On Fri, Mar 16, 2018 at 02:49:00PM +0100, Andrey Konovalov wrote: > Hi! Hi, > I've recently tried to boot clang built kernel on real hardware > (Odroid C2 board) instead of using a VM. The issue that I stumbled > upon is that arm64 kvm built with clang doesn't boot. > > Adding -fno-jump-tables compiler flag to arch/arm64/kvm/* helps. There > was a patch some time ago that did exactly that > (https://patchwork.kernel.org/patch/10060381/), but it wasn't accepted > AFAICT (see the discussion on that thread). > > What would be the best way to get this fixed? I think that patch is our best bet currently, but to save ourselves pain in future it would be *really* nice if GCC and clang could provide an option line -fno-absolute-addressing that would implicitly disable any feature that would generate an absolute address as jump tables do. > I've also had to disable CONFIG_JUMP_LABEL to get the kernel boot > (even without kvm enabled), but that might be a different (though > related) issue. With v4.15 (and clang 5.0.0), I did not have to disable jump labels to get a kernel booting on a Juno platform, though I did have to pass -fno-jump-tables to the hyp code. Which kernel version and clang version are you using? Thanks, Mark. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
