return ret;
}
-/*
- * This is like a special single-page "expand_{down|up}wards()",
- * except we must first make sure that 'address{-|+}PAGE_SIZE'
- * doesn't hit another vma.
- */
-static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
-{
- address &= PAGE_MASK;
- if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
- struct vm_area_struct *prev = vma->vm_prev;
- /*
- * Is there a mapping abutting this one below?
- *
- * That's only ok if it's the same stack mapping
- * that has gotten split..
- */
- if (prev && prev->vm_end == address)
- return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
-
- return expand_downwards(vma, address - PAGE_SIZE);
- }
- if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
- struct vm_area_struct *next = vma->vm_next;
-
- /* As VM_GROWSDOWN but s/below/above/ */
- if (next && next->vm_start == address + PAGE_SIZE)
- return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
-
- return expand_upwards(vma, address + PAGE_SIZE);
- }
- return 0;
-}
/*
* We enter with non-exclusive mmap_sem (to exclude vma changes,
return VM_FAULT_SIGBUS;
/* Check if we need to add a guard page to the stack */
- if (check_stack_guard_page(vma, vmf->address) < 0)
- return VM_FAULT_SIGSEGV;
+ if (stack_guard_area(vma, vmf->address)) {
+ if (expand_stack(vma, vmf->address) < 0)
+ return VM_FAULT_SIGSEGV;
+ }
/*
* Use pte_alloc() instead of pte_alloc_map(). We can't run
int last_cpupid;
int target_nid;
bool migrated = false;
- pte_t pte = vmf->orig_pte;
- bool was_writable = pte_write(pte);
+ pte_t pte;
+ bool was_writable = pte_savedwrite(vmf->orig_pte);
int flags = 0;
/*
- * The "pte" at this point cannot be used safely without
- * validation through pte_unmap_same(). It's of NUMA type but
- * the pfn may be screwed if the read is non atomic.
- *
- * We can safely just do a "set_pte_at()", because the old
- * page table entry is not accessible, so there would be no
- * concurrent hardware modifications to the PTE.
- */
+ * The "pte" at this point cannot be used safely without
+ * validation through pte_unmap_same(). It's of NUMA type but
+ * the pfn may be screwed if the read is non atomic.
+ */
vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd);
spin_lock(vmf->ptl);
- if (unlikely(!pte_same(*vmf->pte, pte))) {
+ if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) {
pte_unmap_unlock(vmf->pte, vmf->ptl);
goto out;
}
- /* Make it present again */
+ /*
+ * Make it present again, Depending on how arch implementes non
+ * accessible ptes, some can allow access by kernel mode.
+ */
+ pte = ptep_modify_prot_start(vma->vm_mm, vmf->address, vmf->pte);
pte = pte_modify(pte, vma->vm_page_prot);
pte = pte_mkyoung(pte);
if (was_writable)
pte = pte_mkwrite(pte);
- set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte);
+ ptep_modify_prot_commit(vma->vm_mm, vmf->address, vmf->pte, pte);
update_mmu_cache(vma, vmf->address, vmf->pte);
page = vm_normal_page(vma, vmf->address, pte);