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/vdso_datapage.h> 42 #include <asm/cputhreads.h> 43 #include <asm/xics.h> 44 #include <asm/dbell.h> 45 #include <asm/plpar_wrappers.h> 46 #include <asm/code-patching.h> 47 48 #include "pseries.h" 49 #include "offline_states.h" 50 51 52 /* 53 * The Primary thread of each non-boot processor was started from the OF client 54 * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop. 55 */ 56 static cpumask_var_t of_spin_mask; 57 58 /* 59 * If we multiplex IPI mechanisms, store the appropriate XICS IPI mechanism here 60 */ 61 static void (*xics_cause_ipi)(int cpu, unsigned long data); 62 63 /* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */ 64 int smp_query_cpu_stopped(unsigned int pcpu) 65 { 66 int cpu_status, status; 67 int qcss_tok = rtas_token("query-cpu-stopped-state"); 68 69 if (qcss_tok == RTAS_UNKNOWN_SERVICE) { 70 printk_once(KERN_INFO 71 "Firmware doesn't support query-cpu-stopped-state\n"); 72 return QCSS_HARDWARE_ERROR; 73 } 74 75 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); 76 if (status != 0) { 77 printk(KERN_ERR 78 "RTAS query-cpu-stopped-state failed: %i\n", status); 79 return status; 80 } 81 82 return cpu_status; 83 } 84 85 /** 86 * smp_startup_cpu() - start the given cpu 87 * 88 * At boot time, there is nothing to do for primary threads which were 89 * started from Open Firmware. For anything else, call RTAS with the 90 * appropriate start location. 91 * 92 * Returns: 93 * 0 - failure 94 * 1 - success 95 */ 96 static inline int smp_startup_cpu(unsigned int lcpu) 97 { 98 int status; 99 unsigned long start_here = 100 __pa(ppc_function_entry(generic_secondary_smp_init)); 101 unsigned int pcpu; 102 int start_cpu; 103 104 if (cpumask_test_cpu(lcpu, of_spin_mask)) 105 /* Already started by OF and sitting in spin loop */ 106 return 1; 107 108 pcpu = get_hard_smp_processor_id(lcpu); 109 110 /* Check to see if the CPU out of FW already for kexec */ 111 if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){ 112 cpumask_set_cpu(lcpu, of_spin_mask); 113 return 1; 114 } 115 116 /* Fixup atomic count: it exited inside IRQ handler. */ 117 task_thread_info(paca[lcpu].__current)->preempt_count = 0; 118 #ifdef CONFIG_HOTPLUG_CPU 119 if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) 120 goto out; 121 #endif 122 /* 123 * If the RTAS start-cpu token does not exist then presume the 124 * cpu is already spinning. 125 */ 126 start_cpu = rtas_token("start-cpu"); 127 if (start_cpu == RTAS_UNKNOWN_SERVICE) 128 return 1; 129 130 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu); 131 if (status != 0) { 132 printk(KERN_ERR "start-cpu failed: %i\n", status); 133 return 0; 134 } 135 136 #ifdef CONFIG_HOTPLUG_CPU 137 out: 138 #endif 139 return 1; 140 } 141 142 static void smp_setup_cpu(int cpu) 143 { 144 if (cpu != boot_cpuid) 145 xics_setup_cpu(); 146 if (cpu_has_feature(CPU_FTR_DBELL)) 147 doorbell_setup_this_cpu(); 148 149 if (firmware_has_feature(FW_FEATURE_SPLPAR)) 150 vpa_init(cpu); 151 152 cpumask_clear_cpu(cpu, of_spin_mask); 153 #ifdef CONFIG_HOTPLUG_CPU 154 set_cpu_current_state(cpu, CPU_STATE_ONLINE); 155 set_default_offline_state(cpu); 156 #endif 157 } 158 159 static int smp_pSeries_kick_cpu(int nr) 160 { 161 BUG_ON(nr < 0 || nr >= NR_CPUS); 162 163 if (!smp_startup_cpu(nr)) 164 return -ENOENT; 165 166 /* 167 * The processor is currently spinning, waiting for the 168 * cpu_start field to become non-zero After we set cpu_start, 169 * the processor will continue on to secondary_start 170 */ 171 paca[nr].cpu_start = 1; 172 #ifdef CONFIG_HOTPLUG_CPU 173 set_preferred_offline_state(nr, CPU_STATE_ONLINE); 174 175 if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { 176 long rc; 177 unsigned long hcpuid; 178 179 hcpuid = get_hard_smp_processor_id(nr); 180 rc = plpar_hcall_norets(H_PROD, hcpuid); 181 if (rc != H_SUCCESS) 182 printk(KERN_ERR "Error: Prod to wake up processor %d " 183 "Ret= %ld\n", nr, rc); 184 } 185 #endif 186 187 return 0; 188 } 189 190 /* Only used on systems that support multiple IPI mechanisms */ 191 static void pSeries_cause_ipi_mux(int cpu, unsigned long data) 192 { 193 if (cpumask_test_cpu(cpu, cpu_sibling_mask(smp_processor_id()))) 194 doorbell_cause_ipi(cpu, data); 195 else 196 xics_cause_ipi(cpu, data); 197 } 198 199 static __init void pSeries_smp_probe(void) 200 { 201 xics_smp_probe(); 202 203 if (cpu_has_feature(CPU_FTR_DBELL)) { 204 xics_cause_ipi = smp_ops->cause_ipi; 205 smp_ops->cause_ipi = pSeries_cause_ipi_mux; 206 } 207 } 208 209 static struct smp_ops_t pseries_smp_ops = { 210 .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ 211 .cause_ipi = NULL, /* Filled at runtime by pSeries_smp_probe() */ 212 .probe = pSeries_smp_probe, 213 .kick_cpu = smp_pSeries_kick_cpu, 214 .setup_cpu = smp_setup_cpu, 215 .cpu_bootable = smp_generic_cpu_bootable, 216 }; 217 218 /* This is called very early */ 219 void __init smp_init_pseries(void) 220 { 221 int i; 222 223 pr_debug(" -> smp_init_pSeries()\n"); 224 smp_ops = &pseries_smp_ops; 225 226 alloc_bootmem_cpumask_var(&of_spin_mask); 227 228 /* 229 * Mark threads which are still spinning in hold loops 230 * 231 * We know prom_init will not have started them if RTAS supports 232 * query-cpu-stopped-state. 233 */ 234 if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) { 235 if (cpu_has_feature(CPU_FTR_SMT)) { 236 for_each_present_cpu(i) { 237 if (cpu_thread_in_core(i) == 0) 238 cpumask_set_cpu(i, of_spin_mask); 239 } 240 } else 241 cpumask_copy(of_spin_mask, cpu_present_mask); 242 243 cpumask_clear_cpu(boot_cpuid, of_spin_mask); 244 } 245 246 /* Non-lpar has additional take/give timebase */ 247 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { 248 smp_ops->give_timebase = rtas_give_timebase; 249 smp_ops->take_timebase = rtas_take_timebase; 250 } 251 252 pr_debug(" <- smp_init_pSeries()\n"); 253 } 254