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2020-09-04arm64: mte: Add Memory Tagging Extension documentationVincenzo Frascino
Memory Tagging Extension (part of the ARMv8.5 Extensions) provides a mechanism to detect the sources of memory related errors which may be vulnerable to exploitation, including bounds violations, use-after-free, use-after-return, use-out-of-scope and use before initialization errors. Add Memory Tagging Extension documentation for the arm64 linux kernel support. Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Co-developed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Cc: Will Deacon <will@kernel.org>
2020-03-16arm64: Basic Branch Target Identification supportDave Martin
This patch adds the bare minimum required to expose the ARMv8.5 Branch Target Identification feature to userspace. By itself, this does _not_ automatically enable BTI for any initial executable pages mapped by execve(). This will come later, but for now it should be possible to enable BTI manually on those pages by using mprotect() from within the target process. Other arches already using the generic mman.h are already using 0x10 for arch-specific prot flags, so we use that for PROT_BTI here. For consistency, signal handler entry points in BTI guarded pages are required to be annotated as such, just like any other function. This blocks a relatively minor attack vector, but comforming userspace will have the annotations anyway, so we may as well enforce them. Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-01-22Merge branch 'for-next/rng' into for-next/coreWill Deacon
* for-next/rng: (2 commits) arm64: Use v8.5-RNG entropy for KASLR seed ...
2020-01-22arm64: Implement archrandom.h for ARMv8.5-RNGRichard Henderson
Expose the ID_AA64ISAR0.RNDR field to userspace, as the RNG system registers are always available at EL0. Implement arch_get_random_seed_long using RNDR. Given that the TRNG is likely to be a shared resource between cores, and VMs, do not explicitly force re-seeding with RNDRRS. In order to avoid code complexity and potential issues with hetrogenous systems only provide values after cpufeature has finalized the system capabilities. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> [Modified to only function after cpufeature has finalized the system capabilities and move all the code into the header -- broonie] Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> [will: Advertise HWCAP via /proc/cpuinfo] Signed-off-by: Will Deacon <will@kernel.org>
2020-01-15arm64: cpufeature: Export matrix and other features to userspaceSteven Price
Export the features introduced as part of ARMv8.6 exposed in the ID_AA64ISAR1_EL1 and ID_AA64ZFR0_EL1 registers. This introduces the Matrix features (ARMv8.2-I8MM, ARMv8.2-F64MM and ARMv8.2-F32MM) along with BFloat16 (Armv8.2-BF16), speculation invalidation (SPECRES) and Data Gathering Hint (ARMv8.0-DGH). Signed-off-by: Julien Grall <julien.grall@arm.com> [Added other features in those registers] Signed-off-by: Steven Price <steven.price@arm.com> [will: Don't advertise SPECRES to userspace] Signed-off-by: Will Deacon <will@kernel.org>
2019-10-14docs/arm64: elf_hwcaps: Document HWCAP_SBJulien Grall
All the hardware capabilities but HWCAP_SB is not documented in elf_hwcaps.rst. So document it. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Julien Grall <julien.grall@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2019-10-14docs/arm64: elf_hwcaps: sort the HWCAP{, 2} documentation by ascending valueJulien Grall
Part of the hardware capabilities documented in elf_hwcap.rst are ordered following the definition in the header arch/arm64/include/uapi/asm/hwcap.h but others seems to be documented in random order. To make easier to match against the definition in the header, they are now sorted in the same order as they are defined in header. I.e., HWCAP first by ascending value, and then HWCAP2 in the similar fashion. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Julien Grall <julien.grall@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2019-07-09Merge tag 'docs-5.3' of git://git.lwn.net/linuxLinus Torvalds
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 ...
2019-06-14docs: arm64: convert docs to ReST and rename to .rstMauro Carvalho Chehab
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>