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TOMOYO Linux Cross Reference
Linux/fs/pstore/ftrace.c

Version: ~ [ linux-4.20-rc6 ] ~ [ linux-4.19.8 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.87 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.144 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.166 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.128 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.61 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.31.14 ] ~ [ linux-2.6.30.10 ] ~ [ linux-2.6.29.6 ] ~ [ linux-2.6.28.10 ] ~ [ linux-2.6.27.62 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  * Copyright 2012  Google, Inc.
  3  *
  4  * This software is licensed under the terms of the GNU General Public
  5  * License version 2, as published by the Free Software Foundation, and
  6  * may be copied, distributed, and modified under those terms.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 11  * GNU General Public License for more details.
 12  */
 13 
 14 #include <linux/kernel.h>
 15 #include <linux/compiler.h>
 16 #include <linux/irqflags.h>
 17 #include <linux/percpu.h>
 18 #include <linux/smp.h>
 19 #include <linux/atomic.h>
 20 #include <linux/types.h>
 21 #include <linux/mutex.h>
 22 #include <linux/ftrace.h>
 23 #include <linux/fs.h>
 24 #include <linux/debugfs.h>
 25 #include <linux/err.h>
 26 #include <linux/cache.h>
 27 #include <asm/barrier.h>
 28 #include "internal.h"
 29 
 30 /* This doesn't need to be atomic: speed is chosen over correctness here. */
 31 static u64 pstore_ftrace_stamp;
 32 
 33 static void notrace pstore_ftrace_call(unsigned long ip,
 34                                        unsigned long parent_ip,
 35                                        struct ftrace_ops *op,
 36                                        struct pt_regs *regs)
 37 {
 38         unsigned long flags;
 39         struct pstore_ftrace_record rec = {};
 40         struct pstore_record record = {
 41                 .type = PSTORE_TYPE_FTRACE,
 42                 .buf = (char *)&rec,
 43                 .size = sizeof(rec),
 44                 .psi = psinfo,
 45         };
 46 
 47         if (unlikely(oops_in_progress))
 48                 return;
 49 
 50         local_irq_save(flags);
 51 
 52         rec.ip = ip;
 53         rec.parent_ip = parent_ip;
 54         pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
 55         pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
 56         psinfo->write(&record);
 57 
 58         local_irq_restore(flags);
 59 }
 60 
 61 static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
 62         .func   = pstore_ftrace_call,
 63 };
 64 
 65 static DEFINE_MUTEX(pstore_ftrace_lock);
 66 static bool pstore_ftrace_enabled;
 67 
 68 static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
 69                                         size_t count, loff_t *ppos)
 70 {
 71         u8 on;
 72         ssize_t ret;
 73 
 74         ret = kstrtou8_from_user(buf, count, 2, &on);
 75         if (ret)
 76                 return ret;
 77 
 78         mutex_lock(&pstore_ftrace_lock);
 79 
 80         if (!on ^ pstore_ftrace_enabled)
 81                 goto out;
 82 
 83         if (on) {
 84                 ftrace_ops_set_global_filter(&pstore_ftrace_ops);
 85                 ret = register_ftrace_function(&pstore_ftrace_ops);
 86         } else {
 87                 ret = unregister_ftrace_function(&pstore_ftrace_ops);
 88         }
 89 
 90         if (ret) {
 91                 pr_err("%s: unable to %sregister ftrace ops: %zd\n",
 92                        __func__, on ? "" : "un", ret);
 93                 goto err;
 94         }
 95 
 96         pstore_ftrace_enabled = on;
 97 out:
 98         ret = count;
 99 err:
100         mutex_unlock(&pstore_ftrace_lock);
101 
102         return ret;
103 }
104 
105 static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
106                                        size_t count, loff_t *ppos)
107 {
108         char val[] = { '' + pstore_ftrace_enabled, '\n' };
109 
110         return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
111 }
112 
113 static const struct file_operations pstore_knob_fops = {
114         .open   = simple_open,
115         .read   = pstore_ftrace_knob_read,
116         .write  = pstore_ftrace_knob_write,
117 };
118 
119 static struct dentry *pstore_ftrace_dir;
120 
121 void pstore_register_ftrace(void)
122 {
123         struct dentry *file;
124 
125         if (!psinfo->write)
126                 return;
127 
128         pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
129         if (!pstore_ftrace_dir) {
130                 pr_err("%s: unable to create pstore directory\n", __func__);
131                 return;
132         }
133 
134         file = debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir,
135                                    NULL, &pstore_knob_fops);
136         if (!file) {
137                 pr_err("%s: unable to create record_ftrace file\n", __func__);
138                 goto err_file;
139         }
140 
141         return;
142 err_file:
143         debugfs_remove(pstore_ftrace_dir);
144 }
145 
146 void pstore_unregister_ftrace(void)
147 {
148         mutex_lock(&pstore_ftrace_lock);
149         if (pstore_ftrace_enabled) {
150                 unregister_ftrace_function(&pstore_ftrace_ops);
151                 pstore_ftrace_enabled = 0;
152         }
153         mutex_unlock(&pstore_ftrace_lock);
154 
155         debugfs_remove_recursive(pstore_ftrace_dir);
156 }
157 

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