In some scenarios, such as buggy guest or incorrect configuration of the
VMM and firmware description data, userspace will detect a memory access
to a portion of the IPA, which is not mapped to any MMIO region.
For this purpose, the appropriate action is to inject an external abort
to the guest. The kernel already has functionality to inject an
external abort, but we need to wire up a signal from user space that
lets user space tell the kernel to do this.
It turns out, we already have the set event functionality which we can
perfectly reuse for this.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
* ARM: ITS translation cache; support for 512 vCPUs, various cleanups
and bugfixes
* PPC: various minor fixes and preparation
* x86: bugfixes all over the place (posted interrupts, SVM, emulation
corner cases, blocked INIT), some IPI optimizations
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"s390:
- ioctl hardening
- selftests
ARM:
- ITS translation cache
- support for 512 vCPUs
- various cleanups and bugfixes
PPC:
- various minor fixes and preparation
x86:
- bugfixes all over the place (posted interrupts, SVM, emulation
corner cases, blocked INIT)
- some IPI optimizations"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (75 commits)
KVM: X86: Use IPI shorthands in kvm guest when support
KVM: x86: Fix INIT signal handling in various CPU states
KVM: VMX: Introduce exit reason for receiving INIT signal on guest-mode
KVM: VMX: Stop the preemption timer during vCPU reset
KVM: LAPIC: Micro optimize IPI latency
kvm: Nested KVM MMUs need PAE root too
KVM: x86: set ctxt->have_exception in x86_decode_insn()
KVM: x86: always stop emulation on page fault
KVM: nVMX: trace nested VM-Enter failures detected by H/W
KVM: nVMX: add tracepoint for failed nested VM-Enter
x86: KVM: svm: Fix a check in nested_svm_vmrun()
KVM: x86: Return to userspace with internal error on unexpected exit reason
KVM: x86: Add kvm_emulate_{rd,wr}msr() to consolidate VXM/SVM code
KVM: x86: Refactor up kvm_{g,s}et_msr() to simplify callers
doc: kvm: Fix return description of KVM_SET_MSRS
KVM: X86: Tune PLE Window tracepoint
KVM: VMX: Change ple_window type to unsigned int
KVM: X86: Remove tailing newline for tracepoints
KVM: X86: Trace vcpu_id for vmexit
KVM: x86: Manually calculate reserved bits when loading PDPTRS
...
While parts of the VGIC support a large number of vcpus (we
bravely allow up to 512), other parts are more limited.
One of these limits is visible in the KVM_IRQ_LINE ioctl, which
only allows 256 vcpus to be signalled when using the CPU or PPI
types. Unfortunately, we've cornered ourselves badly by allocating
all the bits in the irq field.
Since the irq_type subfield (8 bit wide) is currently only taking
the values 0, 1 and 2 (and we have been careful not to allow anything
else), let's reduce this field to only 4 bits, and allocate the
remaining 4 bits to a vcpu2_index, which acts as a multiplier:
vcpu_id = 256 * vcpu2_index + vcpu_index
With that, and a new capability (KVM_CAP_ARM_IRQ_LINE_LAYOUT_2)
allowing this to be discovered, it becomes possible to inject
PPIs to up to 4096 vcpus. But please just don't.
Whilst we're there, add a clarification about the use of KVM_IRQ_LINE
on arm, which is not completely conditionned by KVM_CAP_IRQCHIP.
Reported-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
stat.h is listed in include/uapi/asm-generic/Kbuild, so Kbuild will
automatically generate it.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Will Deacon <will@kernel.org>
UAPI headers licensed under GPL are supposed to have exception
"WITH Linux-syscall-note" so that they can be included into non-GPL
user space application code.
The exception note is missing in some UAPI headers.
Some of them slipped in by the treewide conversion commit b24413180f
("License cleanup: add SPDX GPL-2.0 license identifier to files with
no license"). Just run:
$ git show --oneline b24413180f -- arch/x86/include/uapi/asm/
I believe they are not intentional, and should be fixed too.
This patch was generated by the following script:
git grep -l --not -e Linux-syscall-note --and -e SPDX-License-Identifier \
-- :arch/*/include/uapi/asm/*.h :include/uapi/ :^*/Kbuild |
while read file
do
sed -i -e '/[[:space:]]OR[[:space:]]/s/\(GPL-[^[:space:]]*\)/(\1 WITH Linux-syscall-note)/g' \
-e '/[[:space:]]or[[:space:]]/s/\(GPL-[^[:space:]]*\)/(\1 WITH Linux-syscall-note)/g' \
-e '/[[:space:]]OR[[:space:]]/!{/[[:space:]]or[[:space:]]/!s/\(GPL-[^[:space:]]*\)/\1 WITH Linux-syscall-note/g}' $file
done
After this patch is applied, there are 5 UAPI headers that do not contain
"WITH Linux-syscall-note". They are kept untouched since this exception
applies only to GPL variants.
$ git grep --not -e Linux-syscall-note --and -e SPDX-License-Identifier \
-- :arch/*/include/uapi/asm/*.h :include/uapi/ :^*/Kbuild
include/uapi/drm/panfrost_drm.h:/* SPDX-License-Identifier: MIT */
include/uapi/linux/batman_adv.h:/* SPDX-License-Identifier: MIT */
include/uapi/linux/qemu_fw_cfg.h:/* SPDX-License-Identifier: BSD-3-Clause */
include/uapi/linux/vbox_err.h:/* SPDX-License-Identifier: MIT */
include/uapi/linux/virtio_iommu.h:/* SPDX-License-Identifier: BSD-3-Clause */
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* support for chained PMU counters in guests
* improved SError handling
* handle Neoverse N1 erratum #1349291
* allow side-channel mitigation status to be migrated
* standardise most AArch64 system register accesses to msr_s/mrs_s
* fix host MPIDR corruption on 32bit
* selftests ckleanups
x86:
* PMU event {white,black}listing
* ability for the guest to disable host-side interrupt polling
* fixes for enlightened VMCS (Hyper-V pv nested virtualization),
* new hypercall to yield to IPI target
* support for passing cstate MSRs through to the guest
* lots of cleanups and optimizations
Generic:
* Some txt->rST conversions for the documentation
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"ARM:
- support for chained PMU counters in guests
- improved SError handling
- handle Neoverse N1 erratum #1349291
- allow side-channel mitigation status to be migrated
- standardise most AArch64 system register accesses to msr_s/mrs_s
- fix host MPIDR corruption on 32bit
- selftests ckleanups
x86:
- PMU event {white,black}listing
- ability for the guest to disable host-side interrupt polling
- fixes for enlightened VMCS (Hyper-V pv nested virtualization),
- new hypercall to yield to IPI target
- support for passing cstate MSRs through to the guest
- lots of cleanups and optimizations
Generic:
- Some txt->rST conversions for the documentation"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (128 commits)
Documentation: virtual: Add toctree hooks
Documentation: kvm: Convert cpuid.txt to .rst
Documentation: virtual: Convert paravirt_ops.txt to .rst
KVM: x86: Unconditionally enable irqs in guest context
KVM: x86: PMU Event Filter
kvm: x86: Fix -Wmissing-prototypes warnings
KVM: Properly check if "page" is valid in kvm_vcpu_unmap
KVM: arm/arm64: Initialise host's MPIDRs by reading the actual register
KVM: LAPIC: Retry tune per-vCPU timer_advance_ns if adaptive tuning goes insane
kvm: LAPIC: write down valid APIC registers
KVM: arm64: Migrate _elx sysreg accessors to msr_s/mrs_s
KVM: doc: Add API documentation on the KVM_REG_ARM_WORKAROUNDS register
KVM: arm/arm64: Add save/restore support for firmware workaround state
arm64: KVM: Propagate full Spectre v2 workaround state to KVM guests
KVM: arm/arm64: Support chained PMU counters
KVM: arm/arm64: Remove pmc->bitmask
KVM: arm/arm64: Re-create event when setting counter value
KVM: arm/arm64: Extract duplicated code to own function
KVM: arm/arm64: Rename kvm_pmu_{enable/disable}_counter functions
KVM: LAPIC: ARBPRI is a reserved register for x2APIC
...
- A fair pile of RST conversions, many from Mauro. These create more
than the usual number of simple but annoying merge conflicts with other
trees, unfortunately. He has a lot more of these waiting on the wings
that, I think, will go to you directly later on.
- A new document on how to use merges and rebases in kernel repos, and one
on Spectre vulnerabilities.
- Various improvements to the build system, including automatic markup of
function() references because some people, for reasons I will never
understand, were of the opinion that :c:func:``function()`` is
unattractive and not fun to type.
- We now recommend using sphinx 1.7, but still support back to 1.4.
- Lots of smaller improvements, warning fixes, typo fixes, etc.
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Merge tag 'docs-5.3' of git://git.lwn.net/linux
Pull Documentation updates from Jonathan Corbet:
"It's been a relatively busy cycle for docs:
- A fair pile of RST conversions, many from Mauro. These create more
than the usual number of simple but annoying merge conflicts with
other trees, unfortunately. He has a lot more of these waiting on
the wings that, I think, will go to you directly later on.
- A new document on how to use merges and rebases in kernel repos,
and one on Spectre vulnerabilities.
- Various improvements to the build system, including automatic
markup of function() references because some people, for reasons I
will never understand, were of the opinion that
:c:func:``function()`` is unattractive and not fun to type.
- We now recommend using sphinx 1.7, but still support back to 1.4.
- Lots of smaller improvements, warning fixes, typo fixes, etc"
* tag 'docs-5.3' of git://git.lwn.net/linux: (129 commits)
docs: automarkup.py: ignore exceptions when seeking for xrefs
docs: Move binderfs to admin-guide
Disable Sphinx SmartyPants in HTML output
doc: RCU callback locks need only _bh, not necessarily _irq
docs: format kernel-parameters -- as code
Doc : doc-guide : Fix a typo
platform: x86: get rid of a non-existent document
Add the RCU docs to the core-api manual
Documentation: RCU: Add TOC tree hooks
Documentation: RCU: Rename txt files to rst
Documentation: RCU: Convert RCU UP systems to reST
Documentation: RCU: Convert RCU linked list to reST
Documentation: RCU: Convert RCU basic concepts to reST
docs: filesystems: Remove uneeded .rst extension on toctables
scripts/sphinx-pre-install: fix out-of-tree build
docs: zh_CN: submitting-drivers.rst: Remove a duplicated Documentation/
Documentation: PGP: update for newer HW devices
Documentation: Add section about CPU vulnerabilities for Spectre
Documentation: platform: Delete x86-laptop-drivers.txt
docs: Note that :c:func: should no longer be used
...
- 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
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Merge tag 'arm64-upstream' of 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
...
KVM implements the firmware interface for mitigating cache speculation
vulnerabilities. Guests may use this interface to ensure mitigation is
active.
If we want to migrate such a guest to a host with a different support
level for those workarounds, migration might need to fail, to ensure that
critical guests don't loose their protection.
Introduce a way for userland to save and restore the workarounds state.
On restoring we do checks that make sure we don't downgrade our
mitigation level.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
ARMv8.5 introduces the FRINT series of instructions for rounding floating
point numbers to integers. Provide a capability to userspace in order to
allow applications to determine if the system supports these instructions.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
ARMv8.5 adds new instructions XAFLAG and AXFLAG to translate the
representation of the results of floating point comparisons between the
native ARM format and an alternative format used by some software. Add
a hwcap allowing userspace to determine if they are present, since we
referred to earlier CondM extensions as FLAGM call these extensions
FLAGM2.
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Pulling linux/prctl.h into asm/ptrace.h in the arm64 UAPI headers causes
userspace build issues for any program (e.g. strace and qemu) that
includes both <sys/prctl.h> and <linux/ptrace.h> when using musl libc:
| error: redefinition of 'struct prctl_mm_map'
| struct prctl_mm_map {
See 6d4a106e19
for a public example of people working around this issue.
Although it's a bit grotty, fix this breakage by duplicating the prctl
constant definitions. Since these are part of the kernel ABI, they
cannot be changed in future and so it's not the end of the world to have
them open-coded.
Fixes: 43d4da2c45 ("arm64/sve: ptrace and ELF coredump support")
Cc: stable@vger.kernel.org
Acked-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Anisse Astier <aastier@freebox.fr>
Signed-off-by: Will Deacon <will.deacon@arm.com>
The documentation is in a format that is very close to ReST format.
The conversion is actually:
- add blank lines in order to identify paragraphs;
- fixing tables markups;
- adding some lists markups;
- marking literal blocks;
- adjust some title markups.
At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The in-memory representation of SVE and FPSIMD registers is
different: the FPSIMD V-registers are stored as single 128-bit
host-endian values, whereas SVE registers are stored in an
endianness-invariant byte order.
This means that the two representations differ when running on a
big-endian host. But we blindly copy data from one representation
to another when converting between the two, resulting in the
register contents being unintentionally byteswapped in certain
situations. Currently this can be triggered by the first SVE
instruction after a syscall, for example (though the potential
trigger points may vary in future).
So, fix the conversion functions fpsimd_to_sve(), sve_to_fpsimd()
and sve_sync_from_fpsimd_zeropad() to swab where appropriate.
There is no common swahl128() or swab128() that we could use here.
Maybe it would be worth making this generic, but for now add a
simple local hack.
Since the byte order differences are exposed in ABI, also clarify
the documentation.
Cc: Alex Bennée <alex.bennee@linaro.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Alan Hayward <alan.hayward@arm.com>
Cc: Julien Grall <julien.grall@arm.com>
Fixes: bc0ee47603 ("arm64/sve: Core task context handling")
Fixes: 8cd969d28f ("arm64/sve: Signal handling support")
Fixes: 43d4da2c45 ("arm64/sve: ptrace and ELF coredump support")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
[will: Fix typos in comments and docs spotted by Julien]
Signed-off-by: Will Deacon <will.deacon@arm.com>
x86 and um use 31 and 32 for PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP
while powerpc uses different value maybe for legacy reasons.
Though handling of PTRACE_SYSEMU can be made architecture independent,
it's hard to make these definations generic. To add to this existing
mess few architectures like arm, c6x and sh use 31 for PTRACE_GETFDPIC
(get the ELF fdpic loadmap address). It's not possible to move the
definations to generic headers.
So we unfortunately have to duplicate the same defination to ARM64 if
we need to support PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP.
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* POWER: support for direct access to the POWER9 XIVE interrupt controller,
memory and performance optimizations.
* x86: support for accessing memory not backed by struct page, fixes and refactoring
* Generic: dirty page tracking improvements
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"ARM:
- support for SVE and Pointer Authentication in guests
- PMU improvements
POWER:
- support for direct access to the POWER9 XIVE interrupt controller
- memory and performance optimizations
x86:
- support for accessing memory not backed by struct page
- fixes and refactoring
Generic:
- dirty page tracking improvements"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (155 commits)
kvm: fix compilation on aarch64
Revert "KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU"
kvm: x86: Fix L1TF mitigation for shadow MMU
KVM: nVMX: Disable intercept for FS/GS base MSRs in vmcs02 when possible
KVM: PPC: Book3S: Remove useless checks in 'release' method of KVM device
KVM: PPC: Book3S HV: XIVE: Fix spelling mistake "acessing" -> "accessing"
KVM: PPC: Book3S HV: Make sure to load LPID for radix VCPUs
kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete
tests: kvm: Add tests for KVM_SET_NESTED_STATE
KVM: nVMX: KVM_SET_NESTED_STATE - Tear down old EVMCS state before setting new state
tests: kvm: Add tests for KVM_CAP_MAX_VCPUS and KVM_CAP_MAX_CPU_ID
tests: kvm: Add tests to .gitignore
KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
KVM: Fix kvm_clear_dirty_log_protect off-by-(minus-)one
KVM: Fix the bitmap range to copy during clear dirty
KVM: arm64: Fix ptrauth ID register masking logic
KVM: x86: use direct accessors for RIP and RSP
KVM: VMX: Use accessors for GPRs outside of dedicated caching logic
KVM: x86: Omit caching logic for always-available GPRs
kvm, x86: Properly check whether a pfn is an MMIO or not
...
Now that the building blocks of pointer authentication are present, lets
add userspace flags KVM_ARM_VCPU_PTRAUTH_ADDRESS and
KVM_ARM_VCPU_PTRAUTH_GENERIC. These flags will enable pointer
authentication for the KVM guest on a per-vcpu basis through the ioctl
KVM_ARM_VCPU_INIT.
This features will allow the KVM guest to allow the handling of
pointer authentication instructions or to treat them as undefined
if not set.
Necessary documentations are added to reflect the changes done.
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This patch provides support for reporting the presence of SVE2 and
its optional features to userspace.
This will also enable visibility of SVE2 for guests, when KVM
support for SVE-enabled guests is available.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
A complicated DIV_ROUND_UP() expression is currently written out
explicitly in multiple places in order to specify the size of the
bitmap exchanged with userspace to represent the value of the
KVM_REG_ARM64_SVE_VLS pseudo-register.
Userspace currently has no direct way to work this out either: for
documentation purposes, the size is just quoted as 8 u64s.
To make this more intuitive, this patch replaces these with a
single define, which is also exported to userspace as
KVM_ARM64_SVE_VLS_WORDS.
Since the number of words in a bitmap is just the index of the last
word used + 1, this patch expresses the bound that way instead.
This should make it clearer what is being expressed.
For userspace convenience, the minimum and maximum possible vector
lengths relevant to the KVM ABI are exposed to UAPI as
KVM_ARM64_SVE_VQ_MIN, KVM_ARM64_SVE_VQ_MAX. Since the only direct
use for these at present is manipulation of KVM_REG_ARM64_SVE_VLS,
no corresponding _VL_ macros are defined. They could be added
later if a need arises.
Since use of DIV_ROUND_UP() was the only reason for including
<linux/kernel.h> in guest.c, this patch also removes that #include.
Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Currently, the SVE register ID macros are not all defined in the
same way, and advertise the fact that FFR maps onto the nonexistent
predicate register P16. This is really just for kernel
convenience, and may lead userspace into bad habits.
Instead, this patch masks the ID macro arguments so that
architecturally invalid register numbers will not be passed through
any more, and uses a literal KVM_REG_ARM64_SVE_FFR_BASE macro to
define KVM_REG_ARM64_SVE_FFR(), similarly to the way the _ZREG()
and _PREG() macros are defined.
Rather than plugging in magic numbers for the number of Z- and P-
registers and the maximum possible number of register slices, this
patch provides definitions for those too. Userspace is going to
need them in any case, and it makes sense for them to come from
<uapi/asm/kvm.h>.
sve_reg_to_region() uses convenience constants that are defined in
a different way, and also makes use of the fact that the FFR IDs
are really contiguous with the P15 IDs, so this patch retains the
existing convenience constants in guest.c, supplemented with a
couple of sanity checks to check for consistency with the UAPI
header.
Fixes: e1c9c98345 ("KVM: arm64/sve: Add SVE support to register access ioctl interface")
Suggested-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
ARMv8.5 builds upon the ARMv8.2 DC CVAP instruction by introducing a DC
CVADP instruction which cleans the data cache to the point of deep
persistence. Let's expose this support via the arm64 ELF hwcaps.
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
As we will exhaust the first 32 bits of AT_HWCAP let's start
exposing AT_HWCAP2 to userspace to give us up to 64 caps.
Whilst it's possible to use the remaining 32 bits of AT_HWCAP, we
prefer to expand into AT_HWCAP2 in order to provide a consistent
view to userspace between ILP32 and LP64. However internal to the
kernel we prefer to continue to use the full space of elf_hwcap.
To reduce complexity and allow for future expansion, we now
represent hwcaps in the kernel as ordinals and use a
KERNEL_HWCAP_ prefix. This allows us to support automatic feature
based module loading for all our hwcaps.
We introduce cpu_set_feature to set hwcaps which complements the
existing cpu_have_feature helper. These helpers allow us to clean
up existing direct uses of elf_hwcap and reduce any future effort
required to move beyond 64 caps.
For convenience we also introduce cpu_{have,set}_named_feature which
makes use of the cpu_feature macro to allow providing a hwcap name
without a {KERNEL_}HWCAP_ prefix.
Signed-off-by: Andrew Murray <andrew.murray@arm.com>
[will: use const_ilog2() and tweak documentation]
Signed-off-by: Will Deacon <will.deacon@arm.com>
This patch adds a new pseudo-register KVM_REG_ARM64_SVE_VLS to
allow userspace to set and query the set of vector lengths visible
to the guest.
In the future, multiple register slices per SVE register may be
visible through the ioctl interface. Once the set of slices has
been determined we would not be able to allow the vector length set
to be changed any more, in order to avoid userspace seeing
inconsistent sets of registers. For this reason, this patch adds
support for explicit finalization of the SVE configuration via the
KVM_ARM_VCPU_FINALIZE ioctl.
Finalization is the proper place to allocate the SVE register state
storage in vcpu->arch.sve_state, so this patch adds that as
appropriate. The data is freed via kvm_arch_vcpu_uninit(), which
was previously a no-op on arm64.
To simplify the logic for determining what vector lengths can be
supported, some code is added to KVM init to work this out, in the
kvm_arm_init_arch_resources() hook.
The KVM_REG_ARM64_SVE_VLS pseudo-register is not exposed yet.
Subsequent patches will allow SVE to be turned on for guest vcpus,
making it visible.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Tested-by: zhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This patch adds the following registers for access via the
KVM_{GET,SET}_ONE_REG interface:
* KVM_REG_ARM64_SVE_ZREG(n, i) (n = 0..31) (in 2048-bit slices)
* KVM_REG_ARM64_SVE_PREG(n, i) (n = 0..15) (in 256-bit slices)
* KVM_REG_ARM64_SVE_FFR(i) (in 256-bit slices)
In order to adapt gracefully to future architectural extensions,
the registers are logically divided up into slices as noted above:
the i parameter denotes the slice index.
This allows us to reserve space in the ABI for future expansion of
these registers. However, as of today the architecture does not
permit registers to be larger than a single slice, so no code is
needed in the kernel to expose additional slices, for now. The
code can be extended later as needed to expose them up to a maximum
of 32 slices (as carved out in the architecture itself) if they
really exist someday.
The registers are only visible for vcpus that have SVE enabled.
They are not enumerated by KVM_GET_REG_LIST on vcpus that do not
have SVE.
Accesses to the FPSIMD registers via KVM_REG_ARM_CORE is not
allowed for SVE-enabled vcpus: SVE-aware userspace can use the
KVM_REG_ARM64_SVE_ZREG() interface instead to access the same
register state. This avoids some complex and pointless emulation
in the kernel to convert between the two views of these aliased
registers.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Tested-by: zhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Currently, every arch/*/include/uapi/asm/Kbuild explicitly includes
the common Kbuild.asm file. Factor out the duplicated include directives
to scripts/Makefile.asm-generic so that no architecture would opt out
of the mandatory-y mechanism.
um is not forced to include mandatory-y since it is a very exceptional
case which does not support UAPI.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
- Pseudo NMI support for arm64 using GICv3 interrupt priorities
- uaccess macros clean-up (unsafe user accessors also merged but
reverted, waiting for objtool support on arm64)
- ptrace regsets for Pointer Authentication (ARMv8.3) key management
- inX() ordering w.r.t. delay() on arm64 and riscv (acks in place by the
riscv maintainers)
- arm64/perf updates: PMU bindings converted to json-schema, unused
variable and misleading comment removed
- arm64/debug fixes to ensure checking of the triggering exception level
and to avoid the propagation of the UNKNOWN FAR value into the si_code
for debug signals
- Workaround for Fujitsu A64FX erratum 010001
- lib/raid6 ARM NEON optimisations
- NR_CPUS now defaults to 256 on arm64
- Minor clean-ups (documentation/comments, Kconfig warning, unused
asm-offsets, clang warnings)
- MAINTAINERS update for list information to the ARM64 ACPI entry
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Catalin Marinas:
- Pseudo NMI support for arm64 using GICv3 interrupt priorities
- uaccess macros clean-up (unsafe user accessors also merged but
reverted, waiting for objtool support on arm64)
- ptrace regsets for Pointer Authentication (ARMv8.3) key management
- inX() ordering w.r.t. delay() on arm64 and riscv (acks in place by
the riscv maintainers)
- arm64/perf updates: PMU bindings converted to json-schema, unused
variable and misleading comment removed
- arm64/debug fixes to ensure checking of the triggering exception
level and to avoid the propagation of the UNKNOWN FAR value into the
si_code for debug signals
- Workaround for Fujitsu A64FX erratum 010001
- lib/raid6 ARM NEON optimisations
- NR_CPUS now defaults to 256 on arm64
- Minor clean-ups (documentation/comments, Kconfig warning, unused
asm-offsets, clang warnings)
- MAINTAINERS update for list information to the ARM64 ACPI entry
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (54 commits)
arm64: mmu: drop paging_init comments
arm64: debug: Ensure debug handlers check triggering exception level
arm64: debug: Don't propagate UNKNOWN FAR into si_code for debug signals
Revert "arm64: uaccess: Implement unsafe accessors"
arm64: avoid clang warning about self-assignment
arm64: Kconfig.platforms: fix warning unmet direct dependencies
lib/raid6: arm: optimize away a mask operation in NEON recovery routine
lib/raid6: use vdupq_n_u8 to avoid endianness warnings
arm64: io: Hook up __io_par() for inX() ordering
riscv: io: Update __io_[p]ar() macros to take an argument
asm-generic/io: Pass result of I/O accessor to __io_[p]ar()
arm64: Add workaround for Fujitsu A64FX erratum 010001
arm64: Rename get_thread_info()
arm64: Remove documentation about TIF_USEDFPU
arm64: irqflags: Fix clang build warnings
arm64: Enable the support of pseudo-NMIs
arm64: Skip irqflags tracing for NMI in IRQs disabled context
arm64: Skip preemption when exiting an NMI
arm64: Handle serror in NMI context
irqchip/gic-v3: Allow interrupts to be set as pseudo-NMI
...
We don't want new architectures to even provide the old 32-bit time_t
based system calls any more, or define the syscall number macros.
Add a new __ARCH_WANT_TIME32_SYSCALLS macro that gets enabled for all
existing 32-bit architectures using the generic system call table,
so we don't change any current behavior.
Since this symbol is evaluated in user space as well, we cannot use
a Kconfig CONFIG_* macro but have to define it in uapi/asm/unistd.h.
On 64-bit architectures, the same system call numbers mostly refer to
the system calls we want to keep, as they already pass 64-bit time_t.
As new architectures no longer provide these, we need new exceptions
in checksyscalls.sh.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The newer prlimit64 syscall provides all the functionality of getrlimit
and setrlimit syscalls and adds the pid of target process, so future
architectures won't need to include getrlimit and setrlimit.
Therefore drop getrlimit and setrlimit syscalls from the generic syscall
list unless __ARCH_WANT_SET_GET_RLIMIT is defined by the architecture's
unistd.h prior to including asm-generic/unistd.h, and adjust all
architectures using the generic syscall list to define it so that no
in-tree architectures are affected.
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-hexagon@vger.kernel.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: James Hogan <james.hogan@imgtec.com> [metag]
Acked-by: Ley Foon Tan <lftan@altera.com> [nios2]
Acked-by: Stafford Horne <shorne@gmail.com> [openrisc]
Acked-by: Will Deacon <will.deacon@arm.com> [arm64]
Acked-by: Vineet Gupta <vgupta@synopsys.com> #arch/arc bits
Signed-off-by: Yury Norov <ynorov@marvell.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Add two new ptrace regsets, which can be used to request and change the
pointer authentication keys of a thread. NT_ARM_PACA_KEYS gives access
to the instruction/data address keys, and NT_ARM_PACG_KEYS to the
generic authentication key. The keys are also part of the core dump file
of the process.
The regsets are only exposed if the kernel is compiled with
CONFIG_CHECKPOINT_RESTORE=y, as the only intended use case is
checkpointing and restoring processes that are using pointer
authentication. (This can be changed later if there are other use
cases.)
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Now that Kbuild automatically creates asm-generic wrappers for missing
mandatory headers, it is redundant to list the same headers in
generic-y and mandatory-y.
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
These comments are leftovers of commit fcc8487d47 ("uapi: export all
headers under uapi directories").
Prior to that commit, exported headers must be explicitly added to
header-y. Now, all headers under the uapi/ directories are exported.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Currently, <uapi/asm/sigcontext.h> provides common definitions for
describing SVE context structures that are also used by the ptrace
definitions in <uapi/asm/ptrace.h>.
For this reason, a #include of <asm/sigcontext.h> was added in
ptrace.h, but it this turns out that this can interact badly with
userspace code that tries to include ptrace.h on top of the libc
headers (which may provide their own shadow definitions for
sigcontext.h).
To make the headers easier for userspace to consume, this patch
bounces the common definitions into an __SVE_* namespace and moves
them to a backend header <uapi/asm/sve_context.h> that can be
included by the other headers as appropriate. This should allow
ptrace.h to be used alongside libc's sigcontext.h (if any) without
ill effects.
This should make the situation unambiguous: <asm/sigcontext.h> is
the header to include for the sigframe-specific definitions, while
<asm/ptrace.h> is the header to include for ptrace-specific
definitions.
To avoid conflicting with existing usage, <asm/sigcontext.h>
remains the canonical way to get the common definitions for
SVE_VQ_MIN, sve_vq_from_vl() etc., both in userspace and in the
kernel: relying on these being defined as a side effect of
including just <asm/ptrace.h> was never intended to be safe.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
SVE_PT_REGS_OFFSET is supposed to indicate the offset for skipping
over the ptrace NT_ARM_SVE header (struct user_sve_header) to the
start of the SVE register data proper.
However, currently SVE_PT_REGS_OFFSET is defined in terms of struct
sve_context, which is wrong: that structure describes the SVE
header in the signal frame, not in the ptrace regset.
This patch fixes the definition to use the ptrace header structure
struct user_sve_header instead.
By good fortune, the two structures are the same size anyway, so
there is no functional or ABI change.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
When pointer authentication is in use, data/instruction pointers have a
number of PAC bits inserted into them. The number and position of these
bits depends on the configured TCR_ELx.TxSZ and whether tagging is
enabled. ARMv8.3 allows tagging to differ for instruction and data
pointers.
For userspace debuggers to unwind the stack and/or to follow pointer
chains, they need to be able to remove the PAC bits before attempting to
use a pointer.
This patch adds a new structure with masks describing the location of
the PAC bits in userspace instruction and data pointers (i.e. those
addressable via TTBR0), which userspace can query via PTRACE_GETREGSET.
By clearing these bits from pointers (and replacing them with the value
of bit 55), userspace can acquire the PAC-less versions.
This new regset is exposed when the kernel is built with (user) pointer
authentication support, and the address authentication feature is
enabled. Otherwise, the regset is hidden.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[will: Fix to use vabits_user instead of VA_BITS and rename macro]
Signed-off-by: Will Deacon <will.deacon@arm.com>
This patch adds basic support for pointer authentication, allowing
userspace to make use of APIAKey, APIBKey, APDAKey, APDBKey, and
APGAKey. The kernel maintains key values for each process (shared by all
threads within), which are initialised to random values at exec() time.
The ID_AA64ISAR1_EL1.{APA,API,GPA,GPI} fields are exposed to userspace,
to describe that pointer authentication instructions are available and
that the kernel is managing the keys. Two new hwcaps are added for the
same reason: PACA (for address authentication) and PACG (for generic
authentication).
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Tested-by: Adam Wallis <awallis@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
[will: Fix sizeof() usage and unroll address key initialisation]
Signed-off-by: Will Deacon <will.deacon@arm.com>
We currently use a DSB; ISB sequence to inhibit speculation in set_fs().
Whilst this works for current CPUs, future CPUs may implement a new SB
barrier instruction which acts as an architected speculation barrier.
On CPUs that support it, patch in an SB; NOP sequence over the DSB; ISB
sequence and advertise the presence of the new instruction to userspace.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Pull timekeeping updates from Thomas Gleixner:
"The timers and timekeeping departement provides:
- Another large y2038 update with further preparations for providing
the y2038 safe timespecs closer to the syscalls.
- An overhaul of the SHCMT clocksource driver
- SPDX license identifier updates
- Small cleanups and fixes all over the place"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits)
tick/sched : Remove redundant cpu_online() check
clocksource/drivers/dw_apb: Add reset control
clocksource: Remove obsolete CLOCKSOURCE_OF_DECLARE
clocksource/drivers: Unify the names to timer-* format
clocksource/drivers/sh_cmt: Add R-Car gen3 support
dt-bindings: timer: renesas: cmt: document R-Car gen3 support
clocksource/drivers/sh_cmt: Properly line-wrap sh_cmt_of_table[] initializer
clocksource/drivers/sh_cmt: Fix clocksource width for 32-bit machines
clocksource/drivers/sh_cmt: Fixup for 64-bit machines
clocksource/drivers/sh_tmu: Convert to SPDX identifiers
clocksource/drivers/sh_mtu2: Convert to SPDX identifiers
clocksource/drivers/sh_cmt: Convert to SPDX identifiers
clocksource/drivers/renesas-ostm: Convert to SPDX identifiers
clocksource: Convert to using %pOFn instead of device_node.name
tick/broadcast: Remove redundant check
RISC-V: Request newstat syscalls
y2038: signal: Change rt_sigtimedwait to use __kernel_timespec
y2038: socket: Change recvmmsg to use __kernel_timespec
y2038: sched: Change sched_rr_get_interval to use __kernel_timespec
y2038: utimes: Rework #ifdef guards for compat syscalls
...
Pull siginfo updates from Eric Biederman:
"I have been slowly sorting out siginfo and this is the culmination of
that work.
The primary result is in several ways the signal infrastructure has
been made less error prone. The code has been updated so that manually
specifying SEND_SIG_FORCED is never necessary. The conversion to the
new siginfo sending functions is now complete, which makes it
difficult to send a signal without filling in the proper siginfo
fields.
At the tail end of the patchset comes the optimization of decreasing
the size of struct siginfo in the kernel from 128 bytes to about 48
bytes on 64bit. The fundamental observation that enables this is by
definition none of the known ways to use struct siginfo uses the extra
bytes.
This comes at the cost of a small user space observable difference.
For the rare case of siginfo being injected into the kernel only what
can be copied into kernel_siginfo is delivered to the destination, the
rest of the bytes are set to 0. For cases where the signal and the
si_code are known this is safe, because we know those bytes are not
used. For cases where the signal and si_code combination is unknown
the bits that won't fit into struct kernel_siginfo are tested to
verify they are zero, and the send fails if they are not.
I made an extensive search through userspace code and I could not find
anything that would break because of the above change. If it turns out
I did break something it will take just the revert of a single change
to restore kernel_siginfo to the same size as userspace siginfo.
Testing did reveal dependencies on preferring the signo passed to
sigqueueinfo over si->signo, so bit the bullet and added the
complexity necessary to handle that case.
Testing also revealed bad things can happen if a negative signal
number is passed into the system calls. Something no sane application
will do but something a malicious program or a fuzzer might do. So I
have fixed the code that performs the bounds checks to ensure negative
signal numbers are handled"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits)
signal: Guard against negative signal numbers in copy_siginfo_from_user32
signal: Guard against negative signal numbers in copy_siginfo_from_user
signal: In sigqueueinfo prefer sig not si_signo
signal: Use a smaller struct siginfo in the kernel
signal: Distinguish between kernel_siginfo and siginfo
signal: Introduce copy_siginfo_from_user and use it's return value
signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
signal: Fail sigqueueinfo if si_signo != sig
signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
signal/unicore32: Use force_sig_fault where appropriate
signal/unicore32: Generate siginfo in ucs32_notify_die
signal/unicore32: Use send_sig_fault where appropriate
signal/arc: Use force_sig_fault where appropriate
signal/arc: Push siginfo generation into unhandled_exception
signal/ia64: Use force_sig_fault where appropriate
signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn
signal/ia64: Use the generic force_sigsegv in setup_frame
signal/arm/kvm: Use send_sig_mceerr
signal/arm: Use send_sig_fault where appropriate
signal/arm: Use force_sig_fault where appropriate
...
Rework the defintion of struct siginfo so that the array padding
struct siginfo to SI_MAX_SIZE can be placed in a union along side of
the rest of the struct siginfo members. The result is that we no
longer need the __ARCH_SI_PREAMBLE_SIZE or SI_PAD_SIZE definitions.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
On CPUs with support for PSTATE.SSBS, the kernel can toggle the SSBD
state without needing to call into firmware.
This patch hooks into the existing SSBD infrastructure so that SSBS is
used on CPUs that support it, but it's all made horribly complicated by
the very real possibility of big/little systems that don't uniformly
provide the new capability.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Armv8.5 introduces a new PSTATE bit known as Speculative Store Bypass
Safe (SSBS) which can be used as a mitigation against Spectre variant 4.
Additionally, a CPU may provide instructions to manipulate PSTATE.SSBS
directly, so that userspace can toggle the SSBS control without trapping
to the kernel.
This patch probes for the existence of SSBS and advertise the new instructions
to userspace if they exist.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
We have four generations of stat() syscalls:
- the oldstat syscalls that are only used on the older architectures
- the newstat family that is used on all 64-bit architectures but
lacked support for large files on 32-bit architectures.
- the stat64 family that is used mostly on 32-bit architectures to
replace newstat
- statx() to replace all of the above, adding 64-bit timestamps among
other things.
We already compile stat64 only on those architectures that need it,
but newstat is always built, including on those that don't reference
it. This adds a new __ARCH_WANT_NEW_STAT symbol along the lines of
__ARCH_WANT_OLD_STAT and __ARCH_WANT_STAT64 to control compilation of
newstat. All architectures that need it use an explict define, the
others now get a little bit smaller, and future architecture (including
64-bit targets) won't ever see it.
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
For the migrating VMs, user space may need to know the exception
state. For example, in the machine A, KVM make an SError pending,
when migrate to B, KVM also needs to pend an SError.
This new IOCTL exports user-invisible states related to SError.
Together with appropriate user space changes, user space can get/set
the SError exception state to do migrate/snapshot/suspend.
Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
[expanded documentation wording]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
* ARM: lazy context-switching of FPSIMD registers on arm64, "split"
regions for vGIC redistributor
* s390: cleanups for nested, clock handling, crypto, storage keys and
control register bits
* x86: many bugfixes, implement more Hyper-V super powers,
implement lapic_timer_advance_ns even when the LAPIC timer
is emulated using the processor's VMX preemption timer. Two
security-related bugfixes at the top of the branch.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"Small update for KVM:
ARM:
- lazy context-switching of FPSIMD registers on arm64
- "split" regions for vGIC redistributor
s390:
- cleanups for nested
- clock handling
- crypto
- storage keys
- control register bits
x86:
- many bugfixes
- implement more Hyper-V super powers
- implement lapic_timer_advance_ns even when the LAPIC timer is
emulated using the processor's VMX preemption timer.
- two security-related bugfixes at the top of the branch"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (79 commits)
kvm: fix typo in flag name
kvm: x86: use correct privilege level for sgdt/sidt/fxsave/fxrstor access
KVM: x86: pass kvm_vcpu to kvm_read_guest_virt and kvm_write_guest_virt_system
KVM: x86: introduce linear_{read,write}_system
kvm: nVMX: Enforce cpl=0 for VMX instructions
kvm: nVMX: Add support for "VMWRITE to any supported field"
kvm: nVMX: Restrict VMX capability MSR changes
KVM: VMX: Optimize tscdeadline timer latency
KVM: docs: nVMX: Remove known limitations as they do not exist now
KVM: docs: mmu: KVM support exposing SLAT to guests
kvm: no need to check return value of debugfs_create functions
kvm: Make VM ioctl do valloc for some archs
kvm: Change return type to vm_fault_t
KVM: docs: mmu: Fix link to NPT presentation from KVM Forum 2008
kvm: x86: Amend the KVM_GET_SUPPORTED_CPUID API documentation
KVM: x86: hyperv: declare KVM_CAP_HYPERV_TLBFLUSH capability
KVM: x86: hyperv: simplistic HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE}_EX implementation
KVM: x86: hyperv: simplistic HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE} implementation
KVM: introduce kvm_make_vcpus_request_mask() API
KVM: x86: hyperv: do rep check for each hypercall separately
...
Stateful CPU architecture extensions may require the signal frame
to grow to a size that exceeds the arch's MINSIGSTKSZ #define.
However, changing this #define is an ABI break.
To allow userspace the option of determining the signal frame size
in a more forwards-compatible way, this patch adds a new auxv entry
tagged with AT_MINSIGSTKSZ, which provides the maximum signal frame
size that the process can observe during its lifetime.
If AT_MINSIGSTKSZ is absent from the aux vector, the caller can
assume that the MINSIGSTKSZ #define is sufficient. This allows for
a consistent interface with older kernels that do not provide
AT_MINSIGSTKSZ.
The idea is that libc could expose this via sysconf() or some
similar mechanism.
There is deliberately no AT_SIGSTKSZ. The kernel knows nothing
about userspace's own stack overheads and should not pretend to
know.
For arm64:
The primary motivation for this interface is the Scalable Vector
Extension, which can require at least 4KB or so of extra space
in the signal frame for the largest hardware implementations.
To determine the correct value, a "Christmas tree" mode (via the
add_all argument) is added to setup_sigframe_layout(), to simulate
addition of all possible records to the signal frame at maximum
possible size.
If this procedure goes wrong somehow, resulting in a stupidly large
frame layout and hence failure of sigframe_alloc() to allocate a
record to the frame, then this is indicative of a kernel bug. In
this case, we WARN() and no attempt is made to populate
AT_MINSIGSTKSZ for userspace.
For arm64 SVE:
The SVE context block in the signal frame needs to be considered
too when computing the maximum possible signal frame size.
Because the size of this block depends on the vector length, this
patch computes the size based not on the thread's current vector
length but instead on the maximum possible vector length: this
determines the maximum size of SVE context block that can be
observed in any signal frame for the lifetime of the process.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This new attribute allows the userspace to set the base address
of a reditributor region, relaxing the constraint of having all
consecutive redistibutor frames contiguous.
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Although we've implemented PSCI 0.1, 0.2 and 1.0, we expose either 0.1
or 1.0 to a guest, defaulting to the latest version of the PSCI
implementation that is compatible with the requested version. This is
no different from doing a firmware upgrade on KVM.
But in order to give a chance to hypothetical badly implemented guests
that would have a fit by discovering something other than PSCI 0.2,
let's provide a new API that allows userspace to pick one particular
version of the API.
This is implemented as a new class of "firmware" registers, where
we expose the PSCI version. This allows the PSCI version to be
save/restored as part of a guest migration, and also set to
any supported version if the guest requires it.
Cc: stable@vger.kernel.org #4.16
Reviewed-by: Christoffer Dall <cdall@kernel.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Currently a SIGFPE delivered in response to a floating-point
exception trap may have si_code set to 0 on arm64. As reported by
Eric, this is a bad idea since this is the value of SI_USER -- yet
this signal is definitely not the result of kill(2), tgkill(2) etc.
and si_uid and si_pid make limited sense whereas we do want to
yield a value for si_addr (which doesn't exist for SI_USER).
It's not entirely clear whether the architecure permits a
"spurious" fp exception trap where none of the exception flag bits
in ESR_ELx is set. (IMHO the architectural intent is to forbid
this.) However, it does permit those bits to contain garbage if
the TFV bit in ESR_ELx is 0. That case isn't currently handled at
all and may result in si_code == 0 or si_code containing a FPE_FLT*
constant corresponding to an exception that did not in fact happen.
There is nothing sensible we can return for si_code in such cases,
but SI_USER is certainly not appropriate and will lead to violation
of legitimate userspace assumptions.
This patch allocates a new si_code value FPE_UNKNOWN that at least
does not conflict with any existing SI_* or FPE_* code, and yields
this in si_code for undiagnosable cases. This is probably the best
simplicity/incorrectness tradeoff achieveable without relying on
implementation-dependent features or adding a lot of code. In any
case, there appears to be no perfect solution possible that would
justify a lot of effort here.
Yielding FPE_UNKNOWN when some well-defined fp exception caused the
trap is a violation of POSIX, but this is forced by the
architecture. We have no realistic prospect of yielding the
correct code in such cases. At present I am not aware of any ARMv8
implementation that supports trapped floating-point exceptions in
any case.
The new code may be applicable to other architectures for similar
reasons.
No attempt is made to provide ESR_ELx to userspace in the signal
frame, since architectural limitations mean that it is unlikely to
provide much diagnostic value, doesn't benefit existing software
and would create ABI with no proven purpose. The existing
mechanism for passing it also has problems of its own which may
result in the wrong value being passed to userspace due to
interaction with mm faults. The implied rework does not appear
justified.
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reported-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Expose the new features introduced by Arm v8.4 extensions to
Arm v8-A profile.
These include :
1) Data indpendent timing of instructions. (DIT, exposed as HWCAP_DIT)
2) Unaligned atomic instructions and Single-copy atomicity of loads
and stores. (AT, expose as HWCAP_USCAT)
3) LDAPR and STLR instructions with immediate offsets (extension to
LRCPC, exposed as HWCAP_ILRCPC)
4) Flag manipulation instructions (TS, exposed as HWCAP_FLAGM).
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Dave Martin <dave.martin@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Currently, as reported by Eric, an invalid si_code value 0 is
passed in many signals delivered to userspace in response to faults
and other kernel errors. Typically 0 is passed when the fault is
insufficiently diagnosable or when there does not appear to be any
sensible alternative value to choose.
This appears to violate POSIX, and is intuitively wrong for at
least two reasons arising from the fact that 0 == SI_USER:
1) si_code is a union selector, and SI_USER (and si_code <= 0 in
general) implies the existence of a different set of fields
(siginfo._kill) from that which exists for a fault signal
(siginfo._sigfault). However, the code raising the signal
typically writes only the _sigfault fields, and the _kill
fields make no sense in this case.
Thus when userspace sees si_code == 0 (SI_USER) it may
legitimately inspect fields in the inactive union member _kill
and obtain garbage as a result.
There appears to be software in the wild relying on this,
albeit generally only for printing diagnostic messages.
2) Software that wants to be robust against spurious signals may
discard signals where si_code == SI_USER (or <= 0), or may
filter such signals based on the si_uid and si_pid fields of
siginfo._sigkill. In the case of fault signals, this means
that important (and usually fatal) error conditions may be
silently ignored.
In practice, many of the faults for which arm64 passes si_code == 0
are undiagnosable conditions such as exceptions with syndrome
values in ESR_ELx to which the architecture does not yet assign any
meaning, or conditions indicative of a bug or error in the kernel
or system and thus that are unrecoverable and should never occur in
normal operation.
The approach taken in this patch is to translate all such
undiagnosable or "impossible" synchronous fault conditions to
SIGKILL, since these are at least probably localisable to a single
process. Some of these conditions should really result in a kernel
panic, but due to the lack of diagnostic information it is
difficult to be certain: this patch does not add any calls to
panic(), but this could change later if justified.
Although si_code will not reach userspace in the case of SIGKILL,
it is still desirable to pass a nonzero value so that the common
siginfo handling code can detect incorrect use of si_code == 0
without false positives. In this case the si_code dependent
siginfo fields will not be correctly initialised, but since they
are not passed to userspace I deem this not to matter.
A few faults can reasonably occur in realistic userspace scenarios,
and _should_ raise a regular, handleable (but perhaps not
ignorable/blockable) signal: for these, this patch attempts to
choose a suitable standard si_code value for the raised signal in
each case instead of 0.
arm64 was the only arch to define a BUS_FIXME code, so after this
patch nobody defines it. This patch therefore also removes the
relevant code from siginfo_layout().
Cc: James Morse <james.morse@arm.com>
Reported-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
