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linux/Documentation/arm64/pointer-authentication.rst

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docs: arm64: convert docs to ReST and rename to .rst 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>
2019-06-12 14:52:38 -03:00
arm64: docs: document pointer authentication Now that we've added code to support pointer authentication, add some documentation so that people can figure out if/how to use it. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> Cc: Andrew Jones <drjones@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 18:39:31 +00:00
docs: arm64: convert docs to ReST and rename to .rst 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>
2019-06-12 14:52:38 -03:00
arm64: docs: document pointer authentication Now that we've added code to support pointer authentication, add some documentation so that people can figure out if/how to use it. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> Cc: Andrew Jones <drjones@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 18:39:31 +00:00
arm64: update PAC description for kernel Remove the paragraph which has nothing to do with the kernel and add PAC description related to kernel. Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> Link: https://lore.kernel.org/r/20211201034014.20048-1-Kuan-Ying.Lee@mediatek.com Signed-off-by: Will Deacon <will@kernel.org>
2021-12-01 11:40:10 +08:00
arm64: docs: document pointer authentication Now that we've added code to support pointer authentication, add some documentation so that people can figure out if/how to use it. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> Cc: Andrew Jones <drjones@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 18:39:31 +00:00
arm64: add ptrace regsets for ptrauth key management 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>
2019-01-30 12:02:44 +00:00
arm64: docs: document pointer authentication Now that we've added code to support pointer authentication, add some documentation so that people can figure out if/how to use it. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com> Reviewed-by: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> Cc: Andrew Jones <drjones@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ramana Radhakrishnan <ramana.radhakrishnan@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 18:39:31 +00:00
KVM: arm64: Add userspace flag to enable pointer authentication 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>
2019-04-23 10:12:36 +05:30
arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) This change introduces a prctl that allows the user program to control which PAC keys are enabled in a particular task. The main reason why this is useful is to enable a userspace ABI that uses PAC to sign and authenticate function pointers and other pointers exposed outside of the function, while still allowing binaries conforming to the ABI to interoperate with legacy binaries that do not sign or authenticate pointers. The idea is that a dynamic loader or early startup code would issue this prctl very early after establishing that a process may load legacy binaries, but before executing any PAC instructions. This change adds a small amount of overhead to kernel entry and exit due to additional required instruction sequences. On a DragonBoard 845c (Cortex-A75) with the powersave governor, the overhead of similar instruction sequences was measured as 4.9ns when simulating the common case where IA is left enabled, or 43.7ns when simulating the uncommon case where IA is disabled. These numbers can be seen as the worst case scenario, since in more realistic scenarios a better performing governor would be used and a newer chip would be used that would support PAC unlike Cortex-A75 and would be expected to be faster than Cortex-A75. On an Apple M1 under a hypervisor, the overhead of the entry/exit instruction sequences introduced by this patch was measured as 0.3ns in the case where IA is left enabled, and 33.0ns in the case where IA is disabled. Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Dave Martin <Dave.Martin@arm.com> Link: https://linux-review.googlesource.com/id/Ibc41a5e6a76b275efbaa126b31119dc197b927a5 Link: https://lore.kernel.org/r/d6609065f8f40397a4124654eb68c9f490b4d477.1616123271.git.pcc@google.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-03-18 20:10:53 -07:00