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-rw-r--r--fs/pstore/ftrace.c208
1 files changed, 208 insertions, 0 deletions
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
new file mode 100644
index 0000000000..776cae20af
--- /dev/null
+++ b/fs/pstore/ftrace.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2012 Google, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/compiler.h>
+#include <linux/irqflags.h>
+#include <linux/percpu.h>
+#include <linux/smp.h>
+#include <linux/atomic.h>
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/ftrace.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/err.h>
+#include <linux/cache.h>
+#include <linux/slab.h>
+#include <asm/barrier.h>
+#include "internal.h"
+
+/* This doesn't need to be atomic: speed is chosen over correctness here. */
+static u64 pstore_ftrace_stamp;
+
+static void notrace pstore_ftrace_call(unsigned long ip,
+ unsigned long parent_ip,
+ struct ftrace_ops *op,
+ struct ftrace_regs *fregs)
+{
+ int bit;
+ unsigned long flags;
+ struct pstore_ftrace_record rec = {};
+ struct pstore_record record = {
+ .type = PSTORE_TYPE_FTRACE,
+ .buf = (char *)&rec,
+ .size = sizeof(rec),
+ .psi = psinfo,
+ };
+
+ if (unlikely(oops_in_progress))
+ return;
+
+ bit = ftrace_test_recursion_trylock(ip, parent_ip);
+ if (bit < 0)
+ return;
+
+ local_irq_save(flags);
+
+ rec.ip = ip;
+ rec.parent_ip = parent_ip;
+ pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
+ pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
+ psinfo->write(&record);
+
+ local_irq_restore(flags);
+ ftrace_test_recursion_unlock(bit);
+}
+
+static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
+ .func = pstore_ftrace_call,
+};
+
+static DEFINE_MUTEX(pstore_ftrace_lock);
+static bool pstore_ftrace_enabled;
+
+static int pstore_set_ftrace_enabled(bool on)
+{
+ ssize_t ret;
+
+ if (on == pstore_ftrace_enabled)
+ return 0;
+
+ if (on) {
+ ftrace_ops_set_global_filter(&pstore_ftrace_ops);
+ ret = register_ftrace_function(&pstore_ftrace_ops);
+ } else {
+ ret = unregister_ftrace_function(&pstore_ftrace_ops);
+ }
+
+ if (ret) {
+ pr_err("%s: unable to %sregister ftrace ops: %zd\n",
+ __func__, on ? "" : "un", ret);
+ } else {
+ pstore_ftrace_enabled = on;
+ }
+
+ return ret;
+}
+
+static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ u8 on;
+ ssize_t ret;
+
+ ret = kstrtou8_from_user(buf, count, 2, &on);
+ if (ret)
+ return ret;
+
+ mutex_lock(&pstore_ftrace_lock);
+ ret = pstore_set_ftrace_enabled(on);
+ mutex_unlock(&pstore_ftrace_lock);
+
+ if (ret == 0)
+ ret = count;
+
+ return ret;
+}
+
+static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ char val[] = { '0' + pstore_ftrace_enabled, '\n' };
+
+ return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
+}
+
+static const struct file_operations pstore_knob_fops = {
+ .open = simple_open,
+ .read = pstore_ftrace_knob_read,
+ .write = pstore_ftrace_knob_write,
+};
+
+static struct dentry *pstore_ftrace_dir;
+
+static bool record_ftrace;
+module_param(record_ftrace, bool, 0400);
+MODULE_PARM_DESC(record_ftrace,
+ "enable ftrace recording immediately (default: off)");
+
+void pstore_register_ftrace(void)
+{
+ if (!psinfo->write)
+ return;
+
+ pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
+
+ pstore_set_ftrace_enabled(record_ftrace);
+
+ debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
+ &pstore_knob_fops);
+}
+
+void pstore_unregister_ftrace(void)
+{
+ mutex_lock(&pstore_ftrace_lock);
+ if (pstore_ftrace_enabled) {
+ unregister_ftrace_function(&pstore_ftrace_ops);
+ pstore_ftrace_enabled = false;
+ }
+ mutex_unlock(&pstore_ftrace_lock);
+
+ debugfs_remove_recursive(pstore_ftrace_dir);
+}
+
+ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
+ const char *src_log, size_t src_log_size)
+{
+ size_t dest_size, src_size, total, dest_off, src_off;
+ size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
+ void *merged_buf;
+ struct pstore_ftrace_record *drec, *srec, *mrec;
+ size_t record_size = sizeof(struct pstore_ftrace_record);
+
+ dest_off = *dest_log_size % record_size;
+ dest_size = *dest_log_size - dest_off;
+
+ src_off = src_log_size % record_size;
+ src_size = src_log_size - src_off;
+
+ total = dest_size + src_size;
+ merged_buf = kmalloc(total, GFP_KERNEL);
+ if (!merged_buf)
+ return -ENOMEM;
+
+ drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);
+ srec = (struct pstore_ftrace_record *)(src_log + src_off);
+ mrec = (struct pstore_ftrace_record *)(merged_buf);
+
+ while (dest_size > 0 && src_size > 0) {
+ if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
+ pstore_ftrace_read_timestamp(&srec[src_idx])) {
+ mrec[merged_idx++] = drec[dest_idx++];
+ dest_size -= record_size;
+ } else {
+ mrec[merged_idx++] = srec[src_idx++];
+ src_size -= record_size;
+ }
+ }
+
+ while (dest_size > 0) {
+ mrec[merged_idx++] = drec[dest_idx++];
+ dest_size -= record_size;
+ }
+
+ while (src_size > 0) {
+ mrec[merged_idx++] = srec[src_idx++];
+ src_size -= record_size;
+ }
+
+ kfree(*dest_log);
+ *dest_log = merged_buf;
+ *dest_log_size = total;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log);