Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 09c3f0d8 authored by Borislav Petkov's avatar Borislav Petkov Committed by H. Peter Anvin
Browse files

x86, microcode: Cleanup cpu hotplug notifier callback 

Mask out CPU_TASKS_FROZEN bit so that all _FROZEN cases can be dropped.
Also, add some more comments as to why CPU_ONLINE falls through to
CPU_DOWN_FAILED (no break), and for the CPU_DEAD case. Realign debug
printks better.

Idea blatantly stolen from a tglx patch:
http://marc.info/?l=linux-kernel&m=134267779513862



Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1344361461-10076-5-git-send-email-bp@amd64.org


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent bb9d3e47

arch/x86/kernel/microcode_core.c

+16 −9
Original line number Diff line number Diff line
@@ -470,34 +470,41 @@ mc_cpu_callback(struct notifier_block *nb, unsigned long action, void *hcpu) 
	struct device *dev;



	dev = get_cpu_device(cpu);

	switch (action) {



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		microcode_update_cpu(cpu);

	case CPU_DOWN_FAILED:

	case CPU_DOWN_FAILED_FROZEN:

		pr_debug("CPU%d added\n", cpu);

		/*

		 * "break" is missing on purpose here because we want to fall

		 * through in order to create the sysfs group.

		 */



	case CPU_DOWN_FAILED:

		if (sysfs_create_group(&dev->kobj, &mc_attr_group))

			pr_err("Failed to create group for CPU%d\n", cpu);

		break;



	case CPU_DOWN_PREPARE:

	case CPU_DOWN_PREPARE_FROZEN:

		/* Suspend is in progress, only remove the interface */

		sysfs_remove_group(&dev->kobj, &mc_attr_group);

		pr_debug("CPU%d removed\n", cpu);

		break;



	/*

	 * case CPU_DEAD:

	 *

	 * When a CPU goes offline, don't free up or invalidate the copy of

	 * the microcode in kernel memory, so that we can reuse it when the

	 * CPU comes back online without unnecessarily requesting the userspace

	 * for it again.

	 */

	case CPU_UP_CANCELED_FROZEN:

	}



	/* The CPU refused to come up during a system resume */

	if (action == CPU_UP_CANCELED_FROZEN)

		microcode_fini_cpu(cpu);

		break;

	}



	return NOTIFY_OK;

}