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 */ 58 static cpumask_t of_spin_map; 59 60 /** 61 * smp_startup_cpu() - start the given cpu 62 * 63 * At boot time, there is nothing to do for primary threads which were 64 * started from Open Firmware. For anything else, call RTAS with the 65 * appropriate start location. 66 * 67 * Returns: 68 * 0 - failure 69 * 1 - success 70 */ 71 static inline int __devinit smp_startup_cpu(unsigned int lcpu) 72 { 73 int status; 74 unsigned long start_here = __pa((u32)*((unsigned long *) 75 generic_secondary_smp_init)); 76 unsigned int pcpu; 77 int start_cpu; 78 79 if (cpu_isset(lcpu, of_spin_map)) 80 /* Already started by OF and sitting in spin loop */ 81 return 1; 82 83 pcpu = get_hard_smp_processor_id(lcpu); 84 85 /* Fixup atomic count: it exited inside IRQ handler. */ 86 task_thread_info(paca[lcpu].__current)->preempt_count = 0; 87 88 if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) 89 goto out; 90 91 /* 92 * If the RTAS start-cpu token does not exist then presume the 93 * cpu is already spinning. 94 */ 95 start_cpu = rtas_token("start-cpu"); 96 if (start_cpu == RTAS_UNKNOWN_SERVICE) 97 return 1; 98 99 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu); 100 if (status != 0) { 101 printk(KERN_ERR "start-cpu failed: %i\n", status); 102 return 0; 103 } 104 105 out: 106 return 1; 107 } 108 109 #ifdef CONFIG_XICS 110 static void __devinit smp_xics_setup_cpu(int cpu) 111 { 112 if (cpu != boot_cpuid) 113 xics_setup_cpu(); 114 115 if (firmware_has_feature(FW_FEATURE_SPLPAR)) 116 vpa_init(cpu); 117 118 cpu_clear(cpu, of_spin_map); 119 set_cpu_current_state(cpu, CPU_STATE_ONLINE); 120 set_default_offline_state(cpu); 121 122 } 123 #endif /* CONFIG_XICS */ 124 125 static void __devinit smp_pSeries_kick_cpu(int nr) 126 { 127 long rc; 128 unsigned long hcpuid; 129 BUG_ON(nr < 0 || nr >= NR_CPUS); 130 131 if (!smp_startup_cpu(nr)) 132 return; 133 134 /* 135 * The processor is currently spinning, waiting for the 136 * cpu_start field to become non-zero After we set cpu_start, 137 * the processor will continue on to secondary_start 138 */ 139 paca[nr].cpu_start = 1; 140 141 set_preferred_offline_state(nr, CPU_STATE_ONLINE); 142 143 if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { 144 hcpuid = get_hard_smp_processor_id(nr); 145 rc = plpar_hcall_norets(H_PROD, hcpuid); 146 if (rc != H_SUCCESS) 147 printk(KERN_ERR "Error: Prod to wake up processor %d\ 148 Ret= %ld\n", nr, rc); 149 } 150 } 151 152 static int smp_pSeries_cpu_bootable(unsigned int nr) 153 { 154 /* Special case - we inhibit secondary thread startup 155 * during boot if the user requests it. 156 */ 157 if (system_state < SYSTEM_RUNNING && 158 cpu_has_feature(CPU_FTR_SMT) && 159 !smt_enabled_at_boot && cpu_thread_in_core(nr) != 0) 160 return 0; 161 162 return 1; 163 } 164 #ifdef CONFIG_MPIC 165 static struct smp_ops_t pSeries_mpic_smp_ops = { 166 .message_pass = smp_mpic_message_pass, 167 .probe = smp_mpic_probe, 168 .kick_cpu = smp_pSeries_kick_cpu, 169 .setup_cpu = smp_mpic_setup_cpu, 170 }; 171 #endif 172 #ifdef CONFIG_XICS 173 static struct smp_ops_t pSeries_xics_smp_ops = { 174 .message_pass = smp_xics_message_pass, 175 .probe = smp_xics_probe, 176 .kick_cpu = smp_pSeries_kick_cpu, 177 .setup_cpu = smp_xics_setup_cpu, 178 .cpu_bootable = smp_pSeries_cpu_bootable, 179 }; 180 #endif 181 182 /* This is called very early */ 183 static void __init smp_init_pseries(void) 184 { 185 int i; 186 187 pr_debug(" -> smp_init_pSeries()\n"); 188 189 /* Mark threads which are still spinning in hold loops. */ 190 if (cpu_has_feature(CPU_FTR_SMT)) { 191 for_each_present_cpu(i) { 192 if (cpu_thread_in_core(i) == 0) 193 cpu_set(i, of_spin_map); 194 } 195 } else { 196 of_spin_map = cpu_present_map; 197 } 198 199 cpu_clear(boot_cpuid, of_spin_map); 200 201 /* Non-lpar has additional take/give timebase */ 202 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { 203 smp_ops->give_timebase = rtas_give_timebase; 204 smp_ops->take_timebase = rtas_take_timebase; 205 } 206 207 pr_debug(" <- smp_init_pSeries()\n"); 208 } 209 210 #ifdef CONFIG_MPIC 211 void __init smp_init_pseries_mpic(void) 212 { 213 smp_ops = &pSeries_mpic_smp_ops; 214 215 smp_init_pseries(); 216 } 217 #endif 218 219 void __init smp_init_pseries_xics(void) 220 { 221 smp_ops = &pSeries_xics_smp_ops; 222 223 smp_init_pseries(); 224 } 225