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2020-01-14arm64: Introduce system_capabilities_finalized() markerSuzuki K Poulose
We finalize the system wide capabilities after the SMP CPUs are booted by the kernel. This is used as a marker for deciding various checks in the kernel. e.g, sanity check the hotplugged CPUs for missing mandatory features. However there is no explicit helper available for this in the kernel. There is sys_caps_initialised, which is not exposed. The other closest one we have is the jump_label arm64_const_caps_ready which denotes that the capabilities are set and the capability checks could use the individual jump_labels for fast path. This is performed before setting the ELF Hwcaps, which must be checked against the new CPUs. We also perform some of the other initialization e.g, SVE setup, which is important for the use of FP/SIMD where SVE is supported. Normally userspace doesn't get to run before we finish this. However the in-kernel users may potentially start using the neon mode. So, we need to reject uses of neon mode before we are set. Instead of defining a new marker for the completion of SVE setup, we could simply reuse the arm64_const_caps_ready and enable it once we have finished all the setup. Also we could expose this to the various users as "system_capabilities_finalized()" to make it more meaningful than "const_caps_ready". Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
2019-10-18arm64: cpufeature: introduce helper cpu_has_hw_af()Jia He
We unconditionally set the HW_AFDBM capability and only enable it on CPUs which really have the feature. But sometimes we need to know whether this cpu has the capability of HW AF. So decouple AF from DBM by a new helper cpu_has_hw_af(). If later we noticed a potential performance issue on this path, we can turn it into a static label as with other CPU features. Signed-off-by: Jia He <justin.he@arm.com> Suggested-by: Suzuki Poulose <Suzuki.Poulose@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2019-08-14arm64: Clarify when cpu_enable() is calledMark Brown
Strengthen the wording in the documentation for cpu_enable() to make it more obvious to readers not already familiar with the code when the core will call this callback and that this is intentional. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> [will: minor tweak to emphasis in the comment] Signed-off-by: Will Deacon <will@kernel.org>
2019-08-05arm64: Remove unused cpucap_multi_entry_cap_cpu_enable()Mark Brown
The function cpucap_multi_entry_cap_cpu_enable() is unused, remove it to avoid any confusion reading the code and potential for bit rot. Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Will Deacon <will@kernel.org>
2019-07-31arm64: cpufeature: Fix feature comparison for CTR_EL0.{CWG,ERG}Will Deacon
If CTR_EL0.{CWG,ERG} are 0b0000 then they must be interpreted to have their architecturally maximum values, which defeats the use of FTR_HIGHER_SAFE when sanitising CPU ID registers on heterogeneous machines. Introduce FTR_HIGHER_OR_ZERO_SAFE so that these fields effectively saturate at zero. Fixes: 3c739b571084 ("arm64: Keep track of CPU feature registers") Cc: <stable@vger.kernel.org> # 4.4.x- Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2019-07-12Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
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 ...
2019-07-08Merge tag 'arm64-upstream' of ↵Linus Torvalds
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 ...
2019-07-05arm64: KVM: Propagate full Spectre v2 workaround state to KVM guestsAndre Przywara
Recent commits added the explicit notion of "workaround not required" to the state of the Spectre v2 (aka. BP_HARDENING) workaround, where we just had "needed" and "unknown" before. Export this knowledge to the rest of the kernel and enhance the existing kvm_arm_harden_branch_predictor() to report this new state as well. Export this new state to guests when they use KVM's firmware interface emulation. Signed-off-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Steven Price <steven.price@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2019-06-21arm64: irqflags: Introduce explicit debugging for IRQ prioritiesJulien Thierry
Using IRQ priority masking to enable/disable interrupts is a bit sensitive as it requires to deal with both ICC_PMR_EL1 and PSR.I. Introduce some validity checks to both highlight the states in which functions dealing with IRQ enabling/disabling can (not) be called, and bark a warning when called in an unexpected state. Since these checks are done on hotpaths, introduce a build option to choose whether to do the checking. Cc: Will Deacon <will.deacon@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14arm64: mark (__)cpus_have_const_cap as __always_inlineMasahiro Yamada
This prepares to move CONFIG_OPTIMIZE_INLINING from x86 to a common place. We need to eliminate potential issues beforehand. If it is enabled for arm64, the following errors are reported: In file included from include/linux/compiler_types.h:68, from <command-line>: arch/arm64/include/asm/jump_label.h: In function 'cpus_have_const_cap': include/linux/compiler-gcc.h:120:38: warning: asm operand 0 probably doesn't match constraints #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) ^~~ arch/arm64/include/asm/jump_label.h:32:2: note: in expansion of macro 'asm_volatile_goto' asm_volatile_goto( ^~~~~~~~~~~~~~~~~ include/linux/compiler-gcc.h:120:38: error: impossible constraint in 'asm' #define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0) ^~~ arch/arm64/include/asm/jump_label.h:32:2: note: in expansion of macro 'asm_volatile_goto' asm_volatile_goto( ^~~~~~~~~~~~~~~~~ Link: http://lkml.kernel.org/r/20190423034959.13525-3-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Boris Brezillon <bbrezillon@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Norris <computersforpeace@gmail.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Marek Vasut <marek.vasut@gmail.com> Cc: Mathieu Malaterre <malat@debian.org> Cc: Miquel Raynal <miquel.raynal@bootlin.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Stefan Agner <stefan@agner.ch> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-01Merge branch 'for-next/mitigations' of ↵Will Deacon
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into for-next/core
2019-04-26arm64: Always enable ssb vulnerability detectionJeremy Linton
Ensure we are always able to detect whether or not the CPU is affected by SSB, so that we can later advertise this to userspace. Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Reviewed-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Stefan Wahren <stefan.wahren@i2se.com> [will: Use IS_ENABLED instead of #ifdef] Signed-off-by: Will Deacon <will.deacon@arm.com>
2019-04-16arm64: HWCAP: encapsulate elf_hwcapAndrew Murray
The introduction of AT_HWCAP2 introduced accessors which ensure that hwcap features are set and tested appropriately. Let's now mandate access to elf_hwcap via these accessors by making elf_hwcap static within cpufeature.c. Signed-off-by: Andrew Murray <andrew.murray@arm.com> Reviewed-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2019-04-16arm64: HWCAP: add support for AT_HWCAP2Andrew Murray
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>
2019-02-06arm64: alternative: Apply alternatives early in boot processDaniel Thompson
Currently alternatives are applied very late in the boot process (and a long time after we enable scheduling). Some alternative sequences, such as those that alter the way CPU context is stored, must be applied much earlier in the boot sequence. Introduce apply_boot_alternatives() to allow some alternatives to be applied immediately after we detect the CPU features of the boot CPU. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> [julien.thierry@arm.com: rename to fit new cpufeature framework better, apply BOOT_SCOPE feature early in boot] Signed-off-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Christoffer Dall <christoffer.dall@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2019-02-06arm64: cpufeature: Add cpufeature for IRQ priority maskingJulien Thierry
Add a cpufeature indicating whether a cpu supports masking interrupts by priority. The feature will be properly enabled in a later patch. Signed-off-by: Julien Thierry <julien.thierry@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-12-13arm64: cpufeature: Rework ptr auth hwcaps using multi_entry_cap_matchesWill Deacon
Open-coding the pointer-auth HWCAPs is a mess and can be avoided by reusing the multi-cap logic from the CPU errata framework. Move the multi_entry_cap_matches code to cpufeature.h and reuse it for the pointer auth HWCAPs. Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-13arm64: cpufeature: Reduce number of pointer auth CPU caps from 6 to 4Will Deacon
We can easily avoid defining the two meta-capabilities for the address and generic keys, so remove them and instead just check both of the architected and impdef capabilities when determining the level of system support. Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-13arm64/cpufeature: detect pointer authenticationMark Rutland
So that we can dynamically handle the presence of pointer authentication functionality, wire up probing code in cpufeature.c. From ARMv8.3 onwards, ID_AA64ISAR1 is no longer entirely RES0, and now has four fields describing the presence of pointer authentication functionality: * APA - address authentication present, using an architected algorithm * API - address authentication present, using an IMP DEF algorithm * GPA - generic authentication present, using an architected algorithm * GPI - generic authentication present, using an IMP DEF algorithm This patch checks for both address and generic authentication, separately. It is assumed that if all CPUs support an IMP DEF algorithm, the same algorithm is used across all CPUs. 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: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-10Merge branch 'for-next/kexec' into aarch64/for-next/coreWill Deacon
Merge in kexec_file_load() support from Akashi Takahiro.
2018-12-06arm64: capabilities: Batch cpu_enable callbacksSuzuki K Poulose
We use a stop_machine call for each available capability to enable it on all the CPUs available at boot time. Instead we could batch the cpu_enable callbacks to a single stop_machine() call to save us some time. Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com> Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-06arm64: cpufeature: add MMFR0 helper functionsAKASHI Takahiro
Those helper functions for MMFR0 register will be used later by kexec_file loader. Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-10-25Merge tag 'kvm-4.20-1' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM updates from Radim Krčmář: "ARM: - Improved guest IPA space support (32 to 52 bits) - RAS event delivery for 32bit - PMU fixes - Guest entry hardening - Various cleanups - Port of dirty_log_test selftest PPC: - Nested HV KVM support for radix guests on POWER9. The performance is much better than with PR KVM. Migration and arbitrary level of nesting is supported. - Disable nested HV-KVM on early POWER9 chips that need a particular hardware bug workaround - One VM per core mode to prevent potential data leaks - PCI pass-through optimization - merge ppc-kvm topic branch and kvm-ppc-fixes to get a better base s390: - Initial version of AP crypto virtualization via vfio-mdev - Improvement for vfio-ap - Set the host program identifier - Optimize page table locking x86: - Enable nested virtualization by default - Implement Hyper-V IPI hypercalls - Improve #PF and #DB handling - Allow guests to use Enlightened VMCS - Add migration selftests for VMCS and Enlightened VMCS - Allow coalesced PIO accesses - Add an option to perform nested VMCS host state consistency check through hardware - Automatic tuning of lapic_timer_advance_ns - Many fixes, minor improvements, and cleanups" * tag 'kvm-4.20-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (204 commits) KVM/nVMX: Do not validate that posted_intr_desc_addr is page aligned Revert "kvm: x86: optimize dr6 restore" KVM: PPC: Optimize clearing TCEs for sparse tables x86/kvm/nVMX: tweak shadow fields selftests/kvm: add missing executables to .gitignore KVM: arm64: Safety check PSTATE when entering guest and handle IL KVM: PPC: Book3S HV: Don't use streamlined entry path on early POWER9 chips arm/arm64: KVM: Enable 32 bits kvm vcpu events support arm/arm64: KVM: Rename function kvm_arch_dev_ioctl_check_extension() KVM: arm64: Fix caching of host MDCR_EL2 value KVM: VMX: enable nested virtualization by default KVM/x86: Use 32bit xor to clear registers in svm.c kvm: x86: Introduce KVM_CAP_EXCEPTION_PAYLOAD kvm: vmx: Defer setting of DR6 until #DB delivery kvm: x86: Defer setting of CR2 until #PF delivery kvm: x86: Add payload operands to kvm_multiple_exception kvm: x86: Add exception payload fields to kvm_vcpu_events kvm: x86: Add has_payload and payload to kvm_queued_exception KVM: Documentation: Fix omission in struct kvm_vcpu_events KVM: selftests: add Enlightened VMCS test ...
2018-10-01arm64: Add a helper for PARange to physical shift conversionSuzuki K Poulose
On arm64, ID_AA64MMFR0_EL1.PARange encodes the maximum Physical Address range supported by the CPU. Add a helper to decode this to actual physical shift. If we hit an unallocated value, return the maximum range supported by the kernel. This will be used by KVM to set the VTCR_EL2.T0SZ, as it is about to move its place. Having this helper keeps the code movement cleaner. Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: James Morse <james.morse@arm.com> Cc: Christoffer Dall <cdall@kernel.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-09-21arm64/cpufeatures: Factorize emulate_mrs()Anshuman Khandual
MRS emulation gets triggered with exception class (0x00 or 0x18) eventually calling the function emulate_mrs() which fetches the user space instruction and analyses it's encodings (OP0, OP1, OP2, CRN, CRM, RT). The kernel tries to emulate the given instruction looking into the encoding details. Going forward these encodings can also be parsed from ESR_ELx.ISS fields without requiring to fetch/decode faulting userspace instruction which can improve performance. This factorizes emulate_mrs() function in a way that it can be called directly with MRS encodings (OP0, OP1, OP2, CRN, CRM) for any given target register which can then be used directly from 0x18 exception class. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-09-18arm64: mm: Support Common Not Private translationsVladimir Murzin
Common Not Private (CNP) is a feature of ARMv8.2 extension which allows translation table entries to be shared between different PEs in the same inner shareable domain, so the hardware can use this fact to optimise the caching of such entries in the TLB. CNP occupies one bit in TTBRx_ELy and VTTBR_EL2, which advertises to the hardware that the translation table entries pointed to by this TTBR are the same as every PE in the same inner shareable domain for which the equivalent TTBR also has CNP bit set. In case CNP bit is set but TTBR does not point at the same translation table entries for a given ASID and VMID, then the system is mis-configured, so the results of translations are UNPREDICTABLE. For kernel we postpone setting CNP till all cpus are up and rely on cpufeature framework to 1) patch the code which is sensitive to CNP and 2) update TTBR1_EL1 with CNP bit set. TTBR1_EL1 can be reprogrammed as result of hibernation or cpuidle (via __enable_mmu). For these two cases we restore CnP bit via __cpu_suspend_exit(). There are a few cases we need to care of changes in TTBR0_EL1: - a switch to idmap - software emulated PAN we rule out latter via Kconfig options and for the former we make sure that CNP is set for non-zero ASIDs only. Reviewed-by: James Morse <james.morse@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> [catalin.marinas@arm.com: default y for CONFIG_ARM64_CNP] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-09-14arm64: Fix silly typo in commentWill Deacon
I was passing through and figuered I'd fix this up: featuer -> feature Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-06-12Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
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 ...
2018-05-31arm64: ssbd: Restore mitigation status on CPU resumeMarc Zyngier
On a system where firmware can dynamically change the state of the mitigation, the CPU will always come up with the mitigation enabled, including when coming back from suspend. If the user has requested "no mitigation" via a command line option, let's enforce it by calling into the firmware again to disable it. Similarily, for a resume from hibernate, the mitigation could have been disabled by the boot kernel. Let's ensure that it is set back on in that case. Acked-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-05-31arm64: ssbd: Add global mitigation state accessorMarc Zyngier
We're about to need the mitigation state in various parts of the kernel in order to do the right thing for userspace and guests. Let's expose an accessor that will let other subsystems know about the state. Reviewed-by: Julien Grall <julien.grall@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-05-31arm64: Add 'ssbd' command-line optionMarc Zyngier
On a system where the firmware implements ARCH_WORKAROUND_2, it may be useful to either permanently enable or disable the workaround for cases where the user decides that they'd rather not get a trap overhead, and keep the mitigation permanently on or off instead of switching it on exception entry/exit. In any case, default to the mitigation being enabled. Reviewed-by: Julien Grall <julien.grall@arm.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2018-05-25arm64/sve: Move read_zcr_features() out of cpufeature.hDave Martin
Having read_zcr_features() inline in cpufeature.h results in that header requiring #includes which make it hard to include <asm/fpsimd.h> elsewhere without triggering header inclusion cycles. This is not a hot-path function and arguably should not be in cpufeature.h in the first place, so this patch moves it to fpsimd.c, compiled conditionally if CONFIG_ARM64_SVE=y. This allows some SVE-related #includes to be dropped from cpufeature.h, which will ease future maintenance. A couple of missing #includes of <asm/fpsimd.h> are exposed by this change under arch/arm64/. This patch adds the missing #includes as necessary. No functional change. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-03-26arm64: capabilities: Handle shared entriesSuzuki K Poulose
Some capabilities have different criteria for detection and associated actions based on the matching criteria, even though they all share the same capability bit. So far we have used multiple entries with the same capability bit to handle this. This is prone to errors, as the cpu_enable is invoked for each entry, irrespective of whether the detection rule applies to the CPU or not. And also this complicates other helpers, e.g, __this_cpu_has_cap. This patch adds a wrapper entry to cover all the possible variations of a capability by maintaining list of matches + cpu_enable callbacks. To avoid complicating the prototypes for the "matches()", we use arm64_cpu_capabilities maintain the list and we ignore all the other fields except the matches & cpu_enable. This ensures : 1) The capabilitiy is set when at least one of the entry detects 2) Action is only taken for the entries that "matches". This avoids explicit checks in the cpu_enable() take some action. The only constraint here is that, all the entries should have the same "type" (i.e, scope and conflict rules). If a cpu_enable() method is associated with multiple matches for a single capability, care should be taken that either the match criteria are mutually exclusive, or that the method is robust against being called multiple times. This also reverts the changes introduced by commit 67948af41f2e6818ed ("arm64: capabilities: Handle duplicate entries for a capability"). Cc: Robin Murphy <robin.murphy@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>
2018-03-26arm64: capabilities: Add support for checks based on a list of MIDRsSuzuki K Poulose
Add helpers for detecting an errata on list of midr ranges of affected CPUs, with the same work around. Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> 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>
2018-03-26arm64: Add helpers for checking CPU MIDR against a rangeSuzuki K Poulose
Add helpers for checking if the given CPU midr falls in a range of variants/revisions for a given model. Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> 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>
2018-03-26arm64: capabilities: Change scope of VHE to Boot CPU featureSuzuki K Poulose
We expect all CPUs to be running at the same EL inside the kernel with or without VHE enabled and we have strict checks to ensure that any mismatch triggers a kernel panic. If VHE is enabled, we use the feature based on the boot CPU and all other CPUs should follow. This makes it a perfect candidate for a capability based on the boot CPU, which should be matched by all the CPUs (both when is ON and OFF). This saves us some not-so-pretty hooks and special code, just for verifying the conflict. The patch also makes the VHE capability entry depend on CONFIG_ARM64_VHE. Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Will Deacon <will.deacon@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>
2018-03-26arm64: capabilities: Add support for features enabled earlySuzuki K Poulose
The kernel detects and uses some of the features based on the boot CPU and expects that all the following CPUs conform to it. e.g, with VHE and the boot CPU running at EL2, the kernel decides to keep the kernel running at EL2. If another CPU is brought up without this capability, we use custom hooks (via check_early_cpu_features()) to handle it. To handle such capabilities add support for detecting and enabling capabilities based on the boot CPU. A bit is added to indicate if the capability should be detected early on the boot CPU. The infrastructure then ensures that such capabilities are probed and "enabled" early on in the boot CPU and, enabled on the subsequent CPUs. Cc: Julien Thierry <julien.thierry@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Marc Zyngier <marc.zyngier@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>
2018-03-26arm64: capabilities: Restrict KPTI detection to boot-time CPUsSuzuki K Poulose
KPTI is treated as a system wide feature and is only detected if all the CPUs in the sysetm needs the defense, unless it is forced via kernel command line. This leaves a system with a mix of CPUs with and without the defense vulnerable. Also, if a late CPU needs KPTI but KPTI was not activated at boot time, the CPU is currently allowed to boot, which is a potential security vulnerability. This patch ensures that the KPTI is turned on if at least one CPU detects the capability (i.e, change scope to SCOPE_LOCAL_CPU). Also rejetcs a late CPU, if it requires the defense, when the system hasn't enabled it, Cc: Will Deacon <will.deacon@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>
2018-03-26arm64: capabilities: Introduce weak features based on local CPUSuzuki K Poulose
Now that we have the flexibility of defining system features based on individual CPUs, introduce CPU feature type that can be detected on a local SCOPE and ignores the conflict on late CPUs. This is applicable for ARM64_HAS_NO_HW_PREFETCH, where it is fine for the system to have CPUs without hardware prefetch turning up later. We only suffer a performance penalty, nothing fatal. Cc: Will Deacon <will.deacon@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>
2018-03-26arm64: capabilities: Filter the entries based on a given maskSuzuki K Poulose
While processing the list of capabilities, it is useful to filter out some of the entries based on the given mask for the scope of the capabilities to allow better control. This can be used later for handling LOCAL vs SYSTEM wide capabilities and more. All capabilities should have their scope set to either LOCAL_CPU or SYSTEM. No functional/flow change. 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>
2018-03-26arm64: capabilities: Add flags to handle the conflicts on late CPUSuzuki K Poulose
When a CPU is brought up, it is checked against the caps that are known to be enabled on the system (via verify_local_cpu_capabilities()). Based on the state of the capability on the CPU vs. that of System we could have the following combinations of conflict. x-----------------------------x | Type | System | Late CPU | |-----------------------------| | a | y | n | |-----------------------------| | b | n | y | x-----------------------------x Case (a) is not permitted for caps which are system features, which the system expects all the CPUs to have (e.g VHE). While (a) is ignored for all errata work arounds. However, there could be exceptions to the plain filtering approach. e.g, KPTI is an optional feature for a late CPU as long as the system already enables it. Case (b) is not permitted for errata work arounds that cannot be activated after the kernel has finished booting.And we ignore (b) for features. Here, yet again, KPTI is an exception, where if a late CPU needs KPTI we are too late to enable it (because we change the allocation of ASIDs etc). Add two different flags to indicate how the conflict should be handled. ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU - CPUs may have the capability ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU - CPUs may not have the cappability. Now that we have the flags to describe the behavior of the errata and the features, as we treat them, define types for ERRATUM and FEATURE. 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>
2018-03-26arm64: capabilities: Prepare for fine grained capabilitiesSuzuki K Poulose
We use arm64_cpu_capabilities to represent CPU ELF HWCAPs exposed to the userspace and the CPU hwcaps used by the kernel, which include cpu features and CPU errata work arounds. Capabilities have some properties that decide how they should be treated : 1) Detection, i.e scope : A cap could be "detected" either : - if it is present on at least one CPU (SCOPE_LOCAL_CPU) Or - if it is present on all the CPUs (SCOPE_SYSTEM) 2) When is it enabled ? - A cap is treated as "enabled" when the system takes some action based on whether the capability is detected or not. e.g, setting some control register, patching the kernel code. Right now, we treat all caps are enabled at boot-time, after all the CPUs are brought up by the kernel. But there are certain caps, which are enabled early during the boot (e.g, VHE, GIC_CPUIF for NMI) and kernel starts using them, even before the secondary CPUs are brought up. We would need a way to describe this for each capability. 3) Conflict on a late CPU - When a CPU is brought up, it is checked against the caps that are known to be enabled on the system (via verify_local_cpu_capabilities()). Based on the state of the capability on the CPU vs. that of System we could have the following combinations of conflict. x-----------------------------x | Type | System | Late CPU | ------------------------------| | a | y | n | ------------------------------| | b | n | y | x-----------------------------x Case (a) is not permitted for caps which are system features, which the system expects all the CPUs to have (e.g VHE). While (a) is ignored for all errata work arounds. However, there could be exceptions to the plain filtering approach. e.g, KPTI is an optional feature for a late CPU as long as the system already enables it. Case (b) is not permitted for errata work arounds which requires some work around, which cannot be delayed. And we ignore (b) for features. Here, yet again, KPTI is an exception, where if a late CPU needs KPTI we are too late to enable it (because we change the allocation of ASIDs etc). So this calls for a lot more fine grained behavior for each capability. And if we define all the attributes to control their behavior properly, we may be able to use a single table for the CPU hwcaps (which cover errata and features, not the ELF HWCAPs). This is a prepartory step to get there. More bits would be added for the properties listed above. We are going to use a bit-mask to encode all the properties of a capabilities. This patch encodes the "SCOPE" of the capability. As such there is no change in how the capabilities are treated. 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>
2018-03-26arm64: capabilities: Move errata processing codeSuzuki K Poulose
We have errata work around processing code in cpu_errata.c, which calls back into helpers defined in cpufeature.c. Now that we are going to make the handling of capabilities generic, by adding the information to each capability, move the errata work around specific processing code. No functional changes. Cc: Will Deacon <will.deacon@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andre Przywara <andre.przywara@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>
2018-03-26arm64: capabilities: Update prototype for enable call backDave Martin
We issue the enable() call back for all CPU hwcaps capabilities available on the system, on all the CPUs. So far we have ignored the argument passed to the call back, which had a prototype to accept a "void *" for use with on_each_cpu() and later with stop_machine(). However, with commit 0a0d111d40fd1 ("arm64: cpufeature: Pass capability structure to ->enable callback"), there are some users of the argument who wants the matching capability struct pointer where there are multiple matching criteria for a single capability. Clean up the declaration of the call back to make it clear. 1) Renamed to cpu_enable(), to imply taking necessary actions on the called CPU for the entry. 2) Pass const pointer to the capability, to allow the call back to check the entry. (e.,g to check if any action is needed on the CPU) 3) We don't care about the result of the call back, turning this to a void. Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Andre Przywara <andre.przywara@arm.com> Cc: James Morse <james.morse@arm.com> Acked-by: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Dave Martin <dave.martin@arm.com> [suzuki: convert more users, rename call back and drop results] Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-03-09arm64/errata: add REVIDR handling to frameworkArd Biesheuvel
In some cases, core variants that are affected by a certain erratum also exist in versions that have the erratum fixed, and this fact is recorded in a dedicated bit in system register REVIDR_EL1. Since the architecture does not require that a certain bit retains its meaning across different variants of the same model, each such REVIDR bit is tightly coupled to a certain revision/variant value, and so we need a list of revidr_mask/midr pairs to carry this information. So add the struct member and the associated macros and handling to allow REVIDR fixes to be taken into account. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-12-14arm64/sve: Report SVE to userspace via CPUID only if supportedDave Martin
Currently, the SVE field in ID_AA64PFR0_EL1 is visible unconditionally to userspace via the CPU ID register emulation, irrespective of the kernel config. This means that if a kernel configured with CONFIG_ARM64_SVE=n is run on SVE-capable hardware, userspace will see SVE reported as present in the ID regs even though the kernel forbids execution of SVE instructions. This patch makes the exposure of the SVE field in ID_AA64PFR0_EL1 conditional on CONFIG_ARM64_SVE=y. Since future architecture features are likely to encounter a similar requirement, this patch adds a suitable helper macros for use when declaring config-conditional ID register fields. Fixes: 43994d824e84 ("arm64/sve: Detect SVE and activate runtime support") Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reported-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Cc: Suzuki Poulose <suzuki.poulose@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-11-03arm64/sve: Detect SVE and activate runtime supportDave Martin
This patch enables detection of hardware SVE support via the cpufeatures framework, and reports its presence to the kernel and userspace via the new ARM64_SVE cpucap and HWCAP_SVE hwcap respectively. Userspace can also detect SVE using ID_AA64PFR0_EL1, using the cpufeatures MRS emulation. When running on hardware that supports SVE, this enables runtime kernel support for SVE, and allows user tasks to execute SVE instructions and make of the of the SVE-specific user/kernel interface extensions implemented by this series. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-11-03arm64/sve: Probe SVE capabilities and usable vector lengthsDave Martin
This patch uses the cpufeatures framework to determine common SVE capabilities and vector lengths, and configures the runtime SVE support code appropriately. ZCR_ELx is not really a feature register, but it is convenient to use it as a template for recording the maximum vector length supported by a CPU, using the LEN field. This field is similar to a feature field in that it is a contiguous bitfield for which we want to determine the minimum system-wide value. This patch adds ZCR as a pseudo-register in cpuinfo/cpufeatures, with appropriate custom code to populate it. Finding the minimum supported value of the LEN field is left to the cpufeatures framework in the usual way. The meaning of ID_AA64ZFR0_EL1 is not architecturally defined yet, so for now we just require it to be zero. Note that much of this code is dormant and SVE still won't be used yet, since system_supports_sve() remains hardwired to false. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-11-03arm64/sve: Kconfig update and conditional compilation supportDave Martin
This patch adds CONFIG_ARM64_SVE to control building of SVE support into the kernel, and adds a stub predicate system_supports_sve() to control conditional compilation and runtime SVE support. system_supports_sve() just returns false for now: it will be replaced with a non-trivial implementation in a later patch, once SVE support is complete enough to be enabled safely. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>