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added proper locking primitives for 'per task' page tables

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This commit is contained in:
Steffen Vogel 2014-12-04 20:35:19 +01:00
parent 67b8ca111a
commit 27274dad67
1 changed files with 22 additions and 14 deletions
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36
arch/x86/mm/page.c
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@ -77,7 +77,7 @@ size_t page_virt_to_phys(size_t addr)
int page_map(size_t viraddr, size_t phyaddr, size_t npages, size_t bits) int page_map(size_t viraddr, size_t phyaddr, size_t npages, size_t bits)
{ {
int lvl; int lvl, ret = -ENOMEM;
long vpn = viraddr >> PAGE_BITS; long vpn = viraddr >> PAGE_BITS;
long first[PAGE_LEVELS], last[PAGE_LEVELS]; long first[PAGE_LEVELS], last[PAGE_LEVELS];
@ -87,7 +87,11 @@ int page_map(size_t viraddr, size_t phyaddr, size_t npages, size_t bits)
last[lvl] = (vpn+npages-1) >> (lvl * PAGE_MAP_BITS); last[lvl] = (vpn+npages-1) >> (lvl * PAGE_MAP_BITS);
} }
spinlock_lock(&kslock); /** @todo: might not be sufficient! */
if (bits & PG_USER)
spinlock_irqsave_lock(&current_task->page_lock);
else
spinlock_lock(&kslock);
/* Start iterating through the entries /* Start iterating through the entries
* beginning at the root table (PGD or PML4) */ * beginning at the root table (PGD or PML4) */
@ -98,10 +102,8 @@ int page_map(size_t viraddr, size_t phyaddr, size_t npages, size_t bits)
/* There's no table available which covers the region. /* There's no table available which covers the region.
* Therefore we need to create a new empty table. */ * Therefore we need to create a new empty table. */
size_t phyaddr = get_pages(1); size_t phyaddr = get_pages(1);
if (BUILTIN_EXPECT(!phyaddr, 0)) { if (BUILTIN_EXPECT(!phyaddr, 0))
spinlock_unlock(&kslock); goto out;
return -ENOMEM;
}
/* Reference the new table within its parent */ /* Reference the new table within its parent */
self[lvl][vpn] = phyaddr | bits; self[lvl][vpn] = phyaddr | bits;
@ -122,24 +124,30 @@ int page_map(size_t viraddr, size_t phyaddr, size_t npages, size_t bits)
} }
} }
spinlock_unlock(&kslock); out:
if (bits & PG_USER)
spinlock_irqsave_unlock(&current_task->page_lock);
else
spinlock_unlock(&kslock);
return 0; return ret;
} }
/** Tables are freed by page_map_drop() */ /** Tables are freed by page_map_drop() */
int page_unmap(size_t viraddr, size_t npages) int page_unmap(size_t viraddr, size_t npages)
{ {
long vpn, start = viraddr >> PAGE_BITS; /* We aquire both locks for kernel and task tables
long end = start + npages; * as we dont know to which the region belongs. */
spinlock_irqsave_lock(&current_task->page_lock);
spinlock_lock(&kslock); spinlock_lock(&kslock);
/* Start iterating through the entries. /* Start iterating through the entries.
* Only the PGT entries are removed. Tables remain allocated. */ * Only the PGT entries are removed. Tables remain allocated. */
for (vpn=start; vpn<end; vpn++) size_t vpn, start = viraddr>>PAGE_BITS;
for (vpn=start; vpn<start+npages; vpn++)
self[0][vpn] = 0; self[0][vpn] = 0;
spinlock_irqsave_unlock(&current_task->page_lock);
spinlock_unlock(&kslock); spinlock_unlock(&kslock);
return 0; return 0;