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This commit is contained in:
Bahadir Balban
2008-01-13 13:53:52 +00:00
commit e2b791a3d8
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92
tasks/mm0/src/memory.c Normal file
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/*
* Initialise the memory structures.
*
* Copyright (C) 2007 Bahadir Balban
*/
#include <kdata.h>
#include <memory.h>
#include <l4/macros.h>
#include <l4/config.h>
#include <l4/types.h>
#include <l4/generic/space.h>
#include <l4lib/arch/syslib.h>
#include INC_GLUE(memory.h)
#include INC_SUBARCH(mm.h)
#include <memory.h>
struct membank membank[1];
struct page *page_array;
void *phys_to_virt(void *addr)
{
return addr + INITTASK_OFFSET;
}
void *virt_to_phys(void *addr)
{
return addr - INITTASK_OFFSET;
}
/* Allocates page descriptors and initialises them using page_map information */
void init_physmem(struct initdata *initdata, struct membank *membank)
{
struct page_bitmap *pmap = &initdata->page_map;
int npages = pmap->pfn_end - pmap->pfn_start;
/* Allocation marks for the struct page array */
int pg_npages, pg_spfn, pg_epfn;
unsigned long ffree_addr;
/*
* Means the page array won't map one to one to pfns. That's ok,
* but we dont allow it for now.
*/
BUG_ON(pmap->pfn_start);
membank[0].start = __pfn_to_addr(pmap->pfn_start);
membank[0].end = __pfn_to_addr(pmap->pfn_end);
/* First find the first free page after last used page */
for (int i = 0; i < npages; i++)
if ((pmap->map[BITWISE_GETWORD(i)] & BITWISE_GETBIT(i)))
membank[0].free = (i + 1) * PAGE_SIZE;
BUG_ON(membank[0].free >= membank[0].end);
/*
* One struct page for every physical page. Calculate how many pages
* needed for page structs, start and end pfn marks.
*/
pg_npages = __pfn((sizeof(struct page) * npages));
/* These are relative pfn offsets to the start of the memory bank */
pg_spfn = __pfn(membank[0].free) - __pfn(membank[0].start);
pg_epfn = pg_spfn + pg_npages;
/* Use free pages from the bank as the space for struct page array */
membank[0].page_array = l4_map_helper((void *)membank[0].free,
pg_npages);
/* Update free memory left */
membank[0].free += pg_npages * PAGE_SIZE;
/* Update page bitmap for the pages used for the page array */
for (int i = pg_spfn; i < pg_epfn; i++)
pmap->map[BITWISE_GETWORD(i)] |= BITWISE_GETBIT(i);
/* Initialise the page array */
for (int i = 0; i < npages; i++) {
INIT_LIST_HEAD(&membank[0].page_array[i].list);
/* Set use counts for pages the kernel has already used up */
if (!(pmap->map[BITWISE_GETWORD(i)] & BITWISE_GETBIT(i)))
membank[0].page_array[i].count = -1;
else /* Last page used +1 is free */
ffree_addr = (i + 1) * PAGE_SIZE;
}
/* First free address must come up the same for both */
BUG_ON(ffree_addr != membank[0].free);
/* Set global page array to this bank's array */
page_array = membank[0].page_array;
}