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x86, microcode: Cleanup cpu hotplug notifier callback

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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: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1344361461-10076-5-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Borislav Petkov 2012-07-23 20:15:10 +02:00 committed by H. Peter Anvin
parent bb9d3e473d
commit 09c3f0d883
1 changed files with 16 additions and 9 deletions
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25
arch/x86/kernel/microcode_core.c
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@ -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 */
microcode_fini_cpu(cpu);
break;
}
/* The CPU refused to come up during a system resume */
if (action == CPU_UP_CANCELED_FROZEN)
microcode_fini_cpu(cpu);
return NOTIFY_OK;
}