MM: Pass a PTE pointer to update_mmu_cache() rather than the PTE itself
On VIVT ARM, when we have multiple shared mappings of the same file
in the same MM, we need to ensure that we have coherency across all
copies. We do this via make_coherent() by making the pages
uncacheable.
This used to work fine, until we allowed highmem with highpte - we
now have a page table which is mapped as required, and is not available
for modification via update_mmu_cache().
Ralf Beache suggested getting rid of the PTE value passed to
update_mmu_cache():
On MIPS update_mmu_cache() calls __update_tlb() which walks pagetables
to construct a pointer to the pte again. Passing a pte_t * is much
more elegant. Maybe we might even replace the pte argument with the
pte_t?
Ben Herrenschmidt would also like the pte pointer for PowerPC:
Passing the ptep in there is exactly what I want. I want that
-instead- of the PTE value, because I have issue on some ppc cases,
for I$/D$ coherency, where set_pte_at() may decide to mask out the
_PAGE_EXEC.
So, pass in the mapped page table pointer into update_mmu_cache(), and
remove the PTE value, updating all implementations and call sites to
suit.
Includes a fix from Stephen Rothwell:
sparc: fix fallout from update_mmu_cache API change
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/mm/memory.c b/mm/memory.c
index 09e4b1b..72fb5f3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1593,7 +1593,7 @@
/* Ok, finally just insert the thing.. */
entry = pte_mkspecial(pfn_pte(pfn, prot));
set_pte_at(mm, addr, pte, entry);
- update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */
+ update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
retval = 0;
out_unlock:
@@ -2116,7 +2116,7 @@
entry = pte_mkyoung(orig_pte);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
if (ptep_set_access_flags(vma, address, page_table, entry,1))
- update_mmu_cache(vma, address, entry);
+ update_mmu_cache(vma, address, page_table);
ret |= VM_FAULT_WRITE;
goto unlock;
}
@@ -2185,7 +2185,7 @@
* new page to be mapped directly into the secondary page table.
*/
set_pte_at_notify(mm, address, page_table, entry);
- update_mmu_cache(vma, address, entry);
+ update_mmu_cache(vma, address, page_table);
if (old_page) {
/*
* Only after switching the pte to the new page may
@@ -2629,7 +2629,7 @@
}
/* No need to invalidate - it was non-present before */
- update_mmu_cache(vma, address, pte);
+ update_mmu_cache(vma, address, page_table);
unlock:
pte_unmap_unlock(page_table, ptl);
out:
@@ -2694,7 +2694,7 @@
set_pte_at(mm, address, page_table, entry);
/* No need to invalidate - it was non-present before */
- update_mmu_cache(vma, address, entry);
+ update_mmu_cache(vma, address, page_table);
unlock:
pte_unmap_unlock(page_table, ptl);
return 0;
@@ -2855,7 +2855,7 @@
set_pte_at(mm, address, page_table, entry);
/* no need to invalidate: a not-present page won't be cached */
- update_mmu_cache(vma, address, entry);
+ update_mmu_cache(vma, address, page_table);
} else {
if (charged)
mem_cgroup_uncharge_page(page);
@@ -2992,7 +2992,7 @@
}
entry = pte_mkyoung(entry);
if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
- update_mmu_cache(vma, address, entry);
+ update_mmu_cache(vma, address, pte);
} else {
/*
* This is needed only for protection faults but the arch code