1 /* 2 * SMP support for pSeries machines. 3 * 4 * Dave Engebretsen, Peter Bergner, and 5 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com 6 * 7 * Plus various changes from other IBM teams... 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 */ 14 15 16 #include <linux/kernel.h> 17 #include <linux/sched.h> 18 #include <linux/smp.h> 19 #include <linux/interrupt.h> 20 #include <linux/delay.h> 21 #include <linux/init.h> 22 #include <linux/spinlock.h> 23 #include <linux/cache.h> 24 #include <linux/err.h> 25 #include <linux/device.h> 26 #include <linux/cpu.h> 27 28 #include <asm/ptrace.h> 29 #include <linux/atomic.h> 30 #include <asm/irq.h> 31 #include <asm/page.h> 32 #include <asm/pgtable.h> 33 #include <asm/io.h> 34 #include <asm/prom.h> 35 #include <asm/smp.h> 36 #include <asm/paca.h> 37 #include <asm/machdep.h> 38 #include <asm/cputable.h> 39 #include <asm/firmware.h> 40 #include <asm/rtas.h> 41 #include <asm/mpic.h> 42 #include <asm/vdso_datapage.h> 43 #include <asm/cputhreads.h> 44 #include <asm/xics.h> 45 #include <asm/dbell.h> 46 #include <asm/plpar_wrappers.h> 47 #include <asm/code-patching.h> 48 49 #include "pseries.h" 50 #include "offline_states.h" 51 52 53 /* 54 * The Primary thread of each non-boot processor was started from the OF client 55 * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop. 56 */ 57 static cpumask_var_t of_spin_mask; 58 59 /* 60 * If we multiplex IPI mechanisms, store the appropriate XICS IPI mechanism here 61 */ 62 static void (*xics_cause_ipi)(int cpu, unsigned long data); 63 64 /* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */ 65 int smp_query_cpu_stopped(unsigned int pcpu) 66 { 67 int cpu_status, status; 68 int qcss_tok = rtas_token("query-cpu-stopped-state"); 69 70 if (qcss_tok == RTAS_UNKNOWN_SERVICE) { 71 printk_once(KERN_INFO 72 "Firmware doesn't support query-cpu-stopped-state\n"); 73 return QCSS_HARDWARE_ERROR; 74 } 75 76 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); 77 if (status != 0) { 78 printk(KERN_ERR 79 "RTAS query-cpu-stopped-state failed: %i\n", status); 80 return status; 81 } 82 83 return cpu_status; 84 } 85 86 /** 87 * smp_startup_cpu() - start the given cpu 88 * 89 * At boot time, there is nothing to do for primary threads which were 90 * started from Open Firmware. For anything else, call RTAS with the 91 * appropriate start location. 92 * 93 * Returns: 94 * 0 - failure 95 * 1 - success 96 */ 97 static inline int smp_startup_cpu(unsigned int lcpu) 98 { 99 int status; 100 unsigned long start_here = 101 __pa(ppc_function_entry(generic_secondary_smp_init)); 102 unsigned int pcpu; 103 int start_cpu; 104 105 if (cpumask_test_cpu(lcpu, of_spin_mask)) 106 /* Already started by OF and sitting in spin loop */ 107 return 1; 108 109 pcpu = get_hard_smp_processor_id(lcpu); 110 111 /* Check to see if the CPU out of FW already for kexec */ 112 if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){ 113 cpumask_set_cpu(lcpu, of_spin_mask); 114 return 1; 115 } 116 117 /* Fixup atomic count: it exited inside IRQ handler. */ 118 task_thread_info(paca[lcpu].__current)->preempt_count = 0; 119 #ifdef CONFIG_HOTPLUG_CPU 120 if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) 121 goto out; 122 #endif 123 /* 124 * If the RTAS start-cpu token does not exist then presume the 125 * cpu is already spinning. 126 */ 127 start_cpu = rtas_token("start-cpu"); 128 if (start_cpu == RTAS_UNKNOWN_SERVICE) 129 return 1; 130 131 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu); 132 if (status != 0) { 133 printk(KERN_ERR "start-cpu failed: %i\n", status); 134 return 0; 135 } 136 137 #ifdef CONFIG_HOTPLUG_CPU 138 out: 139 #endif 140 return 1; 141 } 142 143 static void smp_xics_setup_cpu(int cpu) 144 { 145 if (cpu != boot_cpuid) 146 xics_setup_cpu(); 147 if (cpu_has_feature(CPU_FTR_DBELL)) 148 doorbell_setup_this_cpu(); 149 150 if (firmware_has_feature(FW_FEATURE_SPLPAR)) 151 vpa_init(cpu); 152 153 cpumask_clear_cpu(cpu, of_spin_mask); 154 #ifdef CONFIG_HOTPLUG_CPU 155 set_cpu_current_state(cpu, CPU_STATE_ONLINE); 156 set_default_offline_state(cpu); 157 #endif 158 } 159 160 static int smp_pSeries_kick_cpu(int nr) 161 { 162 BUG_ON(nr < 0 || nr >= NR_CPUS); 163 164 if (!smp_startup_cpu(nr)) 165 return -ENOENT; 166 167 /* 168 * The processor is currently spinning, waiting for the 169 * cpu_start field to become non-zero After we set cpu_start, 170 * the processor will continue on to secondary_start 171 */ 172 paca[nr].cpu_start = 1; 173 #ifdef CONFIG_HOTPLUG_CPU 174 set_preferred_offline_state(nr, CPU_STATE_ONLINE); 175 176 if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { 177 long rc; 178 unsigned long hcpuid; 179 180 hcpuid = get_hard_smp_processor_id(nr); 181 rc = plpar_hcall_norets(H_PROD, hcpuid); 182 if (rc != H_SUCCESS) 183 printk(KERN_ERR "Error: Prod to wake up processor %d " 184 "Ret= %ld\n", nr, rc); 185 } 186 #endif 187 188 return 0; 189 } 190 191 /* Only used on systems that support multiple IPI mechanisms */ 192 static void pSeries_cause_ipi_mux(int cpu, unsigned long data) 193 { 194 if (cpumask_test_cpu(cpu, cpu_sibling_mask(smp_processor_id()))) 195 doorbell_cause_ipi(cpu, data); 196 else 197 xics_cause_ipi(cpu, data); 198 } 199 200 static __init void pSeries_smp_probe(void) 201 { 202 xics_smp_probe(); 203 204 if (cpu_has_feature(CPU_FTR_DBELL)) { 205 xics_cause_ipi = smp_ops->cause_ipi; 206 smp_ops->cause_ipi = pSeries_cause_ipi_mux; 207 } 208 } 209 210 static struct smp_ops_t pSeries_mpic_smp_ops = { 211 .message_pass = smp_mpic_message_pass, 212 .probe = smp_mpic_probe, 213 .kick_cpu = smp_pSeries_kick_cpu, 214 .setup_cpu = smp_mpic_setup_cpu, 215 }; 216 217 static struct smp_ops_t pSeries_xics_smp_ops = { 218 .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ 219 .cause_ipi = NULL, /* Filled at runtime by pSeries_smp_probe() */ 220 .probe = pSeries_smp_probe, 221 .kick_cpu = smp_pSeries_kick_cpu, 222 .setup_cpu = smp_xics_setup_cpu, 223 .cpu_bootable = smp_generic_cpu_bootable, 224 }; 225 226 /* This is called very early */ 227 static void __init smp_init_pseries(void) 228 { 229 int i; 230 231 pr_debug(" -> smp_init_pSeries()\n"); 232 233 alloc_bootmem_cpumask_var(&of_spin_mask); 234 235 /* 236 * Mark threads which are still spinning in hold loops 237 * 238 * We know prom_init will not have started them if RTAS supports 239 * query-cpu-stopped-state. 240 */ 241 if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) { 242 if (cpu_has_feature(CPU_FTR_SMT)) { 243 for_each_present_cpu(i) { 244 if (cpu_thread_in_core(i) == 0) 245 cpumask_set_cpu(i, of_spin_mask); 246 } 247 } else 248 cpumask_copy(of_spin_mask, cpu_present_mask); 249 250 cpumask_clear_cpu(boot_cpuid, of_spin_mask); 251 } 252 253 /* Non-lpar has additional take/give timebase */ 254 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { 255 smp_ops->give_timebase = rtas_give_timebase; 256 smp_ops->take_timebase = rtas_take_timebase; 257 } 258 259 pr_debug(" <- smp_init_pSeries()\n"); 260 } 261 262 void __init smp_init_pseries_mpic(void) 263 { 264 smp_ops = &pSeries_mpic_smp_ops; 265 266 smp_init_pseries(); 267 } 268 269 void __init smp_init_pseries_xics(void) 270 { 271 smp_ops = &pSeries_xics_smp_ops; 272 273 smp_init_pseries(); 274 } 275