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684 jermar 1
/*
2071 jermar 2
 * Copyright (c) 2006 Jakub Jermar
684 jermar 3
 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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1851 jermar 29
/** @addtogroup genarchmm
1702 cejka 30
 * @{
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 */
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1266 jermar 33
/**
1702 cejka 34
 * @file
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 * @brief   Virtual Address Translation for hierarchical 4-level page tables.
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 */
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#include <genarch/mm/page_pt.h>
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#include <mm/page.h>
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#include <mm/frame.h>
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#include <mm/as.h>
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#include <arch/mm/page.h>
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#include <arch/mm/as.h>
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#include <arch/types.h>
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#include <arch/asm.h>
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#include <memstr.h>
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1780 jermar 48
static void pt_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags);
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static void pt_mapping_remove(as_t *as, uintptr_t page);
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static pte_t *pt_mapping_find(as_t *as, uintptr_t page);
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page_mapping_operations_t pt_mapping_operations = {
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    .mapping_insert = pt_mapping_insert,
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    .mapping_remove = pt_mapping_remove,
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    .mapping_find = pt_mapping_find
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};
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58
/** Map page to frame using hierarchical page tables.
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 *
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 * Map virtual address page to physical address frame
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 * using flags.
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 *
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 * The page table must be locked and interrupts must be disabled.
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 *
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 * @param as Address space to wich page belongs.
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 * @param page Virtual address of the page to be mapped.
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 * @param frame Physical address of memory frame to which the mapping is done.
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 * @param flags Flags to be used for mapping.
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 */
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void pt_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags)
684 jermar 71
{
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    pte_t *ptl0, *ptl1, *ptl2, *ptl3;
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    pte_t *newpt;
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    ptl0 = (pte_t *) PA2KA((uintptr_t) as->page_table);
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77
    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) {
1760 palkovsky 78
        newpt = (pte_t *)frame_alloc(ONE_FRAME, FRAME_KA);
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        memsetb((uintptr_t)newpt, PAGE_SIZE, 0);
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        SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page), KA2PA(newpt));
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        SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
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    }
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84
    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
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86
    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) {
1760 palkovsky 87
        newpt = (pte_t *)frame_alloc(ONE_FRAME, FRAME_KA);
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        memsetb((uintptr_t)newpt, PAGE_SIZE, 0);
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        SET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page), KA2PA(newpt));
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        SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
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    }
92
 
93
    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
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95
    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) {
1760 palkovsky 96
        newpt = (pte_t *)frame_alloc(ONE_FRAME, FRAME_KA);
1780 jermar 97
        memsetb((uintptr_t)newpt, PAGE_SIZE, 0);
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        SET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page), KA2PA(newpt));
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        SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE);
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    }
101
 
102
    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
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104
    SET_FRAME_ADDRESS(ptl3, PTL3_INDEX(page), frame);
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    SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), flags);
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}
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826 jermar 108
/** Remove mapping of page from hierarchical page tables.
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 *
1248 jermar 110
 * Remove any mapping of page within address space as.
826 jermar 111
 * TLB shootdown should follow in order to make effects of
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 * this call visible.
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 *
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 * Empty page tables except PTL0 are freed.
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 *
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 * The page table must be locked and interrupts must be disabled.
826 jermar 117
 *
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 * @param as Address space to wich page belongs.
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 * @param page Virtual address of the page to be demapped.
120
 */
1780 jermar 121
void pt_mapping_remove(as_t *as, uintptr_t page)
826 jermar 122
{
123
    pte_t *ptl0, *ptl1, *ptl2, *ptl3;
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    bool empty = true;
125
    int i;
826 jermar 126
 
832 jermar 127
    /*
128
     * First, remove the mapping, if it exists.
129
     */
130
 
1780 jermar 131
    ptl0 = (pte_t *) PA2KA((uintptr_t) as->page_table);
826 jermar 132
 
133
    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
134
        return;
135
 
136
    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
137
 
138
    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
139
        return;
140
 
141
    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
142
 
143
    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
144
        return;
145
 
146
    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
147
 
148
    /* Destroy the mapping. Setting to PAGE_NOT_PRESENT is not sufficient. */
1780 jermar 149
    memsetb((uintptr_t) &ptl3[PTL3_INDEX(page)], sizeof(pte_t), 0);
832 jermar 150
 
151
    /*
152
     * Second, free all empty tables along the way from PTL3 down to PTL0.
153
     */
154
 
155
    /* check PTL3 */
156
    for (i = 0; i < PTL3_ENTRIES; i++) {
157
        if (PTE_VALID(&ptl3[i])) {
158
            empty = false;
159
            break;
160
        }
161
    }
162
    if (empty) {
163
        /*
164
         * PTL3 is empty.
165
         * Release the frame and remove PTL3 pointer from preceding table.
166
         */
1780 jermar 167
        frame_free(KA2PA((uintptr_t) ptl3));
832 jermar 168
        if (PTL2_ENTRIES)
1780 jermar 169
            memsetb((uintptr_t) &ptl2[PTL2_INDEX(page)], sizeof(pte_t), 0);
832 jermar 170
        else if (PTL1_ENTRIES)
1780 jermar 171
            memsetb((uintptr_t) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
832 jermar 172
        else
1780 jermar 173
            memsetb((uintptr_t) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
832 jermar 174
    } else {
175
        /*
176
         * PTL3 is not empty.
177
         * Therefore, there must be a path from PTL0 to PTL3 and
178
         * thus nothing to free in higher levels.
179
         */
180
        return;
181
    }
182
 
183
    /* check PTL2, empty is still true */
184
    if (PTL2_ENTRIES) {
185
        for (i = 0; i < PTL2_ENTRIES; i++) {
186
            if (PTE_VALID(&ptl2[i])) {
187
                empty = false;
188
                break;
189
            }
190
        }
191
        if (empty) {
192
            /*
193
             * PTL2 is empty.
194
             * Release the frame and remove PTL2 pointer from preceding table.
195
             */
1780 jermar 196
            frame_free(KA2PA((uintptr_t) ptl2));
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            if (PTL1_ENTRIES)
1780 jermar 198
                memsetb((uintptr_t) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
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            else
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                memsetb((uintptr_t) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
832 jermar 201
        }
202
        else {
203
            /*
204
             * PTL2 is not empty.
205
             * Therefore, there must be a path from PTL0 to PTL2 and
206
             * thus nothing to free in higher levels.
207
             */
208
            return;
209
        }
210
    }
211
 
212
    /* check PTL1, empty is still true */
213
    if (PTL1_ENTRIES) {
214
        for (i = 0; i < PTL1_ENTRIES; i++) {
215
            if (PTE_VALID(&ptl1[i])) {
216
                empty = false;
217
                break;
218
            }
219
        }
220
        if (empty) {
221
            /*
222
             * PTL1 is empty.
223
             * Release the frame and remove PTL1 pointer from preceding table.
224
             */
1780 jermar 225
            frame_free(KA2PA((uintptr_t) ptl1));
226
            memsetb((uintptr_t) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
832 jermar 227
        }
228
    }
229
 
826 jermar 230
}
231
 
684 jermar 232
/** Find mapping for virtual page in hierarchical page tables.
233
 *
234
 * Find mapping for virtual page.
235
 *
1044 jermar 236
 * The page table must be locked and interrupts must be disabled.
756 jermar 237
 *
1248 jermar 238
 * @param as Address space to which page belongs.
684 jermar 239
 * @param page Virtual page.
240
 *
241
 * @return NULL if there is no such mapping; entry from PTL3 describing the mapping otherwise.
242
 */
1780 jermar 243
pte_t *pt_mapping_find(as_t *as, uintptr_t page)
684 jermar 244
{
245
    pte_t *ptl0, *ptl1, *ptl2, *ptl3;
246
 
1780 jermar 247
    ptl0 = (pte_t *) PA2KA((uintptr_t) as->page_table);
684 jermar 248
 
249
    if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
250
        return NULL;
251
 
252
    ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
253
 
254
    if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
255
        return NULL;
256
 
257
    ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
258
 
259
    if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
260
        return NULL;
261
 
262
    ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
263
 
264
    return &ptl3[PTL3_INDEX(page)];
265
}
1702 cejka 266
 
1851 jermar 267
/** @}
1702 cejka 268
 */