Chris Wright wrote:
* Zachary Amsden ([email protected]) wrote:
--- linux-2.6.13.orig/arch/i386/mm/init.c 2005-08-24 09:31:05.000000000 -0700
+++ linux-2.6.13/arch/i386/mm/init.c 2005-08-24 09:31:31.000000000 -0700
@@ -79,6 +79,7 @@ static pte_t * __init one_page_table_ini
{
if (pmd_none(*pmd)) {
pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+ SetPagePTE(virt_to_page(page_table));
Xen has this on one_md_table_init() as well for pmd.
I'll add that in another patch. It's easy to miss some of the init time
call sites (we don't actually depend on them for correctness).
spin_lock_irqsave(&pgd_lock, flags);
pgd_list_del(pgd);
spin_unlock_irqrestore(&pgd_lock, flags);
@@ -244,13 +246,16 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
pmd_t *pmd = kmem_cache_alloc(pmd_cache, GFP_KERNEL);
if (!pmd)
goto out_oom;
+ SetPagePDE(virt_to_page(pmd));
set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
}
return pgd;
out_oom:
- for (i--; i >= 0; i--)
+ for (i--; i >= 0; i--) {
+ ClearPagePDE(pfn_to_page(pgd_val(pgd[i]) >> PAGE_SHIFT));
Is that the right pfn? That -1 throws me off.
kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
+ }
kmem_cache_free(pgd_cache, pgd);
return NULL;
}
@@ -261,8 +266,10 @@ void pgd_free(pgd_t *pgd)
/* in the PAE case user pgd entries are overwritten before usage */
if (PTRS_PER_PMD > 1)
- for (i = 0; i < USER_PTRS_PER_PGD; ++i)
- kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
+ for (i = 0; i < USER_PTRS_PER_PGD; ++i) {
+ ClearPagePDE(pfn_to_page(pgd_val(pgd[i]) >> PAGE_SHIFT));
+ kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i]) & PAGE_MASK));
Why the switch of kmem_cache_free call?
Because pgd_val(pgd[i])-1 is confusing. Using (pgd_val(pgd[i]) -
_PAGE_PRESENT) would be better, but the +/- 1s all over the place here
could use some general cleanup as well. I smell a cleanup fit coming
on. Using (pgd_val(pgd[i]) & PAGE_MASK) is a less error prone way to
get the physical frame bits, since it is not wrong if you turn on PCD or
PWD.
Zach
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