*/
#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/module.h>
#include <linux/nmi.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
#include <asm/apic.h>
+#include <asm/current.h>
+#include <asm/kdebug.h>
+#include <asm/local64.h>
#include <asm/nmi.h>
#include <asm/uv/uv.h>
#include <asm/uv/uv_hub.h>
#include <asm/uv/uv_mmrs.h>
-/* BMC sets a bit this MMR non-zero before sending an NMI */
-#define UVH_NMI_MMR UVH_SCRATCH5
-#define UVH_NMI_MMR_CLEAR (UVH_NMI_MMR + 8)
-#define UV_NMI_PENDING_MASK (1UL << 63)
-DEFINE_PER_CPU(unsigned long, cpu_last_nmi_count);
-static DEFINE_SPINLOCK(uv_nmi_lock);
+/*
+ * UV handler for NMI
+ *
+ * Handle system-wide NMI events generated by the global 'power nmi' command.
+ *
+ * Basic operation is to field the NMI interrupt on each cpu and wait
+ * until all cpus have arrived into the nmi handler. If some cpus do not
+ * make it into the handler, try and force them in with the IPI(NMI) signal.
+ *
+ * We also have to lessen UV Hub MMR accesses as much as possible as this
+ * disrupts the UV Hub's primary mission of directing NumaLink traffic and
+ * can cause system problems to occur.
+ *
+ * To do this we register our primary NMI notifier on the NMI_UNKNOWN
+ * chain. This reduces the number of false NMI calls when the perf
+ * tools are running which generate an enormous number of NMIs per
+ * second (~4M/s for 1024 cpu threads). Our secondary NMI handler is
+ * very short as it only checks that if it has been "pinged" with the
+ * IPI(NMI) signal as mentioned above, and does not read the UV Hub's MMR.
+ *
+ */
+
+static struct uv_hub_nmi_s **uv_hub_nmi_list;
+
+DEFINE_PER_CPU(struct uv_cpu_nmi_s, __uv_cpu_nmi);
+EXPORT_PER_CPU_SYMBOL_GPL(__uv_cpu_nmi);
+
+static unsigned long nmi_mmr;
+static unsigned long nmi_mmr_clear;
+static unsigned long nmi_mmr_pending;
+
+static atomic_t uv_in_nmi;
+static atomic_t uv_nmi_cpu = ATOMIC_INIT(-1);
+static atomic_t uv_nmi_cpus_in_nmi = ATOMIC_INIT(-1);
+static atomic_t uv_nmi_slave_continue;
+static cpumask_var_t uv_nmi_cpu_mask;
+
+/* Values for uv_nmi_slave_continue */
+#define SLAVE_CLEAR 0
+#define SLAVE_CONTINUE 1
+#define SLAVE_EXIT 2
/*
- * When NMI is received, print a stack trace.
+ * Default is all stack dumps go to the console and buffer.
+ * Lower level to send to log buffer only.
*/
-int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)
+static int uv_nmi_loglevel = 7;
+module_param_named(dump_loglevel, uv_nmi_loglevel, int, 0644);
+
+/*
+ * The following values show statistics on how perf events are affecting
+ * this system.
+ */
+static int param_get_local64(char *buffer, const struct kernel_param *kp)
{
- unsigned long real_uv_nmi;
- int bid;
+ return sprintf(buffer, "%lu\n", local64_read((local64_t *)kp->arg));
+}
- /*
- * Each blade has an MMR that indicates when an NMI has been sent
- * to cpus on the blade. If an NMI is detected, atomically
- * clear the MMR and update a per-blade NMI count used to
- * cause each cpu on the blade to notice a new NMI.
- */
- bid = uv_numa_blade_id();
- real_uv_nmi = (uv_read_local_mmr(UVH_NMI_MMR) & UV_NMI_PENDING_MASK);
-
- if (unlikely(real_uv_nmi)) {
- spin_lock(&uv_blade_info[bid].nmi_lock);
- real_uv_nmi = (uv_read_local_mmr(UVH_NMI_MMR) &
- UV_NMI_PENDING_MASK);
- if (real_uv_nmi) {
- uv_blade_info[bid].nmi_count++;
- uv_write_local_mmr(UVH_NMI_MMR_CLEAR,
- UV_NMI_PENDING_MASK);
+static int param_set_local64(const char *val, const struct kernel_param *kp)
+{
+ /* clear on any write */
+ local64_set((local64_t *)kp->arg, 0);
+ return 0;
+}
+
+static struct kernel_param_ops param_ops_local64 = {
+ .get = param_get_local64,
+ .set = param_set_local64,
+};
+#define param_check_local64(name, p) __param_check(name, p, local64_t)
+
+static local64_t uv_nmi_count;
+module_param_named(nmi_count, uv_nmi_count, local64, 0644);
+
+static local64_t uv_nmi_misses;
+module_param_named(nmi_misses, uv_nmi_misses, local64, 0644);
+
+static local64_t uv_nmi_ping_count;
+module_param_named(ping_count, uv_nmi_ping_count, local64, 0644);
+
+static local64_t uv_nmi_ping_misses;
+module_param_named(ping_misses, uv_nmi_ping_misses, local64, 0644);
+
+/*
+ * Following values allow tuning for large systems under heavy loading
+ */
+static int uv_nmi_initial_delay = 100;
+module_param_named(initial_delay, uv_nmi_initial_delay, int, 0644);
+
+static int uv_nmi_slave_delay = 100;
+module_param_named(slave_delay, uv_nmi_slave_delay, int, 0644);
+
+static int uv_nmi_loop_delay = 100;
+module_param_named(loop_delay, uv_nmi_loop_delay, int, 0644);
+
+static int uv_nmi_trigger_delay = 10000;
+module_param_named(trigger_delay, uv_nmi_trigger_delay, int, 0644);
+
+static int uv_nmi_wait_count = 100;
+module_param_named(wait_count, uv_nmi_wait_count, int, 0644);
+
+static int uv_nmi_retry_count = 500;
+module_param_named(retry_count, uv_nmi_retry_count, int, 0644);
+
+/* Setup which NMI support is present in system */
+static void uv_nmi_setup_mmrs(void)
+{
+ if (uv_read_local_mmr(UVH_NMI_MMRX_SUPPORTED)) {
+ uv_write_local_mmr(UVH_NMI_MMRX_REQ,
+ 1UL << UVH_NMI_MMRX_REQ_SHIFT);
+ nmi_mmr = UVH_NMI_MMRX;
+ nmi_mmr_clear = UVH_NMI_MMRX_CLEAR;
+ nmi_mmr_pending = 1UL << UVH_NMI_MMRX_SHIFT;
+ pr_info("UV: SMI NMI support: %s\n", UVH_NMI_MMRX_TYPE);
+ } else {
+ nmi_mmr = UVH_NMI_MMR;
+ nmi_mmr_clear = UVH_NMI_MMR_CLEAR;
+ nmi_mmr_pending = 1UL << UVH_NMI_MMR_SHIFT;
+ pr_info("UV: SMI NMI support: %s\n", UVH_NMI_MMR_TYPE);
+ }
+}
+
+/* Read NMI MMR and check if NMI flag was set by BMC. */
+static inline int uv_nmi_test_mmr(struct uv_hub_nmi_s *hub_nmi)
+{
+ hub_nmi->nmi_value = uv_read_local_mmr(nmi_mmr);
+ atomic_inc(&hub_nmi->read_mmr_count);
+ return !!(hub_nmi->nmi_value & nmi_mmr_pending);
+}
+
+static inline void uv_local_mmr_clear_nmi(void)
+{
+ uv_write_local_mmr(nmi_mmr_clear, nmi_mmr_pending);
+}
+
+/*
+ * If first cpu in on this hub, set hub_nmi "in_nmi" and "owner" values and
+ * return true. If first cpu in on the system, set global "in_nmi" flag.
+ */
+static int uv_set_in_nmi(int cpu, struct uv_hub_nmi_s *hub_nmi)
+{
+ int first = atomic_add_unless(&hub_nmi->in_nmi, 1, 1);
+
+ if (first) {
+ atomic_set(&hub_nmi->cpu_owner, cpu);
+ if (atomic_add_unless(&uv_in_nmi, 1, 1))
+ atomic_set(&uv_nmi_cpu, cpu);
+
+ atomic_inc(&hub_nmi->nmi_count);
+ }
+ return first;
+}
+
+/* Check if this is a system NMI event */
+static int uv_check_nmi(struct uv_hub_nmi_s *hub_nmi)
+{
+ int cpu = smp_processor_id();
+ int nmi = 0;
+
+ local64_inc(&uv_nmi_count);
+ uv_cpu_nmi.queries++;
+
+ do {
+ nmi = atomic_read(&hub_nmi->in_nmi);
+ if (nmi)
+ break;
+
+ if (raw_spin_trylock(&hub_nmi->nmi_lock)) {
+
+ /* check hub MMR NMI flag */
+ if (uv_nmi_test_mmr(hub_nmi)) {
+ uv_set_in_nmi(cpu, hub_nmi);
+ nmi = 1;
+ break;
+ }
+
+ /* MMR NMI flag is clear */
+ raw_spin_unlock(&hub_nmi->nmi_lock);
+
+ } else {
+ /* wait a moment for the hub nmi locker to set flag */
+ cpu_relax();
+ udelay(uv_nmi_slave_delay);
+
+ /* re-check hub in_nmi flag */
+ nmi = atomic_read(&hub_nmi->in_nmi);
+ if (nmi)
+ break;
+ }
+
+ /* check if this BMC missed setting the MMR NMI flag */
+ if (!nmi) {
+ nmi = atomic_read(&uv_in_nmi);
+ if (nmi)
+ uv_set_in_nmi(cpu, hub_nmi);
+ }
+
+ } while (0);
+
+ if (!nmi)
+ local64_inc(&uv_nmi_misses);
+
+ return nmi;
+}
+
+/* Need to reset the NMI MMR register, but only once per hub. */
+static inline void uv_clear_nmi(int cpu)
+{
+ struct uv_hub_nmi_s *hub_nmi = uv_hub_nmi;
+
+ if (cpu == atomic_read(&hub_nmi->cpu_owner)) {
+ atomic_set(&hub_nmi->cpu_owner, -1);
+ atomic_set(&hub_nmi->in_nmi, 0);
+ uv_local_mmr_clear_nmi();
+ raw_spin_unlock(&hub_nmi->nmi_lock);
+ }
+}
+
+/* Print non-responding cpus */
+static void uv_nmi_nr_cpus_pr(char *fmt)
+{
+ static char cpu_list[1024];
+ int len = sizeof(cpu_list);
+ int c = cpumask_weight(uv_nmi_cpu_mask);
+ int n = cpulist_scnprintf(cpu_list, len, uv_nmi_cpu_mask);
+
+ if (n >= len-1)
+ strcpy(&cpu_list[len - 6], "...\n");
+
+ printk(fmt, c, cpu_list);
+}
+
+/* Ping non-responding cpus attemping to force them into the NMI handler */
+static void uv_nmi_nr_cpus_ping(void)
+{
+ int cpu;
+
+ for_each_cpu(cpu, uv_nmi_cpu_mask)
+ atomic_set(&uv_cpu_nmi_per(cpu).pinging, 1);
+
+ apic->send_IPI_mask(uv_nmi_cpu_mask, APIC_DM_NMI);
+}
+
+/* Clean up flags for cpus that ignored both NMI and ping */
+static void uv_nmi_cleanup_mask(void)
+{
+ int cpu;
+
+ for_each_cpu(cpu, uv_nmi_cpu_mask) {
+ atomic_set(&uv_cpu_nmi_per(cpu).pinging, 0);
+ atomic_set(&uv_cpu_nmi_per(cpu).state, UV_NMI_STATE_OUT);
+ cpumask_clear_cpu(cpu, uv_nmi_cpu_mask);
+ }
+}
+
+/* Loop waiting as cpus enter nmi handler */
+static int uv_nmi_wait_cpus(int first)
+{
+ int i, j, k, n = num_online_cpus();
+ int last_k = 0, waiting = 0;
+
+ if (first) {
+ cpumask_copy(uv_nmi_cpu_mask, cpu_online_mask);
+ k = 0;
+ } else {
+ k = n - cpumask_weight(uv_nmi_cpu_mask);
+ }
+
+ udelay(uv_nmi_initial_delay);
+ for (i = 0; i < uv_nmi_retry_count; i++) {
+ int loop_delay = uv_nmi_loop_delay;
+
+ for_each_cpu(j, uv_nmi_cpu_mask) {
+ if (atomic_read(&uv_cpu_nmi_per(j).state)) {
+ cpumask_clear_cpu(j, uv_nmi_cpu_mask);
+ if (++k >= n)
+ break;
+ }
+ }
+ if (k >= n) { /* all in? */
+ k = n;
+ break;
+ }
+ if (last_k != k) { /* abort if no new cpus coming in */
+ last_k = k;
+ waiting = 0;
+ } else if (++waiting > uv_nmi_wait_count)
+ break;
+
+ /* extend delay if waiting only for cpu 0 */
+ if (waiting && (n - k) == 1 &&
+ cpumask_test_cpu(0, uv_nmi_cpu_mask))
+ loop_delay *= 100;
+
+ udelay(loop_delay);
+ }
+ atomic_set(&uv_nmi_cpus_in_nmi, k);
+ return n - k;
+}
+
+/* Wait until all slave cpus have entered UV NMI handler */
+static void uv_nmi_wait(int master)
+{
+ /* indicate this cpu is in */
+ atomic_set(&uv_cpu_nmi.state, UV_NMI_STATE_IN);
+
+ /* if not the first cpu in (the master), then we are a slave cpu */
+ if (!master)
+ return;
+
+ do {
+ /* wait for all other cpus to gather here */
+ if (!uv_nmi_wait_cpus(1))
+ break;
+
+ /* if not all made it in, send IPI NMI to them */
+ uv_nmi_nr_cpus_pr(KERN_ALERT
+ "UV: Sending NMI IPI to %d non-responding CPUs: %s\n");
+ uv_nmi_nr_cpus_ping();
+
+ /* if all cpus are in, then done */
+ if (!uv_nmi_wait_cpus(0))
+ break;
+
+ uv_nmi_nr_cpus_pr(KERN_ALERT
+ "UV: %d CPUs not in NMI loop: %s\n");
+ } while (0);
+
+ pr_alert("UV: %d of %d CPUs in NMI\n",
+ atomic_read(&uv_nmi_cpus_in_nmi), num_online_cpus());
+}
+
+/* Dump this cpu's state */
+static void uv_nmi_dump_state_cpu(int cpu, struct pt_regs *regs)
+{
+ const char *dots = " ................................. ";
+
+ printk(KERN_DEFAULT "UV:%sNMI process trace for CPU %d\n", dots, cpu);
+ show_regs(regs);
+ atomic_set(&uv_cpu_nmi.state, UV_NMI_STATE_DUMP_DONE);
+}
+
+/* Trigger a slave cpu to dump it's state */
+static void uv_nmi_trigger_dump(int cpu)
+{
+ int retry = uv_nmi_trigger_delay;
+
+ if (atomic_read(&uv_cpu_nmi_per(cpu).state) != UV_NMI_STATE_IN)
+ return;
+
+ atomic_set(&uv_cpu_nmi_per(cpu).state, UV_NMI_STATE_DUMP);
+ do {
+ cpu_relax();
+ udelay(10);
+ if (atomic_read(&uv_cpu_nmi_per(cpu).state)
+ != UV_NMI_STATE_DUMP)
+ return;
+ } while (--retry > 0);
+
+ pr_crit("UV: CPU %d stuck in process dump function\n", cpu);
+ atomic_set(&uv_cpu_nmi_per(cpu).state, UV_NMI_STATE_DUMP_DONE);
+}
+
+/* Wait until all cpus ready to exit */
+static void uv_nmi_sync_exit(int master)
+{
+ atomic_dec(&uv_nmi_cpus_in_nmi);
+ if (master) {
+ while (atomic_read(&uv_nmi_cpus_in_nmi) > 0)
+ cpu_relax();
+ atomic_set(&uv_nmi_slave_continue, SLAVE_CLEAR);
+ } else {
+ while (atomic_read(&uv_nmi_slave_continue))
+ cpu_relax();
+ }
+}
+
+/* Walk through cpu list and dump state of each */
+static void uv_nmi_dump_state(int cpu, struct pt_regs *regs, int master)
+{
+ if (master) {
+ int tcpu;
+ int ignored = 0;
+ int saved_console_loglevel = console_loglevel;
+
+ pr_alert("UV: tracing processes for %d CPUs from CPU %d\n",
+ atomic_read(&uv_nmi_cpus_in_nmi), cpu);
+
+ console_loglevel = uv_nmi_loglevel;
+ atomic_set(&uv_nmi_slave_continue, SLAVE_EXIT);
+ for_each_online_cpu(tcpu) {
+ if (cpumask_test_cpu(tcpu, uv_nmi_cpu_mask))
+ ignored++;
+ else if (tcpu == cpu)
+ uv_nmi_dump_state_cpu(tcpu, regs);
+ else
+ uv_nmi_trigger_dump(tcpu);
}
- spin_unlock(&uv_blade_info[bid].nmi_lock);
+ if (ignored)
+ printk(KERN_DEFAULT "UV: %d CPUs ignored NMI\n",
+ ignored);
+
+ console_loglevel = saved_console_loglevel;
+ pr_alert("UV: process trace complete\n");
+ } else {
+ while (!atomic_read(&uv_nmi_slave_continue))
+ cpu_relax();
+ while (atomic_read(&uv_cpu_nmi.state) != UV_NMI_STATE_DUMP)
+ cpu_relax();
+ uv_nmi_dump_state_cpu(cpu, regs);
}
+ uv_nmi_sync_exit(master);
+}
- if (likely(__get_cpu_var(cpu_last_nmi_count) ==
- uv_blade_info[bid].nmi_count))
+static void uv_nmi_touch_watchdogs(void)
+{
+ touch_softlockup_watchdog_sync();
+ clocksource_touch_watchdog();
+ rcu_cpu_stall_reset();
+ touch_nmi_watchdog();
+}
+
+/*
+ * UV NMI handler
+ */
+int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)
+{
+ struct uv_hub_nmi_s *hub_nmi = uv_hub_nmi;
+ int cpu = smp_processor_id();
+ int master = 0;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ /* If not a UV System NMI, ignore */
+ if (!atomic_read(&uv_cpu_nmi.pinging) && !uv_check_nmi(hub_nmi)) {
+ local_irq_restore(flags);
return NMI_DONE;
+ }
- __get_cpu_var(cpu_last_nmi_count) = uv_blade_info[bid].nmi_count;
+ /* Indicate we are the first CPU into the NMI handler */
+ master = (atomic_read(&uv_nmi_cpu) == cpu);
- /*
- * Use a lock so only one cpu prints at a time.
- * This prevents intermixed output.
- */
- spin_lock(&uv_nmi_lock);
- pr_info("UV NMI stack dump cpu %u:\n", smp_processor_id());
- dump_stack();
- spin_unlock(&uv_nmi_lock);
+ /* Pause as all cpus enter the NMI handler */
+ uv_nmi_wait(master);
+
+ /* Dump state of each cpu */
+ uv_nmi_dump_state(cpu, regs, master);
+
+ /* Clear per_cpu "in nmi" flag */
+ atomic_set(&uv_cpu_nmi.state, UV_NMI_STATE_OUT);
+
+ /* Clear MMR NMI flag on each hub */
+ uv_clear_nmi(cpu);
+
+ /* Clear global flags */
+ if (master) {
+ if (cpumask_weight(uv_nmi_cpu_mask))
+ uv_nmi_cleanup_mask();
+ atomic_set(&uv_nmi_cpus_in_nmi, -1);
+ atomic_set(&uv_nmi_cpu, -1);
+ atomic_set(&uv_in_nmi, 0);
+ }
+
+ uv_nmi_touch_watchdogs();
+ local_irq_restore(flags);
return NMI_HANDLED;
}
+/*
+ * NMI handler for pulling in CPUs when perf events are grabbing our NMI
+ */
+int uv_handle_nmi_ping(unsigned int reason, struct pt_regs *regs)
+{
+ int ret;
+
+ uv_cpu_nmi.queries++;
+ if (!atomic_read(&uv_cpu_nmi.pinging)) {
+ local64_inc(&uv_nmi_ping_misses);
+ return NMI_DONE;
+ }
+
+ uv_cpu_nmi.pings++;
+ local64_inc(&uv_nmi_ping_count);
+ ret = uv_handle_nmi(reason, regs);
+ atomic_set(&uv_cpu_nmi.pinging, 0);
+ return ret;
+}
+
void uv_register_nmi_notifier(void)
{
if (register_nmi_handler(NMI_UNKNOWN, uv_handle_nmi, 0, "uv"))
- pr_warn("UV NMI handler failed to register\n");
+ pr_warn("UV: NMI handler failed to register\n");
+
+ if (register_nmi_handler(NMI_LOCAL, uv_handle_nmi_ping, 0, "uvping"))
+ pr_warn("UV: PING NMI handler failed to register\n");
}
void uv_nmi_init(void)
apic_write(APIC_LVT1, value);
}
+void uv_nmi_setup(void)
+{
+ int size = sizeof(void *) * (1 << NODES_SHIFT);
+ int cpu, nid;
+
+ /* Setup hub nmi info */
+ uv_nmi_setup_mmrs();
+ uv_hub_nmi_list = kzalloc(size, GFP_KERNEL);
+ pr_info("UV: NMI hub list @ 0x%p (%d)\n", uv_hub_nmi_list, size);
+ BUG_ON(!uv_hub_nmi_list);
+ size = sizeof(struct uv_hub_nmi_s);
+ for_each_present_cpu(cpu) {
+ nid = cpu_to_node(cpu);
+ if (uv_hub_nmi_list[nid] == NULL) {
+ uv_hub_nmi_list[nid] = kzalloc_node(size,
+ GFP_KERNEL, nid);
+ BUG_ON(!uv_hub_nmi_list[nid]);
+ raw_spin_lock_init(&(uv_hub_nmi_list[nid]->nmi_lock));
+ atomic_set(&uv_hub_nmi_list[nid]->cpu_owner, -1);
+ }
+ uv_hub_nmi_per(cpu) = uv_hub_nmi_list[nid];
+ }
+ alloc_cpumask_var(&uv_nmi_cpu_mask, GFP_KERNEL);
+ BUG_ON(!uv_nmi_cpu_mask);
+}
+
+
projects / platform / kernel / linux-starfive.git / commitdiff