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. */ 24static u64 pstore_ftrace_stamp; 25 26static void notrace pstore_ftrace_call(unsigned long ip, 27 unsigned long parent_ip, 28 struct ftrace_ops *op, 29 struct pt_regs *regs) 30{ 31 unsigned long flags; 32 struct pstore_ftrace_record rec = {}; 33 struct pstore_record record = { 34 .type = PSTORE_TYPE_FTRACE, 35 .buf = (char *)&rec, 36 .size = sizeof(rec), 37 .psi = psinfo, 38 }; 39 40 if (unlikely(oops_in_progress)) 41 return; 42 43 local_irq_save(flags); 44 45 rec.ip = ip; 46 rec.parent_ip = parent_ip; 47 pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++); 48 pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id()); 49 psinfo->write(&record); 50 51 local_irq_restore(flags); 52} 53 54static struct ftrace_ops pstore_ftrace_ops __read_mostly = { 55 .func = pstore_ftrace_call, 56}; 57 58static DEFINE_MUTEX(pstore_ftrace_lock); 59static bool pstore_ftrace_enabled; 60 61static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf, 62 size_t count, loff_t *ppos) 63{ 64 u8 on; 65 ssize_t ret; 66 67 ret = kstrtou8_from_user(buf, count, 2, &on); 68 if (ret) 69 return ret; 70 71 mutex_lock(&pstore_ftrace_lock); 72 73 if (!on ^ pstore_ftrace_enabled) 74 goto out; 75 76 if (on) { 77 ftrace_ops_set_global_filter(&pstore_ftrace_ops); 78 ret = register_ftrace_function(&pstore_ftrace_ops); 79 } else { 80 ret = unregister_ftrace_function(&pstore_ftrace_ops); 81 } 82 83 if (ret) { 84 pr_err("%s: unable to %sregister ftrace ops: %zd\n", 85 __func__, on ? "" : "un", ret); 86 goto err; 87 } 88 89 pstore_ftrace_enabled = on; 90out: 91 ret = count; 92err: 93 mutex_unlock(&pstore_ftrace_lock); 94 95 return ret; 96} 97 98static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf, 99 size_t count, loff_t *ppos) 100{ 101 char val[] = { '0' + pstore_ftrace_enabled, '\n' }; 102 103 return simple_read_from_buffer(buf, count, ppos, val, sizeof(val)); 104} 105 106static const struct file_operations pstore_knob_fops = { 107 .open = simple_open, 108 .read = pstore_ftrace_knob_read, 109 .write = pstore_ftrace_knob_write, 110}; 111 112static struct dentry *pstore_ftrace_dir; 113 114void pstore_register_ftrace(void) 115{ 116 if (!psinfo->write) 117 return; 118 119 pstore_ftrace_dir = debugfs_create_dir("pstore", NULL); 120 121 debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL, 122 &pstore_knob_fops); 123} 124 125void pstore_unregister_ftrace(void) 126{ 127 mutex_lock(&pstore_ftrace_lock); 128 if (pstore_ftrace_enabled) { 129 unregister_ftrace_function(&pstore_ftrace_ops); 130 pstore_ftrace_enabled = false; 131 } 132 mutex_unlock(&pstore_ftrace_lock); 133 134 debugfs_remove_recursive(pstore_ftrace_dir); 135} 136 137ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size, 138 const char *src_log, size_t src_log_size) 139{ 140 size_t dest_size, src_size, total, dest_off, src_off; 141 size_t dest_idx = 0, src_idx = 0, merged_idx = 0; 142 void *merged_buf; 143 struct pstore_ftrace_record *drec, *srec, *mrec; 144 size_t record_size = sizeof(struct pstore_ftrace_record); 145 146 dest_off = *dest_log_size % record_size; 147 dest_size = *dest_log_size - dest_off; 148 149 src_off = src_log_size % record_size; 150 src_size = src_log_size - src_off; 151 152 total = dest_size + src_size; 153 merged_buf = kmalloc(total, GFP_KERNEL); 154 if (!merged_buf) 155 return -ENOMEM; 156 157 drec = (struct pstore_ftrace_record *)(*dest_log + dest_off); 158 srec = (struct pstore_ftrace_record *)(src_log + src_off); 159 mrec = (struct pstore_ftrace_record *)(merged_buf); 160 161 while (dest_size > 0 && src_size > 0) { 162 if (pstore_ftrace_read_timestamp(&drec[dest_idx]) < 163 pstore_ftrace_read_timestamp(&srec[src_idx])) { 164 mrec[merged_idx++] = drec[dest_idx++]; 165 dest_size -= record_size; 166 } else { 167 mrec[merged_idx++] = srec[src_idx++]; 168 src_size -= record_size; 169 } 170 } 171 172 while (dest_size > 0) { 173 mrec[merged_idx++] = drec[dest_idx++]; 174 dest_size -= record_size; 175 } 176 177 while (src_size > 0) { 178 mrec[merged_idx++] = srec[src_idx++]; 179 src_size -= record_size; 180 } 181 182 kfree(*dest_log); 183 *dest_log = merged_buf; 184 *dest_log_size = total; 185 186 return 0; 187} 188EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log); 189