Ok, the use of "1 + " and subtraction of one for PAE PDPEs has
confused
many people now. Make it explicit what is going on and why anding with
PAGE_MASK is a better idea to strip these bits.
Signed-off-by: Zachary Amsden <zach@vmware.com>
Depends-on: add-pgtable-allocation-notifiers
Index: linux-2.6.13/arch/i386/mm/pgtable.c
==================================================================---
linux-2.6.13.orig/arch/i386/mm/pgtable.c 2005-08-31 14:48:17.000000000 -0700
+++ linux-2.6.13/arch/i386/mm/pgtable.c 2005-08-31 14:48:53.000000000 -0700
@@ -247,14 +247,14 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
if (!pmd)
goto out_oom;
SetPagePDE(virt_to_page(pmd));
- set_pgd(&pgd[i], __pgd(1 + __pa(pmd)));
+ set_pgd(&pgd[i], __pgd(_PAGE_PRESENT | __pa(pmd)));
}
return pgd;
out_oom:
for (i--; i >= 0; i--) {
ClearPagePDE(pfn_to_page(pgd_val(pgd[i]) >> PAGE_SHIFT));
- kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i])-1));
+ kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i]) & PAGE_MASK));
}
kmem_cache_free(pgd_cache, pgd);
return NULL;
@@ -268,7 +268,7 @@ void pgd_free(pgd_t *pgd)
if (PTRS_PER_PMD > 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])-1));
+ kmem_cache_free(pmd_cache, (void *)__va(pgd_val(pgd[i]) & PAGE_MASK));
}
/* in the non-PAE case, free_pgtables() clears user pgd entries */
kmem_cache_free(pgd_cache, pgd);
Index: linux-2.6.13/arch/i386/mm/init.c
==================================================================---
linux-2.6.13.orig/arch/i386/mm/init.c 2005-08-31 14:48:17.000000000 -0700
+++ linux-2.6.13/arch/i386/mm/init.c 2005-08-31 14:48:53.000000000 -0700
@@ -387,7 +387,7 @@ void zap_low_mappings (void)
*/
for (i = 0; i < USER_PTRS_PER_PGD; i++)
#ifdef CONFIG_X86_PAE
- set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
+ set_pgd(swapper_pg_dir+i, __pgd(_PAGE_PRESENT | __pa(empty_zero_page)));
#else
set_pgd(swapper_pg_dir+i, __pgd(0));
#endif
