On Wed 2007-08-22 18:16:05, Rafael J. Wysocki wrote:
> On Wednesday, 22 August 2007 10:29, Pavel Machek wrote:
> > Hi!
> >
> > > Use temporary page tables for the kernel text mapping during hibernation
> > > restore
> > > on x86_64.
> > >
> > > Without the patch, the original boot kernel's page tables that represent
> > > the
> > > kernel text mapping are used while the core of the image kernel is being
> > > restored. However, in principle, if the boot kernel is not identical to
> > > the
> > > image kernel, the location of these page tables in the image kernel need
> > > not be
> > > the same, so we should create a safe copy of the kernel text mapping
> > > prior to
> > > restoring the core of the image kernel.
> >
> >
> > > @@ -190,25 +190,42 @@ static int res_phys_pud_init(pud_t *pud,
> > > return 0;
> > > }
> > >
> > > +static int res_kernel_text_pud_init(pud_t *pud, unsigned long start)
> > > +{
> > > + pmd_t *pmd;
> > > + unsigned long paddr;
> > > +
> > > + pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
> > > + if (!pmd)
> > > + return -ENOMEM;
> > > + set_pud(pud + pud_index(start), __pud(__pa(pmd) | _KERNPG_TABLE));
> > > + for (paddr = 0; paddr < KERNEL_TEXT_SIZE; pmd++, paddr += PMD_SIZE) {
> > > + unsigned long pe;
> > > +
> > > + pe = __PAGE_KERNEL_LARGE_EXEC | _PAGE_GLOBAL | paddr;
> > > + pe &= __supported_pte_mask;
> > > + set_pmd(pmd, __pmd(pe));
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > static int set_up_temporary_mappings(void)
> > > {
> > > unsigned long start, end, next;
> > > + pud_t *pud;
> > > int error;
> > >
> > > temp_level4_pgt = (pgd_t *)get_safe_page(GFP_ATOMIC);
> > > if (!temp_level4_pgt)
> > > return -ENOMEM;
> > >
> > > - /* It is safe to reuse the original kernel mapping */
> > > - set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),
> > > - init_level4_pgt[pgd_index(__START_KERNEL_map)]);
> > > -
> > > /* Set up the direct mapping from scratch */
> > > start = (unsigned long)pfn_to_kaddr(0);
> > > end = (unsigned long)pfn_to_kaddr(end_pfn);
> > >
> > > for (; start < end; start = next) {
> > > - pud_t *pud = (pud_t *)get_safe_page(GFP_ATOMIC);
> > > + pud = (pud_t *)get_safe_page(GFP_ATOMIC);
> > > if (!pud)
> > > return -ENOMEM;
> >
> > I believe we leak temp_level4_pgt here.
> >
> > > + /* Set up the kernel text mapping from scratch */
> > > + pud = (pud_t *)get_safe_page(GFP_ATOMIC);
> > > + if (!pud)
> > > + return -ENOMEM;
> >
> > ...and some more memory here :-(.
>
> No, these pages will be freed by swsusp_free(), thanks to the get_safe_page().
>
> I'm not _that_ careless. ;-)
Ok, ACK.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures)
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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