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 <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(&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 1048	Rev 1070
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 <macros.h>
54	#include <arch.h>	55	#include <arch.h>
55	#include <print.h>	56	#include <print.h>
56		57
57	as_operations_t *as_operations = NULL;	58	as_operations_t *as_operations = NULL;
58		59
59	/** Address space lock. It protects inactive_as_with_asid_head. */	60	/** Address space lock. It protects inactive_as_with_asid_head. */
60	SPINLOCK_INITIALIZE(as_lock);	61	SPINLOCK_INITIALIZE(as_lock);
61		62
62	/**	63	/**
63	* This list contains address spaces that are not active on any	64	* This list contains address spaces that are not active on any
64	* processor and that have valid ASID.	65	* processor and that have valid ASID.
65	*/	66	*/
66	LIST_INITIALIZE(inactive_as_with_asid_head);	67	LIST_INITIALIZE(inactive_as_with_asid_head);
67		68
68	/** Kernel address space. */	69	/** Kernel address space. */
69	as_t *AS_KERNEL = NULL;	70	as_t *AS_KERNEL = NULL;
70		71
71	static int get_area_flags(as_area_t *a);	72	static int get_area_flags(as_area_t *a);
72	static as_area_t find_area_and_lock(as_t as, __address va);	73	static as_area_t find_area_and_lock(as_t as, __address va);
73	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);	74	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);
74		75
75	/** Initialize address space subsystem. */	76	/** Initialize address space subsystem. */
76	void as_init(void)	77	void as_init(void)
77	{	78	{
78	as_arch_init();	79	as_arch_init();
79	AS_KERNEL = as_create(FLAG_AS_KERNEL);	80	AS_KERNEL = as_create(FLAG_AS_KERNEL);
80	if (!AS_KERNEL)	81	if (!AS_KERNEL)
81	panic("can't create kernel address space\n");	82	panic("can't create kernel address space\n");
82	}	83	}
83		84
84	/** Create address space.	85	/** Create address space.
85	*	86	*
86	* @param flags Flags that influence way in wich the address space is created.	87	* @param flags Flags that influence way in wich the address space is created.
87	*/	88	*/
88	as_t *as_create(int flags)	89	as_t *as_create(int flags)
89	{	90	{
90	as_t *as;	91	as_t *as;
91		92
92	as = (as_t *) malloc(sizeof(as_t), 0);	93	as = (as_t *) malloc(sizeof(as_t), 0);
93	link_initialize(&as->inactive_as_with_asid_link);	94	link_initialize(&as->inactive_as_with_asid_link);
94	spinlock_initialize(&as->lock, "as_lock");	95	spinlock_initialize(&as->lock, "as_lock");
95	list_initialize(&as->as_area_head);	96	list_initialize(&as->as_area_head);
96		97
97	if (flags & FLAG_AS_KERNEL)	98	if (flags & FLAG_AS_KERNEL)
98	as->asid = ASID_KERNEL;	99	as->asid = ASID_KERNEL;
99	else	100	else
100	as->asid = ASID_INVALID;	101	as->asid = ASID_INVALID;
101		102
102	as->refcount = 0;	103	as->refcount = 0;
103	as->page_table = page_table_create(flags);	104	as->page_table = page_table_create(flags);
104		105
105	return as;	106	return as;
106	}	107	}
107		108
108	/** Free Adress space */	109	/** Free Adress space */
109	void as_free(as_t *as)	110	void as_free(as_t *as)
110	{	111	{
111	ASSERT(as->refcount == 0);	112	ASSERT(as->refcount == 0);
112		113
113	/* TODO: free as_areas and other resources held by as */	114	/* TODO: free as_areas and other resources held by as */
114	/* TODO: free page table */	115	/* TODO: free page table */
115	free(as);	116	free(as);
116	}	117	}
117		118
118	/** Create address space area of common attributes.	119	/** Create address space area of common attributes.
119	*	120	*
120	* The created address space area is added to the target address space.	121	* The created address space area is added to the target address space.
121	*	122	*
122	* @param as Target address space.	123	* @param as Target address space.
123	* @param flags Flags of the area.	124	* @param flags Flags of the area.
124	* @param size Size of area.	125	* @param size Size of area.
125	* @param base Base address of area.	126	* @param base Base address of area.
126	*	127	*
127	* @return Address space area on success or NULL on failure.	128	* @return Address space area on success or NULL on failure.
128	*/	129	*/
129	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)	130	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)
130	{	131	{
131	ipl_t ipl;	132	ipl_t ipl;
132	as_area_t *a;	133	as_area_t *a;
133		134
134	if (base % PAGE_SIZE)	135	if (base % PAGE_SIZE)
135	return NULL;	136	return NULL;
136		137
137	/* Writeable executable areas are not supported. */	138	/* Writeable executable areas are not supported. */
138	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))	139	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
139	return NULL;	140	return NULL;
140		141
141	ipl = interrupts_disable();	142	ipl = interrupts_disable();
142	spinlock_lock(&as->lock);	143	spinlock_lock(&as->lock);
143		144
144	if (!check_area_conflicts(as, base, size, NULL)) {	145	if (!check_area_conflicts(as, base, size, NULL)) {
145	spinlock_unlock(&as->lock);	146	spinlock_unlock(&as->lock);
146	interrupts_restore(ipl);	147	interrupts_restore(ipl);
147	return NULL;	148	return NULL;
148	}	149	}
149		150
150	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	151	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
151		152
152	spinlock_initialize(&a->lock, "as_area_lock");	153	spinlock_initialize(&a->lock, "as_area_lock");
153		154
154	link_initialize(&a->link);	155	link_initialize(&a->link);
155	a->flags = flags;	156	a->flags = flags;
156	a->pages = SIZE2FRAMES(size);	157	a->pages = SIZE2FRAMES(size);
157	a->base = base;	158	a->base = base;
158		159
159	list_append(&a->link, &as->as_area_head);	160	list_append(&a->link, &as->as_area_head);
160		161
161	spinlock_unlock(&as->lock);	162	spinlock_unlock(&as->lock);
162	interrupts_restore(ipl);	163	interrupts_restore(ipl);
163		164
164	return a;	165	return a;
165	}	166	}
166		167
167	/** Initialize mapping for one page of address space.	168	/** Initialize mapping for one page of address space.
168	*	169	*
169	* This functions maps 'page' to 'frame' according	170	* This functions maps 'page' to 'frame' according
170	* to attributes of the address space area to	171	* to attributes of the address space area to
171	* wich 'page' belongs.	172	* wich 'page' belongs.
172	*	173	*
173	* @param as Target address space.	174	* @param as Target address space.
174	* @param page Virtual page within the area.	175	* @param page Virtual page within the area.
175	* @param frame Physical frame to which page will be mapped.	176	* @param frame Physical frame to which page will be mapped.
176	*/	177	*/
177	void as_set_mapping(as_t *as, __address page, __address frame)	178	void as_set_mapping(as_t *as, __address page, __address frame)
178	{	179	{
179	as_area_t *area;	180	as_area_t *area;
180	ipl_t ipl;	181	ipl_t ipl;
181		182
182	ipl = interrupts_disable();	183	ipl = interrupts_disable();
183	page_table_lock(as, true);	184	page_table_lock(as, true);
184		185
185	area = find_area_and_lock(as, page);	186	area = find_area_and_lock(as, page);
186	if (!area) {	187	if (!area) {
187	panic("page not part of any as_area\n");	188	panic("page not part of any as_area\n");
188	}	189	}
189		190
190	page_mapping_insert(as, page, frame, get_area_flags(area));	191	page_mapping_insert(as, page, frame, get_area_flags(area));
191		192
192	spinlock_unlock(&area->lock);	193	spinlock_unlock(&area->lock);
193	page_table_unlock(as, true);	194	page_table_unlock(as, true);
194	interrupts_restore(ipl);	195	interrupts_restore(ipl);
195	}	196	}
196		197
197	/** Handle page fault within the current address space.	198	/** Handle page fault within the current address space.
198	*	199	*
199	* This is the high-level page fault handler.	200	* This is the high-level page fault handler.
200	* Interrupts are assumed disabled.	201	* Interrupts are assumed disabled.
201	*	202	*
202	* @param page Faulting page.	203	* @param page Faulting page.
203	*	204	*
204	* @return 0 on page fault, 1 on success.	205	* @return 0 on page fault, 1 on success.
205	*/	206	*/
206	int as_page_fault(__address page)	207	int as_page_fault(__address page)
207	{	208	{
208	pte_t *pte;	209	pte_t *pte;
209	as_area_t *area;	210	as_area_t *area;
210	__address frame;	211	__address frame;
211		212
212	ASSERT(AS);	213	ASSERT(AS);
213		214
214	spinlock_lock(&AS->lock);	215	spinlock_lock(&AS->lock);
215	area = find_area_and_lock(AS, page);	216	area = find_area_and_lock(AS, page);
216	if (!area) {	217	if (!area) {
217	/*	218	/*
218	* No area contained mapping for 'page'.	219	* No area contained mapping for 'page'.
219	* Signal page fault to low-level handler.	220	* Signal page fault to low-level handler.
220	*/	221	*/
221	spinlock_unlock(&AS->lock);	222	spinlock_unlock(&AS->lock);
222	return 0;	223	return 0;
223	}	224	}
224		225
225	page_table_lock(AS, false);	226	page_table_lock(AS, false);
226		227
227	/*	228	/*
228	* To avoid race condition between two page faults	229	* To avoid race condition between two page faults
229	* on the same address, we need to make sure	230	* on the same address, we need to make sure
230	* the mapping has not been already inserted.	231	* the mapping has not been already inserted.
231	*/	232	*/
232	if ((pte = page_mapping_find(AS, page))) {	233	if ((pte = page_mapping_find(AS, page))) {
233	if (PTE_PRESENT(pte)) {	234	if (PTE_PRESENT(pte)) {
234	page_table_unlock(AS, false);	235	page_table_unlock(AS, false);
235	spinlock_unlock(&area->lock);	236	spinlock_unlock(&area->lock);
236	spinlock_unlock(&AS->lock);	237	spinlock_unlock(&AS->lock);
237	return 1;	238	return 1;
238	}	239	}
239	}	240	}
240		241
241	/*	242	/*
242	* In general, there can be several reasons that	243	* In general, there can be several reasons that
243	* can have caused this fault.	244	* can have caused this fault.
244	*	245	*
245	* - non-existent mapping: the area is a scratch	246	* - non-existent mapping: the area is a scratch
246	* area (e.g. stack) and so far has not been	247	* area (e.g. stack) and so far has not been
247	* allocated a frame for the faulting page	248	* allocated a frame for the faulting page
248	*	249	*
249	* - non-present mapping: another possibility,	250	* - non-present mapping: another possibility,
250	* currently not implemented, would be frame	251	* currently not implemented, would be frame
251	* reuse; when this becomes a possibility,	252	* reuse; when this becomes a possibility,
252	* do not forget to distinguish between	253	* do not forget to distinguish between
253	* the different causes	254	* the different causes
254	*/	255	*/
255	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	256	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
256	memsetb(PA2KA(frame), FRAME_SIZE, 0);	257	memsetb(PA2KA(frame), FRAME_SIZE, 0);
257		258
258	/*	259	/*
259	* Map 'page' to 'frame'.	260	* Map 'page' to 'frame'.
260	* Note that TLB shootdown is not attempted as only new information is being	261	* Note that TLB shootdown is not attempted as only new information is being
261	* inserted into page tables.	262	* inserted into page tables.
262	*/	263	*/
263	page_mapping_insert(AS, page, frame, get_area_flags(area));	264	page_mapping_insert(AS, page, frame, get_area_flags(area));
264	page_table_unlock(AS, false);	265	page_table_unlock(AS, false);
265		266
266	spinlock_unlock(&area->lock);	267	spinlock_unlock(&area->lock);
267	spinlock_unlock(&AS->lock);	268	spinlock_unlock(&AS->lock);
268	return 1;	269	return 1;
269	}	270	}
270		271
271	/** Switch address spaces.	272	/** Switch address spaces.
272	*	273	*
273	* @param old Old address space or NULL.	274	* @param old Old address space or NULL.
274	* @param new New address space.	275	* @param new New address space.
275	*/	276	*/
276	void as_switch(as_t old, as_t new)	277	void as_switch(as_t old, as_t new)
277	{	278	{
278	ipl_t ipl;	279	ipl_t ipl;
279	bool needs_asid = false;	280	bool needs_asid = false;
280		281
281	ipl = interrupts_disable();	282	ipl = interrupts_disable();
282	spinlock_lock(&as_lock);	283	spinlock_lock(&as_lock);
283		284
284	/*	285	/*
285	* First, take care of the old address space.	286	* First, take care of the old address space.
286	*/	287	*/
287	if (old) {	288	if (old) {
288	spinlock_lock(&old->lock);	289	spinlock_lock(&old->lock);
289	ASSERT(old->refcount);	290	ASSERT(old->refcount);
290	if((--old->refcount == 0) && (old != AS_KERNEL)) {	291	if((--old->refcount == 0) && (old != AS_KERNEL)) {
291	/*	292	/*
292	* The old address space is no longer active on	293	* The old address space is no longer active on
293	* any processor. It can be appended to the	294	* any processor. It can be appended to the
294	* list of inactive address spaces with assigned	295	* list of inactive address spaces with assigned
295	* ASID.	296	* ASID.
296	*/	297	*/
297	ASSERT(old->asid != ASID_INVALID);	298	ASSERT(old->asid != ASID_INVALID);
298	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);	299	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
299	}	300	}
300	spinlock_unlock(&old->lock);	301	spinlock_unlock(&old->lock);
301	}	302	}
302		303
303	/*	304	/*
304	* Second, prepare the new address space.	305	* Second, prepare the new address space.
305	*/	306	*/
306	spinlock_lock(&new->lock);	307	spinlock_lock(&new->lock);
307	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {	308	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
308	if (new->asid != ASID_INVALID)	309	if (new->asid != ASID_INVALID)
309	list_remove(&new->inactive_as_with_asid_link);	310	list_remove(&new->inactive_as_with_asid_link);
310	else	311	else
311	needs_asid = true; /* defer call to asid_get() until new->lock is released */	312	needs_asid = true; /* defer call to asid_get() until new->lock is released */
312	}	313	}
313	SET_PTL0_ADDRESS(new->page_table);	314	SET_PTL0_ADDRESS(new->page_table);
314	spinlock_unlock(&new->lock);	315	spinlock_unlock(&new->lock);
315		316
316	if (needs_asid) {	317	if (needs_asid) {
317	/*	318	/*
318	* Allocation of new ASID was deferred	319	* Allocation of new ASID was deferred
319	* until now in order to avoid deadlock.	320	* until now in order to avoid deadlock.
320	*/	321	*/
321	asid_t asid;	322	asid_t asid;
322		323
323	asid = asid_get();	324	asid = asid_get();
324	spinlock_lock(&new->lock);	325	spinlock_lock(&new->lock);
325	new->asid = asid;	326	new->asid = asid;
326	spinlock_unlock(&new->lock);	327	spinlock_unlock(&new->lock);
327	}	328	}
328	spinlock_unlock(&as_lock);	329	spinlock_unlock(&as_lock);
329	interrupts_restore(ipl);	330	interrupts_restore(ipl);
330		331
331	/*	332	/*
332	* Perform architecture-specific steps.	333	* Perform architecture-specific steps.
333	* (e.g. write ASID to hardware register etc.)	334	* (e.g. write ASID to hardware register etc.)
334	*/	335	*/
335	as_install_arch(new);	336	as_install_arch(new);
336		337
337	AS = new;	338	AS = new;
338	}	339	}
339		340
340	/** Compute flags for virtual address translation subsytem.	341	/** Compute flags for virtual address translation subsytem.
341	*	342	*
342	* The address space area must be locked.	343	* The address space area must be locked.
343	* Interrupts must be disabled.	344	* Interrupts must be disabled.
344	*	345	*
345	* @param a Address space area.	346	* @param a Address space area.
346	*	347	*
347	* @return Flags to be used in page_mapping_insert().	348	* @return Flags to be used in page_mapping_insert().
348	*/	349	*/
349	int get_area_flags(as_area_t *a)	350	int get_area_flags(as_area_t *a)
350	{	351	{
351	int flags;	352	int flags;
352		353
353	flags = PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	354	flags = PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
354		355
355	if (a->flags & AS_AREA_READ)	356	if (a->flags & AS_AREA_READ)
356	flags \|= PAGE_READ;	357	flags \|= PAGE_READ;
357		358
358	if (a->flags & AS_AREA_WRITE)	359	if (a->flags & AS_AREA_WRITE)
359	flags \|= PAGE_WRITE;	360	flags \|= PAGE_WRITE;
360		361
361	if (a->flags & AS_AREA_EXEC)	362	if (a->flags & AS_AREA_EXEC)
362	flags \|= PAGE_EXEC;	363	flags \|= PAGE_EXEC;
363		364
364	return flags;	365	return flags;
365	}	366	}
366		367
367	/** Create page table.	368	/** Create page table.
368	*	369	*
369	* Depending on architecture, create either address space	370	* Depending on architecture, create either address space
370	* private or global page table.	371	* private or global page table.
371	*	372	*
372	* @param flags Flags saying whether the page table is for kernel address space.	373	* @param flags Flags saying whether the page table is for kernel address space.
373	*	374	*
374	* @return First entry of the page table.	375	* @return First entry of the page table.
375	*/	376	*/
376	pte_t *page_table_create(int flags)	377	pte_t *page_table_create(int flags)
377	{	378	{
378	ASSERT(as_operations);	379	ASSERT(as_operations);
379	ASSERT(as_operations->page_table_create);	380	ASSERT(as_operations->page_table_create);
380		381
381	return as_operations->page_table_create(flags);	382	return as_operations->page_table_create(flags);
382	}	383	}
383		384
384	/** Lock page table.	385	/** Lock page table.
385	*	386	*
386	* This function should be called before any page_mapping_insert(),	387	* This function should be called before any page_mapping_insert(),
387	* page_mapping_remove() and page_mapping_find().	388	* page_mapping_remove() and page_mapping_find().
388	*	389	*
389	* Locking order is such that address space areas must be locked	390	* Locking order is such that address space areas must be locked
390	* prior to this call. Address space can be locked prior to this	391	* prior to this call. Address space can be locked prior to this
391	* call in which case the lock argument is false.	392	* call in which case the lock argument is false.
392	*	393	*
393	* @param as Address space.	394	* @param as Address space.
394	* @param as_locked If false, do not attempt to lock as->lock.	395	* @param as_locked If false, do not attempt to lock as->lock.
395	*/	396	*/
396	void page_table_lock(as_t *as, bool lock)	397	void page_table_lock(as_t *as, bool lock)
397	{	398	{
398	ASSERT(as_operations);	399	ASSERT(as_operations);
399	ASSERT(as_operations->page_table_lock);	400	ASSERT(as_operations->page_table_lock);
400		401
401	as_operations->page_table_lock(as, lock);	402	as_operations->page_table_lock(as, lock);
402	}	403	}
403		404
404	/** Unlock page table.	405	/** Unlock page table.
405	*	406	*
406	* @param as Address space.	407	* @param as Address space.
407	* @param as_locked If false, do not attempt to unlock as->lock.	408	* @param as_locked If false, do not attempt to unlock as->lock.
408	*/	409	*/
409	void page_table_unlock(as_t *as, bool unlock)	410	void page_table_unlock(as_t *as, bool unlock)
410	{	411	{
411	ASSERT(as_operations);	412	ASSERT(as_operations);
412	ASSERT(as_operations->page_table_unlock);	413	ASSERT(as_operations->page_table_unlock);
413		414
414	as_operations->page_table_unlock(as, unlock);	415	as_operations->page_table_unlock(as, unlock);
415	}	416	}
416		417
417	/** Find address space area and change it.	418	/** Find address space area and change it.
418	*	419	*
419	* @param as Address space.	420	* @param as Address space.
420	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	421	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
421	* @param size New size of the virtual memory block starting at address.	422	* @param size New size of the virtual memory block starting at address.
422	* @param flags Flags influencing the remap operation. Currently unused.	423	* @param flags Flags influencing the remap operation. Currently unused.
423	*	424	*
424	* @return address on success, (__address) -1 otherwise.	425	* @return address on success, (__address) -1 otherwise.
425	*/	426	*/
426	__address as_remap(as_t *as, __address address, size_t size, int flags)	427	__address as_remap(as_t *as, __address address, size_t size, int flags)
427	{	428	{
428	as_area_t *area = NULL;	429	as_area_t *area = NULL;
429	ipl_t ipl;	430	ipl_t ipl;
430	size_t pages;	431	size_t pages;
431		432
432	ipl = interrupts_disable();	433	ipl = interrupts_disable();
433	spinlock_lock(&as->lock);	434	spinlock_lock(&as->lock);
434		435
435	/*	436	/*
436	* Locate the area.	437	* Locate the area.
437	*/	438	*/
438	area = find_area_and_lock(as, address);	439	area = find_area_and_lock(as, address);
439	if (!area) {	440	if (!area) {
440	spinlock_unlock(&as->lock);	441	spinlock_unlock(&as->lock);
441	interrupts_restore(ipl);	442	interrupts_restore(ipl);
442	return (__address) -1;	443	return (__address) -1;
443	}	444	}
444		445
445	pages = SIZE2FRAMES((address - area->base) + size);	446	pages = SIZE2FRAMES((address - area->base) + size);
446	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {	447	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
447	spinlock_unlock(&as->lock);	448	spinlock_unlock(&as->lock);
448	interrupts_restore(ipl);	449	interrupts_restore(ipl);
449	return (__address) -1;	450	return (__address) -1;
450	}	451	}
451		452
452	if (pages < area->pages) {	453	if (pages < area->pages) {
453	int i;	454	int i;
454		455
455	/*	456	/*
456	* Shrinking the area.	457	* Shrinking the area.
457	*/	458	*/
458	for (i = pages; i < area->pages; i++) {	459	for (i = pages; i < area->pages; i++) {
459	pte_t *pte;	460	pte_t *pte;
460		461
461	/*	462	/*
462	* Releasing physical memory.	463	* Releasing physical memory.
463	* This depends on the fact that the memory was allocated using frame_alloc().	464	* This depends on the fact that the memory was allocated using frame_alloc().
464	*/	465	*/
465	page_table_lock(as, false);	466	page_table_lock(as, false);
466	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);	467	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
467	if (pte && PTE_VALID(pte)) {	468	if (pte && PTE_VALID(pte)) {
468	__address frame;	469	__address frame;
469		470
470	ASSERT(PTE_PRESENT(pte));	471	ASSERT(PTE_PRESENT(pte));
471	frame = PTE_GET_FRAME(pte);	472	frame = PTE_GET_FRAME(pte);
472	page_mapping_remove(as, area->base + i*PAGE_SIZE);	473	page_mapping_remove(as, area->base + i*PAGE_SIZE);
473	page_table_unlock(as, false);	474	page_table_unlock(as, false);
474		475
475	frame_free(ADDR2PFN(frame));	476	frame_free(ADDR2PFN(frame));
476	} else {	477	} else {
477	page_table_unlock(as, false);	478	page_table_unlock(as, false);
478	}	479	}
479	}	480	}
480	/*	481	/*
481	* Invalidate TLB's.	482	* Invalidate TLB's.
482	*/	483	*/
483	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	484	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
484	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	485	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
485	tlb_shootdown_finalize();	486	tlb_shootdown_finalize();
486	}	487	}
487		488
488	area->pages = pages;	489	area->pages = pages;
489		490
490	spinlock_unlock(&area->lock);	491	spinlock_unlock(&area->lock);
491	spinlock_unlock(&as->lock);	492	spinlock_unlock(&as->lock);
492	interrupts_restore(ipl);	493	interrupts_restore(ipl);
493		494
494	return address;	495	return address;
495	}	496	}
496		497
497	/** Find address space area and lock it.	498	/** Find address space area and lock it.
498	*	499	*
499	* The address space must be locked and interrupts must be disabled.	500	* The address space must be locked and interrupts must be disabled.

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/as.c – Rev 1048 → 1070