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 46 #include "plpar_wrappers.h" 47 #include "pseries.h" 48 #include "offline_states.h" 49 50 51 /* 52 * The Primary thread of each non-boot processor was started from the OF client 53 * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop. 54 */ 55 static cpumask_var_t of_spin_mask; 56 57 /* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */ 58 int smp_query_cpu_stopped(unsigned int pcpu) 59 { 60 int cpu_status, status; 61 int qcss_tok = rtas_token("query-cpu-stopped-state"); 62 63 if (qcss_tok == RTAS_UNKNOWN_SERVICE) { 64 printk_once(KERN_INFO 65 "Firmware doesn't support query-cpu-stopped-state\n"); 66 return QCSS_HARDWARE_ERROR; 67 } 68 69 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); 70 if (status != 0) { 71 printk(KERN_ERR 72 "RTAS query-cpu-stopped-state failed: %i\n", status); 73 return status; 74 } 75 76 return cpu_status; 77 } 78 79 /** 80 * smp_startup_cpu() - start the given cpu 81 * 82 * At boot time, there is nothing to do for primary threads which were 83 * started from Open Firmware. For anything else, call RTAS with the 84 * appropriate start location. 85 * 86 * Returns: 87 * 0 - failure 88 * 1 - success 89 */ 90 static inline int smp_startup_cpu(unsigned int lcpu) 91 { 92 int status; 93 unsigned long start_here = __pa((u32)*((unsigned long *) 94 generic_secondary_smp_init)); 95 unsigned int pcpu; 96 int start_cpu; 97 98 if (cpumask_test_cpu(lcpu, of_spin_mask)) 99 /* Already started by OF and sitting in spin loop */ 100 return 1; 101 102 pcpu = get_hard_smp_processor_id(lcpu); 103 104 /* Check to see if the CPU out of FW already for kexec */ 105 if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){ 106 cpumask_set_cpu(lcpu, of_spin_mask); 107 return 1; 108 } 109 110 /* Fixup atomic count: it exited inside IRQ handler. */ 111 task_thread_info(paca[lcpu].__current)->preempt_count = 0; 112 #ifdef CONFIG_HOTPLUG_CPU 113 if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) 114 goto out; 115 #endif 116 /* 117 * If the RTAS start-cpu token does not exist then presume the 118 * cpu is already spinning. 119 */ 120 start_cpu = rtas_token("start-cpu"); 121 if (start_cpu == RTAS_UNKNOWN_SERVICE) 122 return 1; 123 124 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu); 125 if (status != 0) { 126 printk(KERN_ERR "start-cpu failed: %i\n", status); 127 return 0; 128 } 129 130 #ifdef CONFIG_HOTPLUG_CPU 131 out: 132 #endif 133 return 1; 134 } 135 136 static void smp_xics_setup_cpu(int cpu) 137 { 138 if (cpu != boot_cpuid) 139 xics_setup_cpu(); 140 141 if (firmware_has_feature(FW_FEATURE_SPLPAR)) 142 vpa_init(cpu); 143 144 cpumask_clear_cpu(cpu, of_spin_mask); 145 #ifdef CONFIG_HOTPLUG_CPU 146 set_cpu_current_state(cpu, CPU_STATE_ONLINE); 147 set_default_offline_state(cpu); 148 #endif 149 } 150 151 static int smp_pSeries_kick_cpu(int nr) 152 { 153 BUG_ON(nr < 0 || nr >= NR_CPUS); 154 155 if (!smp_startup_cpu(nr)) 156 return -ENOENT; 157 158 /* 159 * The processor is currently spinning, waiting for the 160 * cpu_start field to become non-zero After we set cpu_start, 161 * the processor will continue on to secondary_start 162 */ 163 paca[nr].cpu_start = 1; 164 #ifdef CONFIG_HOTPLUG_CPU 165 set_preferred_offline_state(nr, CPU_STATE_ONLINE); 166 167 if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { 168 long rc; 169 unsigned long hcpuid; 170 171 hcpuid = get_hard_smp_processor_id(nr); 172 rc = plpar_hcall_norets(H_PROD, hcpuid); 173 if (rc != H_SUCCESS) 174 printk(KERN_ERR "Error: Prod to wake up processor %d " 175 "Ret= %ld\n", nr, rc); 176 } 177 #endif 178 179 return 0; 180 } 181 182 static int smp_pSeries_cpu_bootable(unsigned int nr) 183 { 184 /* Special case - we inhibit secondary thread startup 185 * during boot if the user requests it. 186 */ 187 if (system_state < SYSTEM_RUNNING && cpu_has_feature(CPU_FTR_SMT)) { 188 if (!smt_enabled_at_boot && cpu_thread_in_core(nr) != 0) 189 return 0; 190 if (smt_enabled_at_boot 191 && cpu_thread_in_core(nr) >= smt_enabled_at_boot) 192 return 0; 193 } 194 195 return 1; 196 } 197 198 static struct smp_ops_t pSeries_mpic_smp_ops = { 199 .message_pass = smp_mpic_message_pass, 200 .probe = smp_mpic_probe, 201 .kick_cpu = smp_pSeries_kick_cpu, 202 .setup_cpu = smp_mpic_setup_cpu, 203 }; 204 205 static struct smp_ops_t pSeries_xics_smp_ops = { 206 .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ 207 .cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */ 208 .probe = xics_smp_probe, 209 .kick_cpu = smp_pSeries_kick_cpu, 210 .setup_cpu = smp_xics_setup_cpu, 211 .cpu_bootable = smp_pSeries_cpu_bootable, 212 }; 213 214 /* This is called very early */ 215 static void __init smp_init_pseries(void) 216 { 217 int i; 218 219 pr_debug(" -> smp_init_pSeries()\n"); 220 221 alloc_bootmem_cpumask_var(&of_spin_mask); 222 223 /* Mark threads which are still spinning in hold loops. */ 224 if (cpu_has_feature(CPU_FTR_SMT)) { 225 for_each_present_cpu(i) { 226 if (cpu_thread_in_core(i) == 0) 227 cpumask_set_cpu(i, of_spin_mask); 228 } 229 } else { 230 cpumask_copy(of_spin_mask, cpu_present_mask); 231 } 232 233 cpumask_clear_cpu(boot_cpuid, of_spin_mask); 234 235 /* Non-lpar has additional take/give timebase */ 236 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { 237 smp_ops->give_timebase = rtas_give_timebase; 238 smp_ops->take_timebase = rtas_take_timebase; 239 } 240 241 pr_debug(" <- smp_init_pSeries()\n"); 242 } 243 244 void __init smp_init_pseries_mpic(void) 245 { 246 smp_ops = &pSeries_mpic_smp_ops; 247 248 smp_init_pseries(); 249 } 250 251 void __init smp_init_pseries_xics(void) 252 { 253 smp_ops = &pSeries_xics_smp_ops; 254 255 smp_init_pseries(); 256 } 257