/*
* 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.
*/
/**
* @file page_pt.c
* @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 <typedefs.h>
#include <arch/asm.h>
#include <memstr.h>
static void pt_mapping_insert(as_t *as, __address page, __address frame, int flags);
static void pt_mapping_remove(as_t *as, __address page);
static pte_t *pt_mapping_find(as_t *as, __address 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, __address page, __address frame, int flags)
{
pte_t *ptl0, *ptl1, *ptl2, *ptl3;
__address newpt;
ptl0 = (pte_t *) PA2KA((__address) as->page_table);
if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) {
newpt = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
memsetb(newpt, PAGE_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)));
if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) {
newpt = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
memsetb(newpt, PAGE_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 = PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA)));
memsetb(newpt, PAGE_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);
}
ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
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, __address page)
{
pte_t *ptl0, *ptl1, *ptl2, *ptl3;
bool empty = true;
int i;
/*
* First, remove the mapping, if it exists.
*/
ptl0 = (pte_t *) PA2KA((__address) as->page_table);
if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
return;
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((__address) &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(ADDR2PFN(KA2PA((__address) ptl3)));
if (PTL2_ENTRIES)
memsetb((__address) &ptl2[PTL2_INDEX(page)], sizeof(pte_t), 0);
else if (PTL1_ENTRIES)
memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
else
memsetb((__address) &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(ADDR2PFN(KA2PA((__address) ptl2)));
if (PTL1_ENTRIES)
memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
else
memsetb((__address) &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(ADDR2PFN(KA2PA((__address) ptl1)));
memsetb((__address) &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, __address page)
{
pte_t *ptl0, *ptl1, *ptl2, *ptl3;
ptl0 = (pte_t *) PA2KA((__address) as->page_table);
if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
return NULL;
ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
return NULL;
ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
return NULL;
ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
return &ptl3[PTL3_INDEX(page)];
}