1 // SPDX-License-Identifier: GPL-2.0 2 #ifdef HAVE_BPF_SKEL 3 #define _GNU_SOURCE 4 #include "timerlat.h" 5 #include "timerlat_bpf.h" 6 #include "timerlat.skel.h" 7 8 static struct timerlat_bpf *bpf; 9 10 /* BPF object and program for action program */ 11 static struct bpf_object *obj; 12 static struct bpf_program *prog; 13 14 /* 15 * timerlat_bpf_init - load and initialize BPF program to collect timerlat data 16 */ 17 int timerlat_bpf_init(struct timerlat_params *params) 18 { 19 int err; 20 21 debug_msg("Loading BPF program\n"); 22 23 bpf = timerlat_bpf__open(); 24 if (!bpf) 25 return 1; 26 27 /* Pass common options */ 28 bpf->rodata->output_divisor = params->common.output_divisor; 29 bpf->rodata->entries = params->common.hist.entries; 30 bpf->rodata->irq_threshold = params->common.stop_us; 31 bpf->rodata->thread_threshold = params->common.stop_total_us; 32 bpf->rodata->aa_only = params->common.aa_only; 33 34 if (params->common.hist.entries != 0) { 35 /* Pass histogram options */ 36 bpf->rodata->bucket_size = params->common.hist.bucket_size; 37 38 /* Set histogram array sizes */ 39 bpf_map__set_max_entries(bpf->maps.hist_irq, params->common.hist.entries); 40 bpf_map__set_max_entries(bpf->maps.hist_thread, params->common.hist.entries); 41 bpf_map__set_max_entries(bpf->maps.hist_user, params->common.hist.entries); 42 } else { 43 /* No entries, disable histogram */ 44 bpf_map__set_autocreate(bpf->maps.hist_irq, false); 45 bpf_map__set_autocreate(bpf->maps.hist_thread, false); 46 bpf_map__set_autocreate(bpf->maps.hist_user, false); 47 } 48 49 if (params->common.aa_only) { 50 /* Auto-analysis only, disable summary */ 51 bpf_map__set_autocreate(bpf->maps.summary_irq, false); 52 bpf_map__set_autocreate(bpf->maps.summary_thread, false); 53 bpf_map__set_autocreate(bpf->maps.summary_user, false); 54 } 55 56 /* Load and verify BPF program */ 57 err = timerlat_bpf__load(bpf); 58 if (err) { 59 timerlat_bpf__destroy(bpf); 60 return err; 61 } 62 63 return 0; 64 } 65 66 /* 67 * timerlat_bpf_set_action - set action on threshold executed on BPF side 68 */ 69 static int timerlat_bpf_set_action(struct bpf_program *prog) 70 { 71 unsigned int key = 0, value = bpf_program__fd(prog); 72 73 return bpf_map__update_elem(bpf->maps.bpf_action, 74 &key, sizeof(key), 75 &value, sizeof(value), 76 BPF_ANY); 77 } 78 79 /* 80 * timerlat_bpf_attach - attach BPF program to collect timerlat data 81 */ 82 int timerlat_bpf_attach(void) 83 { 84 debug_msg("Attaching BPF program\n"); 85 86 return timerlat_bpf__attach(bpf); 87 } 88 89 /* 90 * timerlat_bpf_detach - detach BPF program to collect timerlat data 91 */ 92 void timerlat_bpf_detach(void) 93 { 94 timerlat_bpf__detach(bpf); 95 } 96 97 /* 98 * timerlat_bpf_detach - destroy BPF program to collect timerlat data 99 */ 100 void timerlat_bpf_destroy(void) 101 { 102 timerlat_bpf__destroy(bpf); 103 bpf = NULL; 104 if (obj) 105 bpf_object__close(obj); 106 obj = NULL; 107 prog = NULL; 108 } 109 110 static int handle_rb_event(void *ctx, void *data, size_t data_sz) 111 { 112 return 0; 113 } 114 115 /* 116 * timerlat_bpf_wait - wait until tracing is stopped or signal 117 */ 118 int timerlat_bpf_wait(int timeout) 119 { 120 struct ring_buffer *rb; 121 int retval; 122 123 rb = ring_buffer__new(bpf_map__fd(bpf->maps.signal_stop_tracing), 124 handle_rb_event, NULL, NULL); 125 retval = ring_buffer__poll(rb, timeout * 1000); 126 ring_buffer__free(rb); 127 128 return retval; 129 } 130 131 /* 132 * timerlat_bpf_restart_tracing - restart stopped tracing 133 */ 134 int timerlat_bpf_restart_tracing(void) 135 { 136 unsigned int key = 0; 137 unsigned long long value = 0; 138 139 return bpf_map__update_elem(bpf->maps.stop_tracing, 140 &key, sizeof(key), 141 &value, sizeof(value), BPF_ANY); 142 } 143 144 static int get_value(struct bpf_map *map_irq, 145 struct bpf_map *map_thread, 146 struct bpf_map *map_user, 147 int key, 148 long long *value_irq, 149 long long *value_thread, 150 long long *value_user) 151 { 152 int err; 153 154 err = bpf_map__lookup_elem(map_irq, &key, 155 sizeof(unsigned int), value_irq, 156 sizeof(long long) * nr_cpus, 0); 157 if (err) 158 return err; 159 err = bpf_map__lookup_elem(map_thread, &key, 160 sizeof(unsigned int), value_thread, 161 sizeof(long long) * nr_cpus, 0); 162 if (err) 163 return err; 164 err = bpf_map__lookup_elem(map_user, &key, 165 sizeof(unsigned int), value_user, 166 sizeof(long long) * nr_cpus, 0); 167 if (err) 168 return err; 169 return 0; 170 } 171 172 /* 173 * timerlat_bpf_get_hist_value - get value from BPF hist map 174 */ 175 int timerlat_bpf_get_hist_value(int key, 176 long long *value_irq, 177 long long *value_thread, 178 long long *value_user) 179 { 180 return get_value(bpf->maps.hist_irq, 181 bpf->maps.hist_thread, 182 bpf->maps.hist_user, 183 key, value_irq, value_thread, value_user); 184 } 185 186 /* 187 * timerlat_bpf_get_summary_value - get value from BPF summary map 188 */ 189 int timerlat_bpf_get_summary_value(enum summary_field key, 190 long long *value_irq, 191 long long *value_thread, 192 long long *value_user) 193 { 194 return get_value(bpf->maps.summary_irq, 195 bpf->maps.summary_thread, 196 bpf->maps.summary_user, 197 key, value_irq, value_thread, value_user); 198 } 199 200 /* 201 * timerlat_load_bpf_action_program - load and register a BPF action program 202 */ 203 int timerlat_load_bpf_action_program(const char *program_path) 204 { 205 int err; 206 207 obj = bpf_object__open_file(program_path, NULL); 208 if (!obj) { 209 err_msg("Failed to open BPF action program: %s\n", program_path); 210 goto out_err; 211 } 212 213 err = bpf_object__load(obj); 214 if (err) { 215 err_msg("Failed to load BPF action program: %s\n", program_path); 216 goto out_obj_err; 217 } 218 219 prog = bpf_object__find_program_by_name(obj, "action_handler"); 220 if (!prog) { 221 err_msg("BPF action program must have 'action_handler' function: %s\n", 222 program_path); 223 goto out_obj_err; 224 } 225 226 err = timerlat_bpf_set_action(prog); 227 if (err) { 228 err_msg("Failed to register BPF action program: %s\n", program_path); 229 goto out_prog_err; 230 } 231 232 return 0; 233 234 out_prog_err: 235 prog = NULL; 236 out_obj_err: 237 bpf_object__close(obj); 238 obj = NULL; 239 out_err: 240 return 1; 241 } 242 243 #endif /* HAVE_BPF_SKEL */ 244