On Sun, 23 Jan 2005 11:08:46 +1100
Nick Piggin <[EMAIL PROTECTED]> wrote:
> * replace
> #include <asm-generic/4level-fixup.h>
> in asm/pgtable.h with
> #include <asm-generic/pgtable-nopud.h>
This breaks platforms like sparc64 because PTRS_PER_PMD is not
a compile time constant. It is actually dependant upon whether
the current thread is using a 32-bit or 64-bit address space.
If I move Sparc64 over to real 4-level page tables some day,
then PTRS_PER_PUD will have the same problem.
I think it's safe and nearly as efficient to turn these into
run-time tests. We'll get two extraneous functions which do
nothing but return NULL on platforms where they really are
a constant "1".
===== mm/memory.c 1.217 vs edited =====
--- 1.217/mm/memory.c 2005-01-20 12:49:13 -08:00
+++ edited/mm/memory.c 2005-01-25 19:18:29 -08:00
@@ -2089,7 +2089,6 @@
}
#ifndef __ARCH_HAS_4LEVEL_HACK
-#if (PTRS_PER_PUD > 1)
/*
* Allocate page upper directory.
*
@@ -2101,29 +2100,30 @@
*/
pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long
address)
{
- pud_t *new;
+ if (PTRS_PER_PUD > 1) {
+ pud_t *new;
- spin_unlock(&mm->page_table_lock);
- new = pud_alloc_one(mm, address);
- spin_lock(&mm->page_table_lock);
- if (!new)
- return NULL;
+ spin_unlock(&mm->page_table_lock);
+ new = pud_alloc_one(mm, address);
+ spin_lock(&mm->page_table_lock);
+ if (!new)
+ return NULL;
- /*
- * Because we dropped the lock, we should re-check the
- * entry, as somebody else could have populated it..
- */
- if (pgd_present(*pgd)) {
- pud_free(new);
- goto out;
+ /*
+ * Because we dropped the lock, we should re-check the
+ * entry, as somebody else could have populated it..
+ */
+ if (pgd_present(*pgd)) {
+ pud_free(new);
+ goto out;
+ }
+ pgd_populate(mm, pgd, new);
+ out:
+ return pud_offset(pgd, address);
}
- pgd_populate(mm, pgd, new);
-out:
- return pud_offset(pgd, address);
+ return NULL;
}
-#endif
-#if (PTRS_PER_PMD > 1)
/*
* Allocate page middle directory.
*
@@ -2135,27 +2135,29 @@
*/
pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long
address)
{
- pmd_t *new;
+ if (PTRS_PER_PMD > 1) {
+ pmd_t *new;
- spin_unlock(&mm->page_table_lock);
- new = pmd_alloc_one(mm, address);
- spin_lock(&mm->page_table_lock);
- if (!new)
- return NULL;
+ spin_unlock(&mm->page_table_lock);
+ new = pmd_alloc_one(mm, address);
+ spin_lock(&mm->page_table_lock);
+ if (!new)
+ return NULL;
- /*
- * Because we dropped the lock, we should re-check the
- * entry, as somebody else could have populated it..
- */
- if (pud_present(*pud)) {
- pmd_free(new);
- goto out;
+ /*
+ * Because we dropped the lock, we should re-check the
+ * entry, as somebody else could have populated it..
+ */
+ if (pud_present(*pud)) {
+ pmd_free(new);
+ goto out;
+ }
+ pud_populate(mm, pud, new);
+ out:
+ return pmd_offset(pud, address);
}
- pud_populate(mm, pud, new);
-out:
- return pmd_offset(pud, address);
+ return NULL;
}
-#endif
#else
pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long
address)
{
