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