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- // 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 pt_regs *regs)
- {
- 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;
- 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);
- }
- 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 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);
- if (!on ^ pstore_ftrace_enabled)
- goto out;
- 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);
- goto err;
- }
- pstore_ftrace_enabled = on;
- out:
- ret = count;
- err:
- mutex_unlock(&pstore_ftrace_lock);
- 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;
- void pstore_register_ftrace(void)
- {
- if (!psinfo->write)
- return;
- pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
- 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);
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