1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright 2012 Google, Inc. 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/compiler.h> 8 #include <linux/irqflags.h> 9 #include <linux/percpu.h> 10 #include <linux/smp.h> 11 #include <linux/atomic.h> 12 #include <linux/types.h> 13 #include <linux/mutex.h> 14 #include <linux/ftrace.h> 15 #include <linux/fs.h> 16 #include <linux/debugfs.h> 17 #include <linux/err.h> 18 #include <linux/cache.h> 19 #include <linux/slab.h> 20 #include <asm/barrier.h> 21 #include "internal.h" 22 23 /* This doesn't need to be atomic: speed is chosen over correctness here. */ 24 static u64 pstore_ftrace_stamp; 25 26 static void notrace pstore_ftrace_call(unsigned long ip, 27 unsigned long parent_ip, 28 struct ftrace_ops *op, 29 struct ftrace_regs *fregs) 30 { 31 int bit; 32 unsigned long flags; 33 struct pstore_ftrace_record rec = {}; 34 struct pstore_record record = { 35 .type = PSTORE_TYPE_FTRACE, 36 .buf = (char *)&rec, 37 .size = sizeof(rec), 38 .psi = psinfo, 39 }; 40 41 if (unlikely(oops_in_progress)) 42 return; 43 44 bit = ftrace_test_recursion_trylock(ip, parent_ip); 45 if (bit < 0) 46 return; 47 48 local_irq_save(flags); 49 50 rec.ip = ip; 51 rec.parent_ip = parent_ip; 52 pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++); 53 pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id()); 54 psinfo->write(&record); 55 56 local_irq_restore(flags); 57 ftrace_test_recursion_unlock(bit); 58 } 59 60 static struct ftrace_ops pstore_ftrace_ops __read_mostly = { 61 .func = pstore_ftrace_call, 62 }; 63 64 static DEFINE_MUTEX(pstore_ftrace_lock); 65 static bool pstore_ftrace_enabled; 66 67 static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf, 68 size_t count, loff_t *ppos) 69 { 70 u8 on; 71 ssize_t ret; 72 73 ret = kstrtou8_from_user(buf, count, 2, &on); 74 if (ret) 75 return ret; 76 77 mutex_lock(&pstore_ftrace_lock); 78 79 if (!on ^ pstore_ftrace_enabled) 80 goto out; 81 82 if (on) { 83 ftrace_ops_set_global_filter(&pstore_ftrace_ops); 84 ret = register_ftrace_function(&pstore_ftrace_ops); 85 } else { 86 ret = unregister_ftrace_function(&pstore_ftrace_ops); 87 } 88 89 if (ret) { 90 pr_err("%s: unable to %sregister ftrace ops: %zd\n", 91 __func__, on ? "" : "un", ret); 92 goto err; 93 } 94 95 pstore_ftrace_enabled = on; 96 out: 97 ret = count; 98 err: 99 mutex_unlock(&pstore_ftrace_lock); 100 101 return ret; 102 } 103 104 static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf, 105 size_t count, loff_t *ppos) 106 { 107 char val[] = { '0' + pstore_ftrace_enabled, '\n' }; 108 109 return simple_read_from_buffer(buf, count, ppos, val, sizeof(val)); 110 } 111 112 static const struct file_operations pstore_knob_fops = { 113 .open = simple_open, 114 .read = pstore_ftrace_knob_read, 115 .write = pstore_ftrace_knob_write, 116 }; 117 118 static struct dentry *pstore_ftrace_dir; 119 120 void pstore_register_ftrace(void) 121 { 122 if (!psinfo->write) 123 return; 124 125 pstore_ftrace_dir = debugfs_create_dir("pstore", NULL); 126 127 debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL, 128 &pstore_knob_fops); 129 } 130 131 void pstore_unregister_ftrace(void) 132 { 133 mutex_lock(&pstore_ftrace_lock); 134 if (pstore_ftrace_enabled) { 135 unregister_ftrace_function(&pstore_ftrace_ops); 136 pstore_ftrace_enabled = false; 137 } 138 mutex_unlock(&pstore_ftrace_lock); 139 140 debugfs_remove_recursive(pstore_ftrace_dir); 141 } 142 143 ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size, 144 const char *src_log, size_t src_log_size) 145 { 146 size_t dest_size, src_size, total, dest_off, src_off; 147 size_t dest_idx = 0, src_idx = 0, merged_idx = 0; 148 void *merged_buf; 149 struct pstore_ftrace_record *drec, *srec, *mrec; 150 size_t record_size = sizeof(struct pstore_ftrace_record); 151 152 dest_off = *dest_log_size % record_size; 153 dest_size = *dest_log_size - dest_off; 154 155 src_off = src_log_size % record_size; 156 src_size = src_log_size - src_off; 157 158 total = dest_size + src_size; 159 merged_buf = kmalloc(total, GFP_KERNEL); 160 if (!merged_buf) 161 return -ENOMEM; 162 163 drec = (struct pstore_ftrace_record *)(*dest_log + dest_off); 164 srec = (struct pstore_ftrace_record *)(src_log + src_off); 165 mrec = (struct pstore_ftrace_record *)(merged_buf); 166 167 while (dest_size > 0 && src_size > 0) { 168 if (pstore_ftrace_read_timestamp(&drec[dest_idx]) < 169 pstore_ftrace_read_timestamp(&srec[src_idx])) { 170 mrec[merged_idx++] = drec[dest_idx++]; 171 dest_size -= record_size; 172 } else { 173 mrec[merged_idx++] = srec[src_idx++]; 174 src_size -= record_size; 175 } 176 } 177 178 while (dest_size > 0) { 179 mrec[merged_idx++] = drec[dest_idx++]; 180 dest_size -= record_size; 181 } 182 183 while (src_size > 0) { 184 mrec[merged_idx++] = srec[src_idx++]; 185 src_size -= record_size; 186 } 187 188 kfree(*dest_log); 189 *dest_log = merged_buf; 190 *dest_log_size = total; 191 192 return 0; 193 } 194 EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log); 195