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);
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;
   
    for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
        __address start;
        __address end;
   
        a = list_get_instance(cur, as_area_t, link);
        if (a == avoid_area)
            continue;
           
        spinlock_lock(&a->lock);
 
        start = a->base;
        end = a->base + a->pages * PAGE_SIZE - 1;
 
        spinlock_unlock(&a->lock);
 
        if ((va >= start) && (va <= end)) {
            /*
             * Tested area is inside another area.
             */
            return false;
        }
       
        if ((start >= va) && (start < va + size)) {
            /*
             * Another area starts in tested area.
             */
            return false;
        }
       
        if ((end >= va) && (end < va + size)) {
            /*
             * Another area ends in tested area.
             */
            return false;
        }
 
    }
 
    return true;
}
 

Rev 1044	Rev 1048
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	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);
73		74
74	/** Initialize address space subsystem. */	75	/** Initialize address space subsystem. */
75	void as_init(void)	76	void as_init(void)
76	{	77	{
77	as_arch_init();	78	as_arch_init();
78	AS_KERNEL = as_create(FLAG_AS_KERNEL);	79	AS_KERNEL = as_create(FLAG_AS_KERNEL);
79	if (!AS_KERNEL)	80	if (!AS_KERNEL)
80	panic("can't create kernel address space\n");	81	panic("can't create kernel address space\n");
81	}	82	}
82		83
83	/** Create address space.	84	/** Create address space.
84	*	85	*
85	* @param flags Flags that influence way in wich the address space is created.	86	* @param flags Flags that influence way in wich the address space is created.
86	*/	87	*/
87	as_t *as_create(int flags)	88	as_t *as_create(int flags)
88	{	89	{
89	as_t *as;	90	as_t *as;
90		91
91	as = (as_t *) malloc(sizeof(as_t), 0);	92	as = (as_t *) malloc(sizeof(as_t), 0);
92	link_initialize(&as->inactive_as_with_asid_link);	93	link_initialize(&as->inactive_as_with_asid_link);
93	spinlock_initialize(&as->lock, "as_lock");	94	spinlock_initialize(&as->lock, "as_lock");
94	list_initialize(&as->as_area_head);	95	list_initialize(&as->as_area_head);
95		96
96	if (flags & FLAG_AS_KERNEL)	97	if (flags & FLAG_AS_KERNEL)
97	as->asid = ASID_KERNEL;	98	as->asid = ASID_KERNEL;
98	else	99	else
99	as->asid = ASID_INVALID;	100	as->asid = ASID_INVALID;
100		101
101	as->refcount = 0;	102	as->refcount = 0;
102	as->page_table = page_table_create(flags);	103	as->page_table = page_table_create(flags);
103		104
104	return as;	105	return as;
105	}	106	}
106		107
107	/** Free Adress space */	108	/** Free Adress space */
108	void as_free(as_t *as)	109	void as_free(as_t *as)
109	{	110	{
110	ASSERT(as->refcount == 0);	111	ASSERT(as->refcount == 0);
111		112
112	/* TODO: free as_areas and other resources held by as */	113	/* TODO: free as_areas and other resources held by as */
113	/* TODO: free page table */	114	/* TODO: free page table */
114	free(as);	115	free(as);
115	}	116	}
116		117
117	/** Create address space area of common attributes.	118	/** Create address space area of common attributes.
118	*	119	*
119	* The created address space area is added to the target address space.	120	* The created address space area is added to the target address space.
120	*	121	*
121	* @param as Target address space.	122	* @param as Target address space.
122	* @param flags Flags of the area.	123	* @param flags Flags of the area.
123	* @param size Size of area in multiples of PAGE_SIZE.	124	* @param size Size of area.
124	* @param base Base address of area.	125	* @param base Base address of area.
125	*	126	*
126	* @return Address space area on success or NULL on failure.	127	* @return Address space area on success or NULL on failure.
127	*/	128	*/
128	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)	129	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)
129	{	130	{
130	ipl_t ipl;	131	ipl_t ipl;
131	as_area_t *a;	132	as_area_t *a;
132		133
133	if (base % PAGE_SIZE)	134	if (base % PAGE_SIZE)
-		135	return NULL;
-		136
134	panic("addr not aligned to a page boundary");	137	/* Writeable executable areas are not supported. */
-		138	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
-		139	return NULL;
135		140
136	ipl = interrupts_disable();	141	ipl = interrupts_disable();
137	spinlock_lock(&as->lock);	142	spinlock_lock(&as->lock);
138		143
139	/*	-
140	* TODO: test as_area which is to be created doesn't overlap with an existing one.	144	if (!check_area_conflicts(as, base, size, NULL)) {
-		145	spinlock_unlock(&as->lock);
-		146	interrupts_restore(ipl);
-		147	return NULL;
141	*/	148	}
142		149
143	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	150	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
144		151
145	spinlock_initialize(&a->lock, "as_area_lock");	152	spinlock_initialize(&a->lock, "as_area_lock");
146		153
147	link_initialize(&a->link);	154	link_initialize(&a->link);
148	a->flags = flags;	155	a->flags = flags;
149	a->size = size;	156	a->pages = SIZE2FRAMES(size);
150	a->base = base;	157	a->base = base;
151		158
152	list_append(&a->link, &as->as_area_head);	159	list_append(&a->link, &as->as_area_head);
153		160
154	spinlock_unlock(&as->lock);	161	spinlock_unlock(&as->lock);
155	interrupts_restore(ipl);	162	interrupts_restore(ipl);
156		163
157	return a;	164	return a;
158	}	165	}
159		166
160	/** Initialize mapping for one page of address space.	167	/** Initialize mapping for one page of address space.
161	*	168	*
162	* This functions maps 'page' to 'frame' according	169	* This functions maps 'page' to 'frame' according
163	* to attributes of the address space area to	170	* to attributes of the address space area to
164	* wich 'page' belongs.	171	* wich 'page' belongs.
165	*	172	*
166	* @param as Target address space.	173	* @param as Target address space.
167	* @param page Virtual page within the area.	174	* @param page Virtual page within the area.
168	* @param frame Physical frame to which page will be mapped.	175	* @param frame Physical frame to which page will be mapped.
169	*/	176	*/
170	void as_set_mapping(as_t *as, __address page, __address frame)	177	void as_set_mapping(as_t *as, __address page, __address frame)
171	{	178	{
172	as_area_t *area;	179	as_area_t *area;
173	ipl_t ipl;	180	ipl_t ipl;
174		181
175	ipl = interrupts_disable();	182	ipl = interrupts_disable();
176	page_table_lock(as, true);	183	page_table_lock(as, true);
177		184
178	area = find_area_and_lock(as, page);	185	area = find_area_and_lock(as, page);
179	if (!area) {	186	if (!area) {
180	panic("page not part of any as_area\n");	187	panic("page not part of any as_area\n");
181	}	188	}
182		189
183	page_mapping_insert(as, page, frame, get_area_flags(area));	190	page_mapping_insert(as, page, frame, get_area_flags(area));
184		191
185	spinlock_unlock(&area->lock);	192	spinlock_unlock(&area->lock);
186	page_table_unlock(as, true);	193	page_table_unlock(as, true);
187	interrupts_restore(ipl);	194	interrupts_restore(ipl);
188	}	195	}
189		196
190	/** Handle page fault within the current address space.	197	/** Handle page fault within the current address space.
191	*	198	*
192	* This is the high-level page fault handler.	199	* This is the high-level page fault handler.
193	* Interrupts are assumed disabled.	200	* Interrupts are assumed disabled.
194	*	201	*
195	* @param page Faulting page.	202	* @param page Faulting page.
196	*	203	*
197	* @return 0 on page fault, 1 on success.	204	* @return 0 on page fault, 1 on success.
198	*/	205	*/
199	int as_page_fault(__address page)	206	int as_page_fault(__address page)
200	{	207	{
201	pte_t *pte;	208	pte_t *pte;
202	as_area_t *area;	209	as_area_t *area;
203	__address frame;	210	__address frame;
204		211
205	ASSERT(AS);	212	ASSERT(AS);
206		213
207	spinlock_lock(&AS->lock);	214	spinlock_lock(&AS->lock);
208	area = find_area_and_lock(AS, page);	215	area = find_area_and_lock(AS, page);
209	if (!area) {	216	if (!area) {
210	/*	217	/*
211	* No area contained mapping for 'page'.	218	* No area contained mapping for 'page'.
212	* Signal page fault to low-level handler.	219	* Signal page fault to low-level handler.
213	*/	220	*/
214	spinlock_unlock(&AS->lock);	221	spinlock_unlock(&AS->lock);
215	return 0;	222	return 0;
216	}	223	}
217		224
218	page_table_lock(AS, false);	225	page_table_lock(AS, false);
219		226
220	/*	227	/*
221	* To avoid race condition between two page faults	228	* To avoid race condition between two page faults
222	* on the same address, we need to make sure	229	* on the same address, we need to make sure
223	* the mapping has not been already inserted.	230	* the mapping has not been already inserted.
224	*/	231	*/
225	if ((pte = page_mapping_find(AS, page))) {	232	if ((pte = page_mapping_find(AS, page))) {
226	if (PTE_PRESENT(pte)) {	233	if (PTE_PRESENT(pte)) {
227	page_table_unlock(AS, false);	234	page_table_unlock(AS, false);
228	spinlock_unlock(&area->lock);	235	spinlock_unlock(&area->lock);
229	spinlock_unlock(&AS->lock);	236	spinlock_unlock(&AS->lock);
230	return 1;	237	return 1;
231	}	238	}
232	}	239	}
233		240
234	/*	241	/*
235	* In general, there can be several reasons that	242	* In general, there can be several reasons that
236	* can have caused this fault.	243	* can have caused this fault.
237	*	244	*
238	* - non-existent mapping: the area is a scratch	245	* - non-existent mapping: the area is a scratch
239	* area (e.g. stack) and so far has not been	246	* area (e.g. stack) and so far has not been
240	* allocated a frame for the faulting page	247	* allocated a frame for the faulting page
241	*	248	*
242	* - non-present mapping: another possibility,	249	* - non-present mapping: another possibility,
243	* currently not implemented, would be frame	250	* currently not implemented, would be frame
244	* reuse; when this becomes a possibility,	251	* reuse; when this becomes a possibility,
245	* do not forget to distinguish between	252	* do not forget to distinguish between
246	* the different causes	253	* the different causes
247	*/	254	*/
248	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	255	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
249	memsetb(PA2KA(frame), FRAME_SIZE, 0);	256	memsetb(PA2KA(frame), FRAME_SIZE, 0);
250		257
251	/*	258	/*
252	* Map 'page' to 'frame'.	259	* Map 'page' to 'frame'.
253	* Note that TLB shootdown is not attempted as only new information is being	260	* Note that TLB shootdown is not attempted as only new information is being
254	* inserted into page tables.	261	* inserted into page tables.
255	*/	262	*/
256	page_mapping_insert(AS, page, frame, get_area_flags(area));	263	page_mapping_insert(AS, page, frame, get_area_flags(area));
257	page_table_unlock(AS, false);	264	page_table_unlock(AS, false);
258		265
259	spinlock_unlock(&area->lock);	266	spinlock_unlock(&area->lock);
260	spinlock_unlock(&AS->lock);	267	spinlock_unlock(&AS->lock);
261	return 1;	268	return 1;
262	}	269	}
263		270
264	/** Switch address spaces.	271	/** Switch address spaces.
265	*	272	*
266	* @param old Old address space or NULL.	273	* @param old Old address space or NULL.
267	* @param new New address space.	274	* @param new New address space.
268	*/	275	*/
269	void as_switch(as_t old, as_t new)	276	void as_switch(as_t old, as_t new)
270	{	277	{
271	ipl_t ipl;	278	ipl_t ipl;
272	bool needs_asid = false;	279	bool needs_asid = false;
273		280
274	ipl = interrupts_disable();	281	ipl = interrupts_disable();
275	spinlock_lock(&as_lock);	282	spinlock_lock(&as_lock);
276		283
277	/*	284	/*
278	* First, take care of the old address space.	285	* First, take care of the old address space.
279	*/	286	*/
280	if (old) {	287	if (old) {
281	spinlock_lock(&old->lock);	288	spinlock_lock(&old->lock);
282	ASSERT(old->refcount);	289	ASSERT(old->refcount);
283	if((--old->refcount == 0) && (old != AS_KERNEL)) {	290	if((--old->refcount == 0) && (old != AS_KERNEL)) {
284	/*	291	/*
285	* The old address space is no longer active on	292	* The old address space is no longer active on
286	* any processor. It can be appended to the	293	* any processor. It can be appended to the
287	* list of inactive address spaces with assigned	294	* list of inactive address spaces with assigned
288	* ASID.	295	* ASID.
289	*/	296	*/
290	ASSERT(old->asid != ASID_INVALID);	297	ASSERT(old->asid != ASID_INVALID);
291	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);	298	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
292	}	299	}
293	spinlock_unlock(&old->lock);	300	spinlock_unlock(&old->lock);
294	}	301	}
295		302
296	/*	303	/*
297	* Second, prepare the new address space.	304	* Second, prepare the new address space.
298	*/	305	*/
299	spinlock_lock(&new->lock);	306	spinlock_lock(&new->lock);
300	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {	307	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
301	if (new->asid != ASID_INVALID)	308	if (new->asid != ASID_INVALID)
302	list_remove(&new->inactive_as_with_asid_link);	309	list_remove(&new->inactive_as_with_asid_link);
303	else	310	else
304	needs_asid = true; /* defer call to asid_get() until new->lock is released */	311	needs_asid = true; /* defer call to asid_get() until new->lock is released */
305	}	312	}
306	SET_PTL0_ADDRESS(new->page_table);	313	SET_PTL0_ADDRESS(new->page_table);
307	spinlock_unlock(&new->lock);	314	spinlock_unlock(&new->lock);
308		315
309	if (needs_asid) {	316	if (needs_asid) {
310	/*	317	/*
311	* Allocation of new ASID was deferred	318	* Allocation of new ASID was deferred
312	* until now in order to avoid deadlock.	319	* until now in order to avoid deadlock.
313	*/	320	*/
314	asid_t asid;	321	asid_t asid;
315		322
316	asid = asid_get();	323	asid = asid_get();
317	spinlock_lock(&new->lock);	324	spinlock_lock(&new->lock);
318	new->asid = asid;	325	new->asid = asid;
319	spinlock_unlock(&new->lock);	326	spinlock_unlock(&new->lock);
320	}	327	}
321	spinlock_unlock(&as_lock);	328	spinlock_unlock(&as_lock);
322	interrupts_restore(ipl);	329	interrupts_restore(ipl);
323		330
324	/*	331	/*
325	* Perform architecture-specific steps.	332	* Perform architecture-specific steps.
326	* (e.g. write ASID to hardware register etc.)	333	* (e.g. write ASID to hardware register etc.)
327	*/	334	*/
328	as_install_arch(new);	335	as_install_arch(new);
329		336
330	AS = new;	337	AS = new;
331	}	338	}
332		339
333	/** Compute flags for virtual address translation subsytem.	340	/** Compute flags for virtual address translation subsytem.
334	*	341	*
335	* The address space area must be locked.	342	* The address space area must be locked.
336	* Interrupts must be disabled.	343	* Interrupts must be disabled.
337	*	344	*
338	* @param a Address space area.	345	* @param a Address space area.
339	*	346	*
340	* @return Flags to be used in page_mapping_insert().	347	* @return Flags to be used in page_mapping_insert().
341	*/	348	*/
342	int get_area_flags(as_area_t *a)	349	int get_area_flags(as_area_t *a)
343	{	350	{
344	int flags;	351	int flags;
345		352
346	flags = PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;	353	flags = PAGE_USER \| PAGE_PRESENT \| PAGE_CACHEABLE;
347		354
348	if (a->flags & AS_AREA_READ)	355	if (a->flags & AS_AREA_READ)
349	flags \|= PAGE_READ;	356	flags \|= PAGE_READ;
350		357
351	if (a->flags & AS_AREA_WRITE)	358	if (a->flags & AS_AREA_WRITE)
352	flags \|= PAGE_WRITE;	359	flags \|= PAGE_WRITE;
353		360
354	if (a->flags & AS_AREA_EXEC)	361	if (a->flags & AS_AREA_EXEC)
355	flags \|= PAGE_EXEC;	362	flags \|= PAGE_EXEC;
356		363
357	return flags;	364	return flags;
358	}	365	}
359		366
360	/** Create page table.	367	/** Create page table.
361	*	368	*
362	* Depending on architecture, create either address space	369	* Depending on architecture, create either address space
363	* private or global page table.	370	* private or global page table.
364	*	371	*
365	* @param flags Flags saying whether the page table is for kernel address space.	372	* @param flags Flags saying whether the page table is for kernel address space.
366	*	373	*
367	* @return First entry of the page table.	374	* @return First entry of the page table.
368	*/	375	*/
369	pte_t *page_table_create(int flags)	376	pte_t *page_table_create(int flags)
370	{	377	{
371	ASSERT(as_operations);	378	ASSERT(as_operations);
372	ASSERT(as_operations->page_table_create);	379	ASSERT(as_operations->page_table_create);
373		380
374	return as_operations->page_table_create(flags);	381	return as_operations->page_table_create(flags);
375	}	382	}
376		383
377	/** Lock page table.	384	/** Lock page table.
378	*	385	*
379	* This function should be called before any page_mapping_insert(),	386	* This function should be called before any page_mapping_insert(),
380	* page_mapping_remove() and page_mapping_find().	387	* page_mapping_remove() and page_mapping_find().
381	*	388	*
382	* Locking order is such that address space areas must be locked	389	* Locking order is such that address space areas must be locked
383	* prior to this call. Address space can be locked prior to this	390	* prior to this call. Address space can be locked prior to this
384	* call in which case the lock argument is false.	391	* call in which case the lock argument is false.
385	*	392	*
386	* @param as Address space.	393	* @param as Address space.
387	* @param as_locked If false, do not attempt to lock as->lock.	394	* @param as_locked If false, do not attempt to lock as->lock.
388	*/	395	*/
389	void page_table_lock(as_t *as, bool lock)	396	void page_table_lock(as_t *as, bool lock)
390	{	397	{
391	ASSERT(as_operations);	398	ASSERT(as_operations);
392	ASSERT(as_operations->page_table_lock);	399	ASSERT(as_operations->page_table_lock);
393		400
394	as_operations->page_table_lock(as, lock);	401	as_operations->page_table_lock(as, lock);
395	}	402	}
396		403
397	/** Unlock page table.	404	/** Unlock page table.
398	*	405	*
399	* @param as Address space.	406	* @param as Address space.
400	* @param as_locked If false, do not attempt to unlock as->lock.	407	* @param as_locked If false, do not attempt to unlock as->lock.
401	*/	408	*/
402	void page_table_unlock(as_t *as, bool unlock)	409	void page_table_unlock(as_t *as, bool unlock)
403	{	410	{
404	ASSERT(as_operations);	411	ASSERT(as_operations);
405	ASSERT(as_operations->page_table_unlock);	412	ASSERT(as_operations->page_table_unlock);
406		413
407	as_operations->page_table_unlock(as, unlock);	414	as_operations->page_table_unlock(as, unlock);
408	}	415	}
409		416
410	/** Find address space area and change it.	417	/** Find address space area and change it.
411	*	418	*
412	* @param as Address space.	419	* @param as Address space.
413	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	420	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
414	* @param size New size of the virtual memory block starting at address.	421	* @param size New size of the virtual memory block starting at address.
415	* @param flags Flags influencing the remap operation. Currently unused.	422	* @param flags Flags influencing the remap operation. Currently unused.
416	*	423	*
417	* @return address on success, (__address) -1 otherwise.	424	* @return address on success, (__address) -1 otherwise.
418	*/	425	*/
419	__address as_remap(as_t *as, __address address, size_t size, int flags)	426	__address as_remap(as_t *as, __address address, size_t size, int flags)
420	{	427	{
421	as_area_t *area = NULL;	428	as_area_t *area = NULL;
422	ipl_t ipl;	429	ipl_t ipl;
423	size_t pages;	430	size_t pages;
424		431
425	ipl = interrupts_disable();	432	ipl = interrupts_disable();
426	spinlock_lock(&as->lock);	433	spinlock_lock(&as->lock);
427		434
428	/*	435	/*
429	* Locate the area.	436	* Locate the area.
430	*/	437	*/
431	area = find_area_and_lock(as, address);	438	area = find_area_and_lock(as, address);
432	if (!area) {	439	if (!area) {
433	spinlock_unlock(&as->lock);	440	spinlock_unlock(&as->lock);
-		441	interrupts_restore(ipl);
434	return (__address) -1;	442	return (__address) -1;
435	}	443	}
436		444
437	pages = SIZE2FRAMES((address - area->base) + size);	445	pages = SIZE2FRAMES((address - area->base) + size);
-		446	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
-		447	spinlock_unlock(&as->lock);
-		448	interrupts_restore(ipl);
-		449	return (__address) -1;
-		450	}
-		451
438	if (pages < area->size) {	452	if (pages < area->pages) {
439	int i;	453	int i;
440		454
441	/*	455	/*
442	* Shrinking the area.	456	* Shrinking the area.
443	*/	457	*/
444	for (i = pages; i < area->size; i++) {	458	for (i = pages; i < area->pages; i++) {
445	pte_t *pte;	459	pte_t *pte;
446		460
447	/*	461	/*
448	* Releasing physical memory.	462	* Releasing physical memory.
449	* This depends on the fact that the memory was allocated using frame_alloc().	463	* This depends on the fact that the memory was allocated using frame_alloc().
450	*/	464	*/
451	page_table_lock(as, false);	465	page_table_lock(as, false);
452	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);	466	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
453	if (pte && PTE_VALID(pte)) {	467	if (pte && PTE_VALID(pte)) {
454	__address frame;	468	__address frame;
455		469
456	ASSERT(PTE_PRESENT(pte));	470	ASSERT(PTE_PRESENT(pte));
457	frame = PTE_GET_FRAME(pte);	471	frame = PTE_GET_FRAME(pte);
458	page_mapping_remove(as, area->base + i*PAGE_SIZE);	472	page_mapping_remove(as, area->base + i*PAGE_SIZE);
459	page_table_unlock(as, false);	473	page_table_unlock(as, false);
460		474
461	frame_free(ADDR2PFN(frame));	475	frame_free(ADDR2PFN(frame));
462	} else {	476	} else {
463	page_table_unlock(as, false);	477	page_table_unlock(as, false);
464	}	478	}
465	}	479	}
466	/*	480	/*
467	* Invalidate TLB's.	481	* Invalidate TLB's.
468	*/	482	*/
469	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);	483	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
470	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);	484	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
471	tlb_shootdown_finalize();	485	tlb_shootdown_finalize();
472	}	486	}
473		487
474	area->size = pages;	488	area->pages = pages;
475		489
476	spinlock_unlock(&area->lock);	490	spinlock_unlock(&area->lock);
477	spinlock_unlock(&as->lock);	491	spinlock_unlock(&as->lock);
478	interrupts_restore(ipl);	492	interrupts_restore(ipl);
479		493
480	return address;	494	return address;
481	}	495	}
482		496
483	/** Find address space area and lock it.	497	/** Find address space area and lock it.
484	*	498	*
485	* The address space must be locked and interrupts must be disabled.	499	* The address space must be locked and interrupts must be disabled.

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/as.c – Rev 1044 → 1048