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Changeset 609a417 in mainline


Ignore:
Timestamp:
2012-07-01T22:28:15Z (8 years ago)
Author:
Jakub Jermar <jakub@…>
Branches:
master
Children:
7d68da80
Parents:
0d8269b
Message:

Add write memory barriers to pt_mapping_insert() so that setting a new
page table level is separated from marking it present in the previous
level.

This is to make sure that a concurrent hardware page table walk or
pt_page_find() will see the new level only after it is fully
initialized.

File:
1 edited

Legend:

Unmodified
Added
Removed
  • kernel/genarch/src/mm/page_pt.c

    r0d8269b r609a417  
    4343#include <arch/mm/page.h>
    4444#include <arch/mm/as.h>
     45#include <arch/barrier.h>
    4546#include <typedefs.h>
    4647#include <arch/asm.h>
     
    8687                SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page), KA2PA(newpt));
    8788                SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page),
    88                     PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
     89                    PAGE_NOT_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
    8990                    PAGE_WRITE);
     91                write_barrier();
     92                SET_PTL1_PRESENT(ptl0, PTL0_INDEX(page));
    9093        }
    9194       
     
    98101                SET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page), KA2PA(newpt));
    99102                SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page),
    100                     PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
     103                    PAGE_NOT_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
    101104                    PAGE_WRITE);
     105                write_barrier();
     106                SET_PTL2_PRESENT(ptl1, PTL1_INDEX(page));       
    102107        }
    103108       
     
    110115                SET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page), KA2PA(newpt));
    111116                SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page),
    112                     PAGE_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
     117                    PAGE_NOT_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
    113118                    PAGE_WRITE);
     119                write_barrier();
     120                SET_PTL3_PRESENT(ptl2, PTL2_INDEX(page));
    114121        }
    115122       
     
    117124       
    118125        SET_FRAME_ADDRESS(ptl3, PTL3_INDEX(page), frame);
    119         SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), flags);
     126        SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), flags | PAGE_NOT_PRESENT);
     127        write_barrier();
     128        SET_FRAME_PRESENT(ptl3, PTL3_INDEX(page));
    120129}
    121130
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