On 12/09/2017 01:16 PM, Florian Weimer wrote: > The attached patch addresses a problem with the current x86 pkey > implementation, which makes default-readable pkeys unusable from signal > handlers because the default init_pkru value blocks access. Thanks for looking into this! What do you mean by "default-readable pkeys"? I think you mean that, for any data that needs to be accessed to enter a signal handler, it must be set to pkey=0 with the current implementation. All other keys are inaccessible when entering a signal handler because the "init" value disables access. My only nit with this is whether it is the *right* interface. The signal vs. XSAVE state thing is pretty x86 specific and I doubt that this will be the last feature that we encounter that needs special signal behavior. A question more for the x86 maintainers is whether they would rather see a pkeys-specific interface for this, or an XSAVE-specific interface where you could specify a non-init XSAVE state for a set of XSAVE components.
