| /* |
| * pseries CPU Hotplug infrastructure. |
| * |
| * Split out from arch/powerpc/platforms/pseries/setup.c |
| * arch/powerpc/kernel/rtas.c, and arch/powerpc/platforms/pseries/smp.c |
| * |
| * Peter Bergner, IBM March 2001. |
| * Copyright (C) 2001 IBM. |
| * Dave Engebretsen, Peter Bergner, and |
| * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com |
| * Plus various changes from other IBM teams... |
| * |
| * Copyright (C) 2006 Michael Ellerman, IBM Corporation |
| * |
| * 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. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/interrupt.h> |
| #include <linux/delay.h> |
| #include <linux/sched.h> /* for idle_task_exit */ |
| #include <linux/cpu.h> |
| #include <linux/of.h> |
| #include <asm/prom.h> |
| #include <asm/rtas.h> |
| #include <asm/firmware.h> |
| #include <asm/machdep.h> |
| #include <asm/vdso_datapage.h> |
| #include <asm/xics.h> |
| #include "plpar_wrappers.h" |
| #include "offline_states.h" |
| |
| /* This version can't take the spinlock, because it never returns */ |
| static struct rtas_args rtas_stop_self_args = { |
| .token = RTAS_UNKNOWN_SERVICE, |
| .nargs = 0, |
| .nret = 1, |
| .rets = &rtas_stop_self_args.args[0], |
| }; |
| |
| static DEFINE_PER_CPU(enum cpu_state_vals, preferred_offline_state) = |
| CPU_STATE_OFFLINE; |
| static DEFINE_PER_CPU(enum cpu_state_vals, current_state) = CPU_STATE_OFFLINE; |
| |
| static enum cpu_state_vals default_offline_state = CPU_STATE_OFFLINE; |
| |
| static int cede_offline_enabled __read_mostly = 1; |
| |
| /* |
| * Enable/disable cede_offline when available. |
| */ |
| static int __init setup_cede_offline(char *str) |
| { |
| if (!strcmp(str, "off")) |
| cede_offline_enabled = 0; |
| else if (!strcmp(str, "on")) |
| cede_offline_enabled = 1; |
| else |
| return 0; |
| return 1; |
| } |
| |
| __setup("cede_offline=", setup_cede_offline); |
| |
| enum cpu_state_vals get_cpu_current_state(int cpu) |
| { |
| return per_cpu(current_state, cpu); |
| } |
| |
| void set_cpu_current_state(int cpu, enum cpu_state_vals state) |
| { |
| per_cpu(current_state, cpu) = state; |
| } |
| |
| enum cpu_state_vals get_preferred_offline_state(int cpu) |
| { |
| return per_cpu(preferred_offline_state, cpu); |
| } |
| |
| void set_preferred_offline_state(int cpu, enum cpu_state_vals state) |
| { |
| per_cpu(preferred_offline_state, cpu) = state; |
| } |
| |
| void set_default_offline_state(int cpu) |
| { |
| per_cpu(preferred_offline_state, cpu) = default_offline_state; |
| } |
| |
| static void rtas_stop_self(void) |
| { |
| struct rtas_args *args = &rtas_stop_self_args; |
| |
| local_irq_disable(); |
| |
| BUG_ON(args->token == RTAS_UNKNOWN_SERVICE); |
| |
| printk("cpu %u (hwid %u) Ready to die...\n", |
| smp_processor_id(), hard_smp_processor_id()); |
| enter_rtas(__pa(args)); |
| |
| panic("Alas, I survived.\n"); |
| } |
| |
| static void pseries_mach_cpu_die(void) |
| { |
| unsigned int cpu = smp_processor_id(); |
| unsigned int hwcpu = hard_smp_processor_id(); |
| u8 cede_latency_hint = 0; |
| |
| local_irq_disable(); |
| idle_task_exit(); |
| xics_teardown_cpu(); |
| |
| if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) { |
| set_cpu_current_state(cpu, CPU_STATE_INACTIVE); |
| if (ppc_md.suspend_disable_cpu) |
| ppc_md.suspend_disable_cpu(); |
| |
| cede_latency_hint = 2; |
| |
| get_lppaca()->idle = 1; |
| if (!get_lppaca()->shared_proc) |
| get_lppaca()->donate_dedicated_cpu = 1; |
| |
| while (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) { |
| extended_cede_processor(cede_latency_hint); |
| } |
| |
| if (!get_lppaca()->shared_proc) |
| get_lppaca()->donate_dedicated_cpu = 0; |
| get_lppaca()->idle = 0; |
| |
| if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) { |
| unregister_slb_shadow(hwcpu); |
| |
| /* |
| * Call to start_secondary_resume() will not return. |
| * Kernel stack will be reset and start_secondary() |
| * will be called to continue the online operation. |
| */ |
| start_secondary_resume(); |
| } |
| } |
| |
| /* Requested state is CPU_STATE_OFFLINE at this point */ |
| WARN_ON(get_preferred_offline_state(cpu) != CPU_STATE_OFFLINE); |
| |
| set_cpu_current_state(cpu, CPU_STATE_OFFLINE); |
| unregister_slb_shadow(hwcpu); |
| rtas_stop_self(); |
| |
| /* Should never get here... */ |
| BUG(); |
| for(;;); |
| } |
| |
| static int pseries_cpu_disable(void) |
| { |
| int cpu = smp_processor_id(); |
| |
| set_cpu_online(cpu, false); |
| vdso_data->processorCount--; |
| |
| /*fix boot_cpuid here*/ |
| if (cpu == boot_cpuid) |
| boot_cpuid = cpumask_any(cpu_online_mask); |
| |
| /* FIXME: abstract this to not be platform specific later on */ |
| xics_migrate_irqs_away(); |
| return 0; |
| } |
| |
| /* |
| * pseries_cpu_die: Wait for the cpu to die. |
| * @cpu: logical processor id of the CPU whose death we're awaiting. |
| * |
| * This function is called from the context of the thread which is performing |
| * the cpu-offline. Here we wait for long enough to allow the cpu in question |
| * to self-destroy so that the cpu-offline thread can send the CPU_DEAD |
| * notifications. |
| * |
| * OTOH, pseries_mach_cpu_die() is called by the @cpu when it wants to |
| * self-destruct. |
| */ |
| static void pseries_cpu_die(unsigned int cpu) |
| { |
| int tries; |
| int cpu_status = 1; |
| unsigned int pcpu = get_hard_smp_processor_id(cpu); |
| |
| if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) { |
| cpu_status = 1; |
| for (tries = 0; tries < 5000; tries++) { |
| if (get_cpu_current_state(cpu) == CPU_STATE_INACTIVE) { |
| cpu_status = 0; |
| break; |
| } |
| msleep(1); |
| } |
| } else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) { |
| |
| for (tries = 0; tries < 25; tries++) { |
| cpu_status = smp_query_cpu_stopped(pcpu); |
| if (cpu_status == QCSS_STOPPED || |
| cpu_status == QCSS_HARDWARE_ERROR) |
| break; |
| cpu_relax(); |
| } |
| } |
| |
| if (cpu_status != 0) { |
| printk("Querying DEAD? cpu %i (%i) shows %i\n", |
| cpu, pcpu, cpu_status); |
| } |
| |
| /* Isolation and deallocation are definitely done by |
| * drslot_chrp_cpu. If they were not they would be |
| * done here. Change isolate state to Isolate and |
| * change allocation-state to Unusable. |
| */ |
| paca[cpu].cpu_start = 0; |
| } |
| |
| /* |
| * Update cpu_present_mask and paca(s) for a new cpu node. The wrinkle |
| * here is that a cpu device node may represent up to two logical cpus |
| * in the SMT case. We must honor the assumption in other code that |
| * the logical ids for sibling SMT threads x and y are adjacent, such |
| * that x^1 == y and y^1 == x. |
| */ |
| static int pseries_add_processor(struct device_node *np) |
| { |
| unsigned int cpu; |
| cpumask_var_t candidate_mask, tmp; |
| int err = -ENOSPC, len, nthreads, i; |
| const u32 *intserv; |
| |
| intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len); |
| if (!intserv) |
| return 0; |
| |
| zalloc_cpumask_var(&candidate_mask, GFP_KERNEL); |
| zalloc_cpumask_var(&tmp, GFP_KERNEL); |
| |
| nthreads = len / sizeof(u32); |
| for (i = 0; i < nthreads; i++) |
| cpumask_set_cpu(i, tmp); |
| |
| cpu_maps_update_begin(); |
| |
| BUG_ON(!cpumask_subset(cpu_present_mask, cpu_possible_mask)); |
| |
| /* Get a bitmap of unoccupied slots. */ |
| cpumask_xor(candidate_mask, cpu_possible_mask, cpu_present_mask); |
| if (cpumask_empty(candidate_mask)) { |
| /* If we get here, it most likely means that NR_CPUS is |
| * less than the partition's max processors setting. |
| */ |
| printk(KERN_ERR "Cannot add cpu %s; this system configuration" |
| " supports %d logical cpus.\n", np->full_name, |
| cpumask_weight(cpu_possible_mask)); |
| goto out_unlock; |
| } |
| |
| while (!cpumask_empty(tmp)) |
| if (cpumask_subset(tmp, candidate_mask)) |
| /* Found a range where we can insert the new cpu(s) */ |
| break; |
| else |
| cpumask_shift_left(tmp, tmp, nthreads); |
| |
| if (cpumask_empty(tmp)) { |
| printk(KERN_ERR "Unable to find space in cpu_present_mask for" |
| " processor %s with %d thread(s)\n", np->name, |
| nthreads); |
| goto out_unlock; |
| } |
| |
| for_each_cpu(cpu, tmp) { |
| BUG_ON(cpu_present(cpu)); |
| set_cpu_present(cpu, true); |
| set_hard_smp_processor_id(cpu, *intserv++); |
| } |
| err = 0; |
| out_unlock: |
| cpu_maps_update_done(); |
| free_cpumask_var(candidate_mask); |
| free_cpumask_var(tmp); |
| return err; |
| } |
| |
| /* |
| * Update the present map for a cpu node which is going away, and set |
| * the hard id in the paca(s) to -1 to be consistent with boot time |
| * convention for non-present cpus. |
| */ |
| static void pseries_remove_processor(struct device_node *np) |
| { |
| unsigned int cpu; |
| int len, nthreads, i; |
| const u32 *intserv; |
| |
| intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len); |
| if (!intserv) |
| return; |
| |
| nthreads = len / sizeof(u32); |
| |
| cpu_maps_update_begin(); |
| for (i = 0; i < nthreads; i++) { |
| for_each_present_cpu(cpu) { |
| if (get_hard_smp_processor_id(cpu) != intserv[i]) |
| continue; |
| BUG_ON(cpu_online(cpu)); |
| set_cpu_present(cpu, false); |
| set_hard_smp_processor_id(cpu, -1); |
| break; |
| } |
| if (cpu >= nr_cpu_ids) |
| printk(KERN_WARNING "Could not find cpu to remove " |
| "with physical id 0x%x\n", intserv[i]); |
| } |
| cpu_maps_update_done(); |
| } |
| |
| static int pseries_smp_notifier(struct notifier_block *nb, |
| unsigned long action, void *node) |
| { |
| int err = 0; |
| |
| switch (action) { |
| case OF_RECONFIG_ATTACH_NODE: |
| err = pseries_add_processor(node); |
| break; |
| case OF_RECONFIG_DETACH_NODE: |
| pseries_remove_processor(node); |
| break; |
| } |
| return notifier_from_errno(err); |
| } |
| |
| static struct notifier_block pseries_smp_nb = { |
| .notifier_call = pseries_smp_notifier, |
| }; |
| |
| #define MAX_CEDE_LATENCY_LEVELS 4 |
| #define CEDE_LATENCY_PARAM_LENGTH 10 |
| #define CEDE_LATENCY_PARAM_MAX_LENGTH \ |
| (MAX_CEDE_LATENCY_LEVELS * CEDE_LATENCY_PARAM_LENGTH * sizeof(char)) |
| #define CEDE_LATENCY_TOKEN 45 |
| |
| static char cede_parameters[CEDE_LATENCY_PARAM_MAX_LENGTH]; |
| |
| static int parse_cede_parameters(void) |
| { |
| memset(cede_parameters, 0, CEDE_LATENCY_PARAM_MAX_LENGTH); |
| return rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, |
| NULL, |
| CEDE_LATENCY_TOKEN, |
| __pa(cede_parameters), |
| CEDE_LATENCY_PARAM_MAX_LENGTH); |
| } |
| |
| static int __init pseries_cpu_hotplug_init(void) |
| { |
| struct device_node *np; |
| const char *typep; |
| int cpu; |
| int qcss_tok; |
| |
| for_each_node_by_name(np, "interrupt-controller") { |
| typep = of_get_property(np, "compatible", NULL); |
| if (strstr(typep, "open-pic")) { |
| of_node_put(np); |
| |
| printk(KERN_INFO "CPU Hotplug not supported on " |
| "systems using MPIC\n"); |
| return 0; |
| } |
| } |
| |
| rtas_stop_self_args.token = rtas_token("stop-self"); |
| qcss_tok = rtas_token("query-cpu-stopped-state"); |
| |
| if (rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE || |
| qcss_tok == RTAS_UNKNOWN_SERVICE) { |
| printk(KERN_INFO "CPU Hotplug not supported by firmware " |
| "- disabling.\n"); |
| return 0; |
| } |
| |
| ppc_md.cpu_die = pseries_mach_cpu_die; |
| smp_ops->cpu_disable = pseries_cpu_disable; |
| smp_ops->cpu_die = pseries_cpu_die; |
| |
| /* Processors can be added/removed only on LPAR */ |
| if (firmware_has_feature(FW_FEATURE_LPAR)) { |
| of_reconfig_notifier_register(&pseries_smp_nb); |
| cpu_maps_update_begin(); |
| if (cede_offline_enabled && parse_cede_parameters() == 0) { |
| default_offline_state = CPU_STATE_INACTIVE; |
| for_each_online_cpu(cpu) |
| set_default_offline_state(cpu); |
| } |
| cpu_maps_update_done(); |
| } |
| |
| return 0; |
| } |
| arch_initcall(pseries_cpu_hotplug_init); |