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 */ 34 static 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 41 static 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 56 static 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 67 static 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 */ 77 static 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 91 static 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 /* FIXME: abstract this to not be platform specific later on */ 103 xics_migrate_irqs_away(); 104 return 0; 105 } 106 107 static void pseries_cpu_die(unsigned int cpu) 108 { 109 int tries; 110 int cpu_status; 111 unsigned int pcpu = get_hard_smp_processor_id(cpu); 112 113 for (tries = 0; tries < 25; tries++) { 114 cpu_status = query_cpu_stopped(pcpu); 115 if (cpu_status == 0 || cpu_status == -1) 116 break; 117 msleep(200); 118 } 119 if (cpu_status != 0) { 120 printk("Querying DEAD? cpu %i (%i) shows %i\n", 121 cpu, pcpu, cpu_status); 122 } 123 124 /* Isolation and deallocation are definatly done by 125 * drslot_chrp_cpu. If they were not they would be 126 * done here. Change isolate state to Isolate and 127 * change allocation-state to Unusable. 128 */ 129 paca[cpu].cpu_start = 0; 130 } 131 132 /* 133 * Update cpu_present_map and paca(s) for a new cpu node. The wrinkle 134 * here is that a cpu device node may represent up to two logical cpus 135 * in the SMT case. We must honor the assumption in other code that 136 * the logical ids for sibling SMT threads x and y are adjacent, such 137 * that x^1 == y and y^1 == x. 138 */ 139 static int pseries_add_processor(struct device_node *np) 140 { 141 unsigned int cpu; 142 cpumask_t candidate_map, tmp = CPU_MASK_NONE; 143 int err = -ENOSPC, len, nthreads, i; 144 const u32 *intserv; 145 146 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len); 147 if (!intserv) 148 return 0; 149 150 nthreads = len / sizeof(u32); 151 for (i = 0; i < nthreads; i++) 152 cpu_set(i, tmp); 153 154 lock_cpu_hotplug(); 155 156 BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map)); 157 158 /* Get a bitmap of unoccupied slots. */ 159 cpus_xor(candidate_map, cpu_possible_map, cpu_present_map); 160 if (cpus_empty(candidate_map)) { 161 /* If we get here, it most likely means that NR_CPUS is 162 * less than the partition's max processors setting. 163 */ 164 printk(KERN_ERR "Cannot add cpu %s; this system configuration" 165 " supports %d logical cpus.\n", np->full_name, 166 cpus_weight(cpu_possible_map)); 167 goto out_unlock; 168 } 169 170 while (!cpus_empty(tmp)) 171 if (cpus_subset(tmp, candidate_map)) 172 /* Found a range where we can insert the new cpu(s) */ 173 break; 174 else 175 cpus_shift_left(tmp, tmp, nthreads); 176 177 if (cpus_empty(tmp)) { 178 printk(KERN_ERR "Unable to find space in cpu_present_map for" 179 " processor %s with %d thread(s)\n", np->name, 180 nthreads); 181 goto out_unlock; 182 } 183 184 for_each_cpu_mask(cpu, tmp) { 185 BUG_ON(cpu_isset(cpu, cpu_present_map)); 186 cpu_set(cpu, cpu_present_map); 187 set_hard_smp_processor_id(cpu, *intserv++); 188 } 189 err = 0; 190 out_unlock: 191 unlock_cpu_hotplug(); 192 return err; 193 } 194 195 /* 196 * Update the present map for a cpu node which is going away, and set 197 * the hard id in the paca(s) to -1 to be consistent with boot time 198 * convention for non-present cpus. 199 */ 200 static void pseries_remove_processor(struct device_node *np) 201 { 202 unsigned int cpu; 203 int len, nthreads, i; 204 const u32 *intserv; 205 206 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len); 207 if (!intserv) 208 return; 209 210 nthreads = len / sizeof(u32); 211 212 lock_cpu_hotplug(); 213 for (i = 0; i < nthreads; i++) { 214 for_each_present_cpu(cpu) { 215 if (get_hard_smp_processor_id(cpu) != intserv[i]) 216 continue; 217 BUG_ON(cpu_online(cpu)); 218 cpu_clear(cpu, cpu_present_map); 219 set_hard_smp_processor_id(cpu, -1); 220 break; 221 } 222 if (cpu == NR_CPUS) 223 printk(KERN_WARNING "Could not find cpu to remove " 224 "with physical id 0x%x\n", intserv[i]); 225 } 226 unlock_cpu_hotplug(); 227 } 228 229 static int pseries_smp_notifier(struct notifier_block *nb, 230 unsigned long action, void *node) 231 { 232 int err = NOTIFY_OK; 233 234 switch (action) { 235 case PSERIES_RECONFIG_ADD: 236 if (pseries_add_processor(node)) 237 err = NOTIFY_BAD; 238 break; 239 case PSERIES_RECONFIG_REMOVE: 240 pseries_remove_processor(node); 241 break; 242 default: 243 err = NOTIFY_DONE; 244 break; 245 } 246 return err; 247 } 248 249 static struct notifier_block pseries_smp_nb = { 250 .notifier_call = pseries_smp_notifier, 251 }; 252 253 static int __init pseries_cpu_hotplug_init(void) 254 { 255 struct device_node *np; 256 const char *typep; 257 258 for_each_node_by_name(np, "interrupt-controller") { 259 typep = of_get_property(np, "compatible", NULL); 260 if (strstr(typep, "open-pic")) { 261 of_node_put(np); 262 263 printk(KERN_INFO "CPU Hotplug not supported on " 264 "systems using MPIC\n"); 265 return 0; 266 } 267 } 268 269 rtas_stop_self_args.token = rtas_token("stop-self"); 270 qcss_tok = rtas_token("query-cpu-stopped-state"); 271 272 if (rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE || 273 qcss_tok == RTAS_UNKNOWN_SERVICE) { 274 printk(KERN_INFO "CPU Hotplug not supported by firmware " 275 "- disabling.\n"); 276 return 0; 277 } 278 279 ppc_md.cpu_die = pseries_mach_cpu_die; 280 smp_ops->cpu_disable = pseries_cpu_disable; 281 smp_ops->cpu_die = pseries_cpu_die; 282 283 /* Processors can be added/removed only on LPAR */ 284 if (firmware_has_feature(FW_FEATURE_LPAR)) 285 pSeries_reconfig_notifier_register(&pseries_smp_nb); 286 287 return 0; 288 } 289 arch_initcall(pseries_cpu_hotplug_init); 290