On Wed, Apr 29, 2020 at 1:01 PM James Morse <james.morse@xxxxxxx> wrote: > > Hi Pavel, > > On 26/03/2020 03:24, Pavel Tatashin wrote: > > From: James Morse <james.morse@xxxxxxx> > > > > To resume from hibernate, the contents of memory are restored from > > the swap image. This may overwrite any page, including the running > > kernel and its page tables. > > > > Hibernate copies the code it uses to do the restore into a single > > page that it knows won't be overwritten, and maps it with page tables > > built from pages that won't be overwritten. > > > > Today the address it uses for this mapping is arbitrary, but to allow > > kexec to reuse this code, it needs to be idmapped. To idmap the page > > we must avoid the kernel helpers that have VA_BITS baked in. > > > > Convert create_single_mapping() to take a single PA, and idmap it. > > The page tables are built in the reverse order to normal using > > pfn_pte() to stir in any bits between 52:48. T0SZ is always increased > > to cover 48bits, or 52 if the copy code has bits 52:48 in its PA. > > > > Pasha: The original patch from James > > inux-arm-kernel/20200115143322.214247-4-james.morse@xxxxxxx > > -EBROKENLINK > > The convention is to use a 'Link:' tag in the signed-off area. > e.g. 5a3577039cbe OK Fixed. > > > Adopted it to trans_pgd, so it can be commonly used by both Kexec > > and Hibernate. Some minor clean-ups. > > Please describe your changes just before your SoB. This means each author sign's off on > the stuff above their SoB, and its obvious who made which changes. > > Search for 'Lucky K Maintainer' in process/submitting-patches.rst for an example. OK, Fixed. eed the maximum T0SZ. > > + * > > + * Returns 0 on success, and -ENOMEM on failure. > > + * On success trans_ttbr0 contains page table with idmapped page, t0sz is set to > > > + * maxumum T0SZ for this page. > > maxumum > Ok.
