}
static struct microcode_ops microcode_amd_ops = {
- .request_microcode_fw = request_microcode_amd,
- .collect_cpu_info = collect_cpu_info_amd,
- .apply_microcode = apply_microcode_amd,
- .microcode_fini_cpu = microcode_fini_cpu_amd,
+ .request_microcode_fw = request_microcode_amd,
+ .collect_cpu_info = collect_cpu_info_amd,
+ .apply_microcode = apply_microcode_amd,
+ .microcode_fini_cpu = microcode_fini_cpu_amd,
+ .nmi_safe = true,
};
struct microcode_ops * __init init_amd_microcode(void)
*/
#define SPINUNIT 100 /* 100 nsec */
-static int check_online_cpus(void)
-{
- unsigned int cpu;
-
- /*
- * Make sure all CPUs are online. It's fine for SMT to be disabled if
- * all the primary threads are still online.
- */
- for_each_present_cpu(cpu) {
- if (topology_is_primary_thread(cpu) && !cpu_online(cpu)) {
- pr_err("Not all CPUs online, aborting microcode update.\n");
- return -EINVAL;
- }
- }
-
- return 0;
-}
static atomic_t late_cpus_in;
static atomic_t late_cpus_out;
return ret;
}
+/*
+ * Ensure that all required CPUs which are present and have been booted
+ * once are online.
+ *
+ * To pass this check, all primary threads must be online.
+ *
+ * If the microcode load is not safe against NMI then all SMT threads
+ * must be online as well because they still react to NMIs when they are
+ * soft-offlined and parked in one of the play_dead() variants. So if a
+ * NMI hits while the primary thread updates the microcode the resulting
+ * behaviour is undefined. The default play_dead() implementation on
+ * modern CPUs uses MWAIT, which is also not guaranteed to be safe
+ * against a microcode update which affects MWAIT.
+ */
+static bool ensure_cpus_are_online(void)
+{
+ unsigned int cpu;
+
+ for_each_cpu_and(cpu, cpu_present_mask, &cpus_booted_once_mask) {
+ if (!cpu_online(cpu)) {
+ if (topology_is_primary_thread(cpu) || !microcode_ops->nmi_safe) {
+ pr_err("CPU %u not online\n", cpu);
+ return false;
+ }
+ }
+ }
+ return true;
+}
+
static ssize_t reload_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
cpus_read_lock();
- ret = check_online_cpus();
- if (ret)
+ if (!ensure_cpus_are_online()) {
+ ret = -EBUSY;
goto put;
+ }
tmp_ret = microcode_ops->request_microcode_fw(bsp, µcode_pdev->dev);
if (tmp_ret != UCODE_NEW)
struct microcode_ops {
enum ucode_state (*request_microcode_fw)(int cpu, struct device *dev);
-
void (*microcode_fini_cpu)(int cpu);
/*
- * The generic 'microcode_core' part guarantees that
- * the callbacks below run on a target cpu when they
- * are being called.
+ * The generic 'microcode_core' part guarantees that the callbacks
+ * below run on a target CPU when they are being called.
* See also the "Synchronization" section in microcode_core.c.
*/
- enum ucode_state (*apply_microcode)(int cpu);
- int (*collect_cpu_info)(int cpu, struct cpu_signature *csig);
- void (*finalize_late_load)(int result);
+ enum ucode_state (*apply_microcode)(int cpu);
+ int (*collect_cpu_info)(int cpu, struct cpu_signature *csig);
+ void (*finalize_late_load)(int result);
+ unsigned int nmi_safe : 1;
};
extern struct ucode_cpu_info ucode_cpu_info[];