1 /* 2 * Secondary cpu support 3 * 4 * Copyright 2016 Suraj Jitindar Singh, IBM. 5 * 6 * This work is licensed under the terms of the GNU LGPL, version 2. 7 */ 8 9 #include <devicetree.h> 10 #include <asm/setup.h> 11 #include <asm/rtas.h> 12 #include <asm/smp.h> 13 14 int nr_threads; 15 16 struct secondary_entry_data { 17 secondary_entry_fn entry; 18 uint64_t r3; 19 int nr_started; 20 }; 21 22 /* 23 * Start stopped thread cpu_id at entry 24 * Returns: <0 on failure to start stopped cpu 25 * 0 on success 26 * >0 on cpu not in stopped state 27 */ 28 int start_thread(int cpu_id, secondary_entry_fn entry, uint32_t r3) 29 { 30 uint32_t query_token, start_token; 31 int outputs[1], ret; 32 33 ret = rtas_token("query-cpu-stopped-state", &query_token); 34 assert(ret == 0); 35 ret = rtas_token("start-cpu", &start_token); 36 assert(ret == 0); 37 38 ret = rtas_call(query_token, 1, 2, outputs, cpu_id); 39 if (ret) { 40 printf("query-cpu-stopped-state failed for cpu %d\n", cpu_id); 41 } else if (!outputs[0]) { /* cpu in stopped state */ 42 ret = rtas_call(start_token, 3, 1, NULL, cpu_id, entry, r3); 43 if (ret) 44 printf("failed to start cpu %d\n", cpu_id); 45 } else { /* cpu not in stopped state */ 46 ret = outputs[0]; 47 } 48 49 return ret; 50 } 51 52 /* 53 * Start all stopped threads (vcpus) on cpu_node 54 * Returns: Number of stopped cpus which were successfully started 55 */ 56 struct start_threads start_cpu(int cpu_node, secondary_entry_fn entry, 57 uint32_t r3) 58 { 59 int len, i, nr_threads, nr_started = 0; 60 const struct fdt_property *prop; 61 u32 *threads; 62 63 /* Get the id array of threads on this cpu_node */ 64 prop = fdt_get_property(dt_fdt(), cpu_node, 65 "ibm,ppc-interrupt-server#s", &len); 66 assert(prop); 67 68 nr_threads = len >> 2; /* Divide by 4 since 4 bytes per thread */ 69 threads = (u32 *)prop->data; /* Array of valid ids */ 70 71 for (i = 0; i < nr_threads; i++) { 72 if (!start_thread(fdt32_to_cpu(threads[i]), entry, r3)) 73 nr_started++; 74 } 75 76 return (struct start_threads) { nr_threads, nr_started }; 77 } 78 79 static void start_each_secondary(int fdtnode, u64 regval __unused, void *info) 80 { 81 struct secondary_entry_data *datap = info; 82 struct start_threads ret = start_cpu(fdtnode, datap->entry, datap->r3); 83 84 nr_threads += ret.nr_threads; 85 datap->nr_started += ret.nr_started; 86 } 87 88 /* 89 * Start all stopped cpus on the guest at entry with register 3 set to r3 90 * We expect that we come in with only one thread currently started 91 * Returns: TRUE on success 92 * FALSE on failure 93 */ 94 bool start_all_cpus(secondary_entry_fn entry, uint32_t r3) 95 { 96 struct secondary_entry_data data = { entry, r3, 0 }; 97 int ret; 98 99 ret = dt_for_each_cpu_node(start_each_secondary, &data); 100 assert(ret == 0); 101 102 /* We expect that we come in with one thread already started */ 103 return data.nr_started == nr_threads - 1; 104 } 105