Subject: [PATCH v7 00/22] Kernel userspace access/execution prevention with hash translation

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Fri, 27 Nov 2020 10:14:02 +0530

This patch series implements KUAP and KUEP with hash translation mode using
memory keys. The kernel now uses memory protection key 3 to control access
to the kernel. Kernel page table entries are now configured with key 3.
Access to locations configured with any other key value is denied when in
kernel mode (MSR_PR=0). This includes userspace which is by default configured
with key 0.

null-syscall benchmark results:

With smap/smep disabled:
Without patch:
	845.29 ns    2451.44 cycles
With patch series:
	858.38 ns    2489.30 cycles

With smap/smep enabled:
Without patch:
	NA
With patch series:
	1021.51 ns    2962.44 cycles

Changes from v6:
* Address review comments
* Rename MMU FTR defines

Changes from v5:
* Rework the patch based on suggestion from Michael to avoid the
  usage of CONFIG_PPC_PKEY on BOOKE platforms. 

Changes from v4:
* Repost with other pkey related changes split out as a separate series.
* Improve null-syscall benchmark by optimizing SPRN save and restore.

Changes from v3:
* Fix build error reported by kernel test robot <[email-masked]>

Changes from v2:
* Rebase to the latest kernel.
* Fixed a bug with disabling KUEP/KUAP on kernel command line
* Added a patch to make kup key dynamic.

Changes from V1:
* Rebased on latest kernel

Aneesh Kumar K.V (22):
  powerpc: Add new macro to handle NESTED_IFCLR
  KVM: PPC: BOOK3S: PR: Ignore UAMOR SPR
  powerpc/book3s64/kuap/kuep: Add PPC_PKEY config on book3s64
  powerpc/book3s64/kuap/kuep: Move uamor setup to pkey init
  powerpc/book3s64/kuap: Move KUAP related function outside radix
  powerpc/book3s64/kuep: Move KUEP related function outside radix
  powerpc/book3s64/kuap: Rename MMU_FTR_RADIX_KUAP and MMU_FTR_KUEP
  powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash
    translation
  powerpc/exec: Set thread.regs early during exec
  powerpc/book3s64/pkeys: Store/restore userspace AMR/IAMR correctly on
    entry and exit from kernel
  powerpc/book3s64/pkeys: Inherit correctly on fork.
  powerpc/book3s64/pkeys: Reset userspace AMR correctly on exec
  powerpc/ptrace-view: Use pt_regs values instead of thread_struct based
    one.
  powerpc/book3s64/pkeys: Don't update SPRN_AMR when in kernel mode.
  powerpc/book3s64/kuap: Restrict access to userspace based on userspace
    AMR
  powerpc/book3s64/kuap: Improve error reporting with KUAP
  powerpc/book3s64/kuap: Use Key 3 to implement KUAP with hash
    translation.
  powerpc/book3s64/kuep: Use Key 3 to implement KUEP with hash
    translation.
  powerpc/book3s64/hash/kuap: Enable kuap on hash
  powerpc/book3s64/hash/kuep: Enable KUEP on hash
  powerpc/book3s64/hash/kup: Don't hardcode kup key
  powerpc/book3s64/pkeys: Optimize KUAP and KUEP feature disabled case

 arch/powerpc/include/asm/book3s/32/kup.h      |   4 +-
 .../powerpc/include/asm/book3s/64/hash-pkey.h |  10 +-
 arch/powerpc/include/asm/book3s/64/hash.h     |   2 +-
 .../powerpc/include/asm/book3s/64/kup-radix.h | 203 --------
 arch/powerpc/include/asm/book3s/64/kup.h      | 442 ++++++++++++++++++
 arch/powerpc/include/asm/book3s/64/mmu-hash.h |   1 +
 arch/powerpc/include/asm/book3s/64/mmu.h      |   2 +-
 arch/powerpc/include/asm/book3s/64/pkeys.h    |   3 +
 arch/powerpc/include/asm/feature-fixups.h     |   3 +
 arch/powerpc/include/asm/kup.h                |   8 +-
 arch/powerpc/include/asm/mmu.h                |  24 +-
 arch/powerpc/include/asm/mmu_context.h        |   2 +-
 arch/powerpc/include/asm/nohash/32/kup-8xx.h  |   4 +-
 arch/powerpc/include/asm/processor.h          |   4 -
 arch/powerpc/include/asm/ptrace.h             |  12 +-
 arch/powerpc/include/asm/thread_info.h        |   2 -
 arch/powerpc/kernel/asm-offsets.c             |   5 +
 arch/powerpc/kernel/entry_64.S                |   6 +-
 arch/powerpc/kernel/exceptions-64s.S          |   4 +-
 arch/powerpc/kernel/process.c                 |  47 +-
 arch/powerpc/kernel/ptrace/ptrace-view.c      |   7 +-
 arch/powerpc/kernel/syscall_64.c              |  38 +-
 arch/powerpc/kernel/traps.c                   |   6 -
 arch/powerpc/kvm/book3s_emulate.c             |   6 +
 arch/powerpc/mm/book3s64/Makefile             |   2 +-
 arch/powerpc/mm/book3s64/hash_4k.c            |   2 +-
 arch/powerpc/mm/book3s64/hash_64k.c           |   4 +-
 arch/powerpc/mm/book3s64/hash_hugepage.c      |   2 +-
 arch/powerpc/mm/book3s64/hash_hugetlbpage.c   |   2 +-
 arch/powerpc/mm/book3s64/hash_pgtable.c       |   2 +-
 arch/powerpc/mm/book3s64/hash_utils.c         |  10 +-
 arch/powerpc/mm/book3s64/pkeys.c              | 177 ++++---
 arch/powerpc/mm/book3s64/radix_pgtable.c      |  45 +-
 arch/powerpc/mm/fault.c                       |   2 +-
 arch/powerpc/platforms/Kconfig.cputype        |   5 +
 35 files changed, 709 insertions(+), 389 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/book3s/64/kup-radix.h
 create mode 100644 arch/powerpc/include/asm/book3s/64/kup.h

-- 
2.28.0