- Userspace support for the Memory Tagging Extension introduced by Armv8.5.
Kernel support (via KASAN) is likely to follow in 5.11.
- Selftests for MTE, Pointer Authentication and FPSIMD/SVE context
switching.
- Fix and subsequent rewrite of our Spectre mitigations, including the
addition of support for PR_SPEC_DISABLE_NOEXEC.
- Support for the Armv8.3 Pointer Authentication enhancements.
- Support for ASID pinning, which is required when sharing page-tables with
the SMMU.
- MM updates, including treating flush_tlb_fix_spurious_fault() as a no-op.
- Perf/PMU driver updates, including addition of the ARM CMN PMU driver and
also support to handle CPU PMU IRQs as NMIs.
- Allow prefetchable PCI BARs to be exposed to userspace using normal
non-cacheable mappings.
- Implementation of ARCH_STACKWALK for unwinding.
- Improve reporting of unexpected kernel traps due to BPF JIT failure.
- Improve robustness of user-visible HWCAP strings and their corresponding
numerical constants.
- Removal of TEXT_OFFSET.
- Removal of some unused functions, parameters and prototypes.
- Removal of MPIDR-based topology detection in favour of firmware
description.
- Cleanups to handling of SVE and FPSIMD register state in preparation
for potential future optimisation of handling across syscalls.
- Cleanups to the SDEI driver in preparation for support in KVM.
- Miscellaneous cleanups and refactoring work.
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"There's quite a lot of code here, but much of it is due to the
addition of a new PMU driver as well as some arm64-specific selftests
which is an area where we've traditionally been lagging a bit.
In terms of exciting features, this includes support for the Memory
Tagging Extension which narrowly missed 5.9, hopefully allowing
userspace to run with use-after-free detection in production on CPUs
that support it. Work is ongoing to integrate the feature with KASAN
for 5.11.
Another change that I'm excited about (assuming they get the hardware
right) is preparing the ASID allocator for sharing the CPU page-table
with the SMMU. Those changes will also come in via Joerg with the
IOMMU pull.
We do stray outside of our usual directories in a few places, mostly
due to core changes required by MTE. Although much of this has been
Acked, there were a couple of places where we unfortunately didn't get
any review feedback.
Other than that, we ran into a handful of minor conflicts in -next,
but nothing that should post any issues.
Summary:
- Userspace support for the Memory Tagging Extension introduced by
Armv8.5. Kernel support (via KASAN) is likely to follow in 5.11.
- Selftests for MTE, Pointer Authentication and FPSIMD/SVE context
switching.
- Fix and subsequent rewrite of our Spectre mitigations, including
the addition of support for PR_SPEC_DISABLE_NOEXEC.
- Support for the Armv8.3 Pointer Authentication enhancements.
- Support for ASID pinning, which is required when sharing
page-tables with the SMMU.
- MM updates, including treating flush_tlb_fix_spurious_fault() as a
no-op.
- Perf/PMU driver updates, including addition of the ARM CMN PMU
driver and also support to handle CPU PMU IRQs as NMIs.
- Allow prefetchable PCI BARs to be exposed to userspace using normal
non-cacheable mappings.
- Implementation of ARCH_STACKWALK for unwinding.
- Improve reporting of unexpected kernel traps due to BPF JIT
failure.
- Improve robustness of user-visible HWCAP strings and their
corresponding numerical constants.
- Removal of TEXT_OFFSET.
- Removal of some unused functions, parameters and prototypes.
- Removal of MPIDR-based topology detection in favour of firmware
description.
- Cleanups to handling of SVE and FPSIMD register state in
preparation for potential future optimisation of handling across
syscalls.
- Cleanups to the SDEI driver in preparation for support in KVM.
- Miscellaneous cleanups and refactoring work"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (148 commits)
Revert "arm64: initialize per-cpu offsets earlier"
arm64: random: Remove no longer needed prototypes
arm64: initialize per-cpu offsets earlier
kselftest/arm64: Check mte tagged user address in kernel
kselftest/arm64: Verify KSM page merge for MTE pages
kselftest/arm64: Verify all different mmap MTE options
kselftest/arm64: Check forked child mte memory accessibility
kselftest/arm64: Verify mte tag inclusion via prctl
kselftest/arm64: Add utilities and a test to validate mte memory
perf: arm-cmn: Fix conversion specifiers for node type
perf: arm-cmn: Fix unsigned comparison to less than zero
arm64: dbm: Invalidate local TLB when setting TCR_EL1.HD
arm64: mm: Make flush_tlb_fix_spurious_fault() a no-op
arm64: Add support for PR_SPEC_DISABLE_NOEXEC prctl() option
arm64: Pull in task_stack_page() to Spectre-v4 mitigation code
KVM: arm64: Allow patching EL2 vectors even with KASLR is not enabled
arm64: Get rid of arm64_ssbd_state
KVM: arm64: Convert ARCH_WORKAROUND_2 to arm64_get_spectre_v4_state()
KVM: arm64: Get rid of kvm_arm_have_ssbd()
KVM: arm64: Simplify handling of ARCH_WORKAROUND_2
...
This reverts commit 353e228eb3.
Qian Cai reports that TX2 no longer boots with his .config as it appears
that task_cpu() gets instrumented and used before KASAN has been
initialised.
Although Mark has a proposed fix, let's take the safe option of reverting
this for now and sorting it out properly later.
Link: https://lore.kernel.org/r/711bc57a314d8d646b41307008db2845b7537b3d.camel@redhat.com
Reported-by: Qian Cai <cai@redhat.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Late patches for 5.10: MTE selftests, minor KCSAN preparation and removal
of some unused prototypes.
(Amit Daniel Kachhap and others)
* for-next/late-arrivals:
arm64: random: Remove no longer needed prototypes
arm64: initialize per-cpu offsets earlier
kselftest/arm64: Check mte tagged user address in kernel
kselftest/arm64: Verify KSM page merge for MTE pages
kselftest/arm64: Verify all different mmap MTE options
kselftest/arm64: Check forked child mte memory accessibility
kselftest/arm64: Verify mte tag inclusion via prctl
kselftest/arm64: Add utilities and a test to validate mte memory
The current initialization of the per-cpu offset register is difficult
to follow and this initialization is not always early enough for
upcoming instrumentation with KCSAN, where the instrumentation callbacks
use the per-cpu offset.
To make it possible to support KCSAN, and to simplify reasoning about
early bringup code, let's initialize the per-cpu offset earlier, before
we run any C code that may consume it. To do so, this patch adds a new
init_this_cpu_offset() helper that's called before the usual
primary/secondary start functions. For consistency, this is also used to
re-initialize the per-cpu offset after the runtime per-cpu areas have
been allocated (which can change CPU0's offset).
So that init_this_cpu_offset() isn't subject to any instrumentation that
might consume the per-cpu offset, it is marked with noinstr, preventing
instrumentation.
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>
Link: https://lore.kernel.org/r/20201005164303.21389-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Add userspace support for the Memory Tagging Extension introduced by
Armv8.5.
(Catalin Marinas and others)
* for-next/mte: (30 commits)
arm64: mte: Fix typo in memory tagging ABI documentation
arm64: mte: Add Memory Tagging Extension documentation
arm64: mte: Kconfig entry
arm64: mte: Save tags when hibernating
arm64: mte: Enable swap of tagged pages
mm: Add arch hooks for saving/restoring tags
fs: Handle intra-page faults in copy_mount_options()
arm64: mte: ptrace: Add NT_ARM_TAGGED_ADDR_CTRL regset
arm64: mte: ptrace: Add PTRACE_{PEEK,POKE}MTETAGS support
arm64: mte: Allow {set,get}_tagged_addr_ctrl() on non-current tasks
arm64: mte: Restore the GCR_EL1 register after a suspend
arm64: mte: Allow user control of the generated random tags via prctl()
arm64: mte: Allow user control of the tag check mode via prctl()
mm: Allow arm64 mmap(PROT_MTE) on RAM-based files
arm64: mte: Validate the PROT_MTE request via arch_validate_flags()
mm: Introduce arch_validate_flags()
arm64: mte: Add PROT_MTE support to mmap() and mprotect()
mm: Introduce arch_calc_vm_flag_bits()
arm64: mte: Tags-aware aware memcmp_pages() implementation
arm64: Avoid unnecessary clear_user_page() indirection
...
Fix and subsequently rewrite Spectre mitigations, including the addition
of support for PR_SPEC_DISABLE_NOEXEC.
(Will Deacon and Marc Zyngier)
* for-next/ghostbusters: (22 commits)
arm64: Add support for PR_SPEC_DISABLE_NOEXEC prctl() option
arm64: Pull in task_stack_page() to Spectre-v4 mitigation code
KVM: arm64: Allow patching EL2 vectors even with KASLR is not enabled
arm64: Get rid of arm64_ssbd_state
KVM: arm64: Convert ARCH_WORKAROUND_2 to arm64_get_spectre_v4_state()
KVM: arm64: Get rid of kvm_arm_have_ssbd()
KVM: arm64: Simplify handling of ARCH_WORKAROUND_2
arm64: Rewrite Spectre-v4 mitigation code
arm64: Move SSBD prctl() handler alongside other spectre mitigation code
arm64: Rename ARM64_SSBD to ARM64_SPECTRE_V4
arm64: Treat SSBS as a non-strict system feature
arm64: Group start_thread() functions together
KVM: arm64: Set CSV2 for guests on hardware unaffected by Spectre-v2
arm64: Rewrite Spectre-v2 mitigation code
arm64: Introduce separate file for spectre mitigations and reporting
arm64: Rename ARM64_HARDEN_BRANCH_PREDICTOR to ARM64_SPECTRE_V2
KVM: arm64: Simplify install_bp_hardening_cb()
KVM: arm64: Replace CONFIG_KVM_INDIRECT_VECTORS with CONFIG_RANDOMIZE_BASE
arm64: Remove Spectre-related CONFIG_* options
arm64: Run ARCH_WORKAROUND_2 enabling code on all CPUs
...
Remove unused functions and parameters from ACPI IORT code.
(Zenghui Yu via Lorenzo Pieralisi)
* for-next/acpi:
ACPI/IORT: Remove the unused inline functions
ACPI/IORT: Drop the unused @ops of iort_add_device_replay()
Remove redundant code and fix documentation of caching behaviour for the
HVC_SOFT_RESTART hypercall.
(Pingfan Liu)
* for-next/boot:
Documentation/kvm/arm: improve description of HVC_SOFT_RESTART
arm64/relocate_kernel: remove redundant code
Improve reporting of unexpected kernel traps due to BPF JIT failure.
(Will Deacon)
* for-next/bpf:
arm64: Improve diagnostics when trapping BRK with FAULT_BRK_IMM
Improve robustness of user-visible HWCAP strings and their corresponding
numerical constants.
(Anshuman Khandual)
* for-next/cpuinfo:
arm64/cpuinfo: Define HWCAP name arrays per their actual bit definitions
Cleanups to handling of SVE and FPSIMD register state in preparation
for potential future optimisation of handling across syscalls.
(Julien Grall)
* for-next/fpsimd:
arm64/sve: Implement a helper to load SVE registers from FPSIMD state
arm64/sve: Implement a helper to flush SVE registers
arm64/fpsimdmacros: Allow the macro "for" to be used in more cases
arm64/fpsimdmacros: Introduce a macro to update ZCR_EL1.LEN
arm64/signal: Update the comment in preserve_sve_context
arm64/fpsimd: Update documentation of do_sve_acc
Miscellaneous changes.
(Tian Tao and others)
* for-next/misc:
arm64/mm: return cpu_all_mask when node is NUMA_NO_NODE
arm64: mm: Fix missing-prototypes in pageattr.c
arm64/fpsimd: Fix missing-prototypes in fpsimd.c
arm64: hibernate: Remove unused including <linux/version.h>
arm64/mm: Refactor {pgd, pud, pmd, pte}_ERROR()
arm64: Remove the unused include statements
arm64: get rid of TEXT_OFFSET
arm64: traps: Add str of description to panic() in die()
Memory management updates and cleanups.
(Anshuman Khandual and others)
* for-next/mm:
arm64: dbm: Invalidate local TLB when setting TCR_EL1.HD
arm64: mm: Make flush_tlb_fix_spurious_fault() a no-op
arm64/mm: Unify CONT_PMD_SHIFT
arm64/mm: Unify CONT_PTE_SHIFT
arm64/mm: Remove CONT_RANGE_OFFSET
arm64/mm: Enable THP migration
arm64/mm: Change THP helpers to comply with generic MM semantics
arm64/mm/ptdump: Add address markers for BPF regions
Allow prefetchable PCI BARs to be exposed to userspace using normal
non-cacheable mappings.
(Clint Sbisa)
* for-next/pci:
arm64: Enable PCI write-combine resources under sysfs
Perf/PMU driver updates.
(Julien Thierry and others)
* for-next/perf:
perf: arm-cmn: Fix conversion specifiers for node type
perf: arm-cmn: Fix unsigned comparison to less than zero
arm_pmu: arm64: Use NMIs for PMU
arm_pmu: Introduce pmu_irq_ops
KVM: arm64: pmu: Make overflow handler NMI safe
arm64: perf: Defer irq_work to IPI_IRQ_WORK
arm64: perf: Remove PMU locking
arm64: perf: Avoid PMXEV* indirection
arm64: perf: Add missing ISB in armv8pmu_enable_counter()
perf: Add Arm CMN-600 PMU driver
perf: Add Arm CMN-600 DT binding
arm64: perf: Add support caps under sysfs
drivers/perf: thunderx2_pmu: Fix memory resource error handling
drivers/perf: xgene_pmu: Fix uninitialized resource struct
perf: arm_dsu: Support DSU ACPI devices
arm64: perf: Remove unnecessary event_idx check
drivers/perf: hisi: Add missing include of linux/module.h
arm64: perf: Add general hardware LLC events for PMUv3
Support for the Armv8.3 Pointer Authentication enhancements.
(By Amit Daniel Kachhap)
* for-next/ptrauth:
arm64: kprobe: clarify the comment of steppable hint instructions
arm64: kprobe: disable probe of fault prone ptrauth instruction
arm64: cpufeature: Modify address authentication cpufeature to exact
arm64: ptrauth: Introduce Armv8.3 pointer authentication enhancements
arm64: traps: Allow force_signal_inject to pass esr error code
arm64: kprobe: add checks for ARMv8.3-PAuth combined instructions
Tonnes of cleanup to the SDEI driver.
(Gavin Shan)
* for-next/sdei:
firmware: arm_sdei: Remove _sdei_event_unregister()
firmware: arm_sdei: Remove _sdei_event_register()
firmware: arm_sdei: Introduce sdei_do_local_call()
firmware: arm_sdei: Cleanup on cross call function
firmware: arm_sdei: Remove while loop in sdei_event_unregister()
firmware: arm_sdei: Remove while loop in sdei_event_register()
firmware: arm_sdei: Remove redundant error message in sdei_probe()
firmware: arm_sdei: Remove duplicate check in sdei_get_conduit()
firmware: arm_sdei: Unregister driver on error in sdei_init()
firmware: arm_sdei: Avoid nested statements in sdei_init()
firmware: arm_sdei: Retrieve event number from event instance
firmware: arm_sdei: Common block for failing path in sdei_event_create()
firmware: arm_sdei: Remove sdei_is_err()
Selftests for Pointer Authentication and FPSIMD/SVE context-switching.
(Mark Brown and Boyan Karatotev)
* for-next/selftests:
selftests: arm64: Add build and documentation for FP tests
selftests: arm64: Add wrapper scripts for stress tests
selftests: arm64: Add utility to set SVE vector lengths
selftests: arm64: Add stress tests for FPSMID and SVE context switching
selftests: arm64: Add test for the SVE ptrace interface
selftests: arm64: Test case for enumeration of SVE vector lengths
kselftests/arm64: add PAuth tests for single threaded consistency and differently initialized keys
kselftests/arm64: add PAuth test for whether exec() changes keys
kselftests/arm64: add nop checks for PAuth tests
kselftests/arm64: add a basic Pointer Authentication test
Implementation of ARCH_STACKWALK for unwinding.
(Mark Brown)
* for-next/stacktrace:
arm64: Move console stack display code to stacktrace.c
arm64: stacktrace: Convert to ARCH_STACKWALK
arm64: stacktrace: Make stack walk callback consistent with generic code
stacktrace: Remove reliable argument from arch_stack_walk() callback
Support for ASID pinning, which is required when sharing page-tables with
the SMMU.
(Jean-Philippe Brucker)
* for-next/svm:
arm64: cpufeature: Export symbol read_sanitised_ftr_reg()
arm64: mm: Pin down ASIDs for sharing mm with devices
Rely on firmware tables for establishing CPU topology.
(Valentin Schneider)
* for-next/topology:
arm64: topology: Stop using MPIDR for topology information
Spelling fixes.
(Xiaoming Ni and Yanfei Xu)
* for-next/tpyos:
arm64/numa: Fix a typo in comment of arm64_numa_init
arm64: fix some spelling mistakes in the comments by codespell
vDSO cleanups.
(Will Deacon)
* for-next/vdso:
arm64: vdso: Fix unusual formatting in *setup_additional_pages()
arm64: vdso32: Remove a bunch of #ifdef CONFIG_COMPAT_VDSO guards
TCR_EL1.HD is permitted to be cached in a TLB, so invalidate the local
TLB after setting the bit when detected support for the feature. Although
this isn't strictly necessary, since we can happily operate with the bit
effectively clear, the current code uses an ISB in a half-hearted attempt
to make the change effective, so let's just fix that up.
Link: https://lore.kernel.org/r/20201001110405.18617-1-will@kernel.org
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Jonathan reports that the strict policy for memory mapped by the
ACPI core breaks the use case of passing ACPI table overrides via
initramfs. This is due to the fact that the memory type used for
loading the initramfs in memory is not recognized as a memory type
that is typically used by firmware to pass firmware tables.
Since the purpose of the strict policy is to ensure that no AML or
other ACPI code can manipulate any memory that is used by the kernel
to keep its internal state or the state of user tasks, we can relax
the permission check, and allow mappings of memory that is reserved
and marked as NOMAP via memblock, and therefore not covered by the
linear mapping to begin with.
Fixes: 1583052d11 ("arm64/acpi: disallow AML memory opregions to access kernel memory")
Fixes: 325f5585ec ("arm64/acpi: disallow writeable AML opregion mapping for EFI code regions")
Reported-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Link: https://lore.kernel.org/r/20200929132522.18067-1-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The PR_SPEC_DISABLE_NOEXEC option to the PR_SPEC_STORE_BYPASS prctl()
allows the SSB mitigation to be enabled only until the next execve(),
at which point the state will revert back to PR_SPEC_ENABLE and the
mitigation will be disabled.
Add support for PR_SPEC_DISABLE_NOEXEC on arm64.
Reported-by: Anthony Steinhauser <asteinhauser@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
The kbuild robot reports that we're relying on an implicit inclusion to
get a definition of task_stack_page() in the Spectre-v4 mitigation code,
which is not always in place for some configurations:
| arch/arm64/kernel/proton-pack.c:329:2: error: implicit declaration of function 'task_stack_page' [-Werror,-Wimplicit-function-declaration]
| task_pt_regs(task)->pstate |= val;
| ^
| arch/arm64/include/asm/processor.h:268:36: note: expanded from macro 'task_pt_regs'
| ((struct pt_regs *)(THREAD_SIZE + task_stack_page(p)) - 1)
| ^
| arch/arm64/kernel/proton-pack.c:329:2: note: did you mean 'task_spread_page'?
Add the missing include to fix the build error.
Fixes: a44acf477220 ("arm64: Move SSBD prctl() handler alongside other spectre mitigation code")
Reported-by: Anthony Steinhauser <asteinhauser@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/202009260013.Ul7AD29w%lkp@intel.com
Signed-off-by: Will Deacon <will@kernel.org>
Patching the EL2 exception vectors is integral to the Spectre-v2
workaround, where it can be necessary to execute CPU-specific sequences
to nobble the branch predictor before running the hypervisor text proper.
Remove the dependency on CONFIG_RANDOMIZE_BASE and allow the EL2 vectors
to be patched even when KASLR is not enabled.
Fixes: 7a132017e7a5 ("KVM: arm64: Replace CONFIG_KVM_INDIRECT_VECTORS with CONFIG_RANDOMIZE_BASE")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/202009221053.Jv1XsQUZ%lkp@intel.com
Signed-off-by: Will Deacon <will@kernel.org>
Owing to the fact that the host kernel is always mitigated, we can
drastically simplify the WA2 handling by keeping the mitigation
state ON when entering the guest. This means the guest is either
unaffected or not mitigated.
This results in a nice simplification of the mitigation space,
and the removal of a lot of code that was never really used anyway.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Rewrite the Spectre-v4 mitigation handling code to follow the same
approach as that taken by Spectre-v2.
For now, report to KVM that the system is vulnerable (by forcing
'ssbd_state' to ARM64_SSBD_UNKNOWN), as this will be cleared up in
subsequent steps.
Signed-off-by: Will Deacon <will@kernel.org>
As part of the spectre consolidation effort to shift all of the ghosts
into their own proton pack, move all of the horrible SSBD prctl() code
out of its own 'ssbd.c' file.
Signed-off-by: Will Deacon <will@kernel.org>
In a similar manner to the renaming of ARM64_HARDEN_BRANCH_PREDICTOR
to ARM64_SPECTRE_V2, rename ARM64_SSBD to ARM64_SPECTRE_V4. This isn't
_entirely_ accurate, as we also need to take into account the interaction
with SSBS, but that will be taken care of in subsequent patches.
Signed-off-by: Will Deacon <will@kernel.org>
If all CPUs discovered during boot have SSBS, then spectre-v4 will be
considered to be "mitigated". However, we still allow late CPUs without
SSBS to be onlined, albeit with a "SANITY CHECK" warning. This is
problematic for userspace because it means that the system can quietly
transition to "Vulnerable" at runtime.
Avoid this by treating SSBS as a non-strict system feature: if all of
the CPUs discovered during boot have SSBS, then late arriving secondaries
better have it as well.
Signed-off-by: Will Deacon <will@kernel.org>
The Spectre-v2 mitigation code is pretty unwieldy and hard to maintain.
This is largely due to it being written hastily, without much clue as to
how things would pan out, and also because it ends up mixing policy and
state in such a way that it is very difficult to figure out what's going
on.
Rewrite the Spectre-v2 mitigation so that it clearly separates state from
policy and follows a more structured approach to handling the mitigation.
Signed-off-by: Will Deacon <will@kernel.org>
The spectre mitigation code is spread over a few different files, which
makes it both hard to follow, but also hard to remove it should we want
to do that in future.
Introduce a new file for housing the spectre mitigations, and populate
it with the spectre-v1 reporting code to start with.
Signed-off-by: Will Deacon <will@kernel.org>
For better or worse, the world knows about "Spectre" and not about
"Branch predictor hardening". Rename ARM64_HARDEN_BRANCH_PREDICTOR to
ARM64_SPECTRE_V2 as part of moving all of the Spectre mitigations into
their own little corner.
Signed-off-by: Will Deacon <will@kernel.org>
Use is_hyp_mode_available() to detect whether or not we need to patch
the KVM vectors for branch hardening, which avoids the need to take the
vector pointers as parameters.
Signed-off-by: Will Deacon <will@kernel.org>
The removal of CONFIG_HARDEN_BRANCH_PREDICTOR means that
CONFIG_KVM_INDIRECT_VECTORS is synonymous with CONFIG_RANDOMIZE_BASE,
so replace it.
Signed-off-by: Will Deacon <will@kernel.org>
The spectre mitigations are too configurable for their own good, leading
to confusing logic trying to figure out when we should mitigate and when
we shouldn't. Although the plethora of command-line options need to stick
around for backwards compatibility, the default-on CONFIG options that
depend on EXPERT can be dropped, as the mitigations only do anything if
the system is vulnerable, a mitigation is available and the command-line
hasn't disabled it.
Remove CONFIG_HARDEN_BRANCH_PREDICTOR and CONFIG_ARM64_SSBD in favour of
enabling this code unconditionally.
Signed-off-by: Will Deacon <will@kernel.org>
Commit 606f8e7b27 ("arm64: capabilities: Use linear array for
detection and verification") changed the way we deal with per-CPU errata
by only calling the .matches() callback until one CPU is found to be
affected. At this point, .matches() stop being called, and .cpu_enable()
will be called on all CPUs.
This breaks the ARCH_WORKAROUND_2 handling, as only a single CPU will be
mitigated.
In order to address this, forcefully call the .matches() callback from a
.cpu_enable() callback, which brings us back to the original behaviour.
Fixes: 606f8e7b27 ("arm64: capabilities: Use linear array for detection and verification")
Cc: <stable@vger.kernel.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
The SMMUv3 driver would like to read the MMFR0 PARANGE field in order to
share CPU page tables with devices. Allow the driver to be built as
module by exporting the read_sanitized_ftr_reg() cpufeature symbol.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20200918101852.582559-7-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
When handling events, armv8pmu_handle_irq() calls perf_event_overflow(),
and subsequently calls irq_work_run() to handle any work queued by
perf_event_overflow(). As perf_event_overflow() raises IPI_IRQ_WORK when
queuing the work, this isn't strictly necessary and the work could be
handled as part of the IPI_IRQ_WORK handler.
In the common case the IPI handler will run immediately after the PMU IRQ
handler, and where the PE is heavily loaded with interrupts other handlers
may run first, widening the window where some counters are disabled.
In practice this window is unlikely to be a significant issue, and removing
the call to irq_work_run() would make the PMU IRQ handler NMI safe in
addition to making it simpler, so let's do that.
[Alexandru E.: Reworded commit message]
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200924110706.254996-5-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
The PMU is disabled and enabled, and the counters are programmed from
contexts where interrupts or preemption is disabled.
The functions to toggle the PMU and to program the PMU counters access the
registers directly and don't access data modified by the interrupt handler.
That, and the fact that they're always called from non-preemptible
contexts, means that we don't need to disable interrupts or use a spinlock.
[Alexandru E.: Explained why locking is not needed, removed WARN_ONs]
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox)
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200924110706.254996-4-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Currently we access the counter registers and their respective type
registers indirectly. This requires us to write to PMSELR, issue an ISB,
then access the relevant PMXEV* registers.
This is unfortunate, because:
* Under virtualization, accessing one register requires two traps to
the hypervisor, even though we could access the register directly with
a single trap.
* We have to issue an ISB which we could otherwise avoid the cost of.
* When we use NMIs, the NMI handler will have to save/restore the select
register in case the code it preempted was attempting to access a
counter or its type register.
We can avoid these issues by directly accessing the relevant registers.
This patch adds helpers to do so.
In armv8pmu_enable_event() we still need the ISB to prevent the PE from
reordering the write to PMINTENSET_EL1 register. If the interrupt is
enabled before we disable the counter and the new event is configured,
we might get an interrupt triggered by the previously programmed event
overflowing, but which we wrongly attribute to the event that we are
enabling. Execute an ISB after we disable the counter.
In the process, remove the comment that refers to the ARMv7 PMU.
[Julien T.: Don't inline read/write functions to avoid big code-size
increase, remove unused read_pmevtypern function,
fix counter index issue.]
[Alexandru E.: Removed comment, removed trailing semicolons in macros,
added ISB]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox)
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200924110706.254996-3-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Writes to the PMXEVTYPER_EL0 register are not self-synchronising. In
armv8pmu_enable_event(), the PE can reorder configuring the event type
after we have enabled the counter and the interrupt. This can lead to an
interrupt being asserted because of the previous event type that we were
counting using the same counter, not the one that we've just configured.
The same rationale applies to writes to the PMINTENSET_EL1 register. The PE
can reorder enabling the interrupt at any point in the future after we have
enabled the event.
Prevent both situations from happening by adding an ISB just before we
enable the event counter.
Fixes: 030896885a ("arm64: Performance counters support")
Reported-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox)
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200924110706.254996-2-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
ARMv8.4-PMU introduces the PMMIR_EL1 registers and some new PMU events,
like STALL_SLOT etc, are related to it. Let's add a caps directory to
/sys/bus/event_source/devices/armv8_pmuv3_0/ and support slots from
PMMIR_EL1 registers in this entry. The user programs can get the slots
from sysfs directly.
/sys/bus/event_source/devices/armv8_pmuv3_0/caps/slots is exposed
under sysfs. Both ARMv8.4-PMU and STALL_SLOT event are implemented,
it returns the slots from PMMIR_EL1, otherwise it will return 0.
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/1600754025-53535-1-git-send-email-zhangshaokun@hisilicon.com
Signed-off-by: Will Deacon <will@kernel.org>
Currently the code for displaying a stack trace on the console is located
in traps.c rather than stacktrace.c, using the unwinding code that is in
stacktrace.c. This can be confusing and make the code hard to find since
such output is often referred to as a stack trace which might mislead the
unwary. Due to this and since traps.c doesn't interact with this code
except for via the public interfaces move the code to stacktrace.c to
make it easier to find.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20200921122341.11280-1-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Commit 73f3816609 ("arm64: Advertise mitigation of Spectre-v2, or lack
thereof") changed the way we deal with ARCH_WORKAROUND_1, by moving most
of the enabling code to the .matches() callback.
This has the unfortunate effect that the workaround gets only enabled on
the first affected CPU, and no other.
In order to address this, forcefully call the .matches() callback from a
.cpu_enable() callback, which brings us back to the original behaviour.
Fixes: 73f3816609 ("arm64: Advertise mitigation of Spectre-v2, or lack thereof")
Cc: <stable@vger.kernel.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
We seem to be pretending that we don't have any firmware mitigation
when KVM is not compiled in, which is not quite expected.
Bring back the mitigation in this case.
Fixes: 4db61fef16 ("arm64: kvm: Modernize __smccc_workaround_1_smc_start annotations")
Cc: <stable@vger.kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
In a follow-up patch, we may save the FPSIMD rather than the full SVE
state when the state has to be zeroed on return to userspace (e.g
during a syscall).
Introduce an helper to load SVE vectors from FPSIMD state and zero the rest
of SVE registers.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20200828181155.17745-7-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Introduce a new helper that will zero all SVE registers but the first
128-bits of each vector. This will be used by subsequent patches to
avoid costly store/maipulate/reload sequences in places like do_sve_acc().
Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20200828181155.17745-6-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
The SVE state is saved by fpsimd_signal_preserve_current_state() and not
preserve_fpsimd_context(). Update the comment in preserve_sve_context to
reflect the current behavior.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20200828181155.17745-3-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
fpsimd_restore_current_state() enables and disables the SVE access trap
based on TIF_SVE, not task_fpsimd_load(). Update the documentation of
do_sve_acc to reflect this behavior.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20200828181155.17745-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
When generating instructions at runtime, for example due to kernel text
patching or the BPF JIT, we can emit a trapping BRK instruction if we
are asked to encode an invalid instruction such as an out-of-range]
branch. This is indicative of a bug in the caller, and will result in a
crash on executing the generated code. Unfortunately, the message from
the crash is really unhelpful, and mumbles something about ptrace:
| Unexpected kernel BRK exception at EL1
| Internal error: ptrace BRK handler: f2000100 [#1] SMP
We can do better than this. Install a break handler for FAULT_BRK_IMM,
which is the immediate used to encode the "I've been asked to generate
an invalid instruction" error, and triage the faulting PC to determine
whether or not the failure occurred in the BPF JIT.
Link: https://lore.kernel.org/r/20200915141707.GB26439@willie-the-truck
Reported-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>
Fix the following warnings.
arch/arm64/kernel/fpsimd.c:935:6: warning: no previous prototype for
‘do_sve_acc’ [-Wmissing-prototypes]
arch/arm64/kernel/fpsimd.c:962:6: warning: no previous prototype for
‘do_fpsimd_acc’ [-Wmissing-prototypes]
arch/arm64/kernel/fpsimd.c:971:6: warning: no previous prototype for
‘do_fpsimd_exc’ [-Wmissing-prototypes]
arch/arm64/kernel/fpsimd.c:1266:6: warning: no previous prototype for
‘kernel_neon_begin’ [-Wmissing-prototypes]
arch/arm64/kernel/fpsimd.c:1292:6: warning: no previous prototype for
‘kernel_neon_end’ [-Wmissing-prototypes]
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/1600157999-14802-1-git-send-email-tiantao6@hisilicon.com
Signed-off-by: Will Deacon <will@kernel.org>
Historically architectures have had duplicated code in their stack trace
implementations for filtering what gets traced. In order to avoid this
duplication some generic code has been provided using a new interface
arch_stack_walk(), enabled by selecting ARCH_STACKWALK in Kconfig, which
factors all this out into the generic stack trace code. Convert arm64
to use this common infrastructure.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20200914153409.25097-4-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
As with the generic arch_stack_walk() code the arm64 stack walk code takes
a callback that is called per stack frame. Currently the arm64 code always
passes a struct stackframe to the callback and the generic code just passes
the pc, however none of the users ever reference anything in the struct
other than the pc value. The arm64 code also uses a return type of int
while the generic code uses a return type of bool though in both cases the
return value is a boolean value and the sense is inverted between the two.
In order to reduce code duplication when arm64 is converted to use
arch_stack_walk() change the signature and return sense of the arm64
specific callback to match that of the generic code.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20200914153409.25097-3-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Steal time initialization requires mapping a memory region which
invokes a memory allocation. Doing this at CPU starting time results
in the following trace when CONFIG_DEBUG_ATOMIC_SLEEP is enabled:
BUG: sleeping function called from invalid context at mm/slab.h:498
in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 0, name: swapper/1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.9.0-rc5+ #1
Call trace:
dump_backtrace+0x0/0x208
show_stack+0x1c/0x28
dump_stack+0xc4/0x11c
___might_sleep+0xf8/0x130
__might_sleep+0x58/0x90
slab_pre_alloc_hook.constprop.101+0xd0/0x118
kmem_cache_alloc_node_trace+0x84/0x270
__get_vm_area_node+0x88/0x210
get_vm_area_caller+0x38/0x40
__ioremap_caller+0x70/0xf8
ioremap_cache+0x78/0xb0
memremap+0x9c/0x1a8
init_stolen_time_cpu+0x54/0xf0
cpuhp_invoke_callback+0xa8/0x720
notify_cpu_starting+0xc8/0xd8
secondary_start_kernel+0x114/0x180
CPU1: Booted secondary processor 0x0000000001 [0x431f0a11]
However we don't need to initialize steal time at CPU starting time.
We can simply wait until CPU online time, just sacrificing a bit of
accuracy by returning zero for steal time until we know better.
While at it, add __init to the functions that are only called by
pv_time_init() which is __init.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Fixes: e0685fa228 ("arm64: Retrieve stolen time as paravirtualized guest")
Cc: stable@vger.kernel.org
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://lore.kernel.org/r/20200916154530.40809-1-drjones@redhat.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The function __{pgd, pud, pmd, pte}_error() are introduced so that
they can be called by {pgd, pud, pmd, pte}_ERROR(). However, some
of the functions could never be called when the corresponding page
table level isn't enabled. For example, __{pud, pmd}_error() are
unused when PUD and PMD are folded to PGD.
This removes __{pgd, pud, pmd, pte}_error() and call pr_err() from
{pgd, pud, pmd, pte}_ERROR() directly, similar to what x86/powerpc
are doing. With this, the code looks a bit simplified either.
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20200913234730.23145-1-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
The existing comment about steppable hint instruction is not complete
and only describes NOP instructions as steppable. As the function
aarch64_insn_is_steppable_hint allows all white-listed instruction
to be probed so the comment is updated to reflect this.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Link: https://lore.kernel.org/r/20200914083656.21428-7-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
With the addition of ARMv8.3-FPAC feature, the probe of authenticate
ptrauth instructions (AUT*) may cause ptrauth fault exception in case of
authenticate failure so they cannot be safely single stepped.
Hence the probe of authenticate instructions is disallowed but the
corresponding pac ptrauth instruction (PAC*) is not affected and they can
still be probed. Also AUTH* instructions do not make sense at function
entry points so most realistic probes would be unaffected by this change.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Link: https://lore.kernel.org/r/20200914083656.21428-6-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
The current address authentication cpufeature levels are set as LOWER_SAFE
which is not compatible with the different configurations added for Armv8.3
ptrauth enhancements as the different levels have different behaviour and
there is no tunable to enable the lower safe versions. This is rectified
by setting those cpufeature type as EXACT.
The current cpufeature framework also does not interfere in the booting of
non-exact secondary cpus but rather marks them as tainted. As a workaround
this is fixed by replacing the generic match handler with a new handler
specific to ptrauth.
After this change, if there is any variation in ptrauth configurations in
secondary cpus from boot cpu then those mismatched cpus are parked in an
infinite loop.
Following ptrauth crash log is observed in Arm fastmodel with simulated
mismatched cpus without this fix,
CPU features: SANITY CHECK: Unexpected variation in SYS_ID_AA64ISAR1_EL1. Boot CPU: 0x11111110211402, CPU4: 0x11111110211102
CPU features: Unsupported CPU feature variation detected.
GICv3: CPU4: found redistributor 100 region 0:0x000000002f180000
CPU4: Booted secondary processor 0x0000000100 [0x410fd0f0]
Unable to handle kernel paging request at virtual address bfff800010dadf3c
Mem abort info:
ESR = 0x86000004
EC = 0x21: IABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
[bfff800010dadf3c] address between user and kernel address ranges
Internal error: Oops: 86000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 4 PID: 29 Comm: migration/4 Tainted: G S 5.8.0-rc4-00005-ge658591d66d1-dirty #158
Hardware name: Foundation-v8A (DT)
pstate: 60000089 (nZCv daIf -PAN -UAO BTYPE=--)
pc : 0xbfff800010dadf3c
lr : __schedule+0x2b4/0x5a8
sp : ffff800012043d70
x29: ffff800012043d70 x28: 0080000000000000
x27: ffff800011cbe000 x26: ffff00087ad37580
x25: ffff00087ad37000 x24: ffff800010de7d50
x23: ffff800011674018 x22: 0784800010dae2a8
x21: ffff00087ad37000 x20: ffff00087acb8000
x19: ffff00087f742100 x18: 0000000000000030
x17: 0000000000000000 x16: 0000000000000000
x15: ffff800011ac1000 x14: 00000000000001bd
x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000000000 x10: 71519a147ddfeb82
x9 : 825d5ec0fb246314 x8 : ffff00087ad37dd8
x7 : 0000000000000000 x6 : 00000000fffedb0e
x5 : 00000000ffffffff x4 : 0000000000000000
x3 : 0000000000000028 x2 : ffff80086e11e000
x1 : ffff00087ad37000 x0 : ffff00087acdc600
Call trace:
0xbfff800010dadf3c
schedule+0x78/0x110
schedule_preempt_disabled+0x24/0x40
__kthread_parkme+0x68/0xd0
kthread+0x138/0x160
ret_from_fork+0x10/0x34
Code: bad PC value
After this fix, the mismatched CPU4 is parked as,
CPU features: CPU4: Detected conflict for capability 39 (Address authentication (IMP DEF algorithm)), System: 1, CPU: 0
CPU4: will not boot
CPU4: failed to come online
CPU4: died during early boot
[Suzuki: Introduce new matching function for address authentication]
Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20200914083656.21428-5-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Some Armv8.3 Pointer Authentication enhancements have been introduced
which are mandatory for Armv8.6 and optional for Armv8.3. These features
are,
* ARMv8.3-PAuth2 - An enhanced PAC generation logic is added which hardens
finding the correct PAC value of the authenticated pointer.
* ARMv8.3-FPAC - Fault is generated now when the ptrauth authentication
instruction fails in authenticating the PAC present in the address.
This is different from earlier case when such failures just adds an
error code in the top byte and waits for subsequent load/store to abort.
The ptrauth instructions which may cause this fault are autiasp, retaa
etc.
The above features are now represented by additional configurations
for the Address Authentication cpufeature and a new ESR exception class.
The userspace fault received in the kernel due to ARMv8.3-FPAC is treated
as Illegal instruction and hence signal SIGILL is injected with ILL_ILLOPN
as the signal code. Note that this is different from earlier ARMv8.3
ptrauth where signal SIGSEGV is issued due to Pointer authentication
failures. The in-kernel PAC fault causes kernel to crash.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20200914083656.21428-4-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Some error signal need to pass proper ARM esr error code to userspace to
better identify the cause of the signal. So the function
force_signal_inject is extended to pass this as a parameter. The
existing code is not affected by this change.
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://lore.kernel.org/r/20200914083656.21428-3-amit.kachhap@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
