linux.git/arch/arm64/kernel, branch v5.15

Merge tag 'acpi-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2021-09-24T18:17:32+00:00

Pull ACPI fix from Rafael Wysocki:
 "Revert a recent commit related to memory management that turned out to
  be problematic (Jia He)"

* tag 'acpi-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "ACPI: Add memory semantics to acpi_os_map_memory()"

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2021-09-24T18:12:17+00:00

Pull arm64 fixes from Catalin Marinas:

 - It turns out that the optimised string routines merged in 5.14 are
   not safe with in-kernel MTE (KASAN_HW_TAGS) because of reading beyond
   the end of a string (strcmp, strncmp). Such reading may go across a
   16 byte tag granule and cause a tag check fault. When KASAN_HW_TAGS
   is enabled, use the generic strcmp/strncmp C implementation.

 - An errata workaround for ThunderX relied on the CPU capabilities
   being enabled in a specific order. This disappeared with the
   automatic generation of the cpucaps.h file (sorted alphabetically).
   Fix it by checking the current CPU only rather than the system-wide
   capability.

 - Add system_supports_mte() checks on the kernel entry/exit path and
   thread switching to avoid unnecessary barriers and function calls on
   systems where MTE is not supported.

 - kselftests: skip arm64 tests if the required features are missing.

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Restore forced disabling of KPTI on ThunderX
  kselftest/arm64: signal: Skip tests if required features are missing
  arm64: Mitigate MTE issues with str{n}cmp()
  arm64: add MTE supported check to thread switching and syscall entry/exit

Revert "ACPI: Add memory semantics to acpi_os_map_memory()"

2021-09-23T18:39:36+00:00

This reverts commit 437b38c51162f8b87beb28a833c4d5dc85fa864e.

The memory semantics added in commit 437b38c51162 causes SystemMemory
Operation region, whose address range is not described in the EFI memory
map to be mapped as NormalNC memory on arm64 platforms (through
acpi_os_map_memory() in acpi_ex_system_memory_space_handler()).

This triggers the following abort on an ARM64 Ampere eMAG machine,
because presumably the physical address range area backing the Opregion
does not support NormalNC memory attributes driven on the bus.

 Internal error: synchronous external abort: 96000410 [#1] SMP
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.14.0+ #462
 Hardware name: MiTAC RAPTOR EV-883832-X3-0001/RAPTOR, BIOS 0.14 02/22/2019
 pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[...snip...]
 Call trace:
  acpi_ex_system_memory_space_handler+0x26c/0x2c8
  acpi_ev_address_space_dispatch+0x228/0x2c4
  acpi_ex_access_region+0x114/0x268
  acpi_ex_field_datum_io+0x128/0x1b8
  acpi_ex_extract_from_field+0x14c/0x2ac
  acpi_ex_read_data_from_field+0x190/0x1b8
  acpi_ex_resolve_node_to_value+0x1ec/0x288
  acpi_ex_resolve_to_value+0x250/0x274
  acpi_ds_evaluate_name_path+0xac/0x124
  acpi_ds_exec_end_op+0x90/0x410
  acpi_ps_parse_loop+0x4ac/0x5d8
  acpi_ps_parse_aml+0xe0/0x2c8
  acpi_ps_execute_method+0x19c/0x1ac
  acpi_ns_evaluate+0x1f8/0x26c
  acpi_ns_init_one_device+0x104/0x140
  acpi_ns_walk_namespace+0x158/0x1d0
  acpi_ns_initialize_devices+0x194/0x218
  acpi_initialize_objects+0x48/0x50
  acpi_init+0xe0/0x498

If the Opregion address range is not present in the EFI memory map there
is no way for us to determine the memory attributes to use to map it -
defaulting to NormalNC does not work (and it is not correct on a memory
region that may have read side-effects) and therefore commit
437b38c51162 should be reverted, which means reverting back to the
original behavior whereby address ranges that are mapped using
acpi_os_map_memory() default to the safe devicenGnRnE attributes on
ARM64 if the mapped address range is not defined in the EFI memory map.

Fixes: 437b38c51162 ("ACPI: Add memory semantics to acpi_os_map_memory()")
Signed-off-by: Jia He 
Acked-by: Lorenzo Pieralisi 
Acked-by: Catalin Marinas 
Signed-off-by: Rafael J. Wysocki

arm64: Restore forced disabling of KPTI on ThunderX

2021-09-23T14:59:15+00:00

A noted side-effect of commit 0c6c2d3615ef ("arm64: Generate cpucaps.h")
is that cpucaps are now sorted, changing the enumeration order. This
assumed no dependencies between cpucaps, which turned out not to be true
in one case. UNMAP_KERNEL_AT_EL0 currently needs to be processed after
WORKAROUND_CAVIUM_27456. ThunderX systems are incompatible with KPTI, so
unmap_kernel_at_el0() bails if WORKAROUND_CAVIUM_27456 is set. But because
of the sorting, WORKAROUND_CAVIUM_27456 will not yet have been considered
when unmap_kernel_at_el0() checks for it, so the kernel tries to
run w/ KPTI - and quickly falls over.

Because all ThunderX implementations have homogeneous CPUs, we can remove
this dependency by just checking the current CPU for the erratum.

Fixes: 0c6c2d3615ef ("arm64: Generate cpucaps.h")
Cc:  # 5.13.x
Signed-off-by: dann frazier 
Suggested-by: Suzuki K Poulose 
Reviewed-by: Suzuki K Poulose 
Reviewed-by: Mark Brown 
Acked-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20210923145002.3394558-1-dann.frazier@canonical.com
Signed-off-by: Catalin Marinas

entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume()

2021-09-22T14:24:01+00:00

Invoke rseq_handle_notify_resume() from tracehook_notify_resume() now
that the two function are always called back-to-back by architectures
that have rseq.  The rseq helper is stubbed out for architectures that
don't support rseq, i.e. this is a nop across the board.

Note, tracehook_notify_resume() is horribly named and arguably does not
belong in tracehook.h as literally every line of code in it has nothing
to do with tracing.  But, that's been true since commit a42c6ded827d
("move key_repace_session_keyring() into tracehook_notify_resume()")
first usurped tracehook_notify_resume() back in 2012.  Punt cleaning that
mess up to future patches.

No functional change intended.

Acked-by: Mathieu Desnoyers 
Signed-off-by: Sean Christopherson 
Message-Id: <20210901203030.1292304-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini

arm64: add MTE supported check to thread switching and syscall entry/exit

2021-09-21T11:17:30+00:00

This lets us avoid doing unnecessary work on hardware that does not
support MTE, and will allow us to freely use MTE instructions in the
code called by mte_thread_switch().

Since this would mean that we do a redundant check in
mte_check_tfsr_el1(), remove it and add two checks now required in its
callers. This also avoids an unnecessary DSB+ISB sequence on the syscall
exit path for hardware not supporting MTE.

Fixes: 65812c6921cc ("arm64: mte: Enable async tag check fault")
Cc:  # 5.13.x
Signed-off-by: Peter Collingbourne 
Link: https://linux-review.googlesource.com/id/I02fd000d1ef2c86c7d2952a7f099b254ec227a5d
Link: https://lore.kernel.org/r/20210915190336.398390-1-pcc@google.com
[catalin.marinas@arm.com: adjust the commit log slightly]
Signed-off-by: Catalin Marinas

arm64: Mark __stack_chk_guard as __ro_after_init

2021-09-16T16:59:17+00:00

__stack_chk_guard is setup once while init stage and never changed
after that.

Although the modification of this variable at runtime will usually
cause the kernel to crash (so does the attacker), it should be marked
as __ro_after_init, and it should not affect performance if it is
placed in the ro_after_init section.

Signed-off-by: Dan Li 
Acked-by: Mark Rutland 
Link: https://lore.kernel.org/r/1631612642-102881-1-git-send-email-ashimida@linux.alibaba.com
Signed-off-by: Catalin Marinas

arm64/kernel: remove duplicate include in process.c

2021-09-16T16:46:49+00:00

Remove all but the first include of linux/sched.h from process.c

Reported-by: Zeal Robot 
Signed-off-by: Lv Ruyi 
Acked-by: Mark Rutland 
Link: https://lore.kernel.org/r/20210902011126.29828-1-lv.ruyi@zte.com.cn
Signed-off-by: Catalin Marinas

arm64/sve: Use correct size when reinitialising SVE state

2021-09-16T16:34:46+00:00

When we need a buffer for SVE register state we call sve_alloc() to make
sure that one is there. In order to avoid repeated allocations and frees
we keep the buffer around unless we change vector length and just memset()
it to ensure a clean register state. The function that deals with this
takes the task to operate on as an argument, however in the case where we
do a memset() we initialise using the SVE state size for the current task
rather than the task passed as an argument.

This is only an issue in the case where we are setting the register state
for a task via ptrace and the task being configured has a different vector
length to the task tracing it. In the case where the buffer is larger in
the traced process we will leak old state from the traced process to
itself, in the case where the buffer is smaller in the traced process we
will overflow the buffer and corrupt memory.

Fixes: bc0ee4760364 ("arm64/sve: Core task context handling")
Cc:  # 4.15.x
Signed-off-by: Mark Brown 
Link: https://lore.kernel.org/r/20210909165356.10675-1-broonie@kernel.org
Signed-off-by: Catalin Marinas

Merge branch 'linus' into smp/urgent

2021-09-10T22:38:47+00:00

Ensure that all usage sites of get/put_online_cpus() except for the
struggler in drivers/thermal are gone. So the last user and the deprecated
inlines can be removed.