On Tue, 2006-10-10 at 17:05 -0700, Ollie Wild wrote:
> + vma->vm_flags &= ~VM_EXEC;
> + // FIXME: Are the next two lines sufficient, or do I need to
> + // do some additional magic?
> + vma->vm_flags |= mm->def_flags;
> + vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
Yeah, you'll need to change the PTEs for those pages you created by
calling get_user_page() by calling an mprotect like function; perhaps
something like:
struct vm_area_struct *prev;
unsigned long vm_flags = vma->vm_flags;
s/vma->vm_flags/vm_flags/g
err = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, vm_flags);
BUG_ON(prev != vma);
mprotect_fixup will then set the new protection on all PTEs and update
vma->vm_flags and vma->vm_page_prot.
> + /* Move stack pages down in memory. */
> + if (stack_shift) {
> + // FIXME: Verify the shift is OK.
> +
What exactly are you wondering about? the call to move_vma looks sane to
me
> + /* This should be safe even with overlap because we
> + * are shifting down. */
> + ret = move_vma(vma, vma->vm_start,
> + vma->vm_end - vma->vm_start,
> + vma->vm_end - vma->vm_start,
> + vma->vm_start - stack_shift);
> + if (ret & ~PAGE_MASK) {
> + up_write(&mm->mmap_sem);
> + return ret;
> + }
> }
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