1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2020 Facebook */ 3 #include <linux/btf.h> 4 #include <linux/btf_ids.h> 5 #include <linux/error-injection.h> 6 #include <linux/init.h> 7 #include <linux/module.h> 8 #include <linux/percpu-defs.h> 9 #include <linux/sysfs.h> 10 #include <linux/tracepoint.h> 11 #include "bpf_testmod.h" 12 13 #define CREATE_TRACE_POINTS 14 #include "bpf_testmod-events.h" 15 16 DEFINE_PER_CPU(int, bpf_testmod_ksym_percpu) = 123; 17 18 noinline void 19 bpf_testmod_test_mod_kfunc(int i) 20 { 21 *(int *)this_cpu_ptr(&bpf_testmod_ksym_percpu) = i; 22 } 23 24 noinline int bpf_testmod_loop_test(int n) 25 { 26 int i, sum = 0; 27 28 /* the primary goal of this test is to test LBR. Create a lot of 29 * branches in the function, so we can catch it easily. 30 */ 31 for (i = 0; i < n; i++) 32 sum += i; 33 return sum; 34 } 35 36 noinline ssize_t 37 bpf_testmod_test_read(struct file *file, struct kobject *kobj, 38 struct bin_attribute *bin_attr, 39 char *buf, loff_t off, size_t len) 40 { 41 struct bpf_testmod_test_read_ctx ctx = { 42 .buf = buf, 43 .off = off, 44 .len = len, 45 }; 46 47 /* This is always true. Use the check to make sure the compiler 48 * doesn't remove bpf_testmod_loop_test. 49 */ 50 if (bpf_testmod_loop_test(101) > 100) 51 trace_bpf_testmod_test_read(current, &ctx); 52 53 /* Magic number to enable writable tp */ 54 if (len == 64) { 55 struct bpf_testmod_test_writable_ctx writable = { 56 .val = 1024, 57 }; 58 trace_bpf_testmod_test_writable_bare(&writable); 59 if (writable.early_ret) 60 return snprintf(buf, len, "%d\n", writable.val); 61 } 62 63 return -EIO; /* always fail */ 64 } 65 EXPORT_SYMBOL(bpf_testmod_test_read); 66 ALLOW_ERROR_INJECTION(bpf_testmod_test_read, ERRNO); 67 68 noinline ssize_t 69 bpf_testmod_test_write(struct file *file, struct kobject *kobj, 70 struct bin_attribute *bin_attr, 71 char *buf, loff_t off, size_t len) 72 { 73 struct bpf_testmod_test_write_ctx ctx = { 74 .buf = buf, 75 .off = off, 76 .len = len, 77 }; 78 79 trace_bpf_testmod_test_write_bare(current, &ctx); 80 81 return -EIO; /* always fail */ 82 } 83 EXPORT_SYMBOL(bpf_testmod_test_write); 84 ALLOW_ERROR_INJECTION(bpf_testmod_test_write, ERRNO); 85 86 static struct bin_attribute bin_attr_bpf_testmod_file __ro_after_init = { 87 .attr = { .name = "bpf_testmod", .mode = 0666, }, 88 .read = bpf_testmod_test_read, 89 .write = bpf_testmod_test_write, 90 }; 91 92 BTF_SET_START(bpf_testmod_kfunc_ids) 93 BTF_ID(func, bpf_testmod_test_mod_kfunc) 94 BTF_SET_END(bpf_testmod_kfunc_ids) 95 96 static DEFINE_KFUNC_BTF_ID_SET(&bpf_testmod_kfunc_ids, bpf_testmod_kfunc_btf_set); 97 98 static int bpf_testmod_init(void) 99 { 100 int ret; 101 102 ret = sysfs_create_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file); 103 if (ret) 104 return ret; 105 register_kfunc_btf_id_set(&prog_test_kfunc_list, &bpf_testmod_kfunc_btf_set); 106 return 0; 107 } 108 109 static void bpf_testmod_exit(void) 110 { 111 unregister_kfunc_btf_id_set(&prog_test_kfunc_list, &bpf_testmod_kfunc_btf_set); 112 return sysfs_remove_bin_file(kernel_kobj, &bin_attr_bpf_testmod_file); 113 } 114 115 module_init(bpf_testmod_init); 116 module_exit(bpf_testmod_exit); 117 118 MODULE_AUTHOR("Andrii Nakryiko"); 119 MODULE_DESCRIPTION("BPF selftests module"); 120 MODULE_LICENSE("Dual BSD/GPL"); 121