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: &rec, val: pstore_ftrace_stamp++); |
53 | pstore_ftrace_encode_cpu(rec: &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(ops: &pstore_ftrace_ops); |
76 | ret = register_ftrace_function(ops: &pstore_ftrace_ops); |
77 | } else { |
78 | ret = unregister_ftrace_function(ops: &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(s: buf, count, base: 2, res: &on); |
98 | if (ret) |
99 | return ret; |
100 | |
101 | mutex_lock(&pstore_ftrace_lock); |
102 | ret = pstore_set_ftrace_enabled(on); |
103 | mutex_unlock(lock: &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(to: buf, count, ppos, from: val, available: 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(name: "pstore" , NULL); |
138 | |
139 | pstore_set_ftrace_enabled(on: record_ftrace); |
140 | |
141 | debugfs_create_file(name: "record_ftrace" , mode: 0600, parent: pstore_ftrace_dir, NULL, |
142 | fops: &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(ops: &pstore_ftrace_ops); |
150 | pstore_ftrace_enabled = false; |
151 | } |
152 | mutex_unlock(lock: &pstore_ftrace_lock); |
153 | |
154 | debugfs_remove_recursive(dentry: 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(size: 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(rec: &drec[dest_idx]) < |
183 | pstore_ftrace_read_timestamp(rec: &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(objp: *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 | |