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authorRobert Morris <[email protected]>2010-08-05 16:00:59 -0400
committerRobert Morris <[email protected]>2010-08-05 16:00:59 -0400
commitc99599784e950169d85bf1e4446e7dbfb1a40f59 (patch)
tree19dce8850f76ceca7d48aab7a5eb693887a486c1 /vm.c
parent2cf6b32d4dbc915f5d3b2d7b0e382c0ad20299be (diff)
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remove some unused vm #defines
fix corner cases with alignment when mapping kernel ELF file
Diffstat (limited to 'vm.c')
-rw-r--r--vm.c60
1 files changed, 23 insertions, 37 deletions
diff --git a/vm.c b/vm.c
index 6689b82..c94e9a3 100644
--- a/vm.c
+++ b/vm.c
@@ -33,27 +33,6 @@ static uint kernend;
static uint freesz;
pde_t *kpgdir; // One kernel page table for scheduler procs
-void
-printpgdir(pde_t *pgdir)
-{
- uint i;
- uint j;
-
- cprintf("printpgdir 0x%x\n", pgdir);
- for (i = 0; i < NPDENTRIES; i++) {
- if (pgdir[i] != 0 && i < 100) {
- cprintf("pgdir %d, v=0x%x\n", i, pgdir[i]);
- pte_t *pgtab = (pte_t*) PTE_ADDR(pgdir[i]);
- for (j = 0; j < NPTENTRIES; j++) {
- if (pgtab[j] != 0)
- cprintf("pgtab %d, v=0x%x, addr=0x%x\n", j, PGADDR(i, j, 0),
- PTE_ADDR(pgtab[j]));
- }
- }
- }
- cprintf("printpgdir done\n", pgdir);
-}
-
// return the address of the PTE in page table pgdir
// that corresponds to linear address va. if create!=0,
// create any required page table pages.
@@ -84,19 +63,25 @@ walkpgdir(pde_t *pgdir, const void *va, int create)
}
// create PTEs for linear addresses starting at la that refer to
-// physical addresses starting at pa.
+// physical addresses starting at pa. la and size might not
+// be page-aligned.
static int
mappages(pde_t *pgdir, void *la, uint size, uint pa, int perm)
{
- uint i;
- pte_t *pte;
-
- for (i = 0; i < size; i += PGSIZE) {
- if (!(pte = walkpgdir(pgdir, (void*)(la + i), 1)))
+ char *first = PGROUNDDOWN(la);
+ char *last = PGROUNDDOWN(la + size - 1);
+ char *a = first;
+ while(1){
+ pte_t *pte = walkpgdir(pgdir, a, 1);
+ if(pte == 0)
return 0;
if(*pte & PTE_P)
panic("remap");
- *pte = (pa + i) | perm | PTE_P;
+ *pte = pa | perm | PTE_P;
+ if(a == last)
+ break;
+ a += PGSIZE;
+ pa += PGSIZE;
}
return 1;
}
@@ -160,10 +145,10 @@ setupkvm(void)
// Map IO space from 640K to 1Mbyte
if (!mappages(pgdir, (void *)USERTOP, 0x60000, USERTOP, PTE_W))
return 0;
- // Map kernel text from kern text addr read-only
+ // Map kernel text read-only
if (!mappages(pgdir, (void *) kerntext, kerntsz, kerntext, 0))
return 0;
- // Map kernel data form kern data addr R/W
+ // Map kernel data read/write
if (!mappages(pgdir, (void *) kerndata, kerndsz, kerndata, PTE_W))
return 0;
// Map dynamically-allocated memory read/write (kernel stacks, user mem)
@@ -194,10 +179,10 @@ allocuvm(pde_t *pgdir, char *addr, uint sz)
{
if (addr + sz >= (char*)USERTOP)
return 0;
- char *start = PGROUNDDOWN(addr);
+ char *first = PGROUNDDOWN(addr);
char *last = PGROUNDDOWN(addr + sz - 1);
char *a;
- for(a = start; a <= last; a += PGSIZE){
+ for(a = first; a <= last; a += PGSIZE){
pte_t *pte = walkpgdir(pgdir, a, 0);
if(pte == 0 || (*pte & PTE_P) == 0){
char *mem = kalloc(PGSIZE);
@@ -212,6 +197,8 @@ allocuvm(pde_t *pgdir, char *addr, uint sz)
return 1;
}
+// free a page table and all the physical memory pages
+// in the user part.
void
freevm(pde_t *pgdir)
{
@@ -227,9 +214,8 @@ freevm(pde_t *pgdir)
if (pgtab[j] != 0) {
uint pa = PTE_ADDR(pgtab[j]);
uint va = PGADDR(i, j, 0);
- if (va >= USERTOP) // done with user part?
- break;
- kfree((void *) pa, PGSIZE);
+ if (va < USERTOP) // user memory
+ kfree((void *) pa, PGSIZE);
pgtab[j] = 0;
}
}
@@ -314,8 +300,8 @@ pminit(void)
kernend = ((uint)end + PGSIZE) & ~(PGSIZE-1);
kerntext = ph[0].va;
kerndata = ph[1].va;
- kerntsz = kerndata - kerntext;
- kerndsz = kernend - kerndata;
+ kerntsz = ph[0].memsz;
+ kerndsz = ph[1].memsz;
freesz = PHYSTOP - kernend;
cprintf("kerntext@0x%x(sz=0x%x), kerndata@0x%x(sz=0x%x), kernend 0x%x freesz = 0x%x\n",