diff options
Diffstat (limited to 'arch/x86/platform/uv/uv_nmi.c')
| -rw-r--r-- | arch/x86/platform/uv/uv_nmi.c | 700 |
1 files changed, 700 insertions, 0 deletions
diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c new file mode 100644 index 000000000000..2e863ad4a772 --- /dev/null +++ b/arch/x86/platform/uv/uv_nmi.c @@ -0,0 +1,700 @@ +/* + * SGI NMI support routines + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * Copyright (c) 2009-2013 Silicon Graphics, Inc. All Rights Reserved. + * Copyright (c) Mike Travis + */ + +#include <linux/cpu.h> +#include <linux/delay.h> +#include <linux/kdb.h> +#include <linux/kexec.h> +#include <linux/kgdb.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/traps.h> +#include <asm/uv/uv.h> +#include <asm/uv/uv_hub.h> +#include <asm/uv/uv_mmrs.h> + +/* + * 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 atomic_t uv_nmi_kexec_failed; +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 + +/* + * Default is all stack dumps go to the console and buffer. + * Lower level to send to log buffer only. + */ +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) +{ + return sprintf(buffer, "%lu\n", local64_read((local64_t *)kp->arg)); +} + +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); + +/* + * Valid NMI Actions: + * "dump" - dump process stack for each cpu + * "ips" - dump IP info for each cpu + * "kdump" - do crash dump + * "kdb" - enter KDB/KGDB (default) + */ +static char uv_nmi_action[8] = "kdb"; +module_param_string(action, uv_nmi_action, sizeof(uv_nmi_action), 0644); + +static inline bool uv_nmi_action_is(const char *action) +{ + return (strncmp(uv_nmi_action, action, strlen(action)) == 0); +} + +/* 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()); +} + +static void uv_nmi_dump_cpu_ip_hdr(void) +{ + printk(KERN_DEFAULT + "\nUV: %4s %6s %-32s %s (Note: PID 0 not listed)\n", + "CPU", "PID", "COMMAND", "IP"); +} + +static void uv_nmi_dump_cpu_ip(int cpu, struct pt_regs *regs) +{ + printk(KERN_DEFAULT "UV: %4d %6d %-32.32s ", + cpu, current->pid, current->comm); + + printk_address(regs->ip, 1); +} + +/* Dump this cpu's state */ +static void uv_nmi_dump_state_cpu(int cpu, struct pt_regs *regs) +{ + const char *dots = " ................................. "; + + if (uv_nmi_action_is("ips")) { + if (cpu == 0) + uv_nmi_dump_cpu_ip_hdr(); + + if (current->pid != 0) + uv_nmi_dump_cpu_ip(cpu, regs); + + } else if (uv_nmi_action_is("dump")) { + 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 %s for %d CPUs from CPU %d\n", + uv_nmi_action_is("ips") ? "IPs" : "processes", + 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); + } + 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); +} + +static void uv_nmi_touch_watchdogs(void) +{ + touch_softlockup_watchdog_sync(); + clocksource_touch_watchdog(); + rcu_cpu_stall_reset(); + touch_nmi_watchdog(); +} + +#if defined(CONFIG_KEXEC) +static void uv_nmi_kdump(int cpu, int master, struct pt_regs *regs) +{ + /* Call crash to dump system state */ + if (master) { + pr_emerg("UV: NMI executing crash_kexec on CPU%d\n", cpu); + crash_kexec(regs); + + pr_emerg("UV: crash_kexec unexpectedly returned, "); + if (!kexec_crash_image) { + pr_cont("crash kernel not loaded\n"); + atomic_set(&uv_nmi_kexec_failed, 1); + uv_nmi_sync_exit(1); + return; + } + pr_cont("kexec busy, stalling cpus while waiting\n"); + } + + /* If crash exec fails the slaves should return, otherwise stall */ + while (atomic_read(&uv_nmi_kexec_failed) == 0) + mdelay(10); + + /* Crash kernel most likely not loaded, return in an orderly fashion */ + uv_nmi_sync_exit(0); +} + +#else /* !CONFIG_KEXEC */ +static inline void uv_nmi_kdump(int cpu, int master, struct pt_regs *regs) +{ + if (master) + pr_err("UV: NMI kdump: KEXEC not supported in this kernel\n"); +} +#endif /* !CONFIG_KEXEC */ + +#ifdef CONFIG_KGDB_KDB +/* Call KDB from NMI handler */ +static void uv_call_kdb(int cpu, struct pt_regs *regs, int master) +{ + int ret; + + if (master) { + /* call KGDB NMI handler as MASTER */ + ret = kgdb_nmicallin(cpu, X86_TRAP_NMI, regs, + &uv_nmi_slave_continue); + if (ret) { + pr_alert("KDB returned error, is kgdboc set?\n"); + atomic_set(&uv_nmi_slave_continue, SLAVE_EXIT); + } + } else { + /* wait for KGDB signal that it's ready for slaves to enter */ + int sig; + + do { + cpu_relax(); + sig = atomic_read(&uv_nmi_slave_continue); + } while (!sig); + + /* call KGDB as slave */ + if (sig == SLAVE_CONTINUE) + kgdb_nmicallback(cpu, regs); + } + uv_nmi_sync_exit(master); +} + +#else /* !CONFIG_KGDB_KDB */ +static inline void uv_call_kdb(int cpu, struct pt_regs *regs, int master) +{ + pr_err("UV: NMI error: KGDB/KDB is not enabled in this kernel\n"); +} +#endif /* !CONFIG_KGDB_KDB */ + +/* + * 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; + } + + /* Indicate we are the first CPU into the NMI handler */ + master = (atomic_read(&uv_nmi_cpu) == cpu); + + /* If NMI action is "kdump", then attempt to do it */ + if (uv_nmi_action_is("kdump")) + uv_nmi_kdump(cpu, master, regs); + + /* Pause as all cpus enter the NMI handler */ + uv_nmi_wait(master); + + /* Dump state of each cpu */ + if (uv_nmi_action_is("ips") || uv_nmi_action_is("dump")) + uv_nmi_dump_state(cpu, regs, master); + + /* Call KDB if enabled */ + else if (uv_nmi_action_is("kdb")) + uv_call_kdb(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"); + + 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) +{ + unsigned int value; + + /* + * Unmask NMI on all cpus + */ + value = apic_read(APIC_LVT1) | APIC_DM_NMI; + value &= ~APIC_LVT_MASKED; + 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]; + } + BUG_ON(!alloc_cpumask_var(&uv_nmi_cpu_mask, GFP_KERNEL)); +} + + |