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 int pstore_set_ftrace_enabled(bool on) 68 { 69 ssize_t ret; 70 71 if (on == pstore_ftrace_enabled) 72 return 0; 73 74 if (on) { 75 ftrace_ops_set_global_filter(&pstore_ftrace_ops); 76 ret = register_ftrace_function(&pstore_ftrace_ops); 77 } else { 78 ret = unregister_ftrace_function(&pstore_ftrace_ops); 79 } 80 81 if (ret) { 82 pr_err("%s: unable to %sregister ftrace ops: %zd\n", 83 __func__, on ? "" : "un", ret); 84 } else { 85 pstore_ftrace_enabled = on; 86 } 87 88 return ret; 89 } 90 91 static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf, 92 size_t count, loff_t *ppos) 93 { 94 u8 on; 95 ssize_t ret; 96 97 ret = kstrtou8_from_user(buf, count, 2, &on); 98 if (ret) 99 return ret; 100 101 mutex_lock(&pstore_ftrace_lock); 102 ret = pstore_set_ftrace_enabled(on); 103 mutex_unlock(&pstore_ftrace_lock); 104 105 if (ret == 0) 106 ret = count; 107 108 return ret; 109 } 110 111 static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf, 112 size_t count, loff_t *ppos) 113 { 114 char val[] = { '0' + pstore_ftrace_enabled, '\n' }; 115 116 return simple_read_from_buffer(buf, count, ppos, val, sizeof(val)); 117 } 118 119 static const struct file_operations pstore_knob_fops = { 120 .open = simple_open, 121 .read = pstore_ftrace_knob_read, 122 .write = pstore_ftrace_knob_write, 123 }; 124 125 static struct dentry *pstore_ftrace_dir; 126 127 static bool record_ftrace; 128 module_param(record_ftrace, bool, 0400); 129 MODULE_PARM_DESC(record_ftrace, 130 "enable ftrace recording immediately (default: off)"); 131 132 void pstore_register_ftrace(void) 133 { 134 if (!psinfo->write) 135 return; 136 137 pstore_ftrace_dir = debugfs_create_dir("pstore", NULL); 138 139 pstore_set_ftrace_enabled(record_ftrace); 140 141 debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL, 142 &pstore_knob_fops); 143 } 144 145 void pstore_unregister_ftrace(void) 146 { 147 mutex_lock(&pstore_ftrace_lock); 148 if (pstore_ftrace_enabled) { 149 unregister_ftrace_function(&pstore_ftrace_ops); 150 pstore_ftrace_enabled = false; 151 } 152 mutex_unlock(&pstore_ftrace_lock); 153 154 debugfs_remove_recursive(pstore_ftrace_dir); 155 } 156 157 ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size, 158 const char *src_log, size_t src_log_size) 159 { 160 size_t dest_size, src_size, total, dest_off, src_off; 161 size_t dest_idx = 0, src_idx = 0, merged_idx = 0; 162 void *merged_buf; 163 struct pstore_ftrace_record *drec, *srec, *mrec; 164 size_t record_size = sizeof(struct pstore_ftrace_record); 165 166 dest_off = *dest_log_size % record_size; 167 dest_size = *dest_log_size - dest_off; 168 169 src_off = src_log_size % record_size; 170 src_size = src_log_size - src_off; 171 172 total = dest_size + src_size; 173 merged_buf = kmalloc(total, GFP_KERNEL); 174 if (!merged_buf) 175 return -ENOMEM; 176 177 drec = (struct pstore_ftrace_record *)(*dest_log + dest_off); 178 srec = (struct pstore_ftrace_record *)(src_log + src_off); 179 mrec = (struct pstore_ftrace_record *)(merged_buf); 180 181 while (dest_size > 0 && src_size > 0) { 182 if (pstore_ftrace_read_timestamp(&drec[dest_idx]) < 183 pstore_ftrace_read_timestamp(&srec[src_idx])) { 184 mrec[merged_idx++] = drec[dest_idx++]; 185 dest_size -= record_size; 186 } else { 187 mrec[merged_idx++] = srec[src_idx++]; 188 src_size -= record_size; 189 } 190 } 191 192 while (dest_size > 0) { 193 mrec[merged_idx++] = drec[dest_idx++]; 194 dest_size -= record_size; 195 } 196 197 while (src_size > 0) { 198 mrec[merged_idx++] = srec[src_idx++]; 199 src_size -= record_size; 200 } 201 202 kfree(*dest_log); 203 *dest_log = merged_buf; 204 *dest_log_size = total; 205 206 return 0; 207 } 208 EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log); 209