/* * 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 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 = CONSOLE_LOGLEVEL_DEFAULT; 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 (default) * "kgdb" - enter KGDB */ 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); this_cpu_inc(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); } } /* 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) 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) { uv_cpu_nmi_per(cpu).pinging = 0; 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 (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 */ this_cpu_write(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 */ pr_alert("UV: Sending NMI IPI to %d non-responding CPUs: %*pbl\n", cpumask_weight(uv_nmi_cpu_mask), cpumask_pr_args(uv_nmi_cpu_mask)); uv_nmi_nr_cpus_ping(); /* if all cpus are in, then done */ if (!uv_nmi_wait_cpus(0)) break; pr_alert("UV: %d CPUs not in NMI loop: %*pbl\n", cpumask_weight(uv_nmi_cpu_mask), cpumask_pr_args(uv_nmi_cpu_mask)); } 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); } /* 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); } this_cpu_write(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 (uv_cpu_nmi_per(cpu).state != UV_NMI_STATE_IN) return; uv_cpu_nmi_per(cpu).state = UV_NMI_STATE_DUMP; do { cpu_relax(); udelay(10); if (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); 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 (this_cpu_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 atomic_t uv_nmi_kexec_failed; 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 #ifdef CONFIG_KGDB_KDB static inline int uv_nmi_kdb_reason(void) { return KDB_REASON_SYSTEM_NMI; } #else /* !CONFIG_KGDB_KDB */ static inline int uv_nmi_kdb_reason(void) { /* Insure user is expecting to attach gdb remote */ if (uv_nmi_action_is("kgdb")) return 0; pr_err("UV: NMI error: KDB is not enabled in this kernel\n"); return -1; } #endif /* CONFIG_KGDB_KDB */ /* * Call KGDB/KDB from NMI handler * * Note that if both KGDB and KDB are configured, then the action of 'kgdb' or * 'kdb' has no affect on which is used. See the KGDB documention for further * information. */ static void uv_call_kgdb_kdb(int cpu, struct pt_regs *regs, int master) { if (master) { int reason = uv_nmi_kdb_reason(); int ret; if (reason < 0) return; /* call KGDB NMI handler as MASTER */ ret = kgdb_nmicallin(cpu, X86_TRAP_NMI, regs, reason, &uv_nmi_slave_continue); if (ret) { pr_alert("KGDB 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 */ static inline void uv_call_kgdb_kdb(int cpu, struct pt_regs *regs, int master) { pr_err("UV: NMI error: KGDB is not enabled in this kernel\n"); } #endif /* !CONFIG_KGDB */ /* * 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 (!this_cpu_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 KGDB/KDB if enabled */ else if (uv_nmi_action_is("kdb") || uv_nmi_action_is("kgdb")) uv_call_kgdb_kdb(cpu, regs, master); /* Clear per_cpu "in nmi" flag */ this_cpu_write(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 */ static int uv_handle_nmi_ping(unsigned int reason, struct pt_regs *regs) { int ret; this_cpu_inc(uv_cpu_nmi.queries); if (!this_cpu_read(uv_cpu_nmi.pinging)) { local64_inc(&uv_nmi_ping_misses); return NMI_DONE; } this_cpu_inc(uv_cpu_nmi.pings); local64_inc(&uv_nmi_ping_count); ret = uv_handle_nmi(reason, regs); this_cpu_write(uv_cpu_nmi.pinging, 0); return ret; } static 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)); uv_register_nmi_notifier(); }