On Tue, 2017-07-11 at 11:11 -0700, Dave Hansen wrote: > On 07/05/2017 02:21 PM, Ram Pai wrote: > > Currently sys_pkey_create() provides the ability to disable read > > and write permission on the key, at creation. powerpc has the > > hardware support to disable execute on a pkey as well.This patch > > enhances the interface to let disable execute at key creation > > time. x86 does not allow this. Hence the next patch will add > > ability in x86 to return error if PKEY_DISABLE_EXECUTE is > > specified. That leads to the question... How do you tell userspace. (apologies if I missed that in an existing patch in the series) How do we inform userspace of the key capabilities ? There are at least two things userspace may want to know already: - What protection bits are supported for a key - How many keys exist - Which keys are available for use by userspace. On PowerPC, the kernel can reserve some keys for itself, so can the hypervisor. In fact, they do. Cheers, Ben.
