On Wed, Jun 06, 2018 at 12:31:21PM +0530, Chintan Pandya wrote: > arm64 requires break-before-make. Originally, before > setting up new pmd/pud entry for huge mapping, in few > cases, the modifying pmd/pud entry was still valid > and pointing to next level page table as we only > clear off leaf PTE in unmap leg. > > a) This was resulting into stale entry in TLBs (as few > TLBs also cache intermediate mapping for performance > reasons) > b) Also, modifying pmd/pud was the only reference to > next level page table and it was getting lost without > freeing it. So, page leaks were happening. > > Implement pud_free_pmd_page() and pmd_free_pte_page() to > enforce BBM and also free the leaking page tables. > > Implementation requires, > 1) Clearing off the current pud/pmd entry > 2) Invalidation of TLB > 3) Freeing of the un-used next level page tables > > Signed-off-by: Chintan Pandya <cpan...@codeaurora.org> > --- > arch/arm64/mm/mmu.c | 48 ++++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 44 insertions(+), 4 deletions(-)
Thanks, I think this looks really good now: Reviewed-by: Will Deacon <will.dea...@arm.com> Will
