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/module.h> 18#include <linux/sched.h> 19#include <linux/smp.h> 20#include <linux/interrupt.h> 21#include <linux/delay.h> 22#include <linux/init.h> 23#include <linux/spinlock.h> 24#include <linux/cache.h> 25#include <linux/err.h> 26#include <linux/sysdev.h> 27#include <linux/cpu.h> 28 29#include <asm/ptrace.h> 30#include <asm/atomic.h> 31#include <asm/irq.h> 32#include <asm/page.h> 33#include <asm/pgtable.h> 34#include <asm/io.h> 35#include <asm/prom.h> 36#include <asm/smp.h> 37#include <asm/paca.h> 38#include <asm/machdep.h> 39#include <asm/cputable.h> 40#include <asm/firmware.h> 41#include <asm/system.h> 42#include <asm/rtas.h> 43#include <asm/pSeries_reconfig.h> 44#include <asm/mpic.h> 45#include <asm/vdso_datapage.h> 46#include <asm/cputhreads.h> 47 48#include "plpar_wrappers.h" 49#include "pseries.h" 50#include "xics.h" 51#include "offline_states.h" 52 53 54/* 55 * The Primary thread of each non-boot processor was started from the OF client 56 * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop. 57 */ 58static cpumask_var_t of_spin_mask; 59 60/* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */ 61int smp_query_cpu_stopped(unsigned int pcpu) 62{ 63 int cpu_status, status; 64 int qcss_tok = rtas_token("query-cpu-stopped-state"); 65 66 if (qcss_tok == RTAS_UNKNOWN_SERVICE) { 67 printk(KERN_INFO "Firmware doesn't support " 68 "query-cpu-stopped-state\n"); 69 return QCSS_HARDWARE_ERROR; 70 } 71 72 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); 73 if (status != 0) { 74 printk(KERN_ERR 75 "RTAS query-cpu-stopped-state failed: %i\n", status); 76 return status; 77 } 78 79 return cpu_status; 80} 81 82/** 83 * smp_startup_cpu() - start the given cpu 84 * 85 * At boot time, there is nothing to do for primary threads which were 86 * started from Open Firmware. For anything else, call RTAS with the 87 * appropriate start location. 88 * 89 * Returns: 90 * 0 - failure 91 * 1 - success 92 */ 93static inline int __devinit smp_startup_cpu(unsigned int lcpu) 94{ 95 int status; 96 unsigned long start_here = __pa((u32)*((unsigned long *) 97 generic_secondary_smp_init)); 98 unsigned int pcpu; 99 int start_cpu; 100 101 if (cpumask_test_cpu(lcpu, of_spin_mask)) 102 /* Already started by OF and sitting in spin loop */ 103 return 1; 104 105 pcpu = get_hard_smp_processor_id(lcpu); 106 107 /* Check to see if the CPU out of FW already for kexec */ 108 if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){ 109 cpumask_set_cpu(lcpu, of_spin_mask); 110 return 1; 111 } 112 113 /* Fixup atomic count: it exited inside IRQ handler. */ 114 task_thread_info(paca[lcpu].__current)->preempt_count = 0; 115 116 if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) 117 goto out; 118 119 /* 120 * If the RTAS start-cpu token does not exist then presume the 121 * cpu is already spinning. 122 */ 123 start_cpu = rtas_token("start-cpu"); 124 if (start_cpu == RTAS_UNKNOWN_SERVICE) 125 return 1; 126 127 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu); 128 if (status != 0) { 129 printk(KERN_ERR "start-cpu failed: %i\n", status); 130 return 0; 131 } 132 133out: 134 return 1; 135} 136 137#ifdef CONFIG_XICS 138static 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 set_cpu_current_state(cpu, CPU_STATE_ONLINE); 148 set_default_offline_state(cpu); 149 150} 151#endif /* CONFIG_XICS */ 152 153static void __devinit smp_pSeries_kick_cpu(int nr) 154{ 155 long rc; 156 unsigned long hcpuid; 157 BUG_ON(nr < 0 || nr >= NR_CPUS); 158 159 if (!smp_startup_cpu(nr)) 160 return; 161 162 /* 163 * The processor is currently spinning, waiting for the 164 * cpu_start field to become non-zero After we set cpu_start, 165 * the processor will continue on to secondary_start 166 */ 167 paca[nr].cpu_start = 1; 168 169 set_preferred_offline_state(nr, CPU_STATE_ONLINE); 170 171 if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { 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} 179 180static int smp_pSeries_cpu_bootable(unsigned int nr) 181{ 182 /* Special case - we inhibit secondary thread startup 183 * during boot if the user requests it. 184 */ 185 if (system_state < SYSTEM_RUNNING && cpu_has_feature(CPU_FTR_SMT)) { 186 if (!smt_enabled_at_boot && cpu_thread_in_core(nr) != 0) 187 return 0; 188 if (smt_enabled_at_boot 189 && cpu_thread_in_core(nr) >= smt_enabled_at_boot) 190 return 0; 191 } 192 193 return 1; 194} 195#ifdef CONFIG_MPIC 196static struct smp_ops_t pSeries_mpic_smp_ops = { 197 .message_pass = smp_mpic_message_pass, 198 .probe = smp_mpic_probe, 199 .kick_cpu = smp_pSeries_kick_cpu, 200 .setup_cpu = smp_mpic_setup_cpu, 201}; 202#endif 203#ifdef CONFIG_XICS 204static struct smp_ops_t pSeries_xics_smp_ops = { 205 .message_pass = smp_xics_message_pass, 206 .probe = smp_xics_probe, 207 .kick_cpu = smp_pSeries_kick_cpu, 208 .setup_cpu = smp_xics_setup_cpu, 209 .cpu_bootable = smp_pSeries_cpu_bootable, 210}; 211#endif 212 213/* This is called very early */ 214static void __init smp_init_pseries(void) 215{ 216 int i; 217 218 pr_debug(" -> smp_init_pSeries()\n"); 219 220 alloc_bootmem_cpumask_var(&of_spin_mask); 221 222 /* Mark threads which are still spinning in hold loops. */ 223 if (cpu_has_feature(CPU_FTR_SMT)) { 224 for_each_present_cpu(i) { 225 if (cpu_thread_in_core(i) == 0) 226 cpumask_set_cpu(i, of_spin_mask); 227 } 228 } else { 229 cpumask_copy(of_spin_mask, cpu_present_mask); 230 } 231 232 cpumask_clear_cpu(boot_cpuid, of_spin_mask); 233 234 /* Non-lpar has additional take/give timebase */ 235 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { 236 smp_ops->give_timebase = rtas_give_timebase; 237 smp_ops->take_timebase = rtas_take_timebase; 238 } 239 240 pr_debug(" <- smp_init_pSeries()\n"); 241} 242 243#ifdef CONFIG_MPIC 244void __init smp_init_pseries_mpic(void) 245{ 246 smp_ops = &pSeries_mpic_smp_ops; 247 248 smp_init_pseries(); 249} 250#endif 251 252void __init smp_init_pseries_xics(void) 253{ 254 smp_ops = &pSeries_xics_smp_ops; 255 256 smp_init_pseries(); 257} 258