linux.git/Documentation/arm64, branch v5.14 Linux kernel source tree userfaultfd: do not untag user pointers 2021-07-24T00:43:28+00:00 Peter Collingbourne pcc@google.com 2021-07-23T22:50:01+00:00 e71e2ace5721a8b921dca18b045069e7bb411277 Patch series "userfaultfd: do not untag user pointers", v5. If a user program uses userfaultfd on ranges of heap memory, it may end up passing a tagged pointer to the kernel in the range.start field of the UFFDIO_REGISTER ioctl. This can happen when using an MTE-capable allocator, or on Android if using the Tagged Pointers feature for MTE readiness [1]. When a fault subsequently occurs, the tag is stripped from the fault address returned to the application in the fault.address field of struct uffd_msg. However, from the application's perspective, the tagged address *is* the memory address, so if the application is unaware of memory tags, it may get confused by receiving an address that is, from its point of view, outside of the bounds of the allocation. We observed this behavior in the kselftest for userfaultfd [2] but other applications could have the same problem. Address this by not untagging pointers passed to the userfaultfd ioctls. Instead, let the system call fail. Also change the kselftest to use mmap so that it doesn't encounter this problem. [1] https://source.android.com/devices/tech/debug/tagged-pointers [2] tools/testing/selftests/vm/userfaultfd.c This patch (of 2): Do not untag pointers passed to the userfaultfd ioctls. Instead, let the system call fail. This will provide an early indication of problems with tag-unaware userspace code instead of letting the code get confused later, and is consistent with how we decided to handle brk/mmap/mremap in commit dcde237319e6 ("mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()"), as well as being consistent with the existing tagged address ABI documentation relating to how ioctl arguments are handled. The code change is a revert of commit 7d0325749a6c ("userfaultfd: untag user pointers") plus some fixups to some additional calls to validate_range that have appeared since then. [1] https://source.android.com/devices/tech/debug/tagged-pointers [2] tools/testing/selftests/vm/userfaultfd.c Link: https://lkml.kernel.org/r/20210714195437.118982-1-pcc@google.com Link: https://lkml.kernel.org/r/20210714195437.118982-2-pcc@google.com Link: https://linux-review.googlesource.com/id/I761aa9f0344454c482b83fcfcce547db0a25501b Fixes: 63f0c6037965 ("arm64: Introduce prctl() options to control the tagged user addresses ABI") Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Alistair Delva <adelva@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dave Martin <Dave.Martin@arm.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Mitch Phillips <mitchp@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Cc: William McVicker <willmcvicker@google.com> Cc: <stable@vger.kernel.org> [5.4] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Patch series "userfaultfd: do not untag user pointers", v5.

If a user program uses userfaultfd on ranges of heap memory, it may end
up passing a tagged pointer to the kernel in the range.start field of
the UFFDIO_REGISTER ioctl.  This can happen when using an MTE-capable
allocator, or on Android if using the Tagged Pointers feature for MTE
readiness [1].

When a fault subsequently occurs, the tag is stripped from the fault
address returned to the application in the fault.address field of struct
uffd_msg.  However, from the application's perspective, the tagged
address *is* the memory address, so if the application is unaware of
memory tags, it may get confused by receiving an address that is, from
its point of view, outside of the bounds of the allocation.  We observed
this behavior in the kselftest for userfaultfd [2] but other
applications could have the same problem.

Address this by not untagging pointers passed to the userfaultfd ioctls.
Instead, let the system call fail.  Also change the kselftest to use
mmap so that it doesn't encounter this problem.

[1] https://source.android.com/devices/tech/debug/tagged-pointers
[2] tools/testing/selftests/vm/userfaultfd.c

This patch (of 2):

Do not untag pointers passed to the userfaultfd ioctls.  Instead, let
the system call fail.  This will provide an early indication of problems
with tag-unaware userspace code instead of letting the code get confused
later, and is consistent with how we decided to handle brk/mmap/mremap
in commit dcde237319e6 ("mm: Avoid creating virtual address aliases in
brk()/mmap()/mremap()"), as well as being consistent with the existing
tagged address ABI documentation relating to how ioctl arguments are
handled.

The code change is a revert of commit 7d0325749a6c ("userfaultfd: untag
user pointers") plus some fixups to some additional calls to
validate_range that have appeared since then.

[1] https://source.android.com/devices/tech/debug/tagged-pointers
[2] tools/testing/selftests/vm/userfaultfd.c

Link: https://lkml.kernel.org/r/20210714195437.118982-1-pcc@google.com
Link: https://lkml.kernel.org/r/20210714195437.118982-2-pcc@google.com
Link: https://linux-review.googlesource.com/id/I761aa9f0344454c482b83fcfcce547db0a25501b
Fixes: 63f0c6037965 ("arm64: Introduce prctl() options to control the tagged user addresses ABI")
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alistair Delva <adelva@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mitch Phillips <mitchp@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: William McVicker <willmcvicker@google.com>
Cc: <stable@vger.kernel.org>	[5.4]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arm64: Document requirement for access to FEAT_HCX 2021-05-25T18:05:28+00:00 Mark Brown broonie@kernel.org 2021-05-12T16:23:50+00:00 ca940790d2ddc91e976f1e9e685052a54a1c50cf v8.7 of the architecture introduced FEAT_HCX which adds an additional hypervisor configuration register HCRX_EL2. Even though Linux does not currently make use of this feature let's document that the EL3 trap for access to the register should be disabled so that we are able to make use of it in future. Signed-off-by: Mark Brown <broonie@kernel.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Link: https://lore.kernel.org/r/20210512162350.20349-1-broonie@kernel.org Signed-off-by: Will Deacon <will@kernel.org> 
v8.7 of the architecture introduced FEAT_HCX which adds an additional
hypervisor configuration register HCRX_EL2. Even though Linux does not
currently make use of this feature let's document that the EL3 trap for
access to the register should be disabled so that we are able to make
use of it in future.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210512162350.20349-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 2021-05-07T19:11:05+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-05-07T19:11:05+00:00 51595e3b4943b0079638b2657f603cf5c8ea3a66 Pull more arm64 updates from Catalin Marinas: "A mix of fixes and clean-ups that turned up too late for the first pull request: - Restore terminal stack frame records. Their previous removal caused traces which cross secondary_start_kernel to terminate one entry too late, with a spurious "0" entry. - Fix boot warning with pseudo-NMI due to the way we manipulate the PMR register. - ACPI fixes: avoid corruption of interrupt mappings on watchdog probe failure (GTDT), prevent unregistering of GIC SGIs. - Force SPARSEMEM_VMEMMAP as the only memory model, it saves with having to test all the other combinations. - Documentation fixes and updates: tagged address ABI exceptions on brk/mmap/mremap(), event stream frequency, update booting requirements on the configuration of traps" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: kernel: Update the stale comment arm64: Fix the documented event stream frequency arm64: entry: always set GIC_PRIO_PSR_I_SET during entry arm64: Explicitly document boot requirements for SVE arm64: Explicitly require that FPSIMD instructions do not trap arm64: Relax booting requirements for configuration of traps arm64: cpufeatures: use min and max arm64: stacktrace: restore terminal records arm64/vdso: Discard .note.gnu.property sections in vDSO arm64: doc: Add brk/mmap/mremap() to the Tagged Address ABI Exceptions psci: Remove unneeded semicolon ACPI: irq: Prevent unregistering of GIC SGIs ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure arm64: Show three registers per line arm64: remove HAVE_DEBUG_BUGVERBOSE arm64: alternative: simplify passing alt_region arm64: Force SPARSEMEM_VMEMMAP as the only memory management model arm64: vdso32: drop -no-integrated-as flag 
Pull more arm64 updates from Catalin Marinas:
 "A mix of fixes and clean-ups that turned up too late for the first
  pull request:

   - Restore terminal stack frame records. Their previous removal caused
     traces which cross secondary_start_kernel to terminate one entry
     too late, with a spurious "0" entry.

   - Fix boot warning with pseudo-NMI due to the way we manipulate the
     PMR register.

   - ACPI fixes: avoid corruption of interrupt mappings on watchdog
     probe failure (GTDT), prevent unregistering of GIC SGIs.

   - Force SPARSEMEM_VMEMMAP as the only memory model, it saves with
     having to test all the other combinations.

   - Documentation fixes and updates: tagged address ABI exceptions on
     brk/mmap/mremap(), event stream frequency, update booting
     requirements on the configuration of traps"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: kernel: Update the stale comment
  arm64: Fix the documented event stream frequency
  arm64: entry: always set GIC_PRIO_PSR_I_SET during entry
  arm64: Explicitly document boot requirements for SVE
  arm64: Explicitly require that FPSIMD instructions do not trap
  arm64: Relax booting requirements for configuration of traps
  arm64: cpufeatures: use min and max
  arm64: stacktrace: restore terminal records
  arm64/vdso: Discard .note.gnu.property sections in vDSO
  arm64: doc: Add brk/mmap/mremap() to the Tagged Address ABI Exceptions
  psci: Remove unneeded semicolon
  ACPI: irq: Prevent unregistering of GIC SGIs
  ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure
  arm64: Show three registers per line
  arm64: remove HAVE_DEBUG_BUGVERBOSE
  arm64: alternative: simplify passing alt_region
  arm64: Force SPARSEMEM_VMEMMAP as the only memory management model
  arm64: vdso32: drop -no-integrated-as flag
arm64: Fix the documented event stream frequency 2021-05-05T17:34:28+00:00 Catalin Marinas catalin.marinas@arm.com 2021-05-05T13:28:45+00:00 5d8505fd039c1e757ad3490e46fe0fe73d78e2e0 It should be 10KHz, matching the ARCH_TIMER_EVT_STREAM_PERIOD_US of 100us. Note that this is only a documentation bug. Fixes: 611a7bc74ed2 ("arm64: docs: describe ELF hwcaps") Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210505132845.23698-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
It should be 10KHz, matching the ARCH_TIMER_EVT_STREAM_PERIOD_US of
100us.

Note that this is only a documentation bug.

Fixes: 611a7bc74ed2 ("arm64: docs: describe ELF hwcaps")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210505132845.23698-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arm64: Explicitly document boot requirements for SVE 2021-04-30T17:53:43+00:00 Mark Brown broonie@kernel.org 2021-04-12T15:19:55+00:00 ff1c42cdfbcfba4cc75f3e21ed819ded2dad5f3e We do not currently document the requirements for configuration of the SVE system registers when booting the kernel, let's do so for completeness. We don't have a hard requirement that the vector lengths configured on different CPUs on initial boot be consistent since we have logic to constrain to the minimum supported value but we will reject any late CPUs which can't support the current maximum and introducing the concept of late CPUs seemed more complex than was useful so we require that all CPUs use the same value. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20210412151955.16078-4-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
We do not currently document the requirements for configuration of the
SVE system registers when booting the kernel, let's do so for completeness.

We don't have a hard requirement that the vector lengths configured on
different CPUs on initial boot be consistent since we have logic to
constrain to the minimum supported value but we will reject any late CPUs
which can't support the current maximum and introducing the concept of
late CPUs seemed more complex than was useful so we require that all CPUs
use the same value.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210412151955.16078-4-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arm64: Explicitly require that FPSIMD instructions do not trap 2021-04-30T17:53:43+00:00 Mark Brown broonie@kernel.org 2021-04-12T15:19:54+00:00 b30dbf4d936224f83a98bea2328ff09e644a25b2 We do not explicitly require that systems with FPSIMD support and EL3 have disabled EL3 traps when the kernel is started, while it is unlikely that systems will get this wrong for the sake of completeness let's spell it out. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20210412151955.16078-3-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
We do not explicitly require that systems with FPSIMD support and EL3 have
disabled EL3 traps when the kernel is started, while it is unlikely that
systems will get this wrong for the sake of completeness let's spell it
out.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210412151955.16078-3-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arm64: Relax booting requirements for configuration of traps 2021-04-30T17:53:42+00:00 Mark Brown broonie@kernel.org 2021-04-12T15:19:53+00:00 ee61f36d3e46bdb1c8910d1bd5c0863130c7b951 Currently we require that a number of system registers be configured to disable traps when starting the kernel. Add an explicit note that the requirement is that the system behave as if the traps are disabled so transparent handling of the traps is fine, this should be implicit for people familiar with working with standards documents but it doesn't hurt to be explicit. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20210412151955.16078-2-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
Currently we require that a number of system registers be configured to
disable traps when starting the kernel. Add an explicit note that the
requirement is that the system behave as if the traps are disabled so
transparent handling of the traps is fine, this should be implicit for
people familiar with working with standards documents but it doesn't hurt
to be explicit.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210412151955.16078-2-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arm64: doc: Add brk/mmap/mremap() to the Tagged Address ABI Exceptions 2021-04-29T09:23:45+00:00 Catalin Marinas catalin.marinas@arm.com 2021-04-23T17:51:34+00:00 75516c75a72b5629736c611cf45058d95978a9f2 Prior to commit dcde237319e6 ("mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()"), the kernel allowed tagged addresses to be passed to the brk/mmap/mremap() syscalls. This relaxation was tightened in 5.6 (backported to stable 5.4) but the tagged-address-abi.rst document was only partially updated. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Fixes: dcde237319e6 ("mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()") Reported-by: Peter Maydell <peter.maydell@linaro.org> Cc: Will Deacon <will@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Link: https://lore.kernel.org/r/20210423175134.14838-1-catalin.marinas@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
Prior to commit dcde237319e6 ("mm: Avoid creating virtual address
aliases in brk()/mmap()/mremap()"), the kernel allowed tagged addresses
to be passed to the brk/mmap/mremap() syscalls. This relaxation was
tightened in 5.6 (backported to stable 5.4) but the
tagged-address-abi.rst document was only partially updated.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fixes: dcde237319e6 ("mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()")
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Cc: Will Deacon <will@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20210423175134.14838-1-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 2021-04-26T17:25:03+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-04-26T17:25:03+00:00 31a24ae89c92d5533c049046a76c6a2d649efb72 Pull arm64 updates from Catalin Marinas: - MTE asynchronous support for KASan. Previously only synchronous (slower) mode was supported. Asynchronous is faster but does not allow precise identification of the illegal access. - Run kernel mode SIMD with softirqs disabled. This allows using NEON in softirq context for crypto performance improvements. The conditional yield support is modified to take softirqs into account and reduce the latency. - Preparatory patches for Apple M1: handle CPUs that only have the VHE mode available (host kernel running at EL2), add FIQ support. - arm64 perf updates: support for HiSilicon PA and SLLC PMU drivers, new functions for the HiSilicon HHA and L3C PMU, cleanups. - Re-introduce support for execute-only user permissions but only when the EPAN (Enhanced Privileged Access Never) architecture feature is available. - Disable fine-grained traps at boot and improve the documented boot requirements. - Support CONFIG_KASAN_VMALLOC on arm64 (only with KASAN_GENERIC). - Add hierarchical eXecute Never permissions for all page tables. - Add arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) allowing user programs to control which PAC keys are enabled in a particular task. - arm64 kselftests for BTI and some improvements to the MTE tests. - Minor improvements to the compat vdso and sigpage. - Miscellaneous cleanups. * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (86 commits) arm64/sve: Add compile time checks for SVE hooks in generic functions arm64/kernel/probes: Use BUG_ON instead of if condition followed by BUG. arm64: pac: Optimize kernel entry/exit key installation code paths arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere arm64/sve: Remove redundant system_supports_sve() tests arm64: fpsimd: run kernel mode NEON with softirqs disabled arm64: assembler: introduce wxN aliases for wN registers arm64: assembler: remove conditional NEON yield macros kasan, arm64: tests supports for HW_TAGS async mode arm64: mte: Report async tag faults before suspend arm64: mte: Enable async tag check fault arm64: mte: Conditionally compile mte_enable_kernel_*() arm64: mte: Enable TCO in functions that can read beyond buffer limits kasan: Add report for async mode arm64: mte: Drop arch_enable_tagging() kasan: Add KASAN mode kernel parameter arm64: mte: Add asynchronous mode support arm64: Get rid of CONFIG_ARM64_VHE arm64: Cope with CPUs stuck in VHE mode ... 
Pull arm64 updates from Catalin Marinas:

 - MTE asynchronous support for KASan. Previously only synchronous
   (slower) mode was supported. Asynchronous is faster but does not
   allow precise identification of the illegal access.

 - Run kernel mode SIMD with softirqs disabled. This allows using NEON
   in softirq context for crypto performance improvements. The
   conditional yield support is modified to take softirqs into account
   and reduce the latency.

 - Preparatory patches for Apple M1: handle CPUs that only have the VHE
   mode available (host kernel running at EL2), add FIQ support.

 - arm64 perf updates: support for HiSilicon PA and SLLC PMU drivers,
   new functions for the HiSilicon HHA and L3C PMU, cleanups.

 - Re-introduce support for execute-only user permissions but only when
   the EPAN (Enhanced Privileged Access Never) architecture feature is
   available.

 - Disable fine-grained traps at boot and improve the documented boot
   requirements.

 - Support CONFIG_KASAN_VMALLOC on arm64 (only with KASAN_GENERIC).

 - Add hierarchical eXecute Never permissions for all page tables.

 - Add arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) allowing user programs
   to control which PAC keys are enabled in a particular task.

 - arm64 kselftests for BTI and some improvements to the MTE tests.

 - Minor improvements to the compat vdso and sigpage.

 - Miscellaneous cleanups.

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (86 commits)
  arm64/sve: Add compile time checks for SVE hooks in generic functions
  arm64/kernel/probes: Use BUG_ON instead of if condition followed by BUG.
  arm64: pac: Optimize kernel entry/exit key installation code paths
  arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)
  arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere
  arm64/sve: Remove redundant system_supports_sve() tests
  arm64: fpsimd: run kernel mode NEON with softirqs disabled
  arm64: assembler: introduce wxN aliases for wN registers
  arm64: assembler: remove conditional NEON yield macros
  kasan, arm64: tests supports for HW_TAGS async mode
  arm64: mte: Report async tag faults before suspend
  arm64: mte: Enable async tag check fault
  arm64: mte: Conditionally compile mte_enable_kernel_*()
  arm64: mte: Enable TCO in functions that can read beyond buffer limits
  kasan: Add report for async mode
  arm64: mte: Drop arch_enable_tagging()
  kasan: Add KASAN mode kernel parameter
  arm64: mte: Add asynchronous mode support
  arm64: Get rid of CONFIG_ARM64_VHE
  arm64: Cope with CPUs stuck in VHE mode
  ...
Merge branch 'for-next/pac-set-get-enabled-keys' into for-next/core 2021-04-15T13:00:48+00:00 Catalin Marinas catalin.marinas@arm.com 2021-04-15T13:00:48+00:00 a27a8816568964fcef62a3ae5f9d2228ec1ebc68 * for-next/pac-set-get-enabled-keys: : Introduce arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS). arm64: pac: Optimize kernel entry/exit key installation code paths arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere 
* for-next/pac-set-get-enabled-keys:
  : Introduce arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS).
  arm64: pac: Optimize kernel entry/exit key installation code paths
  arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)
  arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere