On Wed, 8 Jun 2016, Dave Hansen wrote: > Proposed semantics: > 1. protection key 0 is special and represents the default, > unassigned protection key. It is always allocated. > 2. mprotect() never affects a mapping's pkey_mprotect()-assigned > protection key. A protection key of 0 (even if set explicitly) > represents an unassigned protection key. > 2a. mprotect(PROT_EXEC) on a mapping with an assigned protection > key may or may not result in a mapping with execute-only > properties. pkey_mprotect() plus pkey_set() on all threads > should be used to _guarantee_ execute-only semantics. > 3. mprotect(PROT_EXEC) may result in an "execute-only" mapping. The > kernel will internally attempt to allocate and dedicate a > protection key for the purpose of execute-only mappings. This > may not be possible in cases where there are no free protection > keys available. Shouldn't we just reserve a protection key for PROT_EXEC unconditionally? Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
