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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
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 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
60static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
61 .func = pstore_ftrace_call,
62};
63
64static DEFINE_MUTEX(pstore_ftrace_lock);
65static bool pstore_ftrace_enabled;
66
67static 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;
96out:
97 ret = count;
98err:
99 mutex_unlock(&pstore_ftrace_lock);
100
101 return ret;
102}
103
104static 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
112static 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
118static struct dentry *pstore_ftrace_dir;
119
120void 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
131void 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
143ssize_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}
194EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log);
195
