and other resources held by as */	112	/* TODO: free as_areas and other resources held by as */
113	/* TODO: free page table */	113	/* TODO: free page table */
114	free(as);	114	free(as);
115	}	115	}
116		116
117	/** Create address space area of common attributes.	117	/** Create address space area of common attributes.
118	*	118	*
119	* The created address space area is added to the target address space.	119	* The created address space area is added to the target address space.
120	*	120	*
121	* @param as Target address space.	121	* @param as Target address space.
122	* @param flags Flags of the area.	122	* @param flags Flags of the area.
123	* @param size Size of area in multiples of PAGE_SIZE.	123	* @param size Size of area in multiples of PAGE_SIZE.
124	* @param base Base address of area.	124	* @param base Base address of area.
125	*	125	*
126	* @return Address space area on success or NULL on failure.	126	* @return Address space area on success or NULL on failure.
127	*/	127	*/
128	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)	128	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)
129	{	129	{
130	ipl_t ipl;	130	ipl_t ipl;
131	as_area_t *a;	131	as_area_t *a;
132		132
133	if (base % PAGE_SIZE)	133	if (base % PAGE_SIZE)
134	panic("addr not aligned to a page boundary");	134	panic("addr not aligned to a page boundary");
135		135
136	ipl = interrupts_disable();	136	ipl = interrupts_disable();
137	spinlock_lock(&as->lock);	137	spinlock_lock(&as->lock);
138		138
139	/*	139	/*
140	* TODO: test as_area which is to be created doesn't overlap with an existing one.	140	* TODO: test as_area which is to be created doesn't overlap with an existing one.
141	*/	141	*/
142		142
143	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	143	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
144		144
145	spinlock_initialize(&a->lock, "as_area_lock");	145	spinlock_initialize(&a->lock, "as_area_lock");
146		146
147	link_initialize(&a->link);	147	link_initialize(&a->link);
148	a->flags = flags;	148	a->flags = flags;
149	a->size = size;	149	a->size = size;
150	a->base = base;	150	a->base = base;
151		151
152	list_append(&a->link, &as->as_area_head);	152	list_append(&a->link, &as->as_area_head);
153		153
154	spinlock_unlock(&as->lock);	154	spinlock_unlock(&as->lock);
155	interrupts_restore(ipl);	155	interrupts_restore(ipl);
156		156
157	return a;	157	return a;
158	}	158	}
159		159
160	/** Initialize mapping for one page of address space.	160	/** Initialize mapping for one page of address space.
161	*	161	*
162	* This functions maps 'page' to 'frame' according	162	* This functions maps 'page' to 'frame' according
163	* to attributes of the address space area to	163	* to attributes of the address space area to
164	* wich 'page' belongs.	164	* wich 'page' belongs.
165	*	165	*
166	* @param as Target address space.	166	* @param as Target address space.
167	* @param page Virtual page within the area.	167	* @param page Virtual page within the area.
168	* @param frame Physical frame to which page will be mapped.	168	* @param frame Physical frame to which page will be mapped.
169	*/	169	*/
170	void as_set_mapping(as_t *as, __address page, __address frame)	170	void as_set_mapping(as_t *as, __address page, __address frame)
171	{	171	{
172	as_area_t *area;	172	as_area_t *area;
173	ipl_t ipl;	173	ipl_t ipl;
174		174
175	ipl = interrupts_disable();	175	ipl = interrupts_disable();
176	spinlock_lock(&as->lock);	176	page_table_lock(as, true);
177		177
178	area = find_area_and_lock(as, page);	178	area = find_area_and_lock(as, page);
179	if (!area) {	179	if (!area) {
180	panic("page not part of any as_area\n");	180	panic("page not part of any as_area\n");
181	}	181	}
182		182
183	page_mapping_insert(as, page, frame, get_area_flags(area));	183	page_mapping_insert(as, page, frame, get_area_flags(area));
184		184
185	spinlock_unlock(&area->lock);	185	spinlock_unlock(&area->lock);
186	spinlock_unlock(&as->lock);	186	page_table_unlock(as, true);
187	interrupts_restore(ipl);	187	interrupts_restore(ipl);
188	}	188	}
189		189
190	/** Handle page fault within the current address space.	190	/** Handle page fault within the current address space.
191	*	191	*
192	* This is the high-level page fault handler.	192	* This is the high-level page fault handler.
193	* Interrupts are assumed disabled.	193	* Interrupts are assumed disabled.
194	*	194	*
195	* @param page Faulting page.	195	* @param page Faulting page.
196	*	196	*
197	* @return 0 on page fault, 1 on success.	197	* @return 0 on page fault, 1 on success.
198	*/	198	*/
199	int as_page_fault(__address page)	199	int as_page_fault(__address page)
200	{	200	{
-		201	pte_t *pte;
201	as_area_t *area;	202	as_area_t *area;
202	__address frame;	203	__address frame;
203		204
204	ASSERT(AS);	205	ASSERT(AS);
-		206
205	spinlock_lock(&AS->lock);	207	spinlock_lock(&AS->lock);
206		-
207	area = find_area_and_lock(AS, page);	208	area = find_area_and_lock(AS, page);
208	if (!area) {	209	if (!area) {
209	/*	210	/*
210	* No area contained mapping for 'page'.	211	* No area contained mapping for 'page'.
211	* Signal page fault to low-level handler.	212	* Signal page fault to low-level handler.
212	*/	213	*/
213	spinlock_unlock(&AS->lock);	214	spinlock_unlock(&AS->lock);
214	return 0;	215	return 0;
215	}	216	}
216		217
-		218	page_table_lock(AS, false);
-		219
-		220	/*
-		221	* To avoid race condition between two page faults
-		222	* on the same address, we need to make sure
-		223	* the mapping has not been already inserted.
-		224	*/
-		225	if ((pte = page_mapping_find(AS, page))) {
-		226	if (PTE_PRESENT(pte)) {
-		227	page_table_unlock(AS, false);
-		228	spinlock_unlock(&area->lock);
-		229	spinlock_unlock(&AS->lock);
-		230	return 1;
-		231	}
-		232	}
-		233
217	/*	234	/*
218	* In general, there can be several reasons that	235	* In general, there can be several reasons that
219	* can have caused this fault.	236	* can have caused this fault.
220	*	237	*
221	* - non-existent mapping: the area is a scratch	238	* - non-existent mapping: the area is a scratch
222	* area (e.g. stack) and so far has not been	239	* area (e.g. stack) and so far has not been
223	* allocated a frame for the faulting page	240	* allocated a frame for the faulting page
224	*	241	*
225	* - non-present mapping: another possibility,	242	* - non-present mapping: another possibility,
226	* currently not implemented, would be frame	243	* currently not implemented, would be frame
227	* reuse; when this becomes a possibility,	244	* reuse; when this becomes a possibility,
228	* do not forget to distinguish between	245	* do not forget to distinguish between
229	* the different causes	246	* the different causes
230	*/	247	*/
231	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	248	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
232	memsetb(PA2KA(frame), FRAME_SIZE, 0);	249	memsetb(PA2KA(frame), FRAME_SIZE, 0);
233		250
234	/*	251	/*
235	* Map 'page' to 'frame'.	252	* Map 'page' to 'frame'.
236	* Note that TLB shootdown is not attempted as only new information is being	253	* Note that TLB shootdown is not attempted as only new information is being
237	* inserted into page tables.	254	* inserted into page tables.
238	*/	255	*/
239	page_mapping_insert(AS, page, frame, get_area_flags(area));	256	page_mapping_insert(AS, page, frame, get_area_flags(area));
-		257	page_table_unlock(AS, false);
240		258
241	spinlock_unlock(&area->lock);	259	spinlock_unlock(&area->lock);
242	spinlock_unlock(&AS->lock);	260	spinlock_unlock(&AS->lock);
243		-
244	return 1;	261	return 1;
245	}	262	}
246		263
247	/** Switch address spaces.	264	/** Switch address spaces.
248	*	265	*
249	* @param old Old address space or NULL.	266	* @param old Old address space or NULL.
250	* @param new New address space.	267	* @param new New address space.
251	*/	268	*/
252	void as_switch(as_t old, as_t new)	269	void as_switch(as_t old, as_t new)
253	{	270	{
254	ipl_t ipl;	271	ipl_t ipl;
255	bool needs_asid = false;	272	bool needs_asid = false;
256		273
257	ipl = interrupts_disable();	274	ipl = interrupts_disable();
258	spinlock_lock(&as_lock);	275	spinlock_lock(&as_lock);
259		276
260	/*	277	/*
261	* First, take care of the old address space.	278	* First, take care of the old address space.
262	*/	279	*/
263	if (old) {	280	if (old) {
264	spinlock_lock(&old->lock);	281	spinlock_lock(&old->lock);
265	ASSERT(old->refcount);	282	ASSERT(old->refcount);
266	if((--old->refcount == 0) && (old != AS_KERNEL)) {	283	if((--old->refcount == 0) && (old != AS_KERNEL)) {
267	/*	284	/*
268	* The old address space is no longer active on	285	* The old address space is no longer active on
269	* any processor. It can be appended to the	286	* any processor. It can be appended to the
270	* list of inactive address spaces with assigned	287	* list of inactive address spaces with assigned
271	* ASID.	288	* ASID.
272	*/	289	*/
273	ASSERT(old->asid != ASID_INVALID);	290	ASSERT(old->asid != ASID_INVALID);
274	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);	291	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
275	}	292	}
276	spinlock_unlock(&old->lock);	293	spinlock_unlock(&old->lock);
277	}	294	}
278		295
279	/*	296	/*
280	* Second, prepare the new address space.	297	* Second, prepare the new address space.
281	*/	298	*/
282	spinlock_lock(&new->lock);	299	spinlock_lock(&new->lock);
283	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {	300	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
284	if (new->asid != ASID_INVALID)	301	if (new->asid != ASID_INVALID)
285	list_remove(&new->inactive_as_with_asid_link);	302	list_remove(&new->inactive_as_with_asid_link);
286	else	303	else
287	needs_asid = true; /* defer call to asid_get() until new->lock is released */	304	needs_asid = true; /* defer call to asid_get() until new->lock is released */
288	}	305	}
289	SET_PTL0_ADDRESS(new->page_table);	306	SET_PTL0_ADDRESS(new->page_table);
290	spinlock_unlock(&new->lock);	307	spinlock_unlock(&new->lock);
291		308
292	if (needs_asid) {	309	if (needs_asid) {
293	/*	310	/*
294	* Allocation of new ASID was deferred	311	* Allocation of new ASID was deferred
295	* until now in order to avoid deadlock.	312	* until now in order to avoid deadlock.
296	*/	313	*/
297	asid_t asid;	314	asid_t asid;
298		315
299	asid = asid_get();	316	asid = asid_get();
300	spinlock_lock(&new->lock);	317	spinlock_lock(&new->lock);
301	new->asid = asid;	318	new->asid = asid;
302	spinlock_unlock(&new->lock);	319	spinlock_unlock(&new->lock);
303	}	320	}
304	spinlock_unlock(&as_lock);	321	spinlock_unlock(&as_lock);
305	interrupts_restore(ipl);	322	interrupts_restore(ipl);
306		323
307	/*	324	/*
308	* Perform architecture-specific steps.	325	* Perform architecture-specific steps.
309	* (e.g. write ASID to hardware register etc.)	326	* (e.g. write ASID to hardware register etc.)
310	*/	327	*/
311	as_install_arch(new);	328	as_install_arch(new);
312		329
313	AS = new;	330	AS = new;
314	}	331	}
315		332
316	/** Compute flags for virtual address translation subsytem.	333	/** Compute flags for virtual address translation subsytem.
317	*	334	*
318	* The address space area must be locked.	335	* The address space area must be locked.
319	* Interrupts must be disabled.	336	* Interrupts must be disabled.
320	*	337	*
321	* @param a Address space area.	338	* @param a Address space area.
322	*	339	*
323	* @return Flags to be used in page_mapping_insert().	340	* @return Flags to be used in page_mapping_insert().
324	*/	341	*/
325	int get_area_flags(as_area_t *a)	342	int get_area_flags(as_area_t *a)
326	{	343	{
327	int flags;	344	int flags;
328		345
329	flags = PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	346	flags = PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
330		347
331	if (a->flags & AS_AREA_READ)	348	if (a->flags & AS_AREA_READ)
332	flags \|= PAGE_READ;	349	flags \|= PAGE_READ;
333		350
334	if (a->flags & AS_AREA_WRITE)	351	if (a->flags & AS_AREA_WRITE)
335	flags \|= PAGE_WRITE;	352	flags \|= PAGE_WRITE;
336		353
337	if (a->flags & AS_AREA_EXEC)	354	if (a->flags & AS_AREA_EXEC)
338	flags \|= PAGE_EXEC;	355	flags \|= PAGE_EXEC;
339		356
340	return flags;	357	return flags;
341	}	358	}
342		359
343	/** Create page table.	360	/** Create page table.
344	*	361	*
345	* Depending on architecture, create either address space	362	* Depending on architecture, create either address space
346	* private or global page table.	363	* private or global page table.
347	*	364	*
348	* @param flags Flags saying whether the page table is for kernel address space.	365	* @param flags Flags saying whether the page table is for kernel address space.
349	*	366	*
350	* @return First entry of the page table.	367	* @return First entry of the page table.
351	*/	368	*/
352	pte_t *page_table_create(int flags)	369	pte_t *page_table_create(int flags)
353	{	370	{
354	ASSERT(as_operations);	371	ASSERT(as_operations);
355	ASSERT(as_operations->page_table_create);	372	ASSERT(as_operations->page_table_create);
356		373
357	return as_operations->page_table_create(flags);	374	return as_operations->page_table_create(flags);
358	}	375	}
359		376
-		377	/** Lock page table.
-		378	*
-		379	* This function should be called before any page_mapping_insert(),
-		380	* page_mapping_remove() and page_mapping_find().
-		381	*
-		382	* Locking order is such that address space areas must be locked
-		383	* prior to this call. Address space can be locked prior to this
-		384	* call in which case the lock argument is false.
-		385	*
-		386	* @param as Address space.
-		387	* @param as_locked If false, do not attempt to lock as->lock.
-		388	*/
-		389	void page_table_lock(as_t *as, bool lock)
-		390	{
-		391	ASSERT(as_operations);
-		392	ASSERT(as_operations->page_table_lock);
-		393
-		394	as_operations->page_table_lock(as, lock);
-		395	}
-		396
-		397	/** Unlock page table.
-		398	*
-		399	* @param as Address space.
-		400	* @param as_locked If false, do not attempt to unlock as->lock.
-		401	*/
-		402	void page_table_unlock(as_t *as, bool unlock)
-		403	{
-		404	ASSERT(as_operations);
-		405	ASSERT(as_operations->page_table_unlock);
-		406
-		407	as_operations->page_table_unlock(as, unlock);
-		408	}
-		409
360	/** Find address space area and change it.	410	/** Find address space area and change it.
361	*	411	*
362	* @param as Address space.	412	* @param as Address space.
363	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	413	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
364	* @param size New size of the virtual memory block starting at address.	414	* @param size New size of the virtual memory block starting at address.
365	* @param flags Flags influencing the remap operation. Currently unused.	415	* @param flags Flags influencing the remap operation. Currently unused.
366	*	416	*
367	* @return address on success, (__address) -1 otherwise.	417	* @return address on success, (__address) -1 otherwise.
368	*/	418	*/
369	__address as_remap(as_t *as, __address address, size_t size, int flags)	419	__address as_remap(as_t *as, __address address, size_t size, int flags)
370	{	420	{
371	as_area_t *area = NULL;	421	as_area_t *area = NULL;
372	ipl_t ipl;	422	ipl_t ipl;
373	size_t pages;	423	size_t pages;
374		424
375	ipl = interrupts_disable();	425	ipl = interrupts_disable();
376	spinlock_lock(&as->lock);	426	spinlock_lock(&as->lock);
377		427
378	/*	428	/*
379	* Locate the area.	429	* Locate the area.
380	*/	430	*/
381	area = find_area_and_lock(as, address);	431	area = find_area_and_lock(as, address);
382	if (!area) {	432	if (!area) {
383	spinlock_unlock(&as->lock);	433	spinlock_unlock(&as->lock);
384	return (__address) -1;	434	return (__address) -1;
385	}	435	}
386		436
387	pages = SIZE2FRAMES((address - area->base) + size);	437	pages = SIZE2FRAMES((address - area->base) + size);
388	if (pages < area->size) {	438	if (pages < area->size) {
389	int i;	439	int i;
390		440
391	/*	441	/*
392	* Shrinking the area.	442	* Shrinking the area.
393	*/	443	*/
394	for (i = pages; i < area->size; i++) {	444	for (i = pages; i < area->size; i++) {
395	pte_t *pte;	445	pte_t *pte;
396		446
397	/*	447	/*
398	* Releasing physical memory.	448	* Releasing physical memory.
399	* This depends on the fact that the memory was allocated using frame_alloc().	449	* This depends on the fact that the memory was allocated using frame_alloc().
400	*/	450	*/
-		451	page_table_lock(as, false);
401	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);	452	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
402	if (pte && PTE_VALID(pte)) {	453	if (pte && PTE_VALID(pte)) {
-		454	__address frame;
-		455
403	ASSERT(PTE_PRESENT(pte));	456	ASSERT(PTE_PRESENT(pte));
404	frame_free(ADDR2PFN(PTE_GET_FRAME(pte)));	457	frame = PTE_GET_FRAME(pte);
405	page_mapping_remove(as, area->base + i*PAGE_SIZE);	458	page_mapping_remove(as, area->base + i*PAGE_SIZE);
-		459	page_table_unlock(as, false);
-		460
-		461	frame_free(ADDR2PFN(frame));
-		462	} else {
-		463	page_table_unlock(as, false);
406	}	464	}
407	}	465	}
408	/*	466	/*
409	* Invalidate TLB's.	467	* Invalidate TLB's.
410	*/	468	*/
411	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);	469	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
412	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);	470	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
413	tlb_shootdown_finalize();	471	tlb_shootdown_finalize();
414	}	472	}
415		473
416	area->size = pages;	474	area->size = pages;
417		475
418	spinlock_unlock(&area->lock);	476	spinlock_unlock(&area->lock);
419	spinlock_unlock(&as->lock);	477	spinlock_unlock(&as->lock);
420	interrupts_restore(ipl);	478	interrupts_restore(ipl);
421		479
422	return address;	480	return address;
423	}	481	}
424		482
425	/** Find address space area and lock it.	483	/** Find address space area and lock it.
426	*	484	*
427	* The address space must be locked and interrupts must be disabled.	485	* The address space must be locked and interrupts must be disabled.
428	*	486	*
429	* @param as Address space.	487	* @param as Address space.
430	* @param va Virtual address.	488	* @param va Virtual address.
431	*	489	*
432	* @return Locked address space area containing va on success or NULL on failure.	490	* @return Locked address space area containing va on success or NULL on failure.
433	*/	491	*/
434	as_area_t find_area_and_lock(as_t as, __address va)	492	as_area_t find_area_and_lock(as_t as, __address va)
435	{	493	{
436	link_t *cur;	494	link_t *cur;
437	as_area_t *a;	495	as_area_t *a;
438		496
439	for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {	497	for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
440	a = list_get_instance(cur, as_area_t, link);	498	a = list_get_instance(cur, as_area_t, link);

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/as.c @ 1760 – Rev 1026 → 1044