= Proposed System Wide Change: AARCH64 - 48-bit VA = https://fedoraproject.org/wiki/Changes/aarch64-48bitVA Change owner(s): * Jeremy Linton < jeremy DOT linton AT arm DOT com > Enable 48bit VA on AARCH64 == Detailed Description == The current aarch64 kernel is using a 42-bit process virtual address (VA) space and due to the way aarch64 paging works this limits the max physical address as well. This is fairly limiting for some applications, but aarch64 processors also have support for 48-bit VA's. This is actually 1-bit more than the "47-bit" VA's currently used on x86_64. This change is a fairly minor kernel configuration but it has caused problems with mozjs and luajit based projects because they have stored tags in their pointers in the 48th address bit. The upstream mozjs project has been fixed, and there are a set of changes outstanding for luajit. Futher there, have been patches applied to rawhide to support it (bug #1242326, bug #1375305. bug #1375547), but the packages dependent on js185 require a rebuild due to an ABI change. == Scope == * Proposal owners: The kernel config needs to be changed, and the core mozjs/luajit tagging problems need to be resolved. This can either take the form of patching the remaining mozjs packages that have not yet been patched and rebuilding the affected js185 packages, or it can take the form of moving dependent packages onto mozjs versions that have been patched. Futher lua needs to either be updated to the latest mainline or the critical patches need to be applied to the lua versions currently in use. * Release engineering: Release engineering needs to assure the js185 packages are rebuilt. Peter Robinson has volunteered to assist in this. * Policies and guidelines: N/A * Trademark approval: N/A (not needed for this Change) -- Jan Kuřík Platform & Fedora Program Manager Red Hat Czech s.r.o., Purkynova 99/71, 612 45 Brno, Czech Republic _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx
