Hi Julien, On 27/01/2023 20:55, Julien Grall wrote: > > > From: Julien Grall <[email protected]> > > At the moment, switch_ttbr() is switching the TTBR whilst the MMU is > still on. > > Switching TTBR is like replacing existing mappings with new ones. So > we need to follow the break-before-make sequence. > > In this case, it means the MMU needs to be switched off while the > TTBR is updated. In order to disable the MMU, we need to first > jump to an identity mapping. > > Rename switch_ttbr() to switch_ttbr_id() and create an helper on > top to temporary map the identity mapping and call switch_ttbr() > via the identity address. > > switch_ttbr_id() is now reworked to temporarily turn off the MMU > before updating the TTBR. > > We also need to make sure the helper switch_ttbr() is part of the > identity mapping. So move _end_boot past it. > > The arm32 code will use a different approach. So this issue is for now > only resolved on arm64. > > Signed-off-by: Julien Grall <[email protected]> > Reviewed-by: Luca Fancellu <[email protected]> > Tested-by: Luca Fancellu <[email protected]>
Reviewed-by: Michal Orzel <[email protected]> ~Michal
