Subject: [RFC v4 00/17] powerpc: Memory Protection Keys

From: Ram Pai <[email-masked]>
Date: Tue, 27 Jun 2017 03:11:42 -0700

Memory protection keys enable applications to protect its
address space from inadvertent access or corruption from
itself.

The overall idea:

 A process allocates a   key  and associates it with
 a  address  range  within    its   address   space.
 The process  than  can  dynamically  set read/write 
 permissions on  the   key   without  involving  the 
 kernel. Any  code that  violates   the  permissions
 off the address space; as defined by its associated
 key, will receive a segmentation fault.

This patch series enables the feature on PPC64 HPTE
platform.

ISA3.0 section 5.7.13 describes the detailed specifications.

Testing:
	This patch series has passed all the protection key
	tests available in  the selftests directory.
	The tests are updated to work on both x86 and powerpc.

version v4:
	(1) patches no more depend on the pte bits to program
		the hpte -- comment by Balbir
	(2) documentation updates
	(3) fixed a bug in the selftest.
	(4) unlike x86, powerpc lets signal handler change key
	    permission bits; the change will persist across
	    signal handler boundaries. Earlier we allowed
	    the signal handler to modify a field in the siginfo
	    structure which would than be used by the kernel
	    to program the key protection register (AMR)
       		-- resolves a issue raised by Ben.
    		"Calls to sys_swapcontext with a made-up context
	        will end up with a crap AMR if done by code who
	       	didn't know about that register".
	(5) these changes enable protection keys on 4k-page 
		kernel aswell.

version v3:
	(1) split the patches into smaller consumable
		patches.
	(2) added the ability to disable execute permission
		on a key at creation.
	(3) rename  calc_pte_to_hpte_pkey_bits() to
	    pte_to_hpte_pkey_bits() -- suggested by Anshuman
	(4) some code optimization and clarity in
		do_page_fault()  
	(5) A bug fix while invalidating a hpte slot in 
		__hash_page_4K() -- noticed by Aneesh

version v2:
	(1) documentation and selftest added
 	(2) fixed a bug in 4k hpte backed 64k pte where page
	    invalidation was not done correctly, and 
	    initialization of second-part-of-the-pte was not
	    done correctly if the pte was not yet Hashed
	    with a hpte.  Reported by Aneesh.
	(3) Fixed ABI breakage caused in siginfo structure.
		Reported by Anshuman.

version v1: Initial version

Ram Pai (17):
  mm: introduce an additional vma bit for powerpc pkey
  mm: ability to disable execute permission on a key at creation
  x86: key creation with PKEY_DISABLE_EXECUTE disallowed
  powerpc: Implement sys_pkey_alloc and sys_pkey_free system call
  powerpc: store and restore the pkey state across context switches
  powerpc: Implementation for sys_mprotect_pkey() system call
  powerpc: make the hash functions protection-key aware
  powerpc: Program HPTE key protection bits
  powerpc: call the hash functions with the correct pkey value
  powerpc: Macro the mask used for checking DSI exception
  powerpc: Handle exceptions caused by pkey violation
  powerpc: Deliver SEGV signal on pkey violation
  selftest: Move protecton key selftest to arch neutral directory
  selftest: PowerPC specific test updates to memory protection keys
  Documentation: Move protecton key documentation to arch neutral
    directory
  Documentation: PowerPC specific updates to memory protection keys
  procfs: display the protection-key number associated with a vma

 Documentation/filesystems/proc.txt            |    3 +-
 Documentation/vm/protection-keys.txt          |  134 +++
 Documentation/x86/protection-keys.txt         |   85 --
 Makefile                                      |    2 +-
 arch/powerpc/Kconfig                          |   15 +
 arch/powerpc/include/asm/book3s/64/hash.h     |    2 +-
 arch/powerpc/include/asm/book3s/64/mmu-hash.h |   19 +-
 arch/powerpc/include/asm/book3s/64/mmu.h      |   10 +
 arch/powerpc/include/asm/book3s/64/pgtable.h  |   62 ++
 arch/powerpc/include/asm/mman.h               |    8 +-
 arch/powerpc/include/asm/mmu_context.h        |   12 +
 arch/powerpc/include/asm/paca.h               |    1 +
 arch/powerpc/include/asm/pkeys.h              |  159 +++
 arch/powerpc/include/asm/processor.h          |    5 +
 arch/powerpc/include/asm/reg.h                |    7 +-
 arch/powerpc/include/asm/systbl.h             |    3 +
 arch/powerpc/include/asm/unistd.h             |    6 +-
 arch/powerpc/include/uapi/asm/ptrace.h        |    3 +-
 arch/powerpc/include/uapi/asm/unistd.h        |    3 +
 arch/powerpc/kernel/asm-offsets.c             |    5 +
 arch/powerpc/kernel/exceptions-64s.S          |   18 +-
 arch/powerpc/kernel/process.c                 |   18 +
 arch/powerpc/kernel/signal_32.c               |    5 +
 arch/powerpc/kernel/signal_64.c               |    4 +
 arch/powerpc/kernel/traps.c                   |   49 +
 arch/powerpc/mm/Makefile                      |    1 +
 arch/powerpc/mm/fault.c                       |   22 +
 arch/powerpc/mm/hash64_4k.c                   |    4 +-
 arch/powerpc/mm/hash64_64k.c                  |    8 +-
 arch/powerpc/mm/hash_utils_64.c               |   42 +-
 arch/powerpc/mm/hugepage-hash64.c             |    4 +-
 arch/powerpc/mm/hugetlbpage-hash64.c          |    5 +-
 arch/powerpc/mm/mem.c                         |    7 +
 arch/powerpc/mm/mmu_context_book3s64.c        |    5 +
 arch/powerpc/mm/mmu_decl.h                    |    5 +-
 arch/powerpc/mm/pkeys.c                       |  256 +++++
 arch/x86/kernel/fpu/xstate.c                  |    3 +
 fs/proc/task_mmu.c                            |   18 +-
 include/linux/mm.h                            |   18 +-
 include/uapi/asm-generic/mman-common.h        |    4 +-
 tools/testing/selftests/vm/Makefile           |    1 +
 tools/testing/selftests/vm/pkey-helpers.h     |  365 ++++++
 tools/testing/selftests/vm/protection_keys.c  | 1488 +++++++++++++++++++++++++
 tools/testing/selftests/x86/Makefile          |    2 +-
 tools/testing/selftests/x86/pkey-helpers.h    |  219 ----
 tools/testing/selftests/x86/protection_keys.c | 1395 -----------------------
 46 files changed, 2755 insertions(+), 1755 deletions(-)
 create mode 100644 Documentation/vm/protection-keys.txt
 delete mode 100644 Documentation/x86/protection-keys.txt
 create mode 100644 arch/powerpc/include/asm/pkeys.h
 create mode 100644 arch/powerpc/mm/pkeys.c
 create mode 100644 tools/testing/selftests/vm/pkey-helpers.h
 create mode 100644 tools/testing/selftests/vm/protection_keys.c
 delete mode 100644 tools/testing/selftests/x86/pkey-helpers.h
 delete mode 100644 tools/testing/selftests/x86/protection_keys.c

-- 
1.8.3.1