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 <genarch/mm/page_ht.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 <macros.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);
static bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area);
 
/** 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.
 * @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)
        return NULL;
 
    /* Writeable executable areas are not supported. */
    if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
        return NULL;
   
    ipl = interrupts_disable();
    spinlock_lock(&as->lock);
   
    if (!check_area_conflicts(as, base, size, NULL)) {
        spinlock_unlock(&as->lock);
        interrupts_restore(ipl);
        return NULL;
    }
   
    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->pages = SIZE2FRAMES(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);
        interrupts_restore(ipl);
        return (__address) -1;
    }
 
    pages = SIZE2FRAMES((address - area->base) + size);
    if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
        spinlock_unlock(&area->lock);
        spinlock_unlock(&as->lock);    
        interrupts_restore(ipl);
        return (__address) -1;
    }
 
    if (pages < area->pages) {
        int i;
 
        /*
         * Shrinking the area.
         */
        for (i = pages; i < area->pages; 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->pages - pages);
        tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
        tlb_shootdown_finalize();
    }
 
    area->pages = 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->pages * PAGE_SIZE))
            return a;
       
        spinlock_unlock(&a->lock);
    }
 
    return NULL;
}
 
/** Check area conflicts with other areas.
 *
 * The address space must be locked and interrupts must be disabled.
 *
 * @param as Address space.
 * @param va Starting virtual address of the area being tested.
 * @param size Size of the area being tested.
 * @param avoid_area Do not touch this area.
 *
 * @return True if there is no conflict, false otherwise.
 */
bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area)
{
    link_t *cur;
    as_area_t *a;
   
    /*
     * We don't want any area to have conflicts with NULL page.
     */
    if (overlaps(va, size, NULL, PAGE_SIZE))
        return false;
   
    for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
        __address a_start;
        size_t a_size;
   
        a = list_get_instance(cur, as_area_t, link);
        if (a == avoid_area)
            continue;
           
        spinlock_lock(&a->lock);
 
        a_start = a->base;
        a_size = a->pages * PAGE_SIZE;
 
        spinlock_unlock(&a->lock);
 
        if (overlaps(va, size, a_start, a_size))
            return false;      
 
    }
 
    /*
     * So far, the area does not conflict with other areas.
     * Check if it doesn't conflict with kernel address space.
     */  
    if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
        return !overlaps(va, size,
            KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START);
    }
 
    return true;
}
 

Rev 1076	Rev 1108
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 <genarch/mm/page_ht.h>
43	#include <mm/asid.h>	44	#include <mm/asid.h>
44	#include <arch/mm/asid.h>	45	#include <arch/mm/asid.h>
45	#include <arch/types.h>	46	#include <arch/types.h>
46	#include <typedefs.h>	47	#include <typedefs.h>
47	#include <synch/spinlock.h>	48	#include <synch/spinlock.h>
48	#include <config.h>	49	#include <config.h>
49	#include <adt/list.h>	50	#include <adt/list.h>
50	#include <panic.h>	51	#include <panic.h>
51	#include <arch/asm.h>	52	#include <arch/asm.h>
52	#include <debug.h>	53	#include <debug.h>
53	#include <memstr.h>	54	#include <memstr.h>
54	#include <macros.h>	55	#include <macros.h>
55	#include <arch.h>	56	#include <arch.h>
56	#include <print.h>	57	#include <print.h>
57		58
58	as_operations_t *as_operations = NULL;	59	as_operations_t *as_operations = NULL;
59		60
60	/** Address space lock. It protects inactive_as_with_asid_head. */	61	/** Address space lock. It protects inactive_as_with_asid_head. */
61	SPINLOCK_INITIALIZE(as_lock);	62	SPINLOCK_INITIALIZE(as_lock);
62		63
63	/**	64	/**
64	* This list contains address spaces that are not active on any	65	* This list contains address spaces that are not active on any
65	* processor and that have valid ASID.	66	* processor and that have valid ASID.
66	*/	67	*/
67	LIST_INITIALIZE(inactive_as_with_asid_head);	68	LIST_INITIALIZE(inactive_as_with_asid_head);
68		69
69	/** Kernel address space. */	70	/** Kernel address space. */
70	as_t *AS_KERNEL = NULL;	71	as_t *AS_KERNEL = NULL;
71		72
72	static int get_area_flags(as_area_t *a);	73	static int get_area_flags(as_area_t *a);
73	static as_area_t find_area_and_lock(as_t as, __address va);	74	static as_area_t find_area_and_lock(as_t as, __address va);
74	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);	75	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);
75		76
76	/** Initialize address space subsystem. */	77	/** Initialize address space subsystem. */
77	void as_init(void)	78	void as_init(void)
78	{	79	{
79	as_arch_init();	80	as_arch_init();
80	AS_KERNEL = as_create(FLAG_AS_KERNEL);	81	AS_KERNEL = as_create(FLAG_AS_KERNEL);
81	if (!AS_KERNEL)	82	if (!AS_KERNEL)
82	panic("can't create kernel address space\n");	83	panic("can't create kernel address space\n");
83	}	84	}
84		85
85	/** Create address space.	86	/** Create address space.
86	*	87	*
87	* @param flags Flags that influence way in wich the address space is created.	88	* @param flags Flags that influence way in wich the address space is created.
88	*/	89	*/
89	as_t *as_create(int flags)	90	as_t *as_create(int flags)
90	{	91	{
91	as_t *as;	92	as_t *as;
92		93
93	as = (as_t *) malloc(sizeof(as_t), 0);	94	as = (as_t *) malloc(sizeof(as_t), 0);
94	link_initialize(&as->inactive_as_with_asid_link);	95	link_initialize(&as->inactive_as_with_asid_link);
95	spinlock_initialize(&as->lock, "as_lock");	96	spinlock_initialize(&as->lock, "as_lock");
96	list_initialize(&as->as_area_head);	97	list_initialize(&as->as_area_head);
97		98
98	if (flags & FLAG_AS_KERNEL)	99	if (flags & FLAG_AS_KERNEL)
99	as->asid = ASID_KERNEL;	100	as->asid = ASID_KERNEL;
100	else	101	else
101	as->asid = ASID_INVALID;	102	as->asid = ASID_INVALID;
102		103
103	as->refcount = 0;	104	as->refcount = 0;
104	as->page_table = page_table_create(flags);	105	as->page_table = page_table_create(flags);
105		106
106	return as;	107	return as;
107	}	108	}
108		109
109	/** Free Adress space */	110	/** Free Adress space */
110	void as_free(as_t *as)	111	void as_free(as_t *as)
111	{	112	{
112	ASSERT(as->refcount == 0);	113	ASSERT(as->refcount == 0);
113		114
114	/* TODO: free as_areas and other resources held by as */	115	/* TODO: free as_areas and other resources held by as */
115	/* TODO: free page table */	116	/* TODO: free page table */
116	free(as);	117	free(as);
117	}	118	}
118		119
119	/** Create address space area of common attributes.	120	/** Create address space area of common attributes.
120	*	121	*
121	* The created address space area is added to the target address space.	122	* The created address space area is added to the target address space.
122	*	123	*
123	* @param as Target address space.	124	* @param as Target address space.
124	* @param flags Flags of the area.	125	* @param flags Flags of the area.
125	* @param size Size of area.	126	* @param size Size of area.
126	* @param base Base address of area.	127	* @param base Base address of area.
127	*	128	*
128	* @return Address space area on success or NULL on failure.	129	* @return Address space area on success or NULL on failure.
129	*/	130	*/
130	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)	131	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)
131	{	132	{
132	ipl_t ipl;	133	ipl_t ipl;
133	as_area_t *a;	134	as_area_t *a;
134		135
135	if (base % PAGE_SIZE)	136	if (base % PAGE_SIZE)
136	return NULL;	137	return NULL;
137		138
138	/* Writeable executable areas are not supported. */	139	/* Writeable executable areas are not supported. */
139	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))	140	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
140	return NULL;	141	return NULL;
141		142
142	ipl = interrupts_disable();	143	ipl = interrupts_disable();
143	spinlock_lock(&as->lock);	144	spinlock_lock(&as->lock);
144		145
145	if (!check_area_conflicts(as, base, size, NULL)) {	146	if (!check_area_conflicts(as, base, size, NULL)) {
146	spinlock_unlock(&as->lock);	147	spinlock_unlock(&as->lock);
147	interrupts_restore(ipl);	148	interrupts_restore(ipl);
148	return NULL;	149	return NULL;
149	}	150	}
150		151
151	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	152	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
152		153
153	spinlock_initialize(&a->lock, "as_area_lock");	154	spinlock_initialize(&a->lock, "as_area_lock");
154		155
155	link_initialize(&a->link);	156	link_initialize(&a->link);
156	a->flags = flags;	157	a->flags = flags;
157	a->pages = SIZE2FRAMES(size);	158	a->pages = SIZE2FRAMES(size);
158	a->base = base;	159	a->base = base;
159		160
160	list_append(&a->link, &as->as_area_head);	161	list_append(&a->link, &as->as_area_head);
161		162
162	spinlock_unlock(&as->lock);	163	spinlock_unlock(&as->lock);
163	interrupts_restore(ipl);	164	interrupts_restore(ipl);
164		165
165	return a;	166	return a;
166	}	167	}
167		168
168	/** Initialize mapping for one page of address space.	169	/** Initialize mapping for one page of address space.
169	*	170	*
170	* This functions maps 'page' to 'frame' according	171	* This functions maps 'page' to 'frame' according
171	* to attributes of the address space area to	172	* to attributes of the address space area to
172	* wich 'page' belongs.	173	* wich 'page' belongs.
173	*	174	*
174	* @param as Target address space.	175	* @param as Target address space.
175	* @param page Virtual page within the area.	176	* @param page Virtual page within the area.
176	* @param frame Physical frame to which page will be mapped.	177	* @param frame Physical frame to which page will be mapped.
177	*/	178	*/
178	void as_set_mapping(as_t *as, __address page, __address frame)	179	void as_set_mapping(as_t *as, __address page, __address frame)
179	{	180	{
180	as_area_t *area;	181	as_area_t *area;
181	ipl_t ipl;	182	ipl_t ipl;
182		183
183	ipl = interrupts_disable();	184	ipl = interrupts_disable();
184	page_table_lock(as, true);	185	page_table_lock(as, true);
185		186
186	area = find_area_and_lock(as, page);	187	area = find_area_and_lock(as, page);
187	if (!area) {	188	if (!area) {
188	panic("page not part of any as_area\n");	189	panic("page not part of any as_area\n");
189	}	190	}
190		191
191	page_mapping_insert(as, page, frame, get_area_flags(area));	192	page_mapping_insert(as, page, frame, get_area_flags(area));
192		193
193	spinlock_unlock(&area->lock);	194	spinlock_unlock(&area->lock);
194	page_table_unlock(as, true);	195	page_table_unlock(as, true);
195	interrupts_restore(ipl);	196	interrupts_restore(ipl);
196	}	197	}
197		198
198	/** Handle page fault within the current address space.	199	/** Handle page fault within the current address space.
199	*	200	*
200	* This is the high-level page fault handler.	201	* This is the high-level page fault handler.
201	* Interrupts are assumed disabled.	202	* Interrupts are assumed disabled.
202	*	203	*
203	* @param page Faulting page.	204	* @param page Faulting page.
204	*	205	*
205	* @return 0 on page fault, 1 on success.	206	* @return 0 on page fault, 1 on success.
206	*/	207	*/
207	int as_page_fault(__address page)	208	int as_page_fault(__address page)
208	{	209	{
209	pte_t *pte;	210	pte_t *pte;
210	as_area_t *area;	211	as_area_t *area;
211	__address frame;	212	__address frame;
212		213
213	ASSERT(AS);	214	ASSERT(AS);
214		215
215	spinlock_lock(&AS->lock);	216	spinlock_lock(&AS->lock);
216	area = find_area_and_lock(AS, page);	217	area = find_area_and_lock(AS, page);
217	if (!area) {	218	if (!area) {
218	/*	219	/*
219	* No area contained mapping for 'page'.	220	* No area contained mapping for 'page'.
220	* Signal page fault to low-level handler.	221	* Signal page fault to low-level handler.
221	*/	222	*/
222	spinlock_unlock(&AS->lock);	223	spinlock_unlock(&AS->lock);
223	return 0;	224	return 0;
224	}	225	}
225		226
226	page_table_lock(AS, false);	227	page_table_lock(AS, false);
227		228
228	/*	229	/*
229	* To avoid race condition between two page faults	230	* To avoid race condition between two page faults
230	* on the same address, we need to make sure	231	* on the same address, we need to make sure
231	* the mapping has not been already inserted.	232	* the mapping has not been already inserted.
232	*/	233	*/
233	if ((pte = page_mapping_find(AS, page))) {	234	if ((pte = page_mapping_find(AS, page))) {
234	if (PTE_PRESENT(pte)) {	235	if (PTE_PRESENT(pte)) {
235	page_table_unlock(AS, false);	236	page_table_unlock(AS, false);
236	spinlock_unlock(&area->lock);	237	spinlock_unlock(&area->lock);
237	spinlock_unlock(&AS->lock);	238	spinlock_unlock(&AS->lock);
238	return 1;	239	return 1;
239	}	240	}
240	}	241	}
241		242
242	/*	243	/*
243	* In general, there can be several reasons that	244	* In general, there can be several reasons that
244	* can have caused this fault.	245	* can have caused this fault.
245	*	246	*
246	* - non-existent mapping: the area is a scratch	247	* - non-existent mapping: the area is a scratch
247	* area (e.g. stack) and so far has not been	248	* area (e.g. stack) and so far has not been
248	* allocated a frame for the faulting page	249	* allocated a frame for the faulting page
249	*	250	*
250	* - non-present mapping: another possibility,	251	* - non-present mapping: another possibility,
251	* currently not implemented, would be frame	252	* currently not implemented, would be frame
252	* reuse; when this becomes a possibility,	253	* reuse; when this becomes a possibility,
253	* do not forget to distinguish between	254	* do not forget to distinguish between
254	* the different causes	255	* the different causes
255	*/	256	*/
256	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	257	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
257	memsetb(PA2KA(frame), FRAME_SIZE, 0);	258	memsetb(PA2KA(frame), FRAME_SIZE, 0);
258		259
259	/*	260	/*
260	* Map 'page' to 'frame'.	261	* Map 'page' to 'frame'.
261	* Note that TLB shootdown is not attempted as only new information is being	262	* Note that TLB shootdown is not attempted as only new information is being
262	* inserted into page tables.	263	* inserted into page tables.
263	*/	264	*/
264	page_mapping_insert(AS, page, frame, get_area_flags(area));	265	page_mapping_insert(AS, page, frame, get_area_flags(area));
265	page_table_unlock(AS, false);	266	page_table_unlock(AS, false);
266		267
267	spinlock_unlock(&area->lock);	268	spinlock_unlock(&area->lock);
268	spinlock_unlock(&AS->lock);	269	spinlock_unlock(&AS->lock);
269	return 1;	270	return 1;
270	}	271	}
271		272
272	/** Switch address spaces.	273	/** Switch address spaces.
273	*	274	*
274	* @param old Old address space or NULL.	275	* @param old Old address space or NULL.
275	* @param new New address space.	276	* @param new New address space.
276	*/	277	*/
277	void as_switch(as_t old, as_t new)	278	void as_switch(as_t old, as_t new)
278	{	279	{
279	ipl_t ipl;	280	ipl_t ipl;
280	bool needs_asid = false;	281	bool needs_asid = false;
281		282
282	ipl = interrupts_disable();	283	ipl = interrupts_disable();
283	spinlock_lock(&as_lock);	284	spinlock_lock(&as_lock);
284		285
285	/*	286	/*
286	* First, take care of the old address space.	287	* First, take care of the old address space.
287	*/	288	*/
288	if (old) {	289	if (old) {
289	spinlock_lock(&old->lock);	290	spinlock_lock(&old->lock);
290	ASSERT(old->refcount);	291	ASSERT(old->refcount);
291	if((--old->refcount == 0) && (old != AS_KERNEL)) {	292	if((--old->refcount == 0) && (old != AS_KERNEL)) {
292	/*	293	/*
293	* The old address space is no longer active on	294	* The old address space is no longer active on
294	* any processor. It can be appended to the	295	* any processor. It can be appended to the
295	* list of inactive address spaces with assigned	296	* list of inactive address spaces with assigned
296	* ASID.	297	* ASID.
297	*/	298	*/
298	ASSERT(old->asid != ASID_INVALID);	299	ASSERT(old->asid != ASID_INVALID);
299	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);	300	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
300	}	301	}
301	spinlock_unlock(&old->lock);	302	spinlock_unlock(&old->lock);
302	}	303	}
303		304
304	/*	305	/*
305	* Second, prepare the new address space.	306	* Second, prepare the new address space.
306	*/	307	*/
307	spinlock_lock(&new->lock);	308	spinlock_lock(&new->lock);
308	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {	309	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
309	if (new->asid != ASID_INVALID)	310	if (new->asid != ASID_INVALID)
310	list_remove(&new->inactive_as_with_asid_link);	311	list_remove(&new->inactive_as_with_asid_link);
311	else	312	else
312	needs_asid = true; /* defer call to asid_get() until new->lock is released */	313	needs_asid = true; /* defer call to asid_get() until new->lock is released */
313	}	314	}
314	SET_PTL0_ADDRESS(new->page_table);	315	SET_PTL0_ADDRESS(new->page_table);
315	spinlock_unlock(&new->lock);	316	spinlock_unlock(&new->lock);
316		317
317	if (needs_asid) {	318	if (needs_asid) {
318	/*	319	/*
319	* Allocation of new ASID was deferred	320	* Allocation of new ASID was deferred
320	* until now in order to avoid deadlock.	321	* until now in order to avoid deadlock.
321	*/	322	*/
322	asid_t asid;	323	asid_t asid;
323		324
324	asid = asid_get();	325	asid = asid_get();
325	spinlock_lock(&new->lock);	326	spinlock_lock(&new->lock);
326	new->asid = asid;	327	new->asid = asid;
327	spinlock_unlock(&new->lock);	328	spinlock_unlock(&new->lock);
328	}	329	}
329	spinlock_unlock(&as_lock);	330	spinlock_unlock(&as_lock);
330	interrupts_restore(ipl);	331	interrupts_restore(ipl);
331		332
332	/*	333	/*
333	* Perform architecture-specific steps.	334	* Perform architecture-specific steps.
334	* (e.g. write ASID to hardware register etc.)	335	* (e.g. write ASID to hardware register etc.)
335	*/	336	*/
336	as_install_arch(new);	337	as_install_arch(new);
337		338
338	AS = new;	339	AS = new;
339	}	340	}
340		341
341	/** Compute flags for virtual address translation subsytem.	342	/** Compute flags for virtual address translation subsytem.
342	*	343	*
343	* The address space area must be locked.	344	* The address space area must be locked.
344	* Interrupts must be disabled.	345	* Interrupts must be disabled.
345	*	346	*
346	* @param a Address space area.	347	* @param a Address space area.
347	*	348	*
348	* @return Flags to be used in page_mapping_insert().	349	* @return Flags to be used in page_mapping_insert().
349	*/	350	*/
350	int get_area_flags(as_area_t *a)	351	int get_area_flags(as_area_t *a)
351	{	352	{
352	int flags;	353	int flags;
353		354
354	flags = PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	355	flags = PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
355		356
356	if (a->flags & AS_AREA_READ)	357	if (a->flags & AS_AREA_READ)
357	flags \|= PAGE_READ;	358	flags \|= PAGE_READ;
358		359
359	if (a->flags & AS_AREA_WRITE)	360	if (a->flags & AS_AREA_WRITE)
360	flags \|= PAGE_WRITE;	361	flags \|= PAGE_WRITE;
361		362
362	if (a->flags & AS_AREA_EXEC)	363	if (a->flags & AS_AREA_EXEC)
363	flags \|= PAGE_EXEC;	364	flags \|= PAGE_EXEC;
364		365
365	return flags;	366	return flags;
366	}	367	}
367		368
368	/** Create page table.	369	/** Create page table.
369	*	370	*
370	* Depending on architecture, create either address space	371	* Depending on architecture, create either address space
371	* private or global page table.	372	* private or global page table.
372	*	373	*
373	* @param flags Flags saying whether the page table is for kernel address space.	374	* @param flags Flags saying whether the page table is for kernel address space.
374	*	375	*
375	* @return First entry of the page table.	376	* @return First entry of the page table.
376	*/	377	*/
377	pte_t *page_table_create(int flags)	378	pte_t *page_table_create(int flags)
378	{	379	{
379	ASSERT(as_operations);	380	ASSERT(as_operations);
380	ASSERT(as_operations->page_table_create);	381	ASSERT(as_operations->page_table_create);
381		382
382	return as_operations->page_table_create(flags);	383	return as_operations->page_table_create(flags);
383	}	384	}
384		385
385	/** Lock page table.	386	/** Lock page table.
386	*	387	*
387	* This function should be called before any page_mapping_insert(),	388	* This function should be called before any page_mapping_insert(),
388	* page_mapping_remove() and page_mapping_find().	389	* page_mapping_remove() and page_mapping_find().
389	*	390	*
390	* Locking order is such that address space areas must be locked	391	* Locking order is such that address space areas must be locked
391	* prior to this call. Address space can be locked prior to this	392	* prior to this call. Address space can be locked prior to this
392	* call in which case the lock argument is false.	393	* call in which case the lock argument is false.
393	*	394	*
394	* @param as Address space.	395	* @param as Address space.
395	* @param as_locked If false, do not attempt to lock as->lock.	396	* @param as_locked If false, do not attempt to lock as->lock.
396	*/	397	*/
397	void page_table_lock(as_t *as, bool lock)	398	void page_table_lock(as_t *as, bool lock)
398	{	399	{
399	ASSERT(as_operations);	400	ASSERT(as_operations);
400	ASSERT(as_operations->page_table_lock);	401	ASSERT(as_operations->page_table_lock);
401		402
402	as_operations->page_table_lock(as, lock);	403	as_operations->page_table_lock(as, lock);
403	}	404	}
404		405
405	/** Unlock page table.	406	/** Unlock page table.
406	*	407	*
407	* @param as Address space.	408	* @param as Address space.
408	* @param as_locked If false, do not attempt to unlock as->lock.	409	* @param as_locked If false, do not attempt to unlock as->lock.
409	*/	410	*/
410	void page_table_unlock(as_t *as, bool unlock)	411	void page_table_unlock(as_t *as, bool unlock)
411	{	412	{
412	ASSERT(as_operations);	413	ASSERT(as_operations);
413	ASSERT(as_operations->page_table_unlock);	414	ASSERT(as_operations->page_table_unlock);
414		415
415	as_operations->page_table_unlock(as, unlock);	416	as_operations->page_table_unlock(as, unlock);
416	}	417	}
417		418
418	/** Find address space area and change it.	419	/** Find address space area and change it.
419	*	420	*
420	* @param as Address space.	421	* @param as Address space.
421	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	422	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
422	* @param size New size of the virtual memory block starting at address.	423	* @param size New size of the virtual memory block starting at address.
423	* @param flags Flags influencing the remap operation. Currently unused.	424	* @param flags Flags influencing the remap operation. Currently unused.
424	*	425	*
425	* @return address on success, (__address) -1 otherwise.	426	* @return address on success, (__address) -1 otherwise.
426	*/	427	*/
427	__address as_remap(as_t *as, __address address, size_t size, int flags)	428	__address as_remap(as_t *as, __address address, size_t size, int flags)
428	{	429	{
429	as_area_t *area = NULL;	430	as_area_t *area = NULL;
430	ipl_t ipl;	431	ipl_t ipl;
431	size_t pages;	432	size_t pages;
432		433
433	ipl = interrupts_disable();	434	ipl = interrupts_disable();
434	spinlock_lock(&as->lock);	435	spinlock_lock(&as->lock);
435		436
436	/*	437	/*
437	* Locate the area.	438	* Locate the area.
438	*/	439	*/
439	area = find_area_and_lock(as, address);	440	area = find_area_and_lock(as, address);
440	if (!area) {	441	if (!area) {
441	spinlock_unlock(&as->lock);	442	spinlock_unlock(&as->lock);
442	interrupts_restore(ipl);	443	interrupts_restore(ipl);
443	return (__address) -1;	444	return (__address) -1;
444	}	445	}
445		446
446	pages = SIZE2FRAMES((address - area->base) + size);	447	pages = SIZE2FRAMES((address - area->base) + size);
447	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {	448	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
448	spinlock_unlock(&area->lock);	449	spinlock_unlock(&area->lock);
449	spinlock_unlock(&as->lock);	450	spinlock_unlock(&as->lock);
450	interrupts_restore(ipl);	451	interrupts_restore(ipl);
451	return (__address) -1;	452	return (__address) -1;
452	}	453	}
453		454
454	if (pages < area->pages) {	455	if (pages < area->pages) {
455	int i;	456	int i;
456		457
457	/*	458	/*
458	* Shrinking the area.	459	* Shrinking the area.
459	*/	460	*/
460	for (i = pages; i < area->pages; i++) {	461	for (i = pages; i < area->pages; i++) {
461	pte_t *pte;	462	pte_t *pte;
462		463
463	/*	464	/*
464	* Releasing physical memory.	465	* Releasing physical memory.
465	* This depends on the fact that the memory was allocated using frame_alloc().	466	* This depends on the fact that the memory was allocated using frame_alloc().
466	*/	467	*/
467	page_table_lock(as, false);	468	page_table_lock(as, false);
468	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);	469	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
469	if (pte && PTE_VALID(pte)) {	470	if (pte && PTE_VALID(pte)) {
470	__address frame;	471	__address frame;
471		472
472	ASSERT(PTE_PRESENT(pte));	473	ASSERT(PTE_PRESENT(pte));
473	frame = PTE_GET_FRAME(pte);	474	frame = PTE_GET_FRAME(pte);
474	page_mapping_remove(as, area->base + i*PAGE_SIZE);	475	page_mapping_remove(as, area->base + i*PAGE_SIZE);
475	page_table_unlock(as, false);	476	page_table_unlock(as, false);
476		477
477	frame_free(ADDR2PFN(frame));	478	frame_free(ADDR2PFN(frame));
478	} else {	479	} else {
479	page_table_unlock(as, false);	480	page_table_unlock(as, false);
480	}	481	}
481	}	482	}
482	/*	483	/*
483	* Invalidate TLB's.	484	* Invalidate TLB's.
484	*/	485	*/
485	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	486	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
486	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	487	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
487	tlb_shootdown_finalize();	488	tlb_shootdown_finalize();
488	}	489	}
489		490
490	area->pages = pages;	491	area->pages = pages;
491		492
492	spinlock_unlock(&area->lock);	493	spinlock_unlock(&area->lock);
493	spinlock_unlock(&as->lock);	494	spinlock_unlock(&as->lock);
494	interrupts_restore(ipl);	495	interrupts_restore(ipl);
495		496
496	return address;	497	return address;
497	}	498	}
498		499
499	/** Find address space area and lock it.	500	/** Find address space area and lock it.

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/as.c @ 1147 – Rev 1076 → 1108