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 /* 11 * timerlat_bpf_init - load and initialize BPF program to collect timerlat data 12 */ 13 int timerlat_bpf_init(struct timerlat_params *params) 14 { 15 int err; 16 17 debug_msg("Loading BPF program\n"); 18 19 bpf = timerlat_bpf__open(); 20 if (!bpf) 21 return 1; 22 23 /* Pass common options */ 24 bpf->rodata->output_divisor = params->common.output_divisor; 25 bpf->rodata->entries = params->common.hist.entries; 26 bpf->rodata->irq_threshold = params->common.stop_us; 27 bpf->rodata->thread_threshold = params->common.stop_total_us; 28 bpf->rodata->aa_only = params->common.aa_only; 29 30 if (params->common.hist.entries != 0) { 31 /* Pass histogram options */ 32 bpf->rodata->bucket_size = params->common.hist.bucket_size; 33 34 /* Set histogram array sizes */ 35 bpf_map__set_max_entries(bpf->maps.hist_irq, params->common.hist.entries); 36 bpf_map__set_max_entries(bpf->maps.hist_thread, params->common.hist.entries); 37 bpf_map__set_max_entries(bpf->maps.hist_user, params->common.hist.entries); 38 } else { 39 /* No entries, disable histogram */ 40 bpf_map__set_autocreate(bpf->maps.hist_irq, false); 41 bpf_map__set_autocreate(bpf->maps.hist_thread, false); 42 bpf_map__set_autocreate(bpf->maps.hist_user, false); 43 } 44 45 if (params->common.aa_only) { 46 /* Auto-analysis only, disable summary */ 47 bpf_map__set_autocreate(bpf->maps.summary_irq, false); 48 bpf_map__set_autocreate(bpf->maps.summary_thread, false); 49 bpf_map__set_autocreate(bpf->maps.summary_user, false); 50 } 51 52 /* Load and verify BPF program */ 53 err = timerlat_bpf__load(bpf); 54 if (err) { 55 timerlat_bpf__destroy(bpf); 56 return err; 57 } 58 59 return 0; 60 } 61 62 /* 63 * timerlat_bpf_set_action - set action on threshold executed on BPF side 64 */ 65 static int timerlat_bpf_set_action(struct bpf_program *prog) 66 { 67 unsigned int key = 0, value = bpf_program__fd(prog); 68 69 return bpf_map__update_elem(bpf->maps.bpf_action, 70 &key, sizeof(key), 71 &value, sizeof(value), 72 BPF_ANY); 73 } 74 75 /* 76 * timerlat_bpf_attach - attach BPF program to collect timerlat data 77 */ 78 int timerlat_bpf_attach(void) 79 { 80 debug_msg("Attaching BPF program\n"); 81 82 return timerlat_bpf__attach(bpf); 83 } 84 85 /* 86 * timerlat_bpf_detach - detach BPF program to collect timerlat data 87 */ 88 void timerlat_bpf_detach(void) 89 { 90 timerlat_bpf__detach(bpf); 91 } 92 93 /* 94 * timerlat_bpf_detach - destroy BPF program to collect timerlat data 95 */ 96 void timerlat_bpf_destroy(void) 97 { 98 timerlat_bpf__destroy(bpf); 99 } 100 101 static int handle_rb_event(void *ctx, void *data, size_t data_sz) 102 { 103 return 0; 104 } 105 106 /* 107 * timerlat_bpf_wait - wait until tracing is stopped or signal 108 */ 109 int timerlat_bpf_wait(int timeout) 110 { 111 struct ring_buffer *rb; 112 int retval; 113 114 rb = ring_buffer__new(bpf_map__fd(bpf->maps.signal_stop_tracing), 115 handle_rb_event, NULL, NULL); 116 retval = ring_buffer__poll(rb, timeout * 1000); 117 ring_buffer__free(rb); 118 119 return retval; 120 } 121 122 /* 123 * timerlat_bpf_restart_tracing - restart stopped tracing 124 */ 125 int timerlat_bpf_restart_tracing(void) 126 { 127 unsigned int key = 0; 128 unsigned long long value = 0; 129 130 return bpf_map__update_elem(bpf->maps.stop_tracing, 131 &key, sizeof(key), 132 &value, sizeof(value), BPF_ANY); 133 } 134 135 static int get_value(struct bpf_map *map_irq, 136 struct bpf_map *map_thread, 137 struct bpf_map *map_user, 138 int key, 139 long long *value_irq, 140 long long *value_thread, 141 long long *value_user, 142 int cpus) 143 { 144 int err; 145 146 err = bpf_map__lookup_elem(map_irq, &key, 147 sizeof(unsigned int), value_irq, 148 sizeof(long long) * cpus, 0); 149 if (err) 150 return err; 151 err = bpf_map__lookup_elem(map_thread, &key, 152 sizeof(unsigned int), value_thread, 153 sizeof(long long) * cpus, 0); 154 if (err) 155 return err; 156 err = bpf_map__lookup_elem(map_user, &key, 157 sizeof(unsigned int), value_user, 158 sizeof(long long) * cpus, 0); 159 if (err) 160 return err; 161 return 0; 162 } 163 164 /* 165 * timerlat_bpf_get_hist_value - get value from BPF hist map 166 */ 167 int timerlat_bpf_get_hist_value(int key, 168 long long *value_irq, 169 long long *value_thread, 170 long long *value_user, 171 int cpus) 172 { 173 return get_value(bpf->maps.hist_irq, 174 bpf->maps.hist_thread, 175 bpf->maps.hist_user, 176 key, value_irq, value_thread, value_user, cpus); 177 } 178 179 /* 180 * timerlat_bpf_get_summary_value - get value from BPF summary map 181 */ 182 int timerlat_bpf_get_summary_value(enum summary_field key, 183 long long *value_irq, 184 long long *value_thread, 185 long long *value_user, 186 int cpus) 187 { 188 return get_value(bpf->maps.summary_irq, 189 bpf->maps.summary_thread, 190 bpf->maps.summary_user, 191 key, value_irq, value_thread, value_user, cpus); 192 } 193 #endif /* HAVE_BPF_SKEL */ 194