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![Steven Rostedt (VMware)](/assets/img/avatar_default.png)
In preparation to have arguments of a function passed to callbacks attached to functions as default, change the default callback prototype to receive a struct ftrace_regs as the forth parameter instead of a pt_regs. For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they will now need to get the pt_regs via a ftrace_get_regs() helper call. If this is called by a callback that their ftrace_ops did not have a FL_SAVE_REGS flag set, it that helper function will return NULL. This will allow the ftrace_regs to hold enough just to get the parameters and stack pointer, but without the worry that callbacks may have a pt_regs that is not completely filled. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
194 lines
4.5 KiB
C
194 lines
4.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2012 Google, Inc.
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*/
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#include <linux/kernel.h>
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#include <linux/compiler.h>
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#include <linux/irqflags.h>
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#include <linux/percpu.h>
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#include <linux/smp.h>
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#include <linux/atomic.h>
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#include <linux/types.h>
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#include <linux/mutex.h>
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#include <linux/ftrace.h>
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#include <linux/fs.h>
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#include <linux/debugfs.h>
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#include <linux/err.h>
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#include <linux/cache.h>
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#include <linux/slab.h>
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#include <asm/barrier.h>
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#include "internal.h"
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/* This doesn't need to be atomic: speed is chosen over correctness here. */
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static u64 pstore_ftrace_stamp;
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static void notrace pstore_ftrace_call(unsigned long ip,
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unsigned long parent_ip,
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struct ftrace_ops *op,
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struct ftrace_regs *fregs)
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{
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int bit;
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unsigned long flags;
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struct pstore_ftrace_record rec = {};
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struct pstore_record record = {
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.type = PSTORE_TYPE_FTRACE,
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.buf = (char *)&rec,
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.size = sizeof(rec),
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.psi = psinfo,
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};
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if (unlikely(oops_in_progress))
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return;
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bit = ftrace_test_recursion_trylock(ip, parent_ip);
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if (bit < 0)
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return;
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local_irq_save(flags);
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rec.ip = ip;
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rec.parent_ip = parent_ip;
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pstore_ftrace_write_timestamp(&rec, pstore_ftrace_stamp++);
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pstore_ftrace_encode_cpu(&rec, raw_smp_processor_id());
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psinfo->write(&record);
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local_irq_restore(flags);
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ftrace_test_recursion_unlock(bit);
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}
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static struct ftrace_ops pstore_ftrace_ops __read_mostly = {
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.func = pstore_ftrace_call,
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};
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static DEFINE_MUTEX(pstore_ftrace_lock);
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static bool pstore_ftrace_enabled;
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static ssize_t pstore_ftrace_knob_write(struct file *f, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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u8 on;
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ssize_t ret;
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ret = kstrtou8_from_user(buf, count, 2, &on);
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if (ret)
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return ret;
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mutex_lock(&pstore_ftrace_lock);
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if (!on ^ pstore_ftrace_enabled)
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goto out;
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if (on) {
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ftrace_ops_set_global_filter(&pstore_ftrace_ops);
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ret = register_ftrace_function(&pstore_ftrace_ops);
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} else {
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ret = unregister_ftrace_function(&pstore_ftrace_ops);
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}
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if (ret) {
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pr_err("%s: unable to %sregister ftrace ops: %zd\n",
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__func__, on ? "" : "un", ret);
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goto err;
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}
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pstore_ftrace_enabled = on;
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out:
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ret = count;
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err:
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mutex_unlock(&pstore_ftrace_lock);
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return ret;
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}
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static ssize_t pstore_ftrace_knob_read(struct file *f, char __user *buf,
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size_t count, loff_t *ppos)
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{
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char val[] = { '0' + pstore_ftrace_enabled, '\n' };
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return simple_read_from_buffer(buf, count, ppos, val, sizeof(val));
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}
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static const struct file_operations pstore_knob_fops = {
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.open = simple_open,
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.read = pstore_ftrace_knob_read,
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.write = pstore_ftrace_knob_write,
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};
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static struct dentry *pstore_ftrace_dir;
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void pstore_register_ftrace(void)
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{
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if (!psinfo->write)
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return;
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pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
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debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir, NULL,
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&pstore_knob_fops);
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}
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void pstore_unregister_ftrace(void)
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{
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mutex_lock(&pstore_ftrace_lock);
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if (pstore_ftrace_enabled) {
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unregister_ftrace_function(&pstore_ftrace_ops);
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pstore_ftrace_enabled = false;
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}
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mutex_unlock(&pstore_ftrace_lock);
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debugfs_remove_recursive(pstore_ftrace_dir);
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}
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ssize_t pstore_ftrace_combine_log(char **dest_log, size_t *dest_log_size,
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const char *src_log, size_t src_log_size)
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{
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size_t dest_size, src_size, total, dest_off, src_off;
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size_t dest_idx = 0, src_idx = 0, merged_idx = 0;
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void *merged_buf;
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struct pstore_ftrace_record *drec, *srec, *mrec;
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size_t record_size = sizeof(struct pstore_ftrace_record);
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dest_off = *dest_log_size % record_size;
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dest_size = *dest_log_size - dest_off;
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src_off = src_log_size % record_size;
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src_size = src_log_size - src_off;
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total = dest_size + src_size;
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merged_buf = kmalloc(total, GFP_KERNEL);
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if (!merged_buf)
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return -ENOMEM;
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drec = (struct pstore_ftrace_record *)(*dest_log + dest_off);
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srec = (struct pstore_ftrace_record *)(src_log + src_off);
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mrec = (struct pstore_ftrace_record *)(merged_buf);
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while (dest_size > 0 && src_size > 0) {
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if (pstore_ftrace_read_timestamp(&drec[dest_idx]) <
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pstore_ftrace_read_timestamp(&srec[src_idx])) {
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mrec[merged_idx++] = drec[dest_idx++];
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dest_size -= record_size;
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} else {
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mrec[merged_idx++] = srec[src_idx++];
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src_size -= record_size;
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}
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}
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while (dest_size > 0) {
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mrec[merged_idx++] = drec[dest_idx++];
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dest_size -= record_size;
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}
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while (src_size > 0) {
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mrec[merged_idx++] = srec[src_idx++];
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src_size -= record_size;
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}
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kfree(*dest_log);
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*dest_log = merged_buf;
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*dest_log_size = total;
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return 0;
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}
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EXPORT_SYMBOL_GPL(pstore_ftrace_combine_log);
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