982c350b9e
Impact: correct implementation of dyn ftrace filter The old decisions made by the filter algorithm was complex and incorrect. This lead to inconsistent enabling or disabling of functions when the filter was used. This patch simplifies that code and in doing so, corrects the usage of the filters. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
1491 lines
31 KiB
C
1491 lines
31 KiB
C
/*
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* Infrastructure for profiling code inserted by 'gcc -pg'.
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*
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* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
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* Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
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*
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* Originally ported from the -rt patch by:
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* Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
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*
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* Based on code in the latency_tracer, that is:
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*
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* Copyright (C) 2004-2006 Ingo Molnar
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* Copyright (C) 2004 William Lee Irwin III
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*/
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#include <linux/stop_machine.h>
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#include <linux/clocksource.h>
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#include <linux/kallsyms.h>
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#include <linux/seq_file.h>
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#include <linux/debugfs.h>
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#include <linux/hardirq.h>
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#include <linux/kthread.h>
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#include <linux/uaccess.h>
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#include <linux/kprobes.h>
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#include <linux/ftrace.h>
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#include <linux/sysctl.h>
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#include <linux/ctype.h>
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#include <linux/list.h>
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#include <asm/ftrace.h>
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#include "trace.h"
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#define FTRACE_WARN_ON(cond) \
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do { \
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if (WARN_ON(cond)) \
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ftrace_kill(); \
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} while (0)
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#define FTRACE_WARN_ON_ONCE(cond) \
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do { \
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if (WARN_ON_ONCE(cond)) \
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ftrace_kill(); \
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} while (0)
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/* ftrace_enabled is a method to turn ftrace on or off */
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int ftrace_enabled __read_mostly;
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static int last_ftrace_enabled;
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/* Quick disabling of function tracer. */
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int function_trace_stop;
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/*
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* ftrace_disabled is set when an anomaly is discovered.
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* ftrace_disabled is much stronger than ftrace_enabled.
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*/
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static int ftrace_disabled __read_mostly;
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static DEFINE_SPINLOCK(ftrace_lock);
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static DEFINE_MUTEX(ftrace_sysctl_lock);
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static struct ftrace_ops ftrace_list_end __read_mostly =
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{
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.func = ftrace_stub,
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};
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static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
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ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
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ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
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static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
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{
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struct ftrace_ops *op = ftrace_list;
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/* in case someone actually ports this to alpha! */
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read_barrier_depends();
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while (op != &ftrace_list_end) {
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/* silly alpha */
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read_barrier_depends();
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op->func(ip, parent_ip);
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op = op->next;
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};
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}
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/**
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* clear_ftrace_function - reset the ftrace function
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*
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* This NULLs the ftrace function and in essence stops
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* tracing. There may be lag
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*/
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void clear_ftrace_function(void)
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{
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ftrace_trace_function = ftrace_stub;
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__ftrace_trace_function = ftrace_stub;
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}
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#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
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/*
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* For those archs that do not test ftrace_trace_stop in their
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* mcount call site, we need to do it from C.
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*/
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static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
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{
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if (function_trace_stop)
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return;
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__ftrace_trace_function(ip, parent_ip);
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}
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#endif
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static int __register_ftrace_function(struct ftrace_ops *ops)
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{
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/* should not be called from interrupt context */
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spin_lock(&ftrace_lock);
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ops->next = ftrace_list;
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/*
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* We are entering ops into the ftrace_list but another
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* CPU might be walking that list. We need to make sure
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* the ops->next pointer is valid before another CPU sees
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* the ops pointer included into the ftrace_list.
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*/
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smp_wmb();
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ftrace_list = ops;
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if (ftrace_enabled) {
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/*
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* For one func, simply call it directly.
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* For more than one func, call the chain.
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*/
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#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
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if (ops->next == &ftrace_list_end)
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ftrace_trace_function = ops->func;
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else
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ftrace_trace_function = ftrace_list_func;
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#else
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if (ops->next == &ftrace_list_end)
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__ftrace_trace_function = ops->func;
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else
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__ftrace_trace_function = ftrace_list_func;
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ftrace_trace_function = ftrace_test_stop_func;
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#endif
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}
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spin_unlock(&ftrace_lock);
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return 0;
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}
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static int __unregister_ftrace_function(struct ftrace_ops *ops)
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{
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struct ftrace_ops **p;
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int ret = 0;
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/* should not be called from interrupt context */
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spin_lock(&ftrace_lock);
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/*
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* If we are removing the last function, then simply point
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* to the ftrace_stub.
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*/
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if (ftrace_list == ops && ops->next == &ftrace_list_end) {
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ftrace_trace_function = ftrace_stub;
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ftrace_list = &ftrace_list_end;
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goto out;
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}
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for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
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if (*p == ops)
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break;
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if (*p != ops) {
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ret = -1;
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goto out;
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}
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*p = (*p)->next;
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if (ftrace_enabled) {
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/* If we only have one func left, then call that directly */
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if (ftrace_list->next == &ftrace_list_end)
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ftrace_trace_function = ftrace_list->func;
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}
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out:
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spin_unlock(&ftrace_lock);
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return ret;
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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#ifndef CONFIG_FTRACE_MCOUNT_RECORD
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# error Dynamic ftrace depends on MCOUNT_RECORD
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#endif
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/*
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* Since MCOUNT_ADDR may point to mcount itself, we do not want
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* to get it confused by reading a reference in the code as we
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* are parsing on objcopy output of text. Use a variable for
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* it instead.
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*/
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static unsigned long mcount_addr = MCOUNT_ADDR;
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enum {
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FTRACE_ENABLE_CALLS = (1 << 0),
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FTRACE_DISABLE_CALLS = (1 << 1),
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FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
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FTRACE_ENABLE_MCOUNT = (1 << 3),
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FTRACE_DISABLE_MCOUNT = (1 << 4),
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};
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static int ftrace_filtered;
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static LIST_HEAD(ftrace_new_addrs);
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static DEFINE_MUTEX(ftrace_regex_lock);
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struct ftrace_page {
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struct ftrace_page *next;
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unsigned long index;
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struct dyn_ftrace records[];
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};
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#define ENTRIES_PER_PAGE \
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((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
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/* estimate from running different kernels */
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#define NR_TO_INIT 10000
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static struct ftrace_page *ftrace_pages_start;
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static struct ftrace_page *ftrace_pages;
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static struct dyn_ftrace *ftrace_free_records;
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#ifdef CONFIG_KPROBES
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static int frozen_record_count;
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static inline void freeze_record(struct dyn_ftrace *rec)
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{
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if (!(rec->flags & FTRACE_FL_FROZEN)) {
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rec->flags |= FTRACE_FL_FROZEN;
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frozen_record_count++;
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}
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}
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static inline void unfreeze_record(struct dyn_ftrace *rec)
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{
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if (rec->flags & FTRACE_FL_FROZEN) {
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rec->flags &= ~FTRACE_FL_FROZEN;
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frozen_record_count--;
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}
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}
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static inline int record_frozen(struct dyn_ftrace *rec)
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{
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return rec->flags & FTRACE_FL_FROZEN;
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}
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#else
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# define freeze_record(rec) ({ 0; })
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# define unfreeze_record(rec) ({ 0; })
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# define record_frozen(rec) ({ 0; })
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#endif /* CONFIG_KPROBES */
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static void ftrace_free_rec(struct dyn_ftrace *rec)
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{
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rec->ip = (unsigned long)ftrace_free_records;
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ftrace_free_records = rec;
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rec->flags |= FTRACE_FL_FREE;
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}
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void ftrace_release(void *start, unsigned long size)
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{
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struct dyn_ftrace *rec;
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struct ftrace_page *pg;
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unsigned long s = (unsigned long)start;
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unsigned long e = s + size;
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int i;
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if (ftrace_disabled || !start)
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return;
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/* should not be called from interrupt context */
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spin_lock(&ftrace_lock);
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for (pg = ftrace_pages_start; pg; pg = pg->next) {
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for (i = 0; i < pg->index; i++) {
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rec = &pg->records[i];
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if ((rec->ip >= s) && (rec->ip < e))
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ftrace_free_rec(rec);
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}
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}
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spin_unlock(&ftrace_lock);
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}
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static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
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{
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struct dyn_ftrace *rec;
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/* First check for freed records */
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if (ftrace_free_records) {
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rec = ftrace_free_records;
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if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
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FTRACE_WARN_ON_ONCE(1);
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ftrace_free_records = NULL;
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return NULL;
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}
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ftrace_free_records = (void *)rec->ip;
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memset(rec, 0, sizeof(*rec));
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return rec;
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}
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if (ftrace_pages->index == ENTRIES_PER_PAGE) {
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if (!ftrace_pages->next) {
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/* allocate another page */
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ftrace_pages->next =
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(void *)get_zeroed_page(GFP_KERNEL);
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if (!ftrace_pages->next)
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return NULL;
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}
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ftrace_pages = ftrace_pages->next;
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}
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return &ftrace_pages->records[ftrace_pages->index++];
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}
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static struct dyn_ftrace *
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ftrace_record_ip(unsigned long ip)
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{
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struct dyn_ftrace *rec;
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if (ftrace_disabled)
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return NULL;
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rec = ftrace_alloc_dyn_node(ip);
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if (!rec)
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return NULL;
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rec->ip = ip;
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list_add(&rec->list, &ftrace_new_addrs);
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return rec;
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}
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static void print_ip_ins(const char *fmt, unsigned char *p)
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{
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int i;
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printk(KERN_CONT "%s", fmt);
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for (i = 0; i < MCOUNT_INSN_SIZE; i++)
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printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
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}
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static void ftrace_bug(int failed, unsigned long ip)
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{
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switch (failed) {
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case -EFAULT:
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FTRACE_WARN_ON_ONCE(1);
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pr_info("ftrace faulted on modifying ");
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print_ip_sym(ip);
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break;
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case -EINVAL:
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FTRACE_WARN_ON_ONCE(1);
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pr_info("ftrace failed to modify ");
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print_ip_sym(ip);
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print_ip_ins(" actual: ", (unsigned char *)ip);
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printk(KERN_CONT "\n");
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break;
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case -EPERM:
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FTRACE_WARN_ON_ONCE(1);
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pr_info("ftrace faulted on writing ");
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print_ip_sym(ip);
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break;
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default:
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FTRACE_WARN_ON_ONCE(1);
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pr_info("ftrace faulted on unknown error ");
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print_ip_sym(ip);
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}
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}
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#define FTRACE_ADDR ((long)(ftrace_caller))
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static int
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__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
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{
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unsigned long ip, fl;
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ip = rec->ip;
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/*
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* If this record is not to be traced and
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* it is not enabled then do nothing.
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*
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* If this record is not to be traced and
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* it is enabled then disabled it.
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*
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*/
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if (rec->flags & FTRACE_FL_NOTRACE) {
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if (rec->flags & FTRACE_FL_ENABLED)
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rec->flags &= ~FTRACE_FL_ENABLED;
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else
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return 0;
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} else if (ftrace_filtered && enable) {
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/*
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* Filtering is on:
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*/
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fl = rec->flags & (FTRACE_FL_FILTER | FTRACE_FL_ENABLED);
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/* Record is filtered and enabled, do nothing */
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if (fl == (FTRACE_FL_FILTER | FTRACE_FL_ENABLED))
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return 0;
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/* Record is not filtered and is not enabled do nothing */
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if (!fl)
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return 0;
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/* Record is not filtered but enabled, disable it */
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if (fl == FTRACE_FL_ENABLED)
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rec->flags &= ~FTRACE_FL_ENABLED;
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else
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/* Otherwise record is filtered but not enabled, enable it */
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rec->flags |= FTRACE_FL_ENABLED;
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} else {
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/* Disable or not filtered */
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if (enable) {
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/* if record is enabled, do nothing */
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if (rec->flags & FTRACE_FL_ENABLED)
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return 0;
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rec->flags |= FTRACE_FL_ENABLED;
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} else {
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/* if record is not enabled do nothing */
|
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if (!(rec->flags & FTRACE_FL_ENABLED))
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return 0;
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|
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rec->flags &= ~FTRACE_FL_ENABLED;
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}
|
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}
|
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|
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if (rec->flags & FTRACE_FL_ENABLED)
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return ftrace_make_call(rec, FTRACE_ADDR);
|
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else
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return ftrace_make_nop(NULL, rec, FTRACE_ADDR);
|
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}
|
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|
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static void ftrace_replace_code(int enable)
|
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{
|
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int i, failed;
|
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struct dyn_ftrace *rec;
|
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struct ftrace_page *pg;
|
|
|
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for (pg = ftrace_pages_start; pg; pg = pg->next) {
|
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for (i = 0; i < pg->index; i++) {
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rec = &pg->records[i];
|
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|
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/*
|
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* Skip over free records and records that have
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* failed.
|
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*/
|
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if (rec->flags & FTRACE_FL_FREE ||
|
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rec->flags & FTRACE_FL_FAILED)
|
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continue;
|
|
|
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/* ignore updates to this record's mcount site */
|
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if (get_kprobe((void *)rec->ip)) {
|
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freeze_record(rec);
|
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continue;
|
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} else {
|
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unfreeze_record(rec);
|
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}
|
|
|
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failed = __ftrace_replace_code(rec, enable);
|
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if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
|
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rec->flags |= FTRACE_FL_FAILED;
|
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if ((system_state == SYSTEM_BOOTING) ||
|
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!core_kernel_text(rec->ip)) {
|
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ftrace_free_rec(rec);
|
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} else
|
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ftrace_bug(failed, rec->ip);
|
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}
|
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}
|
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}
|
|
}
|
|
|
|
static int
|
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ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
|
|
{
|
|
unsigned long ip;
|
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int ret;
|
|
|
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ip = rec->ip;
|
|
|
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ret = ftrace_make_nop(mod, rec, mcount_addr);
|
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if (ret) {
|
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ftrace_bug(ret, ip);
|
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rec->flags |= FTRACE_FL_FAILED;
|
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return 0;
|
|
}
|
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return 1;
|
|
}
|
|
|
|
static int __ftrace_modify_code(void *data)
|
|
{
|
|
int *command = data;
|
|
|
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if (*command & FTRACE_ENABLE_CALLS)
|
|
ftrace_replace_code(1);
|
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else if (*command & FTRACE_DISABLE_CALLS)
|
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ftrace_replace_code(0);
|
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|
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if (*command & FTRACE_UPDATE_TRACE_FUNC)
|
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ftrace_update_ftrace_func(ftrace_trace_function);
|
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|
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return 0;
|
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}
|
|
|
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static void ftrace_run_update_code(int command)
|
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{
|
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stop_machine(__ftrace_modify_code, &command, NULL);
|
|
}
|
|
|
|
static ftrace_func_t saved_ftrace_func;
|
|
static int ftrace_start_up;
|
|
static DEFINE_MUTEX(ftrace_start_lock);
|
|
|
|
static void ftrace_startup(void)
|
|
{
|
|
int command = 0;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
ftrace_start_up++;
|
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command |= FTRACE_ENABLE_CALLS;
|
|
|
|
if (saved_ftrace_func != ftrace_trace_function) {
|
|
saved_ftrace_func = ftrace_trace_function;
|
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command |= FTRACE_UPDATE_TRACE_FUNC;
|
|
}
|
|
|
|
if (!command || !ftrace_enabled)
|
|
goto out;
|
|
|
|
ftrace_run_update_code(command);
|
|
out:
|
|
mutex_unlock(&ftrace_start_lock);
|
|
}
|
|
|
|
static void ftrace_shutdown(void)
|
|
{
|
|
int command = 0;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
ftrace_start_up--;
|
|
if (!ftrace_start_up)
|
|
command |= FTRACE_DISABLE_CALLS;
|
|
|
|
if (saved_ftrace_func != ftrace_trace_function) {
|
|
saved_ftrace_func = ftrace_trace_function;
|
|
command |= FTRACE_UPDATE_TRACE_FUNC;
|
|
}
|
|
|
|
if (!command || !ftrace_enabled)
|
|
goto out;
|
|
|
|
ftrace_run_update_code(command);
|
|
out:
|
|
mutex_unlock(&ftrace_start_lock);
|
|
}
|
|
|
|
static void ftrace_startup_sysctl(void)
|
|
{
|
|
int command = FTRACE_ENABLE_MCOUNT;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
/* Force update next time */
|
|
saved_ftrace_func = NULL;
|
|
/* ftrace_start_up is true if we want ftrace running */
|
|
if (ftrace_start_up)
|
|
command |= FTRACE_ENABLE_CALLS;
|
|
|
|
ftrace_run_update_code(command);
|
|
mutex_unlock(&ftrace_start_lock);
|
|
}
|
|
|
|
static void ftrace_shutdown_sysctl(void)
|
|
{
|
|
int command = FTRACE_DISABLE_MCOUNT;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
/* ftrace_start_up is true if ftrace is running */
|
|
if (ftrace_start_up)
|
|
command |= FTRACE_DISABLE_CALLS;
|
|
|
|
ftrace_run_update_code(command);
|
|
mutex_unlock(&ftrace_start_lock);
|
|
}
|
|
|
|
static cycle_t ftrace_update_time;
|
|
static unsigned long ftrace_update_cnt;
|
|
unsigned long ftrace_update_tot_cnt;
|
|
|
|
static int ftrace_update_code(struct module *mod)
|
|
{
|
|
struct dyn_ftrace *p, *t;
|
|
cycle_t start, stop;
|
|
|
|
start = ftrace_now(raw_smp_processor_id());
|
|
ftrace_update_cnt = 0;
|
|
|
|
list_for_each_entry_safe(p, t, &ftrace_new_addrs, list) {
|
|
|
|
/* If something went wrong, bail without enabling anything */
|
|
if (unlikely(ftrace_disabled))
|
|
return -1;
|
|
|
|
list_del_init(&p->list);
|
|
|
|
/* convert record (i.e, patch mcount-call with NOP) */
|
|
if (ftrace_code_disable(mod, p)) {
|
|
p->flags |= FTRACE_FL_CONVERTED;
|
|
ftrace_update_cnt++;
|
|
} else
|
|
ftrace_free_rec(p);
|
|
}
|
|
|
|
stop = ftrace_now(raw_smp_processor_id());
|
|
ftrace_update_time = stop - start;
|
|
ftrace_update_tot_cnt += ftrace_update_cnt;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
|
|
{
|
|
struct ftrace_page *pg;
|
|
int cnt;
|
|
int i;
|
|
|
|
/* allocate a few pages */
|
|
ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
|
|
if (!ftrace_pages_start)
|
|
return -1;
|
|
|
|
/*
|
|
* Allocate a few more pages.
|
|
*
|
|
* TODO: have some parser search vmlinux before
|
|
* final linking to find all calls to ftrace.
|
|
* Then we can:
|
|
* a) know how many pages to allocate.
|
|
* and/or
|
|
* b) set up the table then.
|
|
*
|
|
* The dynamic code is still necessary for
|
|
* modules.
|
|
*/
|
|
|
|
pg = ftrace_pages = ftrace_pages_start;
|
|
|
|
cnt = num_to_init / ENTRIES_PER_PAGE;
|
|
pr_info("ftrace: allocating %ld entries in %d pages\n",
|
|
num_to_init, cnt);
|
|
|
|
for (i = 0; i < cnt; i++) {
|
|
pg->next = (void *)get_zeroed_page(GFP_KERNEL);
|
|
|
|
/* If we fail, we'll try later anyway */
|
|
if (!pg->next)
|
|
break;
|
|
|
|
pg = pg->next;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
enum {
|
|
FTRACE_ITER_FILTER = (1 << 0),
|
|
FTRACE_ITER_CONT = (1 << 1),
|
|
FTRACE_ITER_NOTRACE = (1 << 2),
|
|
FTRACE_ITER_FAILURES = (1 << 3),
|
|
};
|
|
|
|
#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
|
|
|
|
struct ftrace_iterator {
|
|
loff_t pos;
|
|
struct ftrace_page *pg;
|
|
unsigned idx;
|
|
unsigned flags;
|
|
unsigned char buffer[FTRACE_BUFF_MAX+1];
|
|
unsigned buffer_idx;
|
|
unsigned filtered;
|
|
};
|
|
|
|
static void *
|
|
t_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
struct dyn_ftrace *rec = NULL;
|
|
|
|
(*pos)++;
|
|
|
|
/* should not be called from interrupt context */
|
|
spin_lock(&ftrace_lock);
|
|
retry:
|
|
if (iter->idx >= iter->pg->index) {
|
|
if (iter->pg->next) {
|
|
iter->pg = iter->pg->next;
|
|
iter->idx = 0;
|
|
goto retry;
|
|
}
|
|
} else {
|
|
rec = &iter->pg->records[iter->idx++];
|
|
if ((rec->flags & FTRACE_FL_FREE) ||
|
|
|
|
(!(iter->flags & FTRACE_ITER_FAILURES) &&
|
|
(rec->flags & FTRACE_FL_FAILED)) ||
|
|
|
|
((iter->flags & FTRACE_ITER_FAILURES) &&
|
|
!(rec->flags & FTRACE_FL_FAILED)) ||
|
|
|
|
((iter->flags & FTRACE_ITER_FILTER) &&
|
|
!(rec->flags & FTRACE_FL_FILTER)) ||
|
|
|
|
((iter->flags & FTRACE_ITER_NOTRACE) &&
|
|
!(rec->flags & FTRACE_FL_NOTRACE))) {
|
|
rec = NULL;
|
|
goto retry;
|
|
}
|
|
}
|
|
spin_unlock(&ftrace_lock);
|
|
|
|
iter->pos = *pos;
|
|
|
|
return rec;
|
|
}
|
|
|
|
static void *t_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
struct ftrace_iterator *iter = m->private;
|
|
void *p = NULL;
|
|
loff_t l = -1;
|
|
|
|
if (*pos != iter->pos) {
|
|
for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
|
|
;
|
|
} else {
|
|
l = *pos;
|
|
p = t_next(m, p, &l);
|
|
}
|
|
|
|
return p;
|
|
}
|
|
|
|
static void t_stop(struct seq_file *m, void *p)
|
|
{
|
|
}
|
|
|
|
static int t_show(struct seq_file *m, void *v)
|
|
{
|
|
struct dyn_ftrace *rec = v;
|
|
char str[KSYM_SYMBOL_LEN];
|
|
|
|
if (!rec)
|
|
return 0;
|
|
|
|
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
|
|
|
|
seq_printf(m, "%s\n", str);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct seq_operations show_ftrace_seq_ops = {
|
|
.start = t_start,
|
|
.next = t_next,
|
|
.stop = t_stop,
|
|
.show = t_show,
|
|
};
|
|
|
|
static int
|
|
ftrace_avail_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct ftrace_iterator *iter;
|
|
int ret;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -ENODEV;
|
|
|
|
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
|
|
if (!iter)
|
|
return -ENOMEM;
|
|
|
|
iter->pg = ftrace_pages_start;
|
|
iter->pos = -1;
|
|
|
|
ret = seq_open(file, &show_ftrace_seq_ops);
|
|
if (!ret) {
|
|
struct seq_file *m = file->private_data;
|
|
|
|
m->private = iter;
|
|
} else {
|
|
kfree(iter);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
int ftrace_avail_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct seq_file *m = (struct seq_file *)file->private_data;
|
|
struct ftrace_iterator *iter = m->private;
|
|
|
|
seq_release(inode, file);
|
|
kfree(iter);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
ftrace_failures_open(struct inode *inode, struct file *file)
|
|
{
|
|
int ret;
|
|
struct seq_file *m;
|
|
struct ftrace_iterator *iter;
|
|
|
|
ret = ftrace_avail_open(inode, file);
|
|
if (!ret) {
|
|
m = (struct seq_file *)file->private_data;
|
|
iter = (struct ftrace_iterator *)m->private;
|
|
iter->flags = FTRACE_ITER_FAILURES;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
|
|
static void ftrace_filter_reset(int enable)
|
|
{
|
|
struct ftrace_page *pg;
|
|
struct dyn_ftrace *rec;
|
|
unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
|
|
unsigned i;
|
|
|
|
/* should not be called from interrupt context */
|
|
spin_lock(&ftrace_lock);
|
|
if (enable)
|
|
ftrace_filtered = 0;
|
|
pg = ftrace_pages_start;
|
|
while (pg) {
|
|
for (i = 0; i < pg->index; i++) {
|
|
rec = &pg->records[i];
|
|
if (rec->flags & FTRACE_FL_FAILED)
|
|
continue;
|
|
rec->flags &= ~type;
|
|
}
|
|
pg = pg->next;
|
|
}
|
|
spin_unlock(&ftrace_lock);
|
|
}
|
|
|
|
static int
|
|
ftrace_regex_open(struct inode *inode, struct file *file, int enable)
|
|
{
|
|
struct ftrace_iterator *iter;
|
|
int ret = 0;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -ENODEV;
|
|
|
|
iter = kzalloc(sizeof(*iter), GFP_KERNEL);
|
|
if (!iter)
|
|
return -ENOMEM;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
if ((file->f_mode & FMODE_WRITE) &&
|
|
!(file->f_flags & O_APPEND))
|
|
ftrace_filter_reset(enable);
|
|
|
|
if (file->f_mode & FMODE_READ) {
|
|
iter->pg = ftrace_pages_start;
|
|
iter->pos = -1;
|
|
iter->flags = enable ? FTRACE_ITER_FILTER :
|
|
FTRACE_ITER_NOTRACE;
|
|
|
|
ret = seq_open(file, &show_ftrace_seq_ops);
|
|
if (!ret) {
|
|
struct seq_file *m = file->private_data;
|
|
m->private = iter;
|
|
} else
|
|
kfree(iter);
|
|
} else
|
|
file->private_data = iter;
|
|
mutex_unlock(&ftrace_regex_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
ftrace_filter_open(struct inode *inode, struct file *file)
|
|
{
|
|
return ftrace_regex_open(inode, file, 1);
|
|
}
|
|
|
|
static int
|
|
ftrace_notrace_open(struct inode *inode, struct file *file)
|
|
{
|
|
return ftrace_regex_open(inode, file, 0);
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_regex_read(struct file *file, char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
if (file->f_mode & FMODE_READ)
|
|
return seq_read(file, ubuf, cnt, ppos);
|
|
else
|
|
return -EPERM;
|
|
}
|
|
|
|
static loff_t
|
|
ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
|
|
{
|
|
loff_t ret;
|
|
|
|
if (file->f_mode & FMODE_READ)
|
|
ret = seq_lseek(file, offset, origin);
|
|
else
|
|
file->f_pos = ret = 1;
|
|
|
|
return ret;
|
|
}
|
|
|
|
enum {
|
|
MATCH_FULL,
|
|
MATCH_FRONT_ONLY,
|
|
MATCH_MIDDLE_ONLY,
|
|
MATCH_END_ONLY,
|
|
};
|
|
|
|
static void
|
|
ftrace_match(unsigned char *buff, int len, int enable)
|
|
{
|
|
char str[KSYM_SYMBOL_LEN];
|
|
char *search = NULL;
|
|
struct ftrace_page *pg;
|
|
struct dyn_ftrace *rec;
|
|
int type = MATCH_FULL;
|
|
unsigned long flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
|
|
unsigned i, match = 0, search_len = 0;
|
|
|
|
for (i = 0; i < len; i++) {
|
|
if (buff[i] == '*') {
|
|
if (!i) {
|
|
search = buff + i + 1;
|
|
type = MATCH_END_ONLY;
|
|
search_len = len - (i + 1);
|
|
} else {
|
|
if (type == MATCH_END_ONLY) {
|
|
type = MATCH_MIDDLE_ONLY;
|
|
} else {
|
|
match = i;
|
|
type = MATCH_FRONT_ONLY;
|
|
}
|
|
buff[i] = 0;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* should not be called from interrupt context */
|
|
spin_lock(&ftrace_lock);
|
|
if (enable)
|
|
ftrace_filtered = 1;
|
|
pg = ftrace_pages_start;
|
|
while (pg) {
|
|
for (i = 0; i < pg->index; i++) {
|
|
int matched = 0;
|
|
char *ptr;
|
|
|
|
rec = &pg->records[i];
|
|
if (rec->flags & FTRACE_FL_FAILED)
|
|
continue;
|
|
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
|
|
switch (type) {
|
|
case MATCH_FULL:
|
|
if (strcmp(str, buff) == 0)
|
|
matched = 1;
|
|
break;
|
|
case MATCH_FRONT_ONLY:
|
|
if (memcmp(str, buff, match) == 0)
|
|
matched = 1;
|
|
break;
|
|
case MATCH_MIDDLE_ONLY:
|
|
if (strstr(str, search))
|
|
matched = 1;
|
|
break;
|
|
case MATCH_END_ONLY:
|
|
ptr = strstr(str, search);
|
|
if (ptr && (ptr[search_len] == 0))
|
|
matched = 1;
|
|
break;
|
|
}
|
|
if (matched)
|
|
rec->flags |= flag;
|
|
}
|
|
pg = pg->next;
|
|
}
|
|
spin_unlock(&ftrace_lock);
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_regex_write(struct file *file, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos, int enable)
|
|
{
|
|
struct ftrace_iterator *iter;
|
|
char ch;
|
|
size_t read = 0;
|
|
ssize_t ret;
|
|
|
|
if (!cnt || cnt < 0)
|
|
return 0;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
|
|
if (file->f_mode & FMODE_READ) {
|
|
struct seq_file *m = file->private_data;
|
|
iter = m->private;
|
|
} else
|
|
iter = file->private_data;
|
|
|
|
if (!*ppos) {
|
|
iter->flags &= ~FTRACE_ITER_CONT;
|
|
iter->buffer_idx = 0;
|
|
}
|
|
|
|
ret = get_user(ch, ubuf++);
|
|
if (ret)
|
|
goto out;
|
|
read++;
|
|
cnt--;
|
|
|
|
if (!(iter->flags & ~FTRACE_ITER_CONT)) {
|
|
/* skip white space */
|
|
while (cnt && isspace(ch)) {
|
|
ret = get_user(ch, ubuf++);
|
|
if (ret)
|
|
goto out;
|
|
read++;
|
|
cnt--;
|
|
}
|
|
|
|
if (isspace(ch)) {
|
|
file->f_pos += read;
|
|
ret = read;
|
|
goto out;
|
|
}
|
|
|
|
iter->buffer_idx = 0;
|
|
}
|
|
|
|
while (cnt && !isspace(ch)) {
|
|
if (iter->buffer_idx < FTRACE_BUFF_MAX)
|
|
iter->buffer[iter->buffer_idx++] = ch;
|
|
else {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
ret = get_user(ch, ubuf++);
|
|
if (ret)
|
|
goto out;
|
|
read++;
|
|
cnt--;
|
|
}
|
|
|
|
if (isspace(ch)) {
|
|
iter->filtered++;
|
|
iter->buffer[iter->buffer_idx] = 0;
|
|
ftrace_match(iter->buffer, iter->buffer_idx, enable);
|
|
iter->buffer_idx = 0;
|
|
} else
|
|
iter->flags |= FTRACE_ITER_CONT;
|
|
|
|
|
|
file->f_pos += read;
|
|
|
|
ret = read;
|
|
out:
|
|
mutex_unlock(&ftrace_regex_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_filter_write(struct file *file, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
|
|
}
|
|
|
|
static ssize_t
|
|
ftrace_notrace_write(struct file *file, const char __user *ubuf,
|
|
size_t cnt, loff_t *ppos)
|
|
{
|
|
return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
|
|
}
|
|
|
|
static void
|
|
ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
|
|
{
|
|
if (unlikely(ftrace_disabled))
|
|
return;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
if (reset)
|
|
ftrace_filter_reset(enable);
|
|
if (buf)
|
|
ftrace_match(buf, len, enable);
|
|
mutex_unlock(&ftrace_regex_lock);
|
|
}
|
|
|
|
/**
|
|
* ftrace_set_filter - set a function to filter on in ftrace
|
|
* @buf - the string that holds the function filter text.
|
|
* @len - the length of the string.
|
|
* @reset - non zero to reset all filters before applying this filter.
|
|
*
|
|
* Filters denote which functions should be enabled when tracing is enabled.
|
|
* If @buf is NULL and reset is set, all functions will be enabled for tracing.
|
|
*/
|
|
void ftrace_set_filter(unsigned char *buf, int len, int reset)
|
|
{
|
|
ftrace_set_regex(buf, len, reset, 1);
|
|
}
|
|
|
|
/**
|
|
* ftrace_set_notrace - set a function to not trace in ftrace
|
|
* @buf - the string that holds the function notrace text.
|
|
* @len - the length of the string.
|
|
* @reset - non zero to reset all filters before applying this filter.
|
|
*
|
|
* Notrace Filters denote which functions should not be enabled when tracing
|
|
* is enabled. If @buf is NULL and reset is set, all functions will be enabled
|
|
* for tracing.
|
|
*/
|
|
void ftrace_set_notrace(unsigned char *buf, int len, int reset)
|
|
{
|
|
ftrace_set_regex(buf, len, reset, 0);
|
|
}
|
|
|
|
static int
|
|
ftrace_regex_release(struct inode *inode, struct file *file, int enable)
|
|
{
|
|
struct seq_file *m = (struct seq_file *)file->private_data;
|
|
struct ftrace_iterator *iter;
|
|
|
|
mutex_lock(&ftrace_regex_lock);
|
|
if (file->f_mode & FMODE_READ) {
|
|
iter = m->private;
|
|
|
|
seq_release(inode, file);
|
|
} else
|
|
iter = file->private_data;
|
|
|
|
if (iter->buffer_idx) {
|
|
iter->filtered++;
|
|
iter->buffer[iter->buffer_idx] = 0;
|
|
ftrace_match(iter->buffer, iter->buffer_idx, enable);
|
|
}
|
|
|
|
mutex_lock(&ftrace_sysctl_lock);
|
|
mutex_lock(&ftrace_start_lock);
|
|
if (iter->filtered && ftrace_start_up && ftrace_enabled)
|
|
ftrace_run_update_code(FTRACE_ENABLE_CALLS);
|
|
mutex_unlock(&ftrace_start_lock);
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
|
|
kfree(iter);
|
|
mutex_unlock(&ftrace_regex_lock);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
ftrace_filter_release(struct inode *inode, struct file *file)
|
|
{
|
|
return ftrace_regex_release(inode, file, 1);
|
|
}
|
|
|
|
static int
|
|
ftrace_notrace_release(struct inode *inode, struct file *file)
|
|
{
|
|
return ftrace_regex_release(inode, file, 0);
|
|
}
|
|
|
|
static struct file_operations ftrace_avail_fops = {
|
|
.open = ftrace_avail_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = ftrace_avail_release,
|
|
};
|
|
|
|
static struct file_operations ftrace_failures_fops = {
|
|
.open = ftrace_failures_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = ftrace_avail_release,
|
|
};
|
|
|
|
static struct file_operations ftrace_filter_fops = {
|
|
.open = ftrace_filter_open,
|
|
.read = ftrace_regex_read,
|
|
.write = ftrace_filter_write,
|
|
.llseek = ftrace_regex_lseek,
|
|
.release = ftrace_filter_release,
|
|
};
|
|
|
|
static struct file_operations ftrace_notrace_fops = {
|
|
.open = ftrace_notrace_open,
|
|
.read = ftrace_regex_read,
|
|
.write = ftrace_notrace_write,
|
|
.llseek = ftrace_regex_lseek,
|
|
.release = ftrace_notrace_release,
|
|
};
|
|
|
|
static __init int ftrace_init_debugfs(void)
|
|
{
|
|
struct dentry *d_tracer;
|
|
struct dentry *entry;
|
|
|
|
d_tracer = tracing_init_dentry();
|
|
|
|
entry = debugfs_create_file("available_filter_functions", 0444,
|
|
d_tracer, NULL, &ftrace_avail_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs "
|
|
"'available_filter_functions' entry\n");
|
|
|
|
entry = debugfs_create_file("failures", 0444,
|
|
d_tracer, NULL, &ftrace_failures_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs 'failures' entry\n");
|
|
|
|
entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
|
|
NULL, &ftrace_filter_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs "
|
|
"'set_ftrace_filter' entry\n");
|
|
|
|
entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
|
|
NULL, &ftrace_notrace_fops);
|
|
if (!entry)
|
|
pr_warning("Could not create debugfs "
|
|
"'set_ftrace_notrace' entry\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
fs_initcall(ftrace_init_debugfs);
|
|
|
|
static int ftrace_convert_nops(struct module *mod,
|
|
unsigned long *start,
|
|
unsigned long *end)
|
|
{
|
|
unsigned long *p;
|
|
unsigned long addr;
|
|
unsigned long flags;
|
|
|
|
mutex_lock(&ftrace_start_lock);
|
|
p = start;
|
|
while (p < end) {
|
|
addr = ftrace_call_adjust(*p++);
|
|
/*
|
|
* Some architecture linkers will pad between
|
|
* the different mcount_loc sections of different
|
|
* object files to satisfy alignments.
|
|
* Skip any NULL pointers.
|
|
*/
|
|
if (!addr)
|
|
continue;
|
|
ftrace_record_ip(addr);
|
|
}
|
|
|
|
/* disable interrupts to prevent kstop machine */
|
|
local_irq_save(flags);
|
|
ftrace_update_code(mod);
|
|
local_irq_restore(flags);
|
|
mutex_unlock(&ftrace_start_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void ftrace_init_module(struct module *mod,
|
|
unsigned long *start, unsigned long *end)
|
|
{
|
|
if (ftrace_disabled || start == end)
|
|
return;
|
|
ftrace_convert_nops(mod, start, end);
|
|
}
|
|
|
|
extern unsigned long __start_mcount_loc[];
|
|
extern unsigned long __stop_mcount_loc[];
|
|
|
|
void __init ftrace_init(void)
|
|
{
|
|
unsigned long count, addr, flags;
|
|
int ret;
|
|
|
|
/* Keep the ftrace pointer to the stub */
|
|
addr = (unsigned long)ftrace_stub;
|
|
|
|
local_irq_save(flags);
|
|
ftrace_dyn_arch_init(&addr);
|
|
local_irq_restore(flags);
|
|
|
|
/* ftrace_dyn_arch_init places the return code in addr */
|
|
if (addr)
|
|
goto failed;
|
|
|
|
count = __stop_mcount_loc - __start_mcount_loc;
|
|
|
|
ret = ftrace_dyn_table_alloc(count);
|
|
if (ret)
|
|
goto failed;
|
|
|
|
last_ftrace_enabled = ftrace_enabled = 1;
|
|
|
|
ret = ftrace_convert_nops(NULL,
|
|
__start_mcount_loc,
|
|
__stop_mcount_loc);
|
|
|
|
return;
|
|
failed:
|
|
ftrace_disabled = 1;
|
|
}
|
|
|
|
#else
|
|
|
|
static int __init ftrace_nodyn_init(void)
|
|
{
|
|
ftrace_enabled = 1;
|
|
return 0;
|
|
}
|
|
device_initcall(ftrace_nodyn_init);
|
|
|
|
# define ftrace_startup() do { } while (0)
|
|
# define ftrace_shutdown() do { } while (0)
|
|
# define ftrace_startup_sysctl() do { } while (0)
|
|
# define ftrace_shutdown_sysctl() do { } while (0)
|
|
#endif /* CONFIG_DYNAMIC_FTRACE */
|
|
|
|
/**
|
|
* ftrace_kill - kill ftrace
|
|
*
|
|
* This function should be used by panic code. It stops ftrace
|
|
* but in a not so nice way. If you need to simply kill ftrace
|
|
* from a non-atomic section, use ftrace_kill.
|
|
*/
|
|
void ftrace_kill(void)
|
|
{
|
|
ftrace_disabled = 1;
|
|
ftrace_enabled = 0;
|
|
clear_ftrace_function();
|
|
}
|
|
|
|
/**
|
|
* register_ftrace_function - register a function for profiling
|
|
* @ops - ops structure that holds the function for profiling.
|
|
*
|
|
* Register a function to be called by all functions in the
|
|
* kernel.
|
|
*
|
|
* Note: @ops->func and all the functions it calls must be labeled
|
|
* with "notrace", otherwise it will go into a
|
|
* recursive loop.
|
|
*/
|
|
int register_ftrace_function(struct ftrace_ops *ops)
|
|
{
|
|
int ret;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -1;
|
|
|
|
mutex_lock(&ftrace_sysctl_lock);
|
|
ret = __register_ftrace_function(ops);
|
|
ftrace_startup();
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* unregister_ftrace_function - unresgister a function for profiling.
|
|
* @ops - ops structure that holds the function to unregister
|
|
*
|
|
* Unregister a function that was added to be called by ftrace profiling.
|
|
*/
|
|
int unregister_ftrace_function(struct ftrace_ops *ops)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&ftrace_sysctl_lock);
|
|
ret = __unregister_ftrace_function(ops);
|
|
ftrace_shutdown();
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
int
|
|
ftrace_enable_sysctl(struct ctl_table *table, int write,
|
|
struct file *file, void __user *buffer, size_t *lenp,
|
|
loff_t *ppos)
|
|
{
|
|
int ret;
|
|
|
|
if (unlikely(ftrace_disabled))
|
|
return -ENODEV;
|
|
|
|
mutex_lock(&ftrace_sysctl_lock);
|
|
|
|
ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
|
|
|
|
if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
|
|
goto out;
|
|
|
|
last_ftrace_enabled = ftrace_enabled;
|
|
|
|
if (ftrace_enabled) {
|
|
|
|
ftrace_startup_sysctl();
|
|
|
|
/* we are starting ftrace again */
|
|
if (ftrace_list != &ftrace_list_end) {
|
|
if (ftrace_list->next == &ftrace_list_end)
|
|
ftrace_trace_function = ftrace_list->func;
|
|
else
|
|
ftrace_trace_function = ftrace_list_func;
|
|
}
|
|
|
|
} else {
|
|
/* stopping ftrace calls (just send to ftrace_stub) */
|
|
ftrace_trace_function = ftrace_stub;
|
|
|
|
ftrace_shutdown_sysctl();
|
|
}
|
|
|
|
out:
|
|
mutex_unlock(&ftrace_sysctl_lock);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_FUNCTION_RET_TRACER
|
|
trace_function_return_t ftrace_function_return =
|
|
(trace_function_return_t)ftrace_stub;
|
|
void register_ftrace_return(trace_function_return_t func)
|
|
{
|
|
ftrace_function_return = func;
|
|
}
|
|
|
|
void unregister_ftrace_return(void)
|
|
{
|
|
ftrace_function_return = (trace_function_return_t)ftrace_stub;
|
|
}
|
|
#endif
|
|
|
|
|
|
|