On Wed, Jun 06, 2018 at 12:31:19PM +0530, Chintan Pandya wrote:
From: Chintan Pandya cpandya@codeaurora.org
The following kernel panic was observed on ARM64 platform due to a stale TLB entry.
- ioremap with 4K size, a valid pte page table is set.
- iounmap it, its pte entry is set to 0.
- ioremap the same address with 2M size, update its pmd entry with a new value.
- CPU may hit an exception because the old pmd entry is still in TLB, which leads to a kernel panic.
Commit b6bdb7517c3d ("mm/vmalloc: add interfaces to free unmapped page table") has addressed this panic by falling to pte mappings in the above case on ARM64.
To support pmd mappings in all cases, TLB purge needs to be performed in this case on ARM64.
Add a new arg, 'addr', to pud_free_pmd_page() and pmd_free_pte_page() so that TLB purge can be added later in seprate patches.
[toshi@hpe.com: merge changes, rewrite patch description] Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces") Signed-off-by: Chintan Pandya cpandya@codeaurora.org Signed-off-by: Toshi Kani toshi.kani@hpe.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Ingo Molnar mingo@redhat.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: Will Deacon will.deacon@arm.com Cc: Joerg Roedel joro@8bytes.org Cc: stable@vger.kernel.org
arch/arm64/mm/mmu.c | 4 ++-- arch/x86/mm/pgtable.c | 8 +++++--- include/asm-generic/pgtable.h | 8 ++++---- lib/ioremap.c | 4 ++-- 4 files changed, 13 insertions(+), 11 deletions(-)
Reviewed-by: Will Deacon will.deacon@arm.com
Thanks,
Will