[PATCH v10 0/4] Fix issues with huge mapping in ioremap for ARM64

Chintan Pandya
2018-05-24T13:57:49Z

This series of patches re-bring huge vmap back for arm64.

Patch 1/4 has been taken by Toshi in his series of patches
by name "[PATCH v3 0/3] fix free pmd/pte page handlings on x86"
to avoid merge conflict with this series.

Patch 4/4 may conflict with Laura's patch "[PATCHv2] arm64: Make
sure permission updates happen for pmd/pud". It looks to me that,
problem addressed by this patch will also get resolved by below
series of patches. There could be multiple ways to resolve this.
I would let maintainer suggest the best approach, and I will do
the needful.

This patches are tested on 4.16 kernel with Cortex-A75 based SoC.

The test used for verifying these patches is a stress test on
ioremap/unmap which tries to re-use same io-address but changes
size of mapping randomly i.e. 4K to 2M to 16K etc. The same test
used to reproduce 3rd level translation fault without these fixes
(and also of course with Revert "arm64: Enforce BBM for huge IO/VMAP
mappings" being part of the tree).

These patches can also go into '-stable' branch (if accepted)
for 4.6 onwards.

>From V9->V10:
- Updated commit log for patch 1/4 by Toshi
- Addressed review comments by Will on patch 3/4

>From V8->V9:
- Used __TLBI_VADDR macros in new TLB flush API

>From V7->V8:
- Properly fixed compilation issue in x86 file

>From V6->V7:
- Fixed compilation issue in x86 case
- V6 patches were not properly enumarated

>From V5->V6:
- Use __flush_tlb_kernel_pgtable() for both PUD and PMD. Remove
"bool tlb_inv" based variance as it is not need now
- Re-naming for consistency

>From V4->V5:
- Add new API __flush_tlb_kernel_pgtable(unsigned long addr)
for kernel addresses

>From V3->V4:
- Add header for 'addr' in x86 implementation
- Re-order pmd/pud clear and table free
- Avoid redundant TLB invalidatation in one perticular case

>From V2->V3:
- Use the exisiting page table free interface to do arm64
specific things

>From V1->V2:
- Rebased my patches on top of "[PATCH v2 1/2] mm/vmalloc:
Add interfaces to free unmapped page table"
- Honored BBM for ARM64

Chintan Pandya (4):
ioremap: Update pgtable free interfaces with addr
arm64: tlbflush: Introduce __flush_tlb_kernel_pgtable
arm64: Implement page table free interfaces
Revert "arm64: Enforce BBM for huge IO/VMAP mappings"

arch/arm64/include/asm/tlbflush.h | 7 +++++++
arch/arm64/mm/mmu.c | 42 ++++++++++++++++++++++++++++-----------
arch/x86/mm/pgtable.c | 8 +++++---
include/asm-generic/pgtable.h | 8 ++++----
lib/ioremap.c | 4 ++--
5 files changed, 48 insertions(+), 21 deletions(-)