1/* 2 * pseries CPU Hotplug infrastructure. 3 * 4 * Split out from arch/powerpc/platforms/pseries/setup.c 5 * arch/powerpc/kernel/rtas.c, and arch/powerpc/platforms/pseries/smp.c 6 * 7 * Peter Bergner, IBM March 2001. 8 * Copyright (C) 2001 IBM. 9 * Dave Engebretsen, Peter Bergner, and 10 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com 11 * Plus various changes from other IBM teams... 12 * 13 * Copyright (C) 2006 Michael Ellerman, IBM Corporation 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 18 * 2 of the License, or (at your option) any later version. 19 */ 20 21#include <linux/kernel.h> 22#include <linux/delay.h> 23#include <linux/cpu.h> 24#include <asm/system.h> 25#include <asm/prom.h> 26#include <asm/rtas.h> 27#include <asm/firmware.h> 28#include <asm/machdep.h> 29#include <asm/vdso_datapage.h> 30#include <asm/pSeries_reconfig.h> 31#include "xics.h" 32 33/* This version can't take the spinlock, because it never returns */ 34static struct rtas_args rtas_stop_self_args = { 35 .token = RTAS_UNKNOWN_SERVICE, 36 .nargs = 0, 37 .nret = 1, 38 .rets = &rtas_stop_self_args.args[0], 39}; 40 41static void rtas_stop_self(void) 42{ 43 struct rtas_args *args = &rtas_stop_self_args; 44 45 local_irq_disable(); 46 47 BUG_ON(args->token == RTAS_UNKNOWN_SERVICE); 48 49 printk("cpu %u (hwid %u) Ready to die...\n", 50 smp_processor_id(), hard_smp_processor_id()); 51 enter_rtas(__pa(args)); 52 53 panic("Alas, I survived.\n"); 54} 55 56static void pseries_mach_cpu_die(void) 57{ 58 local_irq_disable(); 59 idle_task_exit(); 60 xics_teardown_cpu(0); 61 rtas_stop_self(); 62 /* Should never get here... */ 63 BUG(); 64 for(;;); 65} 66 67static int qcss_tok; /* query-cpu-stopped-state token */ 68 69/* Get state of physical CPU. 70 * Return codes: 71 * 0 - The processor is in the RTAS stopped state 72 * 1 - stop-self is in progress 73 * 2 - The processor is not in the RTAS stopped state 74 * -1 - Hardware Error 75 * -2 - Hardware Busy, Try again later. 76 */ 77static int query_cpu_stopped(unsigned int pcpu) 78{ 79 int cpu_status, status; 80 81 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); 82 if (status != 0) { 83 printk(KERN_ERR 84 "RTAS query-cpu-stopped-state failed: %i\n", status); 85 return status; 86 } 87 88 return cpu_status; 89} 90 91static int pseries_cpu_disable(void) 92{ 93 int cpu = smp_processor_id(); 94 95 cpu_clear(cpu, cpu_online_map); 96 vdso_data->processorCount--; 97 98 /*fix boot_cpuid here*/ 99 if (cpu == boot_cpuid) 100 boot_cpuid = any_online_cpu(cpu_online_map); 101 102 xics_migrate_irqs_away(); 103 return 0; 104} 105 106static void pseries_cpu_die(unsigned int cpu) 107{ 108 int tries; 109 int cpu_status; 110 unsigned int pcpu = get_hard_smp_processor_id(cpu); 111 112 for (tries = 0; tries < 25; tries++) { 113 cpu_status = query_cpu_stopped(pcpu); 114 if (cpu_status == 0 || cpu_status == -1) 115 break; 116 msleep(200); 117 } 118 if (cpu_status != 0) { 119 printk("Querying DEAD? cpu %i (%i) shows %i\n", 120 cpu, pcpu, cpu_status); 121 } 122 123 /* Isolation and deallocation are definatly done by 124 * drslot_chrp_cpu. If they were not they would be 125 * done here. Change isolate state to Isolate and 126 * change allocation-state to Unusable. 127 */ 128 paca[cpu].cpu_start = 0; 129} 130 131/* 132 * Update cpu_present_map and paca(s) for a new cpu node. The wrinkle 133 * here is that a cpu device node may represent up to two logical cpus 134 * in the SMT case. We must honor the assumption in other code that 135 * the logical ids for sibling SMT threads x and y are adjacent, such 136 * that x^1 == y and y^1 == x. 137 */ 138static int pseries_add_processor(struct device_node *np) 139{ 140 unsigned int cpu; 141 cpumask_t candidate_map, tmp = CPU_MASK_NONE; 142 int err = -ENOSPC, len, nthreads, i; 143 const u32 *intserv; 144 145 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len); 146 if (!intserv) 147 return 0; 148 149 nthreads = len / sizeof(u32); 150 for (i = 0; i < nthreads; i++) 151 cpu_set(i, tmp); 152 153 lock_cpu_hotplug(); 154 155 BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map)); 156 157 /* Get a bitmap of unoccupied slots. */ 158 cpus_xor(candidate_map, cpu_possible_map, cpu_present_map); 159 if (cpus_empty(candidate_map)) { 160 /* If we get here, it most likely means that NR_CPUS is 161 * less than the partition's max processors setting. 162 */ 163 printk(KERN_ERR "Cannot add cpu %s; this system configuration" 164 " supports %d logical cpus.\n", np->full_name, 165 cpus_weight(cpu_possible_map)); 166 goto out_unlock; 167 } 168 169 while (!cpus_empty(tmp)) 170 if (cpus_subset(tmp, candidate_map)) 171 /* Found a range where we can insert the new cpu(s) */ 172 break; 173 else 174 cpus_shift_left(tmp, tmp, nthreads); 175 176 if (cpus_empty(tmp)) { 177 printk(KERN_ERR "Unable to find space in cpu_present_map for" 178 " processor %s with %d thread(s)\n", np->name, 179 nthreads); 180 goto out_unlock; 181 } 182 183 for_each_cpu_mask(cpu, tmp) { 184 BUG_ON(cpu_isset(cpu, cpu_present_map)); 185 cpu_set(cpu, cpu_present_map); 186 set_hard_smp_processor_id(cpu, *intserv++); 187 } 188 err = 0; 189out_unlock: 190 unlock_cpu_hotplug(); 191 return err; 192} 193 194/* 195 * Update the present map for a cpu node which is going away, and set 196 * the hard id in the paca(s) to -1 to be consistent with boot time 197 * convention for non-present cpus. 198 */ 199static void pseries_remove_processor(struct device_node *np) 200{ 201 unsigned int cpu; 202 int len, nthreads, i; 203 const u32 *intserv; 204 205 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len); 206 if (!intserv) 207 return; 208 209 nthreads = len / sizeof(u32); 210 211 lock_cpu_hotplug(); 212 for (i = 0; i < nthreads; i++) { 213 for_each_present_cpu(cpu) { 214 if (get_hard_smp_processor_id(cpu) != intserv[i]) 215 continue; 216 BUG_ON(cpu_online(cpu)); 217 cpu_clear(cpu, cpu_present_map); 218 set_hard_smp_processor_id(cpu, -1); 219 break; 220 } 221 if (cpu == NR_CPUS) 222 printk(KERN_WARNING "Could not find cpu to remove " 223 "with physical id 0x%x\n", intserv[i]); 224 } 225 unlock_cpu_hotplug(); 226} 227 228static int pseries_smp_notifier(struct notifier_block *nb, 229 unsigned long action, void *node) 230{ 231 int err = NOTIFY_OK; 232 233 switch (action) { 234 case PSERIES_RECONFIG_ADD: 235 if (pseries_add_processor(node)) 236 err = NOTIFY_BAD; 237 break; 238 case PSERIES_RECONFIG_REMOVE: 239 pseries_remove_processor(node); 240 break; 241 default: 242 err = NOTIFY_DONE; 243 break; 244 } 245 return err; 246} 247 248static struct notifier_block pseries_smp_nb = { 249 .notifier_call = pseries_smp_notifier, 250}; 251 252static int __init pseries_cpu_hotplug_init(void) 253{ 254 rtas_stop_self_args.token = rtas_token("stop-self"); 255 qcss_tok = rtas_token("query-cpu-stopped-state"); 256 257 if (rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE || 258 qcss_tok == RTAS_UNKNOWN_SERVICE) { 259 printk(KERN_INFO "CPU Hotplug not supported by firmware " 260 "- disabling.\n"); 261 return 0; 262 } 263 264 ppc_md.cpu_die = pseries_mach_cpu_die; 265 smp_ops->cpu_disable = pseries_cpu_disable; 266 smp_ops->cpu_die = pseries_cpu_die; 267 268 /* Processors can be added/removed only on LPAR */ 269 if (firmware_has_feature(FW_FEATURE_LPAR)) 270 pSeries_reconfig_notifier_register(&pseries_smp_nb); 271 272 return 0; 273} 274arch_initcall(pseries_cpu_hotplug_init); 275