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/sysdev.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/system.h> 41 #include <asm/rtas.h> 42 #include <asm/pSeries_reconfig.h> 43 #include <asm/mpic.h> 44 #include <asm/vdso_datapage.h> 45 #include <asm/cputhreads.h> 46 #include <asm/xics.h> 47 48 #include "plpar_wrappers.h" 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 /* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */ 60 int smp_query_cpu_stopped(unsigned int pcpu) 61 { 62 int cpu_status, status; 63 int qcss_tok = rtas_token("query-cpu-stopped-state"); 64 65 if (qcss_tok == RTAS_UNKNOWN_SERVICE) { 66 printk_once(KERN_INFO 67 "Firmware doesn't support query-cpu-stopped-state\n"); 68 return QCSS_HARDWARE_ERROR; 69 } 70 71 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); 72 if (status != 0) { 73 printk(KERN_ERR 74 "RTAS query-cpu-stopped-state failed: %i\n", status); 75 return status; 76 } 77 78 return cpu_status; 79 } 80 81 /** 82 * smp_startup_cpu() - start the given cpu 83 * 84 * At boot time, there is nothing to do for primary threads which were 85 * started from Open Firmware. For anything else, call RTAS with the 86 * appropriate start location. 87 * 88 * Returns: 89 * 0 - failure 90 * 1 - success 91 */ 92 static inline int __devinit smp_startup_cpu(unsigned int lcpu) 93 { 94 int status; 95 unsigned long start_here = __pa((u32)*((unsigned long *) 96 generic_secondary_smp_init)); 97 unsigned int pcpu; 98 int start_cpu; 99 100 if (cpumask_test_cpu(lcpu, of_spin_mask)) 101 /* Already started by OF and sitting in spin loop */ 102 return 1; 103 104 pcpu = get_hard_smp_processor_id(lcpu); 105 106 /* Check to see if the CPU out of FW already for kexec */ 107 if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){ 108 cpumask_set_cpu(lcpu, of_spin_mask); 109 return 1; 110 } 111 112 /* Fixup atomic count: it exited inside IRQ handler. */ 113 task_thread_info(paca[lcpu].__current)->preempt_count = 0; 114 #ifdef CONFIG_HOTPLUG_CPU 115 if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) 116 goto out; 117 #endif 118 /* 119 * If the RTAS start-cpu token does not exist then presume the 120 * cpu is already spinning. 121 */ 122 start_cpu = rtas_token("start-cpu"); 123 if (start_cpu == RTAS_UNKNOWN_SERVICE) 124 return 1; 125 126 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu); 127 if (status != 0) { 128 printk(KERN_ERR "start-cpu failed: %i\n", status); 129 return 0; 130 } 131 132 #ifdef CONFIG_HOTPLUG_CPU 133 out: 134 #endif 135 return 1; 136 } 137 138 static void __devinit smp_xics_setup_cpu(int cpu) 139 { 140 if (cpu != boot_cpuid) 141 xics_setup_cpu(); 142 143 if (firmware_has_feature(FW_FEATURE_SPLPAR)) 144 vpa_init(cpu); 145 146 cpumask_clear_cpu(cpu, of_spin_mask); 147 #ifdef CONFIG_HOTPLUG_CPU 148 set_cpu_current_state(cpu, CPU_STATE_ONLINE); 149 set_default_offline_state(cpu); 150 #endif 151 } 152 153 static int __devinit smp_pSeries_kick_cpu(int nr) 154 { 155 BUG_ON(nr < 0 || nr >= NR_CPUS); 156 157 if (!smp_startup_cpu(nr)) 158 return -ENOENT; 159 160 /* 161 * The processor is currently spinning, waiting for the 162 * cpu_start field to become non-zero After we set cpu_start, 163 * the processor will continue on to secondary_start 164 */ 165 paca[nr].cpu_start = 1; 166 #ifdef CONFIG_HOTPLUG_CPU 167 set_preferred_offline_state(nr, CPU_STATE_ONLINE); 168 169 if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { 170 long rc; 171 unsigned long hcpuid; 172 173 hcpuid = get_hard_smp_processor_id(nr); 174 rc = plpar_hcall_norets(H_PROD, hcpuid); 175 if (rc != H_SUCCESS) 176 printk(KERN_ERR "Error: Prod to wake up processor %d " 177 "Ret= %ld\n", nr, rc); 178 } 179 #endif 180 181 return 0; 182 } 183 184 static int smp_pSeries_cpu_bootable(unsigned int nr) 185 { 186 /* Special case - we inhibit secondary thread startup 187 * during boot if the user requests it. 188 */ 189 if (system_state < SYSTEM_RUNNING && cpu_has_feature(CPU_FTR_SMT)) { 190 if (!smt_enabled_at_boot && cpu_thread_in_core(nr) != 0) 191 return 0; 192 if (smt_enabled_at_boot 193 && cpu_thread_in_core(nr) >= smt_enabled_at_boot) 194 return 0; 195 } 196 197 return 1; 198 } 199 200 static struct smp_ops_t pSeries_mpic_smp_ops = { 201 .message_pass = smp_mpic_message_pass, 202 .probe = smp_mpic_probe, 203 .kick_cpu = smp_pSeries_kick_cpu, 204 .setup_cpu = smp_mpic_setup_cpu, 205 }; 206 207 static struct smp_ops_t pSeries_xics_smp_ops = { 208 .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ 209 .cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */ 210 .probe = xics_smp_probe, 211 .kick_cpu = smp_pSeries_kick_cpu, 212 .setup_cpu = smp_xics_setup_cpu, 213 .cpu_bootable = smp_pSeries_cpu_bootable, 214 }; 215 216 /* This is called very early */ 217 static void __init smp_init_pseries(void) 218 { 219 int i; 220 221 pr_debug(" -> smp_init_pSeries()\n"); 222 223 alloc_bootmem_cpumask_var(&of_spin_mask); 224 225 /* Mark threads which are still spinning in hold loops. */ 226 if (cpu_has_feature(CPU_FTR_SMT)) { 227 for_each_present_cpu(i) { 228 if (cpu_thread_in_core(i) == 0) 229 cpumask_set_cpu(i, of_spin_mask); 230 } 231 } else { 232 cpumask_copy(of_spin_mask, cpu_present_mask); 233 } 234 235 cpumask_clear_cpu(boot_cpuid, of_spin_mask); 236 237 /* Non-lpar has additional take/give timebase */ 238 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { 239 smp_ops->give_timebase = rtas_give_timebase; 240 smp_ops->take_timebase = rtas_take_timebase; 241 } 242 243 pr_debug(" <- smp_init_pSeries()\n"); 244 } 245 246 void __init smp_init_pseries_mpic(void) 247 { 248 smp_ops = &pSeries_mpic_smp_ops; 249 250 smp_init_pseries(); 251 } 252 253 void __init smp_init_pseries_xics(void) 254 { 255 smp_ops = &pSeries_xics_smp_ops; 256 257 smp_init_pseries(); 258 } 259