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 /* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */ 59 int smp_query_cpu_stopped(unsigned int pcpu) 60 { 61 int cpu_status, status; 62 int qcss_tok = rtas_token("query-cpu-stopped-state"); 63 64 if (qcss_tok == RTAS_UNKNOWN_SERVICE) { 65 printk_once(KERN_INFO 66 "Firmware doesn't support query-cpu-stopped-state\n"); 67 return QCSS_HARDWARE_ERROR; 68 } 69 70 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); 71 if (status != 0) { 72 printk(KERN_ERR 73 "RTAS query-cpu-stopped-state failed: %i\n", status); 74 return status; 75 } 76 77 return cpu_status; 78 } 79 80 /** 81 * smp_startup_cpu() - start the given cpu 82 * 83 * At boot time, there is nothing to do for primary threads which were 84 * started from Open Firmware. For anything else, call RTAS with the 85 * appropriate start location. 86 * 87 * Returns: 88 * 0 - failure 89 * 1 - success 90 */ 91 static inline int smp_startup_cpu(unsigned int lcpu) 92 { 93 int status; 94 unsigned long start_here = 95 __pa(ppc_function_entry(generic_secondary_smp_init)); 96 unsigned int pcpu; 97 int start_cpu; 98 99 if (cpumask_test_cpu(lcpu, of_spin_mask)) 100 /* Already started by OF and sitting in spin loop */ 101 return 1; 102 103 pcpu = get_hard_smp_processor_id(lcpu); 104 105 /* Check to see if the CPU out of FW already for kexec */ 106 if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){ 107 cpumask_set_cpu(lcpu, of_spin_mask); 108 return 1; 109 } 110 111 /* Fixup atomic count: it exited inside IRQ handler. */ 112 task_thread_info(paca[lcpu].__current)->preempt_count = 0; 113 #ifdef CONFIG_HOTPLUG_CPU 114 if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) 115 goto out; 116 #endif 117 /* 118 * If the RTAS start-cpu token does not exist then presume the 119 * cpu is already spinning. 120 */ 121 start_cpu = rtas_token("start-cpu"); 122 if (start_cpu == RTAS_UNKNOWN_SERVICE) 123 return 1; 124 125 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu); 126 if (status != 0) { 127 printk(KERN_ERR "start-cpu failed: %i\n", status); 128 return 0; 129 } 130 131 #ifdef CONFIG_HOTPLUG_CPU 132 out: 133 #endif 134 return 1; 135 } 136 137 static void smp_setup_cpu(int cpu) 138 { 139 if (cpu != boot_cpuid) 140 xics_setup_cpu(); 141 142 if (firmware_has_feature(FW_FEATURE_SPLPAR)) 143 vpa_init(cpu); 144 145 cpumask_clear_cpu(cpu, of_spin_mask); 146 #ifdef CONFIG_HOTPLUG_CPU 147 set_cpu_current_state(cpu, CPU_STATE_ONLINE); 148 set_default_offline_state(cpu); 149 #endif 150 } 151 152 static int smp_pSeries_kick_cpu(int nr) 153 { 154 BUG_ON(nr < 0 || nr >= NR_CPUS); 155 156 if (!smp_startup_cpu(nr)) 157 return -ENOENT; 158 159 /* 160 * The processor is currently spinning, waiting for the 161 * cpu_start field to become non-zero After we set cpu_start, 162 * the processor will continue on to secondary_start 163 */ 164 paca[nr].cpu_start = 1; 165 #ifdef CONFIG_HOTPLUG_CPU 166 set_preferred_offline_state(nr, CPU_STATE_ONLINE); 167 168 if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { 169 long rc; 170 unsigned long hcpuid; 171 172 hcpuid = get_hard_smp_processor_id(nr); 173 rc = plpar_hcall_norets(H_PROD, hcpuid); 174 if (rc != H_SUCCESS) 175 printk(KERN_ERR "Error: Prod to wake up processor %d " 176 "Ret= %ld\n", nr, rc); 177 } 178 #endif 179 180 return 0; 181 } 182 183 static void smp_pseries_cause_ipi(int cpu) 184 { 185 /* POWER9 should not use this handler */ 186 if (doorbell_try_core_ipi(cpu)) 187 return; 188 189 icp_ops->cause_ipi(cpu); 190 } 191 192 static __init void pSeries_smp_probe(void) 193 { 194 xics_smp_probe(); 195 196 if (cpu_has_feature(CPU_FTR_DBELL)) 197 smp_ops->cause_ipi = smp_pseries_cause_ipi; 198 else 199 smp_ops->cause_ipi = icp_ops->cause_ipi; 200 } 201 202 static struct smp_ops_t pseries_smp_ops = { 203 .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ 204 .cause_ipi = NULL, /* Filled at runtime by pSeries_smp_probe() */ 205 .probe = pSeries_smp_probe, 206 .kick_cpu = smp_pSeries_kick_cpu, 207 .setup_cpu = smp_setup_cpu, 208 .cpu_bootable = smp_generic_cpu_bootable, 209 }; 210 211 /* This is called very early */ 212 void __init smp_init_pseries(void) 213 { 214 int i; 215 216 pr_debug(" -> smp_init_pSeries()\n"); 217 smp_ops = &pseries_smp_ops; 218 219 alloc_bootmem_cpumask_var(&of_spin_mask); 220 221 /* 222 * Mark threads which are still spinning in hold loops 223 * 224 * We know prom_init will not have started them if RTAS supports 225 * query-cpu-stopped-state. 226 */ 227 if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) { 228 if (cpu_has_feature(CPU_FTR_SMT)) { 229 for_each_present_cpu(i) { 230 if (cpu_thread_in_core(i) == 0) 231 cpumask_set_cpu(i, of_spin_mask); 232 } 233 } else 234 cpumask_copy(of_spin_mask, cpu_present_mask); 235 236 cpumask_clear_cpu(boot_cpuid, of_spin_mask); 237 } 238 239 /* Non-lpar has additional take/give timebase */ 240 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { 241 smp_ops->give_timebase = rtas_give_timebase; 242 smp_ops->take_timebase = rtas_take_timebase; 243 } 244 245 pr_debug(" <- smp_init_pSeries()\n"); 246 } 247