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/* |
* 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 genarchmm |
* @{ |
*/ |
|
/** |
* @file |
* @brief Virtual Address Translation for hierarchical 4-level page tables. |
*/ |
|
#include <genarch/mm/page_pt.h> |
#include <mm/page.h> |
#include <mm/frame.h> |
#include <mm/as.h> |
#include <arch/mm/page.h> |
#include <arch/mm/as.h> |
#include <arch/types.h> |
#include <arch/asm.h> |
#include <memstr.h> |
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static void pt_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags); |
static void pt_mapping_remove(as_t *as, uintptr_t page); |
static pte_t *pt_mapping_find(as_t *as, uintptr_t page); |
|
page_mapping_operations_t pt_mapping_operations = { |
.mapping_insert = pt_mapping_insert, |
.mapping_remove = pt_mapping_remove, |
.mapping_find = pt_mapping_find |
}; |
|
/** Map page to frame using hierarchical page tables. |
* |
* Map virtual address page to physical address frame |
* using flags. |
* |
* The page table must be locked and interrupts must be disabled. |
* |
* @param as Address space to wich page belongs. |
* @param page Virtual address of the page to be mapped. |
* @param frame Physical address of memory frame to which the mapping is done. |
* @param flags Flags to be used for mapping. |
*/ |
void pt_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags) |
{ |
pte_t *ptl0, *ptl1, *ptl2, *ptl3; |
pte_t *newpt; |
|
ptl0 = (pte_t *) PA2KA((uintptr_t) as->genarch.page_table); |
|
if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) { |
newpt = (pte_t *)frame_alloc(PTL1_SIZE, FRAME_KA); |
memsetb(newpt, FRAME_SIZE << PTL1_SIZE, 0); |
SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page), KA2PA(newpt)); |
SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE); |
} |
|
ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page))); |
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if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) { |
newpt = (pte_t *)frame_alloc(PTL2_SIZE, FRAME_KA); |
memsetb(newpt, FRAME_SIZE << PTL2_SIZE, 0); |
SET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page), KA2PA(newpt)); |
SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE); |
} |
|
ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page))); |
|
if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) { |
newpt = (pte_t *)frame_alloc(PTL3_SIZE, FRAME_KA); |
memsetb(newpt, FRAME_SIZE << PTL3_SIZE, 0); |
SET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page), KA2PA(newpt)); |
SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page), PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE | PAGE_WRITE); |
} |
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ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page))); |
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SET_FRAME_ADDRESS(ptl3, PTL3_INDEX(page), frame); |
SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), flags); |
} |
|
/** Remove mapping of page from hierarchical page tables. |
* |
* Remove any mapping of page within address space as. |
* TLB shootdown should follow in order to make effects of |
* this call visible. |
* |
* Empty page tables except PTL0 are freed. |
* |
* The page table must be locked and interrupts must be disabled. |
* |
* @param as Address space to wich page belongs. |
* @param page Virtual address of the page to be demapped. |
*/ |
void pt_mapping_remove(as_t *as, uintptr_t page) |
{ |
pte_t *ptl0, *ptl1, *ptl2, *ptl3; |
bool empty = true; |
int i; |
|
/* |
* First, remove the mapping, if it exists. |
*/ |
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ptl0 = (pte_t *) PA2KA((uintptr_t) as->genarch.page_table); |
|
if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) |
return; |
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ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page))); |
|
if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) |
return; |
|
ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page))); |
|
if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) |
return; |
|
ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page))); |
|
/* Destroy the mapping. Setting to PAGE_NOT_PRESENT is not sufficient. */ |
memsetb(&ptl3[PTL3_INDEX(page)], sizeof(pte_t), 0); |
|
/* |
* Second, free all empty tables along the way from PTL3 down to PTL0. |
*/ |
|
/* check PTL3 */ |
for (i = 0; i < PTL3_ENTRIES; i++) { |
if (PTE_VALID(&ptl3[i])) { |
empty = false; |
break; |
} |
} |
if (empty) { |
/* |
* PTL3 is empty. |
* Release the frame and remove PTL3 pointer from preceding table. |
*/ |
frame_free(KA2PA((uintptr_t) ptl3)); |
if (PTL2_ENTRIES) |
memsetb(&ptl2[PTL2_INDEX(page)], sizeof(pte_t), 0); |
else if (PTL1_ENTRIES) |
memsetb(&ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0); |
else |
memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0); |
} else { |
/* |
* PTL3 is not empty. |
* Therefore, there must be a path from PTL0 to PTL3 and |
* thus nothing to free in higher levels. |
*/ |
return; |
} |
|
/* check PTL2, empty is still true */ |
if (PTL2_ENTRIES) { |
for (i = 0; i < PTL2_ENTRIES; i++) { |
if (PTE_VALID(&ptl2[i])) { |
empty = false; |
break; |
} |
} |
if (empty) { |
/* |
* PTL2 is empty. |
* Release the frame and remove PTL2 pointer from preceding table. |
*/ |
frame_free(KA2PA((uintptr_t) ptl2)); |
if (PTL1_ENTRIES) |
memsetb(&ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0); |
else |
memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0); |
} |
else { |
/* |
* PTL2 is not empty. |
* Therefore, there must be a path from PTL0 to PTL2 and |
* thus nothing to free in higher levels. |
*/ |
return; |
} |
} |
|
/* check PTL1, empty is still true */ |
if (PTL1_ENTRIES) { |
for (i = 0; i < PTL1_ENTRIES; i++) { |
if (PTE_VALID(&ptl1[i])) { |
empty = false; |
break; |
} |
} |
if (empty) { |
/* |
* PTL1 is empty. |
* Release the frame and remove PTL1 pointer from preceding table. |
*/ |
frame_free(KA2PA((uintptr_t) ptl1)); |
memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0); |
} |
} |
|
} |
|
/** Find mapping for virtual page in hierarchical page tables. |
* |
* Find mapping for virtual page. |
* |
* The page table must be locked and interrupts must be disabled. |
* |
* @param as Address space to which page belongs. |
* @param page Virtual page. |
* |
* @return NULL if there is no such mapping; entry from PTL3 describing the mapping otherwise. |
*/ |
pte_t *pt_mapping_find(as_t *as, uintptr_t page) |
{ |
pte_t *ptl0, *ptl1, *ptl2, *ptl3; |
|
ptl0 = (pte_t *) PA2KA((uintptr_t) as->genarch.page_table); |
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if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) |
return NULL; |
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ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page))); |
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if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) |
return NULL; |
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ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page))); |
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if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) |
return NULL; |
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ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page))); |
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return &ptl3[PTL3_INDEX(page)]; |
} |
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/** @} |
*/ |