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3.4. INTERFACE & CLASSES CHAPTER 3. VM, PROTECTION AND PAGING
uint32
returns the next free physical page number
getFreePhysicalPage(uint32 type); and marks that page as used. It takes
one parameter "type", which should be either
PAGE_USERSPACE, that is the default, or
PAGE_KERNEL. Note that the type set in the
PageManager does not influence the User/Supervisor
Flag in the Page-Directory.
void freePage(uint32 page_number); marks one physical page identified by its
page_number as free, if it was marked as used
in user or kernel context.
void startUsingSyncMechanism(); to be called after initialising the KernelMemoryManager
and before starting Interrupts to ensure
Mutual Exclusion
Table 3.6: PageManager Interface
3.4.3 Implementation
1 /∗∗
2 ∗ @ f i l e PageManager . cpp
3 ∗/
4
5 #include "mm/PageManager .h"
6 #include "mm/new.h"
7 #include " paging−definitions .h"
8 #include " arch_panic .h"
9 #include "ArchCommon.h"
10 #include "ArchMemory.h"
11 #include " debug_bochs .h"
12 #include " console/kprintf .h"
13 #include " ArchInterrupts .h"
14 #include " assert .h"
15
16 PageManager∗ PageManager : : instance_ =0;
17
18 extern void∗ kernel_end_address ;
19
20 void PageManager : : createPageManager ( )
21 {
22 i f ( instance_ )
23 return ;
24
25 instance_ = new PageManager ( ) ;
26 }
27
28 PageManager : : PageManager ( )
29 {
30 number_of_pages_ = 0;
31 lowest_unreserved_page_ = 256; //physical memory