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