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2025-02-17arm64: Filter out SVE hwcaps when FEAT_SVE isn't implementedMarc Zyngier1-13/+26
commit 064737920bdbca86df91b96aed256e88018fef3a upstream. The hwcaps code that exposes SVE features to userspace only considers ID_AA64ZFR0_EL1, while this is only valid when ID_AA64PFR0_EL1.SVE advertises that SVE is actually supported. The expectations are that when ID_AA64PFR0_EL1.SVE is 0, the ID_AA64ZFR0_EL1 register is also 0. So far, so good. Things become a bit more interesting if the HW implements SME. In this case, a few ID_AA64ZFR0_EL1 fields indicate *SME* features. And these fields overlap with their SVE interpretations. But the architecture says that the SME and SVE feature sets must match, so we're still hunky-dory. This goes wrong if the HW implements SME, but not SVE. In this case, we end-up advertising some SVE features to userspace, even if the HW has none. That's because we never consider whether SVE is actually implemented. Oh well. Fix it by restricting all SVE capabilities to ID_AA64PFR0_EL1.SVE being non-zero. The HWCAPS documentation is amended to reflect the actually checks performed by the kernel. Fixes: 06a916feca2b ("arm64: Expose SVE2 features for userspace") Reported-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: Will Deacon <will@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: stable@vger.kernel.org Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20250107-arm64-2024-dpisa-v5-1-7578da51fc3d@kernel.org Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-09-04arm64: enable the Permission Overlay Extension for EL0Joey Gouly1-0/+2
Expose a HWCAP and ID_AA64MMFR3_EL1_S1POE to userspace, so they can be used to check if the CPU supports the feature. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Link: https://lore.kernel.org/r/20240822151113.1479789-12-joey.gouly@arm.com Signed-off-by: Will Deacon <will@kernel.org>
2024-03-07arm64/hwcap: Define hwcaps for 2023 DPISA featuresMark Brown1-0/+49
The 2023 architecture extensions include a large number of floating point features, most of which simply add new instructions. Add hwcaps so that userspace can enumerate these features. Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20240306-arm64-2023-dpisa-v5-6-c568edc8ed7f@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2023-11-07Documentation/arm64: Fix typos in elf_hwcapsMarielle Novastrider1-3/+3
Small typos in register and field names. Signed-off-by: Marielle Novastrider <marielle@novastrider.com> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20231031200838.55569-1-marielle@novastrider.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2023-10-13arm64: add FEAT_LSE128 HWCAPJoey Gouly1-0/+3
Add HWCAP for FEAT_LSE128 (128-bit Atomic instructions). Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20231003124544.858804-2-joey.gouly@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2023-10-13arm64: add FEAT_LRCPC3 HWCAPJoey Gouly1-0/+3
FEAT_LRCPC3 adds more instructions to support the Release Consistency model. Add a HWCAP so that userspace can make decisions about instructions it can use. Signed-off-by: Joey Gouly <joey.gouly@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20230919162757.2707023-2-joey.gouly@arm.com [catalin.marinas@arm.com: change the HWCAP number] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2023-09-29arm64/sve: Report FEAT_SVE_B16B16 to userspaceMark Brown1-0/+3
SVE 2.1 introduced a new feature FEAT_SVE_B16B16 which adds instructions supporting the BFloat16 floating point format. Report this to userspace through the ID registers and hwcap. Reported-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20230915-arm64-zfr-b16b16-el0-v1-1-f9aba807bdb5@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2023-09-18arm64/hbc: Document HWCAP2_HBCMark Brown1-0/+3
When we added support for FEAT_HBC we added a new hwcap but did not document that we had done so, add the documentation. Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Joey Gouly <joey.gouly@arm.com> Link: https://lore.kernel.org/r/20230914-arm64-feat-hbc-doc-v1-1-797d25f06897@kernel.org Signed-off-by: Will Deacon <will@kernel.org>
2023-06-27Merge tag 'docs-arm64-move' of git://git.lwn.net/linuxLinus Torvalds1-0/+312
Pull arm64 documentation move from Jonathan Corbet: "Move the arm64 architecture documentation under Documentation/arch/. This brings some order to the documentation directory, declutters the top-level directory, and makes the documentation organization more closely match that of the source" * tag 'docs-arm64-move' of git://git.lwn.net/linux: perf arm-spe: Fix a dangling Documentation/arm64 reference mm: Fix a dangling Documentation/arm64 reference arm64: Fix dangling references to Documentation/arm64 dt-bindings: fix dangling Documentation/arm64 reference docs: arm64: Move arm64 documentation under Documentation/arch/
2023-06-21docs: arm64: Move arm64 documentation under Documentation/arch/Jonathan Corbet1-0/+309
Architecture-specific documentation is being moved into Documentation/arch/ as a way of cleaning up the top-level documentation directory and making the docs hierarchy more closely match the source hierarchy. Move Documentation/arm64 into arch/ (along with the Chinese equvalent translations) and fix up documentation references. Cc: Will Deacon <will@kernel.org> Cc: Alex Shi <alexs@kernel.org> Cc: Hu Haowen <src.res@email.cn> Cc: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Yantengsi <siyanteng@loongson.cn> Signed-off-by: Jonathan Corbet <corbet@lwn.net>