cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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trace_sched_switch.c (3180B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * trace context switch
      4 *
      5 * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
      6 *
      7 */
      8#include <linux/module.h>
      9#include <linux/kallsyms.h>
     10#include <linux/uaccess.h>
     11#include <linux/ftrace.h>
     12#include <trace/events/sched.h>
     13
     14#include "trace.h"
     15
     16#define RECORD_CMDLINE	1
     17#define RECORD_TGID	2
     18
     19static int		sched_cmdline_ref;
     20static int		sched_tgid_ref;
     21static DEFINE_MUTEX(sched_register_mutex);
     22
     23static void
     24probe_sched_switch(void *ignore, bool preempt,
     25		   struct task_struct *prev, struct task_struct *next,
     26		   unsigned int prev_state)
     27{
     28	int flags;
     29
     30	flags = (RECORD_TGID * !!sched_tgid_ref) +
     31		(RECORD_CMDLINE * !!sched_cmdline_ref);
     32
     33	if (!flags)
     34		return;
     35	tracing_record_taskinfo_sched_switch(prev, next, flags);
     36}
     37
     38static void
     39probe_sched_wakeup(void *ignore, struct task_struct *wakee)
     40{
     41	int flags;
     42
     43	flags = (RECORD_TGID * !!sched_tgid_ref) +
     44		(RECORD_CMDLINE * !!sched_cmdline_ref);
     45
     46	if (!flags)
     47		return;
     48	tracing_record_taskinfo_sched_switch(current, wakee, flags);
     49}
     50
     51static int tracing_sched_register(void)
     52{
     53	int ret;
     54
     55	ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL);
     56	if (ret) {
     57		pr_info("wakeup trace: Couldn't activate tracepoint"
     58			" probe to kernel_sched_wakeup\n");
     59		return ret;
     60	}
     61
     62	ret = register_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
     63	if (ret) {
     64		pr_info("wakeup trace: Couldn't activate tracepoint"
     65			" probe to kernel_sched_wakeup_new\n");
     66		goto fail_deprobe;
     67	}
     68
     69	ret = register_trace_sched_switch(probe_sched_switch, NULL);
     70	if (ret) {
     71		pr_info("sched trace: Couldn't activate tracepoint"
     72			" probe to kernel_sched_switch\n");
     73		goto fail_deprobe_wake_new;
     74	}
     75
     76	return ret;
     77fail_deprobe_wake_new:
     78	unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
     79fail_deprobe:
     80	unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
     81	return ret;
     82}
     83
     84static void tracing_sched_unregister(void)
     85{
     86	unregister_trace_sched_switch(probe_sched_switch, NULL);
     87	unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL);
     88	unregister_trace_sched_wakeup(probe_sched_wakeup, NULL);
     89}
     90
     91static void tracing_start_sched_switch(int ops)
     92{
     93	bool sched_register;
     94
     95	mutex_lock(&sched_register_mutex);
     96	sched_register = (!sched_cmdline_ref && !sched_tgid_ref);
     97
     98	switch (ops) {
     99	case RECORD_CMDLINE:
    100		sched_cmdline_ref++;
    101		break;
    102
    103	case RECORD_TGID:
    104		sched_tgid_ref++;
    105		break;
    106	}
    107
    108	if (sched_register && (sched_cmdline_ref || sched_tgid_ref))
    109		tracing_sched_register();
    110	mutex_unlock(&sched_register_mutex);
    111}
    112
    113static void tracing_stop_sched_switch(int ops)
    114{
    115	mutex_lock(&sched_register_mutex);
    116
    117	switch (ops) {
    118	case RECORD_CMDLINE:
    119		sched_cmdline_ref--;
    120		break;
    121
    122	case RECORD_TGID:
    123		sched_tgid_ref--;
    124		break;
    125	}
    126
    127	if (!sched_cmdline_ref && !sched_tgid_ref)
    128		tracing_sched_unregister();
    129	mutex_unlock(&sched_register_mutex);
    130}
    131
    132void tracing_start_cmdline_record(void)
    133{
    134	tracing_start_sched_switch(RECORD_CMDLINE);
    135}
    136
    137void tracing_stop_cmdline_record(void)
    138{
    139	tracing_stop_sched_switch(RECORD_CMDLINE);
    140}
    141
    142void tracing_start_tgid_record(void)
    143{
    144	tracing_start_sched_switch(RECORD_TGID);
    145}
    146
    147void tracing_stop_tgid_record(void)
    148{
    149	tracing_stop_sched_switch(RECORD_TGID);
    150}