WebSVN – HelenOS – Diff – /trunk/kernel/generic/src/mm/backend_elf.c


/*
 * Copyright (c) 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.
 */
 
/** @addtogroup genericmm
 * @{
 */
 
/**
 * @file
 * @brief   Backend for address space areas backed by an ELF image.
 */
 
#include <lib/elf.h>
#include <debug.h>
#include <arch/types.h>
#include <mm/as.h>
#include <mm/frame.h>
#include <mm/slab.h>
#include <mm/page.h>
#include <genarch/mm/page_pt.h>
#include <genarch/mm/page_ht.h>
#include <align.h>
#include <memstr.h>
#include <macros.h>
#include <arch.h>
 
#ifdef CONFIG_VIRT_IDX_DCACHE
#include <arch/mm/cache.h>
#endif
 
static int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access);
static void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame);
static void elf_share(as_area_t *area);
 
mem_backend_t elf_backend = {
    .page_fault = elf_page_fault,
    .frame_free = elf_frame_free,
    .share = elf_share
};
 
/** Service a page fault in the ELF backend address space area.
 *
 * The address space area and page tables must be already locked.
 *
 * @param area Pointer to the address space area.
 * @param addr Faulting virtual address.
 * @param access Access mode that caused the fault (i.e. read/write/exec).
 *
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e.
 *     serviced).
 */
int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
{
    elf_header_t *elf = area->backend_data.elf;
    elf_segment_header_t *entry = area->backend_data.segment;
    btree_node_t *leaf;
    uintptr_t base, frame;
    index_t i;
    bool dirty = false;
 
    if (!as_area_check_access(area, access))
        return AS_PF_FAULT;
 
    ASSERT((addr >= entry->p_vaddr) &&
        (addr < entry->p_vaddr + entry->p_memsz));
    i = (addr - entry->p_vaddr) >> PAGE_WIDTH;
    base = (uintptr_t) (((void *) elf) + entry->p_offset);
    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
 
    if (area->sh_info) {
        bool found = false;
 
        /*
         * The address space area is shared.
         */
         
        mutex_lock(&area->sh_info->lock);
        frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
            ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
        if (!frame) {
            int i;
 
            /*
             * Workaround for valid NULL address.
             */
 
            for (i = 0; i < leaf->keys; i++) {
                if (leaf->key[i] ==
                    ALIGN_DOWN(addr, PAGE_SIZE)) {
                    found = true;
                    break;
                }
            }
        }
        if (frame || found) {
            frame_reference_add(ADDR2PFN(frame));
            page_mapping_insert(AS, addr, frame,
                as_area_get_flags(area));
            if (!used_space_insert(area,
                ALIGN_DOWN(addr, PAGE_SIZE), 1))
                panic("Could not insert used space.\n");
            mutex_unlock(&area->sh_info->lock);
            return AS_PF_OK;
        }
    }
   
    /*
     * The area is either not shared or the pagemap does not contain the
     * mapping.
     */
   
    if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE <
        entry->p_vaddr + entry->p_filesz) {
        /*
         * Initialized portion of the segment. The memory is backed
         * directly by the content of the ELF image. Pages are
         * only copied if the segment is writable so that there
         * can be more instantions of the same memory ELF image
         * used at a time. Note that this could be later done
         * as COW.
         */
        if (entry->p_flags & PF_W) {
            frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
            memcpy((void *) PA2KA(frame),
                (void *) (base + i * FRAME_SIZE), FRAME_SIZE);
            dirty = true;
 
            if (area->sh_info) {
                frame_reference_add(ADDR2PFN(frame));
                btree_insert(&area->sh_info->pagemap,
                    ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
                    (void *) frame, leaf);
            }
 
        } else {
            frame = KA2PA(base + i*FRAME_SIZE);
        }  
    } else if (ALIGN_DOWN(addr, PAGE_SIZE) >=
        ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
        /*
         * This is the uninitialized portion of the segment.
         * It is not physically present in the ELF image.
         * To resolve the situation, a frame must be allocated
         * and cleared.
         */
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
        memsetb(PA2KA(frame), FRAME_SIZE, 0);
        dirty = true;
 
        if (area->sh_info) {
            frame_reference_add(ADDR2PFN(frame));
            btree_insert(&area->sh_info->pagemap,
                ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
                (void *) frame, leaf);
        }
 
    } else {
        size_t size;
        /*
         * The mixed case.
         * The lower part is backed by the ELF image and
         * the upper part is anonymous memory.
         */
        size = entry->p_filesz - (i<<PAGE_WIDTH);
        frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
        memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0);
        memcpy((void *) PA2KA(frame), (void *) (base + i * FRAME_SIZE),
            size);
        dirty = true;
 
        if (area->sh_info) {
            frame_reference_add(ADDR2PFN(frame));
            btree_insert(&area->sh_info->pagemap,
                ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
                (void *) frame, leaf);
        }
 
    }
   
    if (area->sh_info)
        mutex_unlock(&area->sh_info->lock);
   
    page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
        panic("Could not insert used space.\n");
 
    return AS_PF_OK;
}
 
/** Free a frame that is backed by the ELF backend.
 *
 * The address space area and page tables must be already locked.
 *
 * @param area Pointer to the address space area.
 * @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE.
 * @param frame Frame to be released.
 *
 */
void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
{
    elf_header_t *elf = area->backend_data.elf;
    elf_segment_header_t *entry = area->backend_data.segment;
    uintptr_t base;
    index_t i;
   
    ASSERT((page >= entry->p_vaddr) &&
        (page < entry->p_vaddr + entry->p_memsz));
    i = (page - entry->p_vaddr) >> PAGE_WIDTH;
    base = (uintptr_t) (((void *) elf) + entry->p_offset);
    ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
   
    if (page + PAGE_SIZE <
        ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
        if (entry->p_flags & PF_W) {
            /*
             * Free the frame with the copy of writable segment
             * data.
             */
            frame_free(frame);
        }
    } else {
        /*
         * The frame is either anonymous memory or the mixed case (i.e.
         * lower part is backed by the ELF image and the upper is
         * anonymous). In any case, a frame needs to be freed.
         */
        frame_free(frame);
    }
}
 
/** Share ELF image backed address space area.
 *
 * If the area is writable, then all mapped pages are duplicated in the pagemap.
 * Otherwise only portions of the area that are not backed by the ELF image
 * are put into the pagemap.
 *
 * The address space and address space area must be locked prior to the call.
 *
 * @param area Address space area.
 */
void elf_share(as_area_t *area)
{
    elf_segment_header_t *entry = area->backend_data.segment;
    link_t *cur;
    btree_node_t *leaf, *node;
    uintptr_t start_anon = entry->p_vaddr + entry->p_filesz;
 
    /*
     * Find the node in which to start linear search.
     */
    if (area->flags & AS_AREA_WRITE) {
        node = list_get_instance(area->used_space.leaf_head.next,
            btree_node_t, leaf_link);
    } else {
        (void) btree_search(&area->sh_info->pagemap, start_anon, &leaf);
        node = btree_leaf_node_left_neighbour(&area->sh_info->pagemap,
            leaf);
        if (!node)
            node = leaf;
    }
 
    /*
     * Copy used anonymous portions of the area to sh_info's page map.
     */
    mutex_lock(&area->sh_info->lock);
    for (cur = &node->leaf_link; cur != &area->used_space.leaf_head;
        cur = cur->next) {
        int i;
       
        node = list_get_instance(cur, btree_node_t, leaf_link);
       
        for (i = 0; i < node->keys; i++) {
            uintptr_t base = node->key[i];
            count_t count = (count_t) node->value[i];
            int j;
           
            /*
             * Skip read-only areas of used space that are backed
             * by the ELF image.
             */
            if (!(area->flags & AS_AREA_WRITE))
                if (base + count*PAGE_SIZE <= start_anon)
                    continue;
           
            for (j = 0; j < count; j++) {
                pte_t *pte;
           
                /*
                 * Skip read-only pages that are backed by the
                 * ELF image.
                 */
                if (!(area->flags & AS_AREA_WRITE))
                    if (base + (j + 1) * PAGE_SIZE <=
                        start_anon)
                        continue;
               
                page_table_lock(area->as, false);
                pte = page_mapping_find(area->as,
                    base + j * PAGE_SIZE);
                ASSERT(pte && PTE_VALID(pte) &&
                    PTE_PRESENT(pte));
                btree_insert(&area->sh_info->pagemap,
                    (base + j * PAGE_SIZE) - area->base,
                    (void *) PTE_GET_FRAME(pte), NULL);
                page_table_unlock(area->as, false);
 
                pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte));
                frame_reference_add(pfn);
            }
               
        }
    }
    mutex_unlock(&area->sh_info->lock);
}
 
/** @}
 */
 

Subversion Repositories HelenOS

(root)/trunk/kernel/generic/src/mm/backend_elf.c – Rev 2141 → 2467

Rev 2141		Rev 2467
1	/*	1	/*
2	* Copyright (c) 2006 Jakub Jermar	2	* Copyright (c) 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	/** @addtogroup genericmm	29	/** @addtogroup genericmm
30	* @{	30	* @{
31	*/	31	*/
32		32
33	/**	33	/**
34	* @file	34	* @file
35	* @brief Backend for address space areas backed by an ELF image.	35	* @brief Backend for address space areas backed by an ELF image.
36	*/	36	*/
37		37
38	#include <lib/elf.h>	38	#include <lib/elf.h>
39	#include <debug.h>	39	#include <debug.h>
40	#include <arch/types.h>	40	#include <arch/types.h>
41	#include <mm/as.h>	41	#include <mm/as.h>
42	#include <mm/frame.h>	42	#include <mm/frame.h>
43	#include <mm/slab.h>	43	#include <mm/slab.h>
44	#include <mm/page.h>	44	#include <mm/page.h>
45	#include <genarch/mm/page_pt.h>	45	#include <genarch/mm/page_pt.h>
46	#include <genarch/mm/page_ht.h>	46	#include <genarch/mm/page_ht.h>
47	#include <align.h>	47	#include <align.h>
48	#include <memstr.h>	48	#include <memstr.h>
49	#include <macros.h>	49	#include <macros.h>
50	#include <arch.h>	50	#include <arch.h>
51		51
52	#ifdef CONFIG_VIRT_IDX_DCACHE	52	#ifdef CONFIG_VIRT_IDX_DCACHE
53	#include <arch/mm/cache.h>	53	#include <arch/mm/cache.h>
54	#endif	54	#endif
55		55
56	static int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access);	56	static int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access);
57	static void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame);	57	static void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame);
58	static void elf_share(as_area_t *area);	58	static void elf_share(as_area_t *area);
59		59
60	mem_backend_t elf_backend = {	60	mem_backend_t elf_backend = {
61	.page_fault = elf_page_fault,	61	.page_fault = elf_page_fault,
62	.frame_free = elf_frame_free,	62	.frame_free = elf_frame_free,
63	.share = elf_share	63	.share = elf_share
64	};	64	};
65		65
66	/** Service a page fault in the ELF backend address space area.	66	/** Service a page fault in the ELF backend address space area.
67	*	67	*
68	* The address space area and page tables must be already locked.	68	* The address space area and page tables must be already locked.
69	*	69	*
70	* @param area Pointer to the address space area.	70	* @param area Pointer to the address space area.
71	* @param addr Faulting virtual address.	71	* @param addr Faulting virtual address.
72	* @param access Access mode that caused the fault (i.e. read/write/exec).	72	* @param access Access mode that caused the fault (i.e. read/write/exec).
73	*	73	*
74	* @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e.	74	* @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e.
75	* serviced).	75	* serviced).
76	*/	76	*/
77	int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)	77	int elf_page_fault(as_area_t *area, uintptr_t addr, pf_access_t access)
78	{	78	{
79	elf_header_t *elf = area->backend_data.elf;	79	elf_header_t *elf = area->backend_data.elf;
80	elf_segment_header_t *entry = area->backend_data.segment;	80	elf_segment_header_t *entry = area->backend_data.segment;
81	btree_node_t *leaf;	81	btree_node_t *leaf;
82	uintptr_t base, frame;	82	uintptr_t base, frame;
83	index_t i;	83	index_t i;
84	bool dirty = false;	84	bool dirty = false;
85		85
86	if (!as_area_check_access(area, access))	86	if (!as_area_check_access(area, access))
87	return AS_PF_FAULT;	87	return AS_PF_FAULT;
88		88
89	ASSERT((addr >= entry->p_vaddr) &&	89	ASSERT((addr >= entry->p_vaddr) &&
90	(addr < entry->p_vaddr + entry->p_memsz));	90	(addr < entry->p_vaddr + entry->p_memsz));
91	i = (addr - entry->p_vaddr) >> PAGE_WIDTH;	91	i = (addr - entry->p_vaddr) >> PAGE_WIDTH;
92	base = (uintptr_t) (((void *) elf) + entry->p_offset);	92	base = (uintptr_t) (((void *) elf) + entry->p_offset);
93	ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);	93	ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
94		94
95	if (area->sh_info) {	95	if (area->sh_info) {
96	bool found = false;	96	bool found = false;
97		97
98	/*	98	/*
99	* The address space area is shared.	99	* The address space area is shared.
100	*/	100	*/
101		101
102	mutex_lock(&area->sh_info->lock);	102	mutex_lock(&area->sh_info->lock);
103	frame = (uintptr_t) btree_search(&area->sh_info->pagemap,	103	frame = (uintptr_t) btree_search(&area->sh_info->pagemap,
104	ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);	104	ALIGN_DOWN(addr, PAGE_SIZE) - area->base, &leaf);
105	if (!frame) {	105	if (!frame) {
106	int i;	106	int i;
107		107
108	/*	108	/*
109	* Workaround for valid NULL address.	109	* Workaround for valid NULL address.
110	*/	110	*/
111		111
112	for (i = 0; i < leaf->keys; i++) {	112	for (i = 0; i < leaf->keys; i++) {
113	if (leaf->key[i] ==	113	if (leaf->key[i] ==
114	ALIGN_DOWN(addr, PAGE_SIZE)) {	114	ALIGN_DOWN(addr, PAGE_SIZE)) {
115	found = true;	115	found = true;
116	break;	116	break;
117	}	117	}
118	}	118	}
119	}	119	}
120	if (frame \|\| found) {	120	if (frame \|\| found) {
121	frame_reference_add(ADDR2PFN(frame));	121	frame_reference_add(ADDR2PFN(frame));
122	page_mapping_insert(AS, addr, frame,	122	page_mapping_insert(AS, addr, frame,
123	as_area_get_flags(area));	123	as_area_get_flags(area));
124	if (!used_space_insert(area,	124	if (!used_space_insert(area,
125	ALIGN_DOWN(addr, PAGE_SIZE), 1))	125	ALIGN_DOWN(addr, PAGE_SIZE), 1))
126	panic("Could not insert used space.\n");	126	panic("Could not insert used space.\n");
127	mutex_unlock(&area->sh_info->lock);	127	mutex_unlock(&area->sh_info->lock);
128	return AS_PF_OK;	128	return AS_PF_OK;
129	}	129	}
130	}	130	}
131		131
132	/*	132	/*
133	* The area is either not shared or the pagemap does not contain the	133	* The area is either not shared or the pagemap does not contain the
134	* mapping.	134	* mapping.
135	*/	135	*/
136		136
137	if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE <	137	if (ALIGN_DOWN(addr, PAGE_SIZE) + PAGE_SIZE <
138	entry->p_vaddr + entry->p_filesz) {	138	entry->p_vaddr + entry->p_filesz) {
139	/*	139	/*
140	* Initialized portion of the segment. The memory is backed	140	* Initialized portion of the segment. The memory is backed
141	* directly by the content of the ELF image. Pages are	141	* directly by the content of the ELF image. Pages are
142	* only copied if the segment is writable so that there	142	* only copied if the segment is writable so that there
143	* can be more instantions of the same memory ELF image	143	* can be more instantions of the same memory ELF image
144	* used at a time. Note that this could be later done	144	* used at a time. Note that this could be later done
145	* as COW.	145	* as COW.
146	*/	146	*/
147	if (entry->p_flags & PF_W) {	147	if (entry->p_flags & PF_W) {
148	frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);	148	frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
149	memcpy((void *) PA2KA(frame),	149	memcpy((void *) PA2KA(frame),
150	(void ) (base + i FRAME_SIZE), FRAME_SIZE);	150	(void ) (base + i FRAME_SIZE), FRAME_SIZE);
151	dirty = true;	151	dirty = true;
152		152
153	if (area->sh_info) {	153	if (area->sh_info) {
154	frame_reference_add(ADDR2PFN(frame));	154	frame_reference_add(ADDR2PFN(frame));
155	btree_insert(&area->sh_info->pagemap,	155	btree_insert(&area->sh_info->pagemap,
156	ALIGN_DOWN(addr, PAGE_SIZE) - area->base,	156	ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
157	(void *) frame, leaf);	157	(void *) frame, leaf);
158	}	158	}
159		159
160	} else {	160	} else {
161	frame = KA2PA(base + i*FRAME_SIZE);	161	frame = KA2PA(base + i*FRAME_SIZE);
162	}	162	}
163	} else if (ALIGN_DOWN(addr, PAGE_SIZE) >=	163	} else if (ALIGN_DOWN(addr, PAGE_SIZE) >=
164	ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {	164	ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
165	/*	165	/*
166	* This is the uninitialized portion of the segment.	166	* This is the uninitialized portion of the segment.
167	* It is not physically present in the ELF image.	167	* It is not physically present in the ELF image.
168	* To resolve the situation, a frame must be allocated	168	* To resolve the situation, a frame must be allocated
169	* and cleared.	169	* and cleared.
170	*/	170	*/
171	frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);	171	frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
172	memsetb(PA2KA(frame), FRAME_SIZE, 0);	172	memsetb(PA2KA(frame), FRAME_SIZE, 0);
173	dirty = true;	173	dirty = true;
174		174
175	if (area->sh_info) {	175	if (area->sh_info) {
176	frame_reference_add(ADDR2PFN(frame));	176	frame_reference_add(ADDR2PFN(frame));
177	btree_insert(&area->sh_info->pagemap,	177	btree_insert(&area->sh_info->pagemap,
178	ALIGN_DOWN(addr, PAGE_SIZE) - area->base,	178	ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
179	(void *) frame, leaf);	179	(void *) frame, leaf);
180	}	180	}
181		181
182	} else {	182	} else {
183	size_t size;	183	size_t size;
184	/*	184	/*
185	* The mixed case.	185	* The mixed case.
186	* The lower part is backed by the ELF image and	186	* The lower part is backed by the ELF image and
187	* the upper part is anonymous memory.	187	* the upper part is anonymous memory.
188	*/	188	*/
189	size = entry->p_filesz - (i<<PAGE_WIDTH);	189	size = entry->p_filesz - (i<<PAGE_WIDTH);
190	frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);	190	frame = (uintptr_t)frame_alloc(ONE_FRAME, 0);
191	memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0);	191	memsetb(PA2KA(frame) + size, FRAME_SIZE - size, 0);
192	memcpy((void ) PA2KA(frame), (void ) (base + i * FRAME_SIZE),	192	memcpy((void ) PA2KA(frame), (void ) (base + i * FRAME_SIZE),
193	size);	193	size);
194	dirty = true;	194	dirty = true;
195		195
196	if (area->sh_info) {	196	if (area->sh_info) {
197	frame_reference_add(ADDR2PFN(frame));	197	frame_reference_add(ADDR2PFN(frame));
198	btree_insert(&area->sh_info->pagemap,	198	btree_insert(&area->sh_info->pagemap,
199	ALIGN_DOWN(addr, PAGE_SIZE) - area->base,	199	ALIGN_DOWN(addr, PAGE_SIZE) - area->base,
200	(void *) frame, leaf);	200	(void *) frame, leaf);
201	}	201	}
202		202
203	}	203	}
204		204
205	if (area->sh_info)	205	if (area->sh_info)
206	mutex_unlock(&area->sh_info->lock);	206	mutex_unlock(&area->sh_info->lock);
207		207
208	page_mapping_insert(AS, addr, frame, as_area_get_flags(area));	208	page_mapping_insert(AS, addr, frame, as_area_get_flags(area));
209	if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))	209	if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
210	panic("Could not insert used space.\n");	210	panic("Could not insert used space.\n");
211		211
212	return AS_PF_OK;	212	return AS_PF_OK;
213	}	213	}
214		214
215	/** Free a frame that is backed by the ELF backend.	215	/** Free a frame that is backed by the ELF backend.
216	*	216	*
217	* The address space area and page tables must be already locked.	217	* The address space area and page tables must be already locked.
218	*	218	*
219	* @param area Pointer to the address space area.	219	* @param area Pointer to the address space area.
220	* @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE.	220	* @param page Page that is mapped to frame. Must be aligned to PAGE_SIZE.
221	* @param frame Frame to be released.	221	* @param frame Frame to be released.
222	*	222	*
223	*/	223	*/
224	void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)	224	void elf_frame_free(as_area_t *area, uintptr_t page, uintptr_t frame)
225	{	225	{
226	elf_header_t *elf = area->backend_data.elf;	226	elf_header_t *elf = area->backend_data.elf;
227	elf_segment_header_t *entry = area->backend_data.segment;	227	elf_segment_header_t *entry = area->backend_data.segment;
228	uintptr_t base;	228	uintptr_t base;
229	index_t i;	229	index_t i;
230		230
231	ASSERT((page >= entry->p_vaddr) &&	231	ASSERT((page >= entry->p_vaddr) &&
232	(page < entry->p_vaddr + entry->p_memsz));	232	(page < entry->p_vaddr + entry->p_memsz));
233	i = (page - entry->p_vaddr) >> PAGE_WIDTH;	233	i = (page - entry->p_vaddr) >> PAGE_WIDTH;
234	base = (uintptr_t) (((void *) elf) + entry->p_offset);	234	base = (uintptr_t) (((void *) elf) + entry->p_offset);
235	ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);	235	ASSERT(ALIGN_UP(base, FRAME_SIZE) == base);
236		236
237	if (page + PAGE_SIZE <	237	if (page + PAGE_SIZE <
238	ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {	238	ALIGN_UP(entry->p_vaddr + entry->p_filesz, PAGE_SIZE)) {
239	if (entry->p_flags & PF_W) {	239	if (entry->p_flags & PF_W) {
240	/*	240	/*
241	* Free the frame with the copy of writable segment	241	* Free the frame with the copy of writable segment
242	* data.	242	* data.
243	*/	243	*/
244	frame_free(frame);	244	frame_free(frame);
245	}	245	}
246	} else {	246	} else {
247	/*	247	/*
248	* The frame is either anonymous memory or the mixed case (i.e.	248	* The frame is either anonymous memory or the mixed case (i.e.
249	* lower part is backed by the ELF image and the upper is	249	* lower part is backed by the ELF image and the upper is
250	* anonymous). In any case, a frame needs to be freed.	250	* anonymous). In any case, a frame needs to be freed.
251	*/	251	*/
252	frame_free(frame);	252	frame_free(frame);
253	}	253	}
254	}	254	}
255		255
256	/** Share ELF image backed address space area.	256	/** Share ELF image backed address space area.
257	*	257	*
258	* If the area is writable, then all mapped pages are duplicated in the pagemap.	258	* If the area is writable, then all mapped pages are duplicated in the pagemap.
259	* Otherwise only portions of the area that are not backed by the ELF image	259	* Otherwise only portions of the area that are not backed by the ELF image
260	* are put into the pagemap.	260	* are put into the pagemap.
261	*	261	*
262	* The address space and address space area must be locked prior to the call.	262	* The address space and address space area must be locked prior to the call.
263	*	263	*
264	* @param area Address space area.	264	* @param area Address space area.
265	*/	265	*/
266	void elf_share(as_area_t *area)	266	void elf_share(as_area_t *area)
267	{	267	{
268	elf_segment_header_t *entry = area->backend_data.segment;	268	elf_segment_header_t *entry = area->backend_data.segment;
269	link_t *cur;	269	link_t *cur;
270	btree_node_t leaf, node;	270	btree_node_t leaf, node;
271	uintptr_t start_anon = entry->p_vaddr + entry->p_filesz;	271	uintptr_t start_anon = entry->p_vaddr + entry->p_filesz;
272		272
273	/*	273	/*
274	* Find the node in which to start linear search.	274	* Find the node in which to start linear search.
275	*/	275	*/
276	if (area->flags & AS_AREA_WRITE) {	276	if (area->flags & AS_AREA_WRITE) {
277	node = list_get_instance(area->used_space.leaf_head.next,	277	node = list_get_instance(area->used_space.leaf_head.next,
278	btree_node_t, leaf_link);	278	btree_node_t, leaf_link);
279	} else {	279	} else {
280	(void) btree_search(&area->sh_info->pagemap, start_anon, &leaf);	280	(void) btree_search(&area->sh_info->pagemap, start_anon, &leaf);
281	node = btree_leaf_node_left_neighbour(&area->sh_info->pagemap,	281	node = btree_leaf_node_left_neighbour(&area->sh_info->pagemap,
282	leaf);	282	leaf);
283	if (!node)	283	if (!node)
284	node = leaf;	284	node = leaf;
285	}	285	}
286		286
287	/*	287	/*
288	* Copy used anonymous portions of the area to sh_info's page map.	288	* Copy used anonymous portions of the area to sh_info's page map.
289	*/	289	*/
290	mutex_lock(&area->sh_info->lock);	290	mutex_lock(&area->sh_info->lock);
291	for (cur = &node->leaf_link; cur != &area->used_space.leaf_head;	291	for (cur = &node->leaf_link; cur != &area->used_space.leaf_head;
292	cur = cur->next) {	292	cur = cur->next) {
293	int i;	293	int i;
294		294
295	node = list_get_instance(cur, btree_node_t, leaf_link);	295	node = list_get_instance(cur, btree_node_t, leaf_link);
296		296
297	for (i = 0; i < node->keys; i++) {	297	for (i = 0; i < node->keys; i++) {
298	uintptr_t base = node->key[i];	298	uintptr_t base = node->key[i];
299	count_t count = (count_t) node->value[i];	299	count_t count = (count_t) node->value[i];
300	int j;	300	int j;
301		301
302	/*	302	/*
303	* Skip read-only areas of used space that are backed	303	* Skip read-only areas of used space that are backed
304	* by the ELF image.	304	* by the ELF image.
305	*/	305	*/
306	if (!(area->flags & AS_AREA_WRITE))	306	if (!(area->flags & AS_AREA_WRITE))
307	if (base + count*PAGE_SIZE <= start_anon)	307	if (base + count*PAGE_SIZE <= start_anon)
308	continue;	308	continue;
309		309
310	for (j = 0; j < count; j++) {	310	for (j = 0; j < count; j++) {
311	pte_t *pte;	311	pte_t *pte;
312		312
313	/*	313	/*
314	* Skip read-only pages that are backed by the	314	* Skip read-only pages that are backed by the
315	* ELF image.	315	* ELF image.
316	*/	316	*/
317	if (!(area->flags & AS_AREA_WRITE))	317	if (!(area->flags & AS_AREA_WRITE))
318	if (base + (j + 1) * PAGE_SIZE <=	318	if (base + (j + 1) * PAGE_SIZE <=
319	start_anon)	319	start_anon)
320	continue;	320	continue;
321		321
322	page_table_lock(area->as, false);	322	page_table_lock(area->as, false);
323	pte = page_mapping_find(area->as,	323	pte = page_mapping_find(area->as,
324	base + j * PAGE_SIZE);	324	base + j * PAGE_SIZE);
325	ASSERT(pte && PTE_VALID(pte) &&	325	ASSERT(pte && PTE_VALID(pte) &&
326	PTE_PRESENT(pte));	326	PTE_PRESENT(pte));
327	btree_insert(&area->sh_info->pagemap,	327	btree_insert(&area->sh_info->pagemap,
328	(base + j * PAGE_SIZE) - area->base,	328	(base + j * PAGE_SIZE) - area->base,
329	(void *) PTE_GET_FRAME(pte), NULL);	329	(void *) PTE_GET_FRAME(pte), NULL);
330	page_table_unlock(area->as, false);	330	page_table_unlock(area->as, false);
331		331
332	pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte));	332	pfn_t pfn = ADDR2PFN(PTE_GET_FRAME(pte));
333	frame_reference_add(pfn);	333	frame_reference_add(pfn);
334	}	334	}
335		335
336	}	336	}
337	}	337	}
338	mutex_unlock(&area->sh_info->lock);	338	mutex_unlock(&area->sh_info->lock);
339	}	339	}
340		340
341	/** @}	341	/** @}
342	*/	342	*/
343		343