[patch 58/66] x86/tboot: Convert to hotplug state machine

From: Anna-Maria Gleixner
Date: Mon Jul 11 2016 - 08:32:42 EST


From: Richard Cochran <rcochran@xxxxxxxxxxxxx>

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Richard Cochran <rcochran@xxxxxxxxxxxxx>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Richard L Maliszewski <richard.l.maliszewski@xxxxxxxxx>
Cc: Gang Wei <gang.wei@xxxxxxxxx>
Cc: Shane Wang <shane.wang@xxxxxxxxx>
Cc: tboot-devel@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>

---
arch/x86/kernel/tboot.c | 25 ++++++++-----------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 9 insertions(+), 17 deletions(-)

--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -323,25 +323,16 @@ static int tboot_wait_for_aps(int num_ap
return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
}

-static int tboot_cpu_callback(struct notifier_block *nfb, unsigned long action,
- void *hcpu)
+static int tboot_dying_cpu(unsigned int cpu)
{
- switch (action) {
- case CPU_DYING:
- atomic_inc(&ap_wfs_count);
- if (num_online_cpus() == 1)
- if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
- return NOTIFY_BAD;
- break;
+ atomic_inc(&ap_wfs_count);
+ if (num_online_cpus() == 1) {
+ if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
+ return -EBUSY;
}
- return NOTIFY_OK;
+ return 0;
}

-static struct notifier_block tboot_cpu_notifier =
-{
- .notifier_call = tboot_cpu_callback,
-};
-
#ifdef CONFIG_DEBUG_FS

#define TBOOT_LOG_UUID { 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \
@@ -417,8 +408,8 @@ static __init int tboot_late_init(void)
tboot_create_trampoline();

atomic_set(&ap_wfs_count, 0);
- register_hotcpu_notifier(&tboot_cpu_notifier);
-
+ cpuhp_setup_state(CPUHP_AP_X86_TBOOT_DYING, "AP_X86_TBOOT_DYING", NULL,
+ tboot_dying_cpu);
#ifdef CONFIG_DEBUG_FS
debugfs_create_file("tboot_log", S_IRUSR,
arch_debugfs_dir, NULL, &tboot_log_fops);
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -59,6 +59,7 @@ enum cpuhp_state {
CPUHP_AP_ARM_CORESIGHT4_STARTING,
CPUHP_AP_ARM64_ISNDEP_STARTING,
CPUHP_AP_LEDTRIG_STARTING,
+ CPUHP_AP_X86_TBOOT_DYING,
CPUHP_AP_NOTIFY_STARTING,
CPUHP_AP_ONLINE,
CPUHP_TEARDOWN_CPU,