On Tue, 26 Mar 2019, Josh Poimboeuf wrote:
> On Tue, Mar 26, 2019 at 02:53:04PM +0100, Thomas Gleixner wrote:
> > > Makes sense. I like #3. I can post another version.
> >
> > Yes, please.
>
> Something like so (on top of the original patch)?
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu
> b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 4a11cba73085..5eea46fefcb2 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -511,11 +511,12 @@ Description: Control Symetric Multi Threading (SMT)
> control: Read/write interface to control SMT. Possible
> values:
>
> - "on" SMT is enabled
> - "off" SMT is disabled
> - "forceoff" SMT is force disabled. Cannot be
> changed.
> - "notsupported" Runtime SMT toggling is not currently
> - supported for the architecture
> + "on" SMT is enabled
> + "off" SMT is disabled
> + "forceoff" SMT is force disabled. Cannot be
> changed.
> + "notsupported" SMT is not supported by the CPU
> + "notimplemented" SMT runtime toggling is not
> + implemented for the architecture
>
> If control status is "forceoff" or "notsupported"
> writes
> are rejected.
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index 517ab1803a22..05a71ee98440 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -2145,7 +2145,11 @@ static const char *smt_states[] = {
> static ssize_t
> show_smt_control(struct device *dev, struct device_attribute *attr, char
> *buf)
> {
> - return snprintf(buf, PAGE_SIZE - 2, "%s\n",
> smt_states[cpu_smt_control]);
> + const char *state = IS_ENABLED(CONFIG_HOTPLUG_SMT) ?
> + smt_states[cpu_smt_control] :
> + "notimplemented";
> +
> + return snprintf(buf, PAGE_SIZE - 2, "%s\n", state);
> }
Looks good!
Thanks,
tglx
