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 #include "plpar_wrappers.h" 33 34 /* This version can't take the spinlock, because it never returns */ 35 static struct rtas_args rtas_stop_self_args = { 36 .token = RTAS_UNKNOWN_SERVICE, 37 .nargs = 0, 38 .nret = 1, 39 .rets = &rtas_stop_self_args.args[0], 40 }; 41 42 static void rtas_stop_self(void) 43 { 44 struct rtas_args *args = &rtas_stop_self_args; 45 46 local_irq_disable(); 47 48 BUG_ON(args->token == RTAS_UNKNOWN_SERVICE); 49 50 printk("cpu %u (hwid %u) Ready to die...\n", 51 smp_processor_id(), hard_smp_processor_id()); 52 enter_rtas(__pa(args)); 53 54 panic("Alas, I survived.\n"); 55 } 56 57 static void pseries_mach_cpu_die(void) 58 { 59 local_irq_disable(); 60 idle_task_exit(); 61 xics_teardown_cpu(); 62 unregister_slb_shadow(hard_smp_processor_id(), __pa(get_slb_shadow())); 63 rtas_stop_self(); 64 /* Should never get here... */ 65 BUG(); 66 for(;;); 67 } 68 69 static int qcss_tok; /* query-cpu-stopped-state token */ 70 71 /* Get state of physical CPU. 72 * Return codes: 73 * 0 - The processor is in the RTAS stopped state 74 * 1 - stop-self is in progress 75 * 2 - The processor is not in the RTAS stopped state 76 * -1 - Hardware Error 77 * -2 - Hardware Busy, Try again later. 78 */ 79 static int query_cpu_stopped(unsigned int pcpu) 80 { 81 int cpu_status, status; 82 83 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); 84 if (status != 0) { 85 printk(KERN_ERR 86 "RTAS query-cpu-stopped-state failed: %i\n", status); 87 return status; 88 } 89 90 return cpu_status; 91 } 92 93 static int pseries_cpu_disable(void) 94 { 95 int cpu = smp_processor_id(); 96 97 cpu_clear(cpu, cpu_online_map); 98 vdso_data->processorCount--; 99 100 /*fix boot_cpuid here*/ 101 if (cpu == boot_cpuid) 102 boot_cpuid = any_online_cpu(cpu_online_map); 103 104 /* FIXME: abstract this to not be platform specific later on */ 105 xics_migrate_irqs_away(); 106 return 0; 107 } 108 109 static void pseries_cpu_die(unsigned int cpu) 110 { 111 int tries; 112 int cpu_status; 113 unsigned int pcpu = get_hard_smp_processor_id(cpu); 114 115 for (tries = 0; tries < 25; tries++) { 116 cpu_status = query_cpu_stopped(pcpu); 117 if (cpu_status == 0 || cpu_status == -1) 118 break; 119 msleep(200); 120 } 121 if (cpu_status != 0) { 122 printk("Querying DEAD? cpu %i (%i) shows %i\n", 123 cpu, pcpu, cpu_status); 124 } 125 126 /* Isolation and deallocation are definatly done by 127 * drslot_chrp_cpu. If they were not they would be 128 * done here. Change isolate state to Isolate and 129 * change allocation-state to Unusable. 130 */ 131 paca[cpu].cpu_start = 0; 132 } 133 134 /* 135 * Update cpu_present_map and paca(s) for a new cpu node. The wrinkle 136 * here is that a cpu device node may represent up to two logical cpus 137 * in the SMT case. We must honor the assumption in other code that 138 * the logical ids for sibling SMT threads x and y are adjacent, such 139 * that x^1 == y and y^1 == x. 140 */ 141 static int pseries_add_processor(struct device_node *np) 142 { 143 unsigned int cpu; 144 cpumask_t candidate_map, tmp = CPU_MASK_NONE; 145 int err = -ENOSPC, len, nthreads, i; 146 const u32 *intserv; 147 148 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len); 149 if (!intserv) 150 return 0; 151 152 nthreads = len / sizeof(u32); 153 for (i = 0; i < nthreads; i++) 154 cpu_set(i, tmp); 155 156 cpu_maps_update_begin(); 157 158 BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map)); 159 160 /* Get a bitmap of unoccupied slots. */ 161 cpus_xor(candidate_map, cpu_possible_map, cpu_present_map); 162 if (cpus_empty(candidate_map)) { 163 /* If we get here, it most likely means that NR_CPUS is 164 * less than the partition's max processors setting. 165 */ 166 printk(KERN_ERR "Cannot add cpu %s; this system configuration" 167 " supports %d logical cpus.\n", np->full_name, 168 cpus_weight(cpu_possible_map)); 169 goto out_unlock; 170 } 171 172 while (!cpus_empty(tmp)) 173 if (cpus_subset(tmp, candidate_map)) 174 /* Found a range where we can insert the new cpu(s) */ 175 break; 176 else 177 cpus_shift_left(tmp, tmp, nthreads); 178 179 if (cpus_empty(tmp)) { 180 printk(KERN_ERR "Unable to find space in cpu_present_map for" 181 " processor %s with %d thread(s)\n", np->name, 182 nthreads); 183 goto out_unlock; 184 } 185 186 for_each_cpu_mask(cpu, tmp) { 187 BUG_ON(cpu_isset(cpu, cpu_present_map)); 188 cpu_set(cpu, cpu_present_map); 189 set_hard_smp_processor_id(cpu, *intserv++); 190 } 191 err = 0; 192 out_unlock: 193 cpu_maps_update_done(); 194 return err; 195 } 196 197 /* 198 * Update the present map for a cpu node which is going away, and set 199 * the hard id in the paca(s) to -1 to be consistent with boot time 200 * convention for non-present cpus. 201 */ 202 static void pseries_remove_processor(struct device_node *np) 203 { 204 unsigned int cpu; 205 int len, nthreads, i; 206 const u32 *intserv; 207 208 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len); 209 if (!intserv) 210 return; 211 212 nthreads = len / sizeof(u32); 213 214 cpu_maps_update_begin(); 215 for (i = 0; i < nthreads; i++) { 216 for_each_present_cpu(cpu) { 217 if (get_hard_smp_processor_id(cpu) != intserv[i]) 218 continue; 219 BUG_ON(cpu_online(cpu)); 220 cpu_clear(cpu, cpu_present_map); 221 set_hard_smp_processor_id(cpu, -1); 222 break; 223 } 224 if (cpu == NR_CPUS) 225 printk(KERN_WARNING "Could not find cpu to remove " 226 "with physical id 0x%x\n", intserv[i]); 227 } 228 cpu_maps_update_done(); 229 } 230 231 static int pseries_smp_notifier(struct notifier_block *nb, 232 unsigned long action, void *node) 233 { 234 int err = NOTIFY_OK; 235 236 switch (action) { 237 case PSERIES_RECONFIG_ADD: 238 if (pseries_add_processor(node)) 239 err = NOTIFY_BAD; 240 break; 241 case PSERIES_RECONFIG_REMOVE: 242 pseries_remove_processor(node); 243 break; 244 default: 245 err = NOTIFY_DONE; 246 break; 247 } 248 return err; 249 } 250 251 static struct notifier_block pseries_smp_nb = { 252 .notifier_call = pseries_smp_notifier, 253 }; 254 255 static int __init pseries_cpu_hotplug_init(void) 256 { 257 struct device_node *np; 258 const char *typep; 259 260 for_each_node_by_name(np, "interrupt-controller") { 261 typep = of_get_property(np, "compatible", NULL); 262 if (strstr(typep, "open-pic")) { 263 of_node_put(np); 264 265 printk(KERN_INFO "CPU Hotplug not supported on " 266 "systems using MPIC\n"); 267 return 0; 268 } 269 } 270 271 rtas_stop_self_args.token = rtas_token("stop-self"); 272 qcss_tok = rtas_token("query-cpu-stopped-state"); 273 274 if (rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE || 275 qcss_tok == RTAS_UNKNOWN_SERVICE) { 276 printk(KERN_INFO "CPU Hotplug not supported by firmware " 277 "- disabling.\n"); 278 return 0; 279 } 280 281 ppc_md.cpu_die = pseries_mach_cpu_die; 282 smp_ops->cpu_disable = pseries_cpu_disable; 283 smp_ops->cpu_die = pseries_cpu_die; 284 285 /* Processors can be added/removed only on LPAR */ 286 if (firmware_has_feature(FW_FEATURE_LPAR)) 287 pSeries_reconfig_notifier_register(&pseries_smp_nb); 288 289 return 0; 290 } 291 arch_initcall(pseries_cpu_hotplug_init); 292