On Wed, Oct 28, 2020 at 12:27:59PM +0000, Will Deacon wrote: > On Wed, Oct 28, 2020 at 12:15:07PM +0000, Catalin Marinas wrote: > > On Tue, Oct 27, 2020 at 09:51:17PM +0000, Will Deacon wrote: > > > diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu > > > index b555df825447..19893fb8e870 100644 > > > --- a/Documentation/ABI/testing/sysfs-devices-system-cpu > > > +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu > > > @@ -472,6 +472,14 @@ Description: AArch64 CPU registers > > > 'identification' directory exposes the CPU ID registers for > > > identifying model and revision of the CPU. > > > > > > +What: /sys/devices/system/cpu/aarch32_el0 > > > > Nitpick: should we call this aarch32_el0_present? It's not exactly > > present as we populate it as CPUs come online but it's closer to this > > mask than to the online one. > > I don't think so, because a CPU could be set in this mask but not in the > present mask, which is hugely confusing it it has "present" in the name! How can it end up here but not in the present mask? We populate present early if they have a corresponding DT entry. > > > +Date: October 2020 > > > +Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx> > > > +Description: Identifies the subset of CPUs in the system that can execute > > > + AArch32 (32-bit ARM) applications. If absent, then all or none > > > + of the CPUs can execute AArch32 applications and execve() will > > > + behave accordingly. > > > > What does "accordingly" mean? Normally, we'd get ENOEXEC but here the > > execve() "succeeds" followed by a SIGKILL if it ends up on the wrong > > CPU. > > No; if the file is absent then execve() behaves as it always has. Ah, I missed the "absent" part and got confused. -- Catalin
