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rewrite of page_map_{copy,drop} functions

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This commit is contained in:
Steffen Vogel 2014-12-04 20:42:58 +01:00
parent 18378417a7
commit 09acfdfdf3
1 changed files with 31 additions and 34 deletions
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65
arch/x86/mm/page.c
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@ -156,22 +156,14 @@ int page_unmap(size_t viraddr, size_t npages)
int page_map_drop()
{
void traverse(int lvl, long vpn) {
kprintf("traverse(lvl=%d, vpn=%#lx)\n", lvl, vpn);
long stop;
for (stop=vpn+PAGE_MAP_ENTRIES; vpn<stop; vpn++) {
if (self[lvl][vpn] & PG_PRESENT) {
if (self[lvl][vpn] & PG_BOOT)
continue;
// ost-order traversal
if (lvl > 1)
if (self[lvl][vpn] & PG_PRESENT && self[lvl][vpn] & PG_USER) {
/* Post-order traversal */
if (lvl)
traverse(lvl-1, vpn<<PAGE_MAP_BITS);
kprintf("%#lx, ", self[lvl][vpn] & PAGE_MASK);
//put_page(self[lvl][vpn] & PAGE_MASK);
atomic_int32_dec(&current_task->user_usage);
put_pages(self[lvl][vpn] & PAGE_MASK, 1);
}
}
}
@ -191,37 +183,42 @@ int page_map_copy(size_t dest)
long stop;
for (stop=vpn+PAGE_MAP_ENTRIES; vpn<stop; vpn++) {
if (self[lvl][vpn] & PG_PRESENT) {
size_t phyaddr = get_pages(1);
if (BUILTIN_EXPECT(phyaddr, 0))
return -ENOMEM;
if (self[lvl][vpn] & PG_USER) {
size_t phyaddr = get_pages(1);
if (BUILTIN_EXPECT(!phyaddr, 0))
return -ENOMEM;
other[lvl][vpn] = phyaddr;
other[lvl][vpn] |= self[lvl][vpn] & ~PAGE_MASK;
memcpy(CHILD(other, lvl, vpn), CHILD(self, lvl, vpn), PAGE_SIZE);
// pre-order traversal
if (lvl)
traverse(lvl-1, vpn<<PAGE_MAP_BITS);
other[lvl][vpn] = phyaddr | (self[lvl][vpn] & ~PAGE_MASK);
if (lvl) /* PML4, PDPT, PGD */
traverse(lvl-1, vpn<<PAGE_MAP_BITS); /* Pre-order traversal */
else { /* PGT */
page_map(PAGE_TMP, phyaddr, 1, PG_PRESENT | PG_RW);
memcpy((void*) PAGE_TMP, (void*) (vpn<<PAGE_BITS), PAGE_SIZE);
}
}
else if (self[lvl][vpn] & PG_SELF)
other[lvl][vpn] = 0;
else
other[lvl][vpn] = self[lvl][vpn];
}
else
other[lvl][vpn] = 0;
}
return 0;
}
spinlock_lock(&kslock);
spinlock_irqsave_lock(&current_task->page_lock);
self[PAGE_LEVELS-1][PAGE_MAP_ENTRIES-2] = dest | PG_PRESENT | PG_SELF | PG_RW;
// create another temporary self-reference
self[PAGE_LEVELS-1][PAGE_MAP_ENTRIES-2] = dest | PG_PRESENT | PG_RW;
int ret = traverse(PAGE_LEVELS-1, 0);
traverse(PAGE_LEVELS-1, 0);
other[PAGE_LEVELS-1][PAGE_MAP_ENTRIES-1] = dest | PG_PRESENT | PG_SELF | PG_RW;
self [PAGE_LEVELS-1][PAGE_MAP_ENTRIES-2] = 0;
spinlock_irqsave_unlock(&current_task->page_lock);
flush_tlb(); /* Flush TLB entries of 'other' self-reference */
// remove temporary self-reference
self[PAGE_LEVELS-1][PAGE_MAP_ENTRIES-2] = 0;
spinlock_unlock(&kslock);
return 0;
return ret;
}
void page_fault_handler(struct state *s)