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This change implements shadow stack switching, initial SCS set-up,
and interrupt shadow stacks for arm64.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will@kernel.org>
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As part of an effort to clarify and clean up the assembler annotations
new macros have been introduced which annotate the start and end of blocks
of code in assembler files. Currently ret_to_user has an out of line slow
path work_pending placed above the main function which makes annotating the
start and end of these blocks of code awkward.
Since work_pending is only referenced from within ret_to_user try to make
things a bit clearer by moving it after the current ret_to_user and then
marking both ret_to_user and work_pending as part of a single ret_to_user
code block.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20200501115430.37315-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
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The 'sync' argument to ptrauth_keys_install_kernel macro is somewhat
opaque at callsites, so instead lets have regular and _nosync variants
of the macro to make this a little more obvious.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200423101606.37601-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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* for-next/kernel-ptrauth:
: Return address signing - in-kernel support
arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH
lkdtm: arm64: test kernel pointer authentication
arm64: compile the kernel with ptrauth return address signing
kconfig: Add support for 'as-option'
arm64: suspend: restore the kernel ptrauth keys
arm64: __show_regs: strip PAC from lr in printk
arm64: unwind: strip PAC from kernel addresses
arm64: mask PAC bits of __builtin_return_address
arm64: initialize ptrauth keys for kernel booting task
arm64: initialize and switch ptrauth kernel keys
arm64: enable ptrauth earlier
arm64: cpufeature: handle conflicts based on capability
arm64: cpufeature: Move cpu capability helpers inside C file
arm64: ptrauth: Add bootup/runtime flags for __cpu_setup
arm64: install user ptrauth keys at kernel exit time
arm64: rename ptrauth key structures to be user-specific
arm64: cpufeature: add pointer auth meta-capabilities
arm64: cpufeature: Fix meta-capability cpufeature check
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This patch restores the kernel keys from current task during cpu resume
after the mmu is turned on and ptrauth is enabled.
A flag is added in macro ptrauth_keys_install_kernel to check if isb
instruction needs to be executed.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Set up keys to use pointer authentication within the kernel. The kernel
will be compiled with APIAKey instructions, the other keys are currently
unused. Each task is given its own APIAKey, which is initialized during
fork. The key is changed during context switch and on kernel entry from
EL0.
The keys for idle threads need to be set before calling any C functions,
because it is not possible to enter and exit a function with different
keys.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[Amit: Modified secondary cores key structure, comments]
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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As we're going to enable pointer auth within the kernel and use a
different APIAKey for the kernel itself, so move the user APIAKey
switch to EL0 exception return.
The other 4 keys could remain switched during task switch, but are also
moved to keep things consistent.
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
[Amit: commit msg, re-positioned the patch, comments]
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In an effort to clarify and simplify the annotation of assembly
functions new macros have been introduced. These replace ENTRY and
ENDPROC with two different annotations for normal functions and those
with unusual calling conventions.
The SDEI entry points are currently annotated as normal functions but
are called from non-kernel contexts with non-standard calling convention
and should therefore be annotated as such so do so.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: James Morse <james.Morse@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In an effort to clarify and simplify the annotation of assembly functions
in the kernel new macros have been introduced. These include specific
annotations for the start and end of data, update symbols for data to use
these.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In an effort to clarify and simplify the annotation of assembly functions
in the kernel new macros have been introduced. These replace ENTRY and
ENDPROC with separate annotations for standard C callable functions,
data and code with different calling conventions. Update the
remaining annotations in the entry.S code to the new macros.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In an effort to clarify and simplify the annotation of assembly
functions new macros have been introduced. These replace ENTRY and
ENDPROC with two different annotations for normal functions and those
with unusual calling conventions.
ret_from_fork is not a normal C function and should therefore be
annotated as code.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In an effort to clarify and simplify the annotation of assembly
functions new macros have been introduced. These replace ENTRY and
ENDPROC with two different annotations for normal functions and those
with unusual calling conventions. The vector table and handlers aren't
normal C style code so should be annotated as CODE.
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"These were the main changes in this cycle:
- More -rt motivated separation of CONFIG_PREEMPT and
CONFIG_PREEMPTION.
- Add more low level scheduling topology sanity checks and warnings
to filter out nonsensical topologies that break scheduling.
- Extend uclamp constraints to influence wakeup CPU placement
- Make the RT scheduler more aware of asymmetric topologies and CPU
capacities, via uclamp metrics, if CONFIG_UCLAMP_TASK=y
- Make idle CPU selection more consistent
- Various fixes, smaller cleanups, updates and enhancements - please
see the git log for details"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (58 commits)
sched/fair: Define sched_idle_cpu() only for SMP configurations
sched/topology: Assert non-NUMA topology masks don't (partially) overlap
idle: fix spelling mistake "iterrupts" -> "interrupts"
sched/fair: Remove redundant call to cpufreq_update_util()
sched/psi: create /proc/pressure and /proc/pressure/{io|memory|cpu} only when psi enabled
sched/fair: Fix sgc->{min,max}_capacity calculation for SD_OVERLAP
sched/fair: calculate delta runnable load only when it's needed
sched/cputime: move rq parameter in irqtime_account_process_tick
stop_machine: Make stop_cpus() static
sched/debug: Reset watchdog on all CPUs while processing sysrq-t
sched/core: Fix size of rq::uclamp initialization
sched/uclamp: Fix a bug in propagating uclamp value in new cgroups
sched/fair: Load balance aggressively for SCHED_IDLE CPUs
sched/fair : Improve update_sd_pick_busiest for spare capacity case
watchdog: Remove soft_lockup_hrtimer_cnt and related code
sched/rt: Make RT capacity-aware
sched/fair: Make EAS wakeup placement consider uclamp restrictions
sched/fair: Make task_fits_capacity() consider uclamp restrictions
sched/uclamp: Rename uclamp_util_with() into uclamp_rq_util_with()
sched/uclamp: Make uclamp util helpers use and return UL values
...
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* for-next/asm-annotations: (6 commits)
arm64: kernel: Correct annotation of end of el0_sync
...
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'for-next/e0pd', 'for-next/entry', 'for-next/kbuild', 'for-next/kexec/cleanup', 'for-next/kexec/file-kdump', 'for-next/misc', 'for-next/nofpsimd', 'for-next/perf' and 'for-next/scs' into for-next/core
* for-next/acpi:
ACPI/IORT: Fix 'Number of IDs' handling in iort_id_map()
* for-next/cpufeatures: (2 commits)
arm64: Introduce ID_ISAR6 CPU register
...
* for-next/csum: (2 commits)
arm64: csum: Fix pathological zero-length calls
...
* for-next/e0pd: (7 commits)
arm64: kconfig: Fix alignment of E0PD help text
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* for-next/entry: (5 commits)
arm64: entry: cleanup sp_el0 manipulation
...
* for-next/kbuild: (4 commits)
arm64: kbuild: remove compressed images on 'make ARCH=arm64 (dist)clean'
...
* for-next/kexec/cleanup: (11 commits)
Revert "arm64: kexec: make dtb_mem always enabled"
...
* for-next/kexec/file-kdump: (2 commits)
arm64: kexec_file: add crash dump support
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* for-next/misc: (12 commits)
arm64: entry: Avoid empty alternatives entries
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* for-next/nofpsimd: (7 commits)
arm64: nofpsmid: Handle TIF_FOREIGN_FPSTATE flag cleanly
...
* for-next/perf: (2 commits)
perf/imx_ddr: Fix cpu hotplug state cleanup
...
* for-next/scs: (6 commits)
arm64: kernel: avoid x18 in __cpu_soft_restart
...
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kernel_ventry will create alternative entries to potentially replace
0 instructions with 0 instructions for EL1 vectors. While this does not
cause an issue, it pointlessly takes up some bytes in the alternatives
section.
Do not generate such entries.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>
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The kernel stashes the current task struct in sp_el0 so that this can be
acquired consistently/cheaply when required. When we take an exception
from EL0 we have to:
1) stash the original sp_el0 value
2) find the current task
3) update sp_el0 with the current task pointer
Currently steps #1 and #2 occur in one place, and step #3 a while later.
As the value of sp_el0 is immaterial between these points, let's move
them together to make the code clearer and minimize ifdeffery. This
necessitates moving the comment for MDSCR_EL1.SS.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
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Commit 582f95835a8fc812c ("arm64: entry: convert el0_sync to C") caused
the ENDPROC() annotating the end of el0_sync to be placed after the code
for el0_sync_compat. This replaced the previous annotation where it was
located after all the cases that are now converted to C, including after
the currently unannotated el0_irq_compat and el0_error_compat. Move the
annotation to the end of the function and add separate annotations for
the _compat ones.
Fixes: 582f95835a8fc812c (arm64: entry: convert el0_sync to C)
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.
Switch the Kconfig dependency, entry code and preemption handling over
to use CONFIG_PREEMPTION. Add PREEMPT_RT output in show_stack().
[bigeasy: +traps.c, Kconfig]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20191015191821.11479-3-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Stack overflow checking can be done by testing sp & (1 << THREAD_SHIFT)
only for the stacks are aligned to (2 << THREAD_SHIFT) with size of
(1 << THREAD_SIZE), and this is the case when CONFIG_VMAP_STACK is set.
Fix the code comment to avoid confusion.
Cc: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Heyi Guo <guoheyi@huawei.com>
[catalin.marinas@arm.com: Updated comment following Mark's suggestion]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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'for-next/zone-dma', 'for-next/relax-icc_pmr_el1-sync', 'for-next/double-page-fault', 'for-next/misc', 'for-next/kselftest-arm64-signal' and 'for-next/kaslr-diagnostics' into for-next/core
* for-next/elf-hwcap-docs:
: Update the arm64 ELF HWCAP documentation
docs/arm64: cpu-feature-registers: Rewrite bitfields that don't follow [e, s]
docs/arm64: cpu-feature-registers: Documents missing visible fields
docs/arm64: elf_hwcaps: Document HWCAP_SB
docs/arm64: elf_hwcaps: sort the HWCAP{, 2} documentation by ascending value
* for-next/smccc-conduit-cleanup:
: SMC calling convention conduit clean-up
firmware: arm_sdei: use common SMCCC_CONDUIT_*
firmware/psci: use common SMCCC_CONDUIT_*
arm: spectre-v2: use arm_smccc_1_1_get_conduit()
arm64: errata: use arm_smccc_1_1_get_conduit()
arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit()
* for-next/zone-dma:
: Reintroduction of ZONE_DMA for Raspberry Pi 4 support
arm64: mm: reserve CMA and crashkernel in ZONE_DMA32
dma/direct: turn ARCH_ZONE_DMA_BITS into a variable
arm64: Make arm64_dma32_phys_limit static
arm64: mm: Fix unused variable warning in zone_sizes_init
mm: refresh ZONE_DMA and ZONE_DMA32 comments in 'enum zone_type'
arm64: use both ZONE_DMA and ZONE_DMA32
arm64: rename variables used to calculate ZONE_DMA32's size
arm64: mm: use arm64_dma_phys_limit instead of calling max_zone_dma_phys()
* for-next/relax-icc_pmr_el1-sync:
: Relax ICC_PMR_EL1 (GICv3) accesses when ICC_CTLR_EL1.PMHE is clear
arm64: Document ICC_CTLR_EL3.PMHE setting requirements
arm64: Relax ICC_PMR_EL1 accesses when ICC_CTLR_EL1.PMHE is clear
* for-next/double-page-fault:
: Avoid a double page fault in __copy_from_user_inatomic() if hw does not support auto Access Flag
mm: fix double page fault on arm64 if PTE_AF is cleared
x86/mm: implement arch_faults_on_old_pte() stub on x86
arm64: mm: implement arch_faults_on_old_pte() on arm64
arm64: cpufeature: introduce helper cpu_has_hw_af()
* for-next/misc:
: Various fixes and clean-ups
arm64: kpti: Add NVIDIA's Carmel core to the KPTI whitelist
arm64: mm: Remove MAX_USER_VA_BITS definition
arm64: mm: simplify the page end calculation in __create_pgd_mapping()
arm64: print additional fault message when executing non-exec memory
arm64: psci: Reduce the waiting time for cpu_psci_cpu_kill()
arm64: pgtable: Correct typo in comment
arm64: docs: cpu-feature-registers: Document ID_AA64PFR1_EL1
arm64: cpufeature: Fix typos in comment
arm64/mm: Poison initmem while freeing with free_reserved_area()
arm64: use generic free_initrd_mem()
arm64: simplify syscall wrapper ifdeffery
* for-next/kselftest-arm64-signal:
: arm64-specific kselftest support with signal-related test-cases
kselftest: arm64: fake_sigreturn_misaligned_sp
kselftest: arm64: fake_sigreturn_bad_size
kselftest: arm64: fake_sigreturn_duplicated_fpsimd
kselftest: arm64: fake_sigreturn_missing_fpsimd
kselftest: arm64: fake_sigreturn_bad_size_for_magic0
kselftest: arm64: fake_sigreturn_bad_magic
kselftest: arm64: add helper get_current_context
kselftest: arm64: extend test_init functionalities
kselftest: arm64: mangle_pstate_invalid_mode_el[123][ht]
kselftest: arm64: mangle_pstate_invalid_daif_bits
kselftest: arm64: mangle_pstate_invalid_compat_toggle and common utils
kselftest: arm64: extend toplevel skeleton Makefile
* for-next/kaslr-diagnostics:
: Provide diagnostics on boot for KASLR
arm64: kaslr: Check command line before looking for a seed
arm64: kaslr: Announce KASLR status on boot
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Move the synchronous exception paths from entry.S into a C file to
improve the code readability.
* for-next/entry-s-to-c:
arm64: entry-common: don't touch daif before bp-hardening
arm64: Remove asmlinkage from updated functions
arm64: entry: convert el0_sync to C
arm64: entry: convert el1_sync to C
arm64: add local_daif_inherit()
arm64: Add prototypes for functions called by entry.S
arm64: remove __exception annotations
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This is largely a 1-1 conversion of asm to C, with a couple of caveats.
The el0_sync{_compat} switches explicitly handle all the EL0 debug
cases, so el0_dbg doesn't have to try to bail out for unexpected EL1
debug ESR values. This also means that an unexpected vector catch from
AArch32 is routed to el0_inv.
We *could* merge the native and compat switches, which would make the
diffstat negative, but I've tried to stay as close to the existing
assembly as possible for the moment.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[split out of a bigger series, added nokprobes. removed irq trace
calls as the C helpers do this. renamed el0_dbg's use of FAR]
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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This patch converts the EL1 sync entry assembly logic to C code.
Doing this will allow us to make changes in a slightly more
readable way. A case in point is supporting kernel-first RAS.
do_sea() should be called on the CPU that took the fault.
Largely the assembly code is converted to C in a relatively
straightforward manner.
Since all sync sites share a common asm entry point, the ASM_BUG()
instances are no longer required for effective backtraces back to
assembly, and we don't need similar BUG() entries.
The ESR_ELx.EC codes for all (supported) debug exceptions are now
checked in the el1_sync_handler's switch statement, which renders the
check in el1_dbg redundant. This both simplifies the el1_dbg handler,
and makes the EL1 exception handling more robust to
currently-unallocated ESR_ELx.EC encodings.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[split out of a bigger series, added nokprobes, moved prototypes]
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Workaround for Cavium/Marvell ThunderX2 erratum #219.
* errata/tx2-219:
arm64: Allow CAVIUM_TX2_ERRATUM_219 to be selected
arm64: Avoid Cavium TX2 erratum 219 when switching TTBR
arm64: Enable workaround for Cavium TX2 erratum 219 when running SMT
arm64: KVM: Trap VM ops when ARM64_WORKAROUND_CAVIUM_TX2_219_TVM is set
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Sign-extending TTBR1 addresses when converting to an untagged address
breaks the documented POSIX semantics for mlock() in some obscure error
cases where we end up returning -EINVAL instead of -ENOMEM as a direct
result of rewriting the upper address bits.
Rework the untagged_addr() macro to preserve the upper address bits for
TTBR1 addresses and only clear the tag bits for user addresses. This
matches the behaviour of the 'clear_address_tag' assembly macro, so
rename that and align the implementations at the same time so that they
use the same instruction sequences for the tag manipulation.
Link: https://lore.kernel.org/stable/20191014162651.GF19200@arrakis.emea.arm.com/
Reported-by: Jan Stancek <jstancek@redhat.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Preempting from IRQ-return means that the task has its PSTATE saved
on the stack, which will get restored when the task is resumed and does
the actual IRQ return.
However, enabling some CPU features requires modifying the PSTATE. This
means that, if a task was scheduled out during an IRQ-return before all
CPU features are enabled, the task might restore a PSTATE that does not
include the feature enablement changes once scheduled back in.
* Task 1:
PAN == 0 ---| |---------------
| |<- return from IRQ, PSTATE.PAN = 0
| <- IRQ |
+--------+ <- preempt() +--
^
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reschedule Task 1, PSTATE.PAN == 1
* Init:
--------------------+------------------------
^
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enable_cpu_features
set PSTATE.PAN on all CPUs
Worse than this, since PSTATE is untouched when task switching is done,
a task missing the new bits in PSTATE might affect another task, if both
do direct calls to schedule() (outside of IRQ/exception contexts).
Fix this by preventing preemption on IRQ-return until features are
enabled on all CPUs.
This way the only PSTATE values that are saved on the stack are from
synchronous exceptions. These are expected to be fatal this early, the
exception is BRK for WARN_ON(), but as this uses do_debug_exception()
which keeps IRQs masked, it shouldn't call schedule().
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
[james: Replaced a really cool hack, with an even simpler static key in C.
expanded commit message with Julien's cover-letter ascii art]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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The GICv3 architecture specification is incredibly misleading when it
comes to PMR and the requirement for a DSB. It turns out that this DSB
is only required if the CPU interface sends an Upstream Control
message to the redistributor in order to update the RD's view of PMR.
This message is only sent when ICC_CTLR_EL1.PMHE is set, which isn't
the case in Linux. It can still be set from EL3, so some special care
is required. But the upshot is that in the (hopefuly large) majority
of the cases, we can drop the DSB altogether.
This relies on a new static key being set if the boot CPU has PMHE
set. The drawback is that this static key has to be exported to
modules.
Cc: Will Deacon <will@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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As a PRFM instruction racing against a TTBR update can have undesirable
effects on TX2, NOP-out such PRFM on cores that are affected by
the TX2-219 erratum.
Cc: <stable@vger.kernel.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Commit bd82d4bd2188 ("arm64: Fix incorrect irqflag restore for priority
masking") added a macro to the entry.S call paths that leave the
PSTATE.I bit set. This tells the pPNMI masking logic that interrupts
are masked by the CPU, not by the PMR. This value is read back by
local_daif_save().
Commit bd82d4bd2188 added this call to el0_svc, as el0_svc_handler
is called with interrupts masked. el0_svc_compat was missed, but should
be covered in the same way as both of these paths end up in
el0_svc_common(), which expects to unmask interrupts.
Fixes: bd82d4bd2188 ("arm64: Fix incorrect irqflag restore for priority masking")
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Signed-off-by: Will Deacon <will@kernel.org>
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When taking an SError or Debug exception from EL0, we run the C
handler for these exceptions before updating the context tracking
code and unmasking lower priority interrupts.
When booting with nohz_full lockdep tells us we got this wrong:
| =============================
| WARNING: suspicious RCU usage
| 5.3.0-rc2-00010-gb4b5e9dcb11b-dirty #11271 Not tainted
| -----------------------------
| include/linux/rcupdate.h:643 rcu_read_unlock() used illegally wh!
|
| other info that might help us debug this:
|
|
| RCU used illegally from idle CPU!
| rcu_scheduler_active = 2, debug_locks = 1
| RCU used illegally from extended quiescent state!
| 1 lock held by a.out/432:
| #0: 00000000c7a79515 (rcu_read_lock){....}, at: brk_handler+0x00
|
| stack backtrace:
| CPU: 1 PID: 432 Comm: a.out Not tainted 5.3.0-rc2-00010-gb4b5e9d1
| Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno De8
| Call trace:
| dump_backtrace+0x0/0x140
| show_stack+0x14/0x20
| dump_stack+0xbc/0x104
| lockdep_rcu_suspicious+0xf8/0x108
| brk_handler+0x164/0x1b0
| do_debug_exception+0x11c/0x278
| el0_dbg+0x14/0x20
Moving the ct_user_exit calls to be before do_debug_exception() means
they are also before trace_hardirqs_off() has been updated. Add a new
ct_user_exit_irqoff macro to avoid the context-tracking code using
irqsave/restore before we've updated trace_hardirqs_off(). To be
consistent, do this everywhere.
The C helper is called enter_from_user_mode() to match x86 in the hope
we can merge them into kernel/context_tracking.c later.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 6c81fe7925cc4c42 ("arm64: enable context tracking")
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
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Comparing the arm-arm's pseudocode for AArch64.PCAlignmentFault() with
AArch64.SPAlignmentFault() shows that SP faults don't copy the faulty-SP
to FAR_EL1, but this is where we read from, and the address we provide
to user-space with the BUS_ADRALN signal.
For user-space this value will be UNKNOWN due to the previous ERET to
user-space. If the last value is preserved, on systems with KASLR or KPTI
this will be the user-space link-register left in FAR_EL1 by tramp_exit().
Fix this to retrieve the original sp_el0 value, and pass this to
do_sp_pc_fault().
SP alignment faults from EL1 will cause us to take the fault again when
trying to store the pt_regs. This eventually takes us to the overflow
stack. Remove the ESR_ELx_EC_SP_ALIGN check as we will never make it
this far.
Fixes: 60ffc30d5652 ("arm64: Exception handling")
Signed-off-by: James Morse <james.morse@arm.com>
[will: change label name and fleshed out comment]
Signed-off-by: Will Deacon <will@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- arm64 support for syscall emulation via PTRACE_SYSEMU{,_SINGLESTEP}
- Wire up VM_FLUSH_RESET_PERMS for arm64, allowing the core code to
manage the permissions of executable vmalloc regions more strictly
- Slight performance improvement by keeping softirqs enabled while
touching the FPSIMD/SVE state (kernel_neon_begin/end)
- Expose a couple of ARMv8.5 features to user (HWCAP): CondM (new
XAFLAG and AXFLAG instructions for floating point comparison flags
manipulation) and FRINT (rounding floating point numbers to integers)
- Re-instate ARM64_PSEUDO_NMI support which was previously marked as
BROKEN due to some bugs (now fixed)
- Improve parking of stopped CPUs and implement an arm64-specific
panic_smp_self_stop() to avoid warning on not being able to stop
secondary CPUs during panic
- perf: enable the ARM Statistical Profiling Extensions (SPE) on ACPI
platforms
- perf: DDR performance monitor support for iMX8QXP
- cache_line_size() can now be set from DT or ACPI/PPTT if provided to
cope with a system cache info not exposed via the CPUID registers
- Avoid warning on hardware cache line size greater than
ARCH_DMA_MINALIGN if the system is fully coherent
- arm64 do_page_fault() and hugetlb cleanups
- Refactor set_pte_at() to avoid redundant READ_ONCE(*ptep)
- Ignore ACPI 5.1 FADTs reported as 5.0 (infer from the
'arm_boot_flags' introduced in 5.1)
- CONFIG_RANDOMIZE_BASE now enabled in defconfig
- Allow the selection of ARM64_MODULE_PLTS, currently only done via
RANDOMIZE_BASE (and an erratum workaround), allowing modules to spill
over into the vmalloc area
- Make ZONE_DMA32 configurable
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (54 commits)
perf: arm_spe: Enable ACPI/Platform automatic module loading
arm_pmu: acpi: spe: Add initial MADT/SPE probing
ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens
ACPI/PPTT: Modify node flag detection to find last IDENTICAL
x86/entry: Simplify _TIF_SYSCALL_EMU handling
arm64: rename dump_instr as dump_kernel_instr
arm64/mm: Drop [PTE|PMD]_TYPE_FAULT
arm64: Implement panic_smp_self_stop()
arm64: Improve parking of stopped CPUs
arm64: Expose FRINT capabilities to userspace
arm64: Expose ARMv8.5 CondM capability to userspace
arm64: defconfig: enable CONFIG_RANDOMIZE_BASE
arm64: ARM64_MODULES_PLTS must depend on MODULES
arm64: bpf: do not allocate executable memory
arm64/kprobes: set VM_FLUSH_RESET_PERMS on kprobe instruction pages
arm64/mm: wire up CONFIG_ARCH_HAS_SET_DIRECT_MAP
arm64: module: create module allocations without exec permissions
arm64: Allow user selection of ARM64_MODULE_PLTS
acpi/arm64: ignore 5.1 FADTs that are reported as 5.0
arm64: Allow selecting Pseudo-NMI again
...
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When using IRQ priority masking to disable interrupts, in order to deal
with the PSR.I state, local_irq_save() would convert the I bit into a
PMR value (GIC_PRIO_IRQOFF). This resulted in local_irq_restore()
potentially modifying the value of PMR in undesired location due to the
state of PSR.I upon flag saving [1].
In an attempt to solve this issue in a less hackish manner, introduce
a bit (GIC_PRIO_IGNORE_PMR) for the PMR values that can represent
whether PSR.I is being used to disable interrupts, in which case it
takes precedence of the status of interrupt masking via PMR.
GIC_PRIO_PSR_I_SET is chosen such that (<pmr_value> |
GIC_PRIO_PSR_I_SET) does not mask more interrupts than <pmr_value> as
some sections (e.g. arch_cpu_idle(), interrupt acknowledge path)
requires PMR not to mask interrupts that could be signaled to the
CPU when using only PSR.I.
[1] https://www.spinics.net/lists/arm-kernel/msg716956.html
Fixes: 4a503217ce37 ("arm64: irqflags: Use ICC_PMR_EL1 for interrupt masking")
Cc: <stable@vger.kernel.org> # 5.1.x-
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Wei Li <liwei391@huawei.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Pouloze <suzuki.poulose@arm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In the presence of any form of instrumentation, nmi_enter() should be
done before calling any traceable code and any instrumentation code.
Currently, nmi_enter() is done in handle_domain_nmi(), which is much
too late as instrumentation code might get called before. Move the
nmi_enter/exit() calls to the arch IRQ vector handler.
On arm64, it is not possible to know if the IRQ vector handler was
called because of an NMI before acknowledging the interrupt. However, It
is possible to know whether normal interrupts could be taken in the
interrupted context (i.e. if taking an NMI in that context could
introduce a potential race condition).
When interrupting a context with IRQs disabled, call nmi_enter() as soon
as possible. In contexts with IRQs enabled, defer this to the interrupt
controller, which is in a better position to know if an interrupt taken
is an NMI.
Fixes: bc3c03ccb464 ("arm64: Enable the support of pseudo-NMIs")
Cc: <stable@vger.kernel.org> # 5.1.x-
Cc: Will Deacon <will.deacon@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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For el0_dbg and el0_error, DAIF bits get explicitly cleared before
calling ct_user_exit.
When context tracking is disabled, DAIF gets set (almost) immediately
after. When context tracking is enabled, among the first things done
is disabling IRQs.
What is actually needed is:
- PSR.D = 0 so the system can be debugged (should be already the case)
- PSR.A = 0 so async error can be handled during context tracking
Do not clear PSR.I in those two locations.
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with this program if not see http www gnu org
licenses
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 503 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Enrico Weigelt <info@metux.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.811534538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We already mitigate erratum 1188873 affecting Cortex-A76 and
Neoverse-N1 r0p0 to r2p0. It turns out that revisions r0p0 to
r3p1 of the same cores are affected by erratum 1418040, which
has the same workaround as 1188873.
Let's expand the range of affected revisions to match 1418040,
and repaint all occurences of 1188873 to 1418040. Whilst we're
there, do a bit of reformating in silicon-errata.txt and drop
a now unnecessary dependency on ARM_ARCH_TIMER_OOL_WORKAROUND.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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We currently deal with ARM64_ERRATUM_1188873 by always trapping EL0
accesses for both instruction sets. Although nothing wrong comes out
of that, people trying to squeeze the last drop of performance from
buggy HW find this over the top. Oh well.
Let's change the mitigation by flipping the counter enable bit
on return to userspace. Non-broken HW gets an extra branch on
the fast path, which is hopefully not the end of the world.
The arch timer workaround is also removed.
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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The assembly macro get_thread_info() actually returns a task_struct and is
analogous to the current/get_current macro/function.
While it could be argued that thread_info sits at the start of
task_struct and the intention could have been to return a thread_info,
instances of loads from/stores to the address obtained from
get_thread_info() use offsets that are generated with
offsetof(struct task_struct, [...]).
Rename get_thread_info() to state it returns a task_struct.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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When an NMI is raised while interrupts where disabled, the IRQ tracing
already is in the correct state (i.e. hardirqs_off) and should be left
as such when returning to the interrupted context.
Check whether PMR was masking interrupts when the NMI was raised and
skip IRQ tracing if necessary.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Handling of an NMI should not set any TIF flags. For NMIs received from
EL0 the current exit path is safe to use.
However, an NMI received at EL1 could have interrupted some task context
that has set the TIF_NEED_RESCHED flag. Preempting a task should not
happen as a result of an NMI.
Skip preemption after handling an NMI from EL1.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In order to replace PSR.I interrupt disabling/enabling with ICC_PMR_EL1
interrupt masking, ICC_PMR_EL1 needs to be saved/restored when
taking/returning from an exception. This mimics the way hardware saves
and restores PSR.I bit in spsr_el1 for exceptions and ERET.
Add PMR to the registers to save in the pt_regs struct upon kernel entry,
and restore it before ERET. Also, initialize it to a sane value when
creating new tasks.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Since the enabling and disabling of IRQs within preempt_schedule_irq()
is contained in a need_resched() loop, we don't need the outer arch
code loop.
Reported-by: Julien Thierry <julien.thierry@arm.com>
Reported-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Julien Grall <julien.grall@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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In commit:
3b7142752e4bee15 ("arm64: convert native/compat syscall entry to C")
... we moved the syscall invocation code from assembly to C, but left
behind a number of register aliases which are now unused.
Let's remove them before they confuse someone.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Commit 396244692232 ("arm64: preempt: Provide our own implementation of
asm/preempt.h") extended the preempt count field in struct thread_info
to 64 bits, so that it consists of a 32-bit count plus a 32-bit flag
indicating whether or not the current task needs rescheduling.
Whilst the asm-offsets definition of TSK_TI_PREEMPT was updated to point
to this new field, the assembly usage was left untouched meaning that a
32-bit load from TSK_TI_PREEMPT on a big-endian machine actually returns
the reschedule flag instead of the count.
Whilst we could fix this by pointing TSK_TI_PREEMPT at the count field,
we're actually better off reworking the two assembly users so that they
operate on the whole 64-bit value in favour of inspecting the thread
flags separately in order to determine whether a reschedule is needed.
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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The comment about SYS_MEMBARRIER_SYNC_CORE relying on ERET being
context-synchronizing is confusing and misplaced with kpti. Given that
this is already documented under Documentation/ (see arch-support.txt
for membarrier), remove the comment altogether.
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Some CPUs can speculate past an ERET instruction and potentially perform
speculative accesses to memory before processing the exception return.
Since the register state is often controlled by a lower privilege level
at the point of an ERET, this could potentially be used as part of a
side-channel attack.
This patch emits an SB sequence after each ERET so that speculation is
held up on exception return.
Signed-off-by: Will Deacon <will.deacon@arm.com>
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It recently came to light that userspace can execute WFI, and that
the arm64 kernel doesn't trap this event. This sounds rather benign,
but the kernel should decide when it wants to wait for an interrupt,
and not userspace.
Let's trap WFI and immediately return after having skipped the
instruction. This effectively makes WFI a rather expensive NOP.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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