--- Jim Bauer <jfbauer@nfr.com> wrote:
> > I couldn't find an example in any 2.5.x driver. But
> > here is what is needed:
> >
> > {
> > struct mm_struct *mm;
> > pgd_t *pgd;
> > pmd_t *pmd;
> > pte_t *ptep, pte;
> > struct page *old_page;
> > struct page *new_page = ...; /* new page to be mapped
> in */
> > pgprot_t prot = ...; /* PTE flags. _PAGE_RW,
> PAGE_SHARED, etc.
> > * Set appropriately. */
> >
> > mm = current->mm;
> > spin_lock(&mm->page_table_lock);
> > pgd = pgd_offset(mm, address);
> > pmd = pmd_offset(pgd, address);
> > ptep = pte_offset_map(pmd, address);
> > pte = ptep_get_and_clear(ptep);
> > set_pte(ptep, mk_pte(new_page, prot));
> > spin_unlock(&mm->page_table_lock);
> > old_page = pte_page(pte);
> > ...
> > }
> >
> > Not many error checks are needed in this case since we
> > know that the required address definitely has a mapping
> > in the process page table.
> >
>
>
> I tried this, but the user-space program's mapping was
> still refering to the old pages.
Are you sure current->mm is what you want always? If the
remapping is triggered from an interrupt context, then
current->mm will refer to the mm structure of some other
process.
> However, if I ran it
> through gdb and single stepped it then it saw the new
> buffer. It I used gdb, but did not single step, then
> the prog being debugged saw the old pages, but gdb saw
> the new ones?
I am not sure I understand that. What do you mean by
'gdb saw new ones'? How exactly did you check that in
gdb?
-Ravi.
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