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9c92ab61 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
060287b8 AV |
2 | /* |
3 | * Copyright 2012 Google, Inc. | |
060287b8 AV |
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> | |
65f8c95e AV |
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> | |
16a58307 | 19 | #include <linux/slab.h> |
060287b8 AV |
20 | #include <asm/barrier.h> |
21 | #include "internal.h" | |
22 | ||
fbccdeb8 JF |
23 | /* This doesn't need to be atomic: speed is chosen over correctness here. */ |
24 | static u64 pstore_ftrace_stamp; | |
25 | ||
65f8c95e | 26 | static void notrace pstore_ftrace_call(unsigned long ip, |
ebacfd1e AV |
27 | unsigned long parent_ip, |
28 | struct ftrace_ops *op, | |
d19ad077 | 29 | struct ftrace_regs *fregs) |
060287b8 | 30 | { |
6cdf9418 | 31 | int bit; |
65f8c95e | 32 | unsigned long flags; |
060287b8 | 33 | struct pstore_ftrace_record rec = {}; |
b10b4711 KC |
34 | struct pstore_record record = { |
35 | .type = PSTORE_TYPE_FTRACE, | |
36 | .buf = (char *)&rec, | |
37 | .size = sizeof(rec), | |
38 | .psi = psinfo, | |
39 | }; | |
060287b8 AV |
40 | |
41 | if (unlikely(oops_in_progress)) | |
42 | return; | |
43 | ||
773c1670 | 44 | bit = ftrace_test_recursion_trylock(ip, parent_ip); |
6cdf9418 SRV |
45 | if (bit < 0) |
46 | return; | |
47 | ||
65f8c95e AV |
48 | local_irq_save(flags); |
49 | ||
060287b8 AV |
50 | rec.ip = ip; |
51 | rec.parent_ip = parent_ip; | |
fbccdeb8 | 52 | pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++); |
060287b8 | 53 | pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id()); |
4c9ec219 | 54 | psinfo->write(&record); |
65f8c95e AV |
55 | |
56 | local_irq_restore(flags); | |
6cdf9418 | 57 | ftrace_test_recursion_unlock(bit); |
65f8c95e AV |
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 | ||
a5d05b07 | 67 | static int pstore_set_ftrace_enabled(bool on) |
65f8c95e | 68 | { |
65f8c95e AV |
69 | ssize_t ret; |
70 | ||
a5d05b07 UKK |
71 | if (on == pstore_ftrace_enabled) |
72 | return 0; | |
65f8c95e | 73 | |
7a0032f5 JF |
74 | if (on) { |
75 | ftrace_ops_set_global_filter(&pstore_ftrace_ops); | |
65f8c95e | 76 | ret = register_ftrace_function(&pstore_ftrace_ops); |
7a0032f5 | 77 | } else { |
65f8c95e | 78 | ret = unregister_ftrace_function(&pstore_ftrace_ops); |
7a0032f5 JF |
79 | } |
80 | ||
65f8c95e AV |
81 | if (ret) { |
82 | pr_err("%s: unable to %sregister ftrace ops: %zd\n", | |
83 | __func__, on ? "" : "un", ret); | |
a5d05b07 UKK |
84 | } else { |
85 | pstore_ftrace_enabled = on; | |
65f8c95e AV |
86 | } |
87 | ||
a5d05b07 UKK |
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); | |
65f8c95e AV |
103 | mutex_unlock(&pstore_ftrace_lock); |
104 | ||
a5d05b07 UKK |
105 | if (ret == 0) |
106 | ret = count; | |
107 | ||
65f8c95e AV |
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 | ||
ee1d2674 GT |
125 | static struct dentry *pstore_ftrace_dir; |
126 | ||
a5d05b07 UKK |
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 | ||
65f8c95e AV |
132 | void pstore_register_ftrace(void) |
133 | { | |
4c9ec219 | 134 | if (!psinfo->write) |
65f8c95e AV |
135 | return; |
136 | ||
ee1d2674 | 137 | pstore_ftrace_dir = debugfs_create_dir("pstore", NULL); |
65f8c95e | 138 | |
a5d05b07 UKK |
139 | pstore_set_ftrace_enabled(record_ftrace); |
140 | ||
fa1af758 GKH |
141 | debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL, |
142 | &pstore_knob_fops); | |
ee1d2674 GT |
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); | |
69596433 | 150 | pstore_ftrace_enabled = false; |
ee1d2674 GT |
151 | } |
152 | mutex_unlock(&pstore_ftrace_lock); | |
153 | ||
154 | debugfs_remove_recursive(pstore_ftrace_dir); | |
060287b8 | 155 | } |
16a58307 KC |
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); |