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    SubjectRe: [PATCH 0/4] kselftests/arm64: add PAuth tests
    On Fri, Aug 28, 2020 at 02:16:02PM +0100, Boyan Karatotev wrote:
    > Pointer Authentication (PAuth) is a security feature introduced in ARMv8.3.
    > It introduces instructions to sign addresses and later check for potential
    > corruption using a second modifier value and one of a set of keys. The
    > signature, in the form of the Pointer Authentication Code (PAC), is stored
    > in some of the top unused bits of the virtual address (e.g. [54: 49] if
    > TBID0 is enabled and TnSZ is set to use a 48 bit VA space). A set of
    > controls are present to enable/disable groups of instructions (which use
    > certain keys) for compatibility with libraries that do not utilize the
    > feature. PAuth is used to verify the integrity of return addresses on the
    > stack with less memory than the stack canary.
    >
    > This patchset adds kselftests to verify the kernel's configuration of the
    > feature and its runtime behaviour. There are 7 tests which verify that:
    > * an authentication failure leads to a SIGSEGV
    > * the data/instruction instruction groups are enabled
    > * the generic instructions are enabled
    > * all 5 keys are unique for a single thread
    > * exec() changes all keys to new unique ones
    > * context switching preserves the 4 data/instruction keys
    > * context switching preserves the generic keys
    >
    > The tests have been verified to work on qemu without a working PAUTH
    > Implementation and on ARM's FVP with a full or partial PAuth
    > implementation.
    >
    > Note: This patchset is only verified for ARMv8.3 and there will be some
    > changes required for ARMv8.6. More details can be found here [1]. Once
    > ARMv8.6 PAuth is merged the first test in this series will required to be
    > updated.

    Nit: is it worth running checkpatch over this series?

    Although this is not kernel code, there are a number of formatting
    weirdnesses and surplus blank lines etc. that checkpatch would probably
    warn about.

    [...]

    Cheers
    ---Dave

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