On Mon, Dec 11, 2017 at 08:13:12AM -0800, Dave Hansen wrote: > On 12/09/2017 10:42 PM, Florian Weimer wrote: > >> 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. > > > > The interface is not specific to XSAVE. To generic code, only the > > two signal mask manipulation functions are exposed. And I expect > > that we're going to need that for other (non-x86) implementations > > because they will have the same issue because the signal handler > > behavior will be identical. > > Let's check with the other implementation... > > Ram, this is a question about the signal handler behavior on POWER. I > thought you ended up having different behavior in signal handlers than x86. On POWER, the value of the pkey_read() i.e contents the AMR register(pkru equivalent), is always the same regardless of its context; signal handler or not. In other words, the permission of any allocated key will not reset in a signal handler context. I was not aware that x86 would reset the key permissions in signal handler. I think, the proposed behavior for PKEY_ALLOC_SETSIGNAL should actually be the default behavior. RP -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
