1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ftrace.h>
3 #include <linux/init.h>
4 #include <linux/kernel.h>
5 #include <linux/module.h>
6 #include <linux/rv.h>
7 #include <linux/sched/deadline.h>
8 #include <linux/sched/rt.h>
9 #include <linux/tracepoint.h>
10 #include <rv/instrumentation.h>
11
12 #define MODULE_NAME "pagefault"
13
14 #include <rv_trace.h>
15 #include <trace/events/exceptions.h>
16 #include <monitors/rtapp/rtapp.h>
17
18 #include "pagefault.h"
19 #include <rv/ltl_monitor.h>
20
ltl_atoms_fetch(struct task_struct * task,struct ltl_monitor * mon)21 static void ltl_atoms_fetch(struct task_struct *task, struct ltl_monitor *mon)
22 {
23 /*
24 * This includes "actual" real-time tasks and also PI-boosted
25 * tasks. A task being PI-boosted means it is blocking an "actual"
26 * real-task, therefore it should also obey the monitor's rule,
27 * otherwise the "actual" real-task may be delayed.
28 */
29 ltl_atom_set(mon, LTL_RT, rt_or_dl_task(task));
30 }
31
ltl_atoms_init(struct task_struct * task,struct ltl_monitor * mon,bool task_creation)32 static void ltl_atoms_init(struct task_struct *task, struct ltl_monitor *mon, bool task_creation)
33 {
34 if (task_creation)
35 ltl_atom_set(mon, LTL_PAGEFAULT, false);
36 }
37
handle_page_fault(void * data,unsigned long address,struct pt_regs * regs,unsigned long error_code)38 static void handle_page_fault(void *data, unsigned long address, struct pt_regs *regs,
39 unsigned long error_code)
40 {
41 ltl_atom_pulse(current, LTL_PAGEFAULT, true);
42 }
43
enable_pagefault(void)44 static int enable_pagefault(void)
45 {
46 int retval;
47
48 retval = ltl_monitor_init();
49 if (retval)
50 return retval;
51
52 rv_attach_trace_probe("rtapp_pagefault", page_fault_kernel, handle_page_fault);
53 rv_attach_trace_probe("rtapp_pagefault", page_fault_user, handle_page_fault);
54
55 return 0;
56 }
57
disable_pagefault(void)58 static void disable_pagefault(void)
59 {
60 rv_detach_trace_probe("rtapp_pagefault", page_fault_kernel, handle_page_fault);
61 rv_detach_trace_probe("rtapp_pagefault", page_fault_user, handle_page_fault);
62
63 ltl_monitor_destroy();
64 }
65
66 static struct rv_monitor rv_pagefault = {
67 .name = "pagefault",
68 .description = "Monitor that RT tasks do not raise page faults",
69 .enable = enable_pagefault,
70 .disable = disable_pagefault,
71 };
72
register_pagefault(void)73 static int __init register_pagefault(void)
74 {
75 return rv_register_monitor(&rv_pagefault, &rv_rtapp);
76 }
77
unregister_pagefault(void)78 static void __exit unregister_pagefault(void)
79 {
80 rv_unregister_monitor(&rv_pagefault);
81 }
82
83 module_init(register_pagefault);
84 module_exit(unregister_pagefault);
85
86 MODULE_LICENSE("GPL");
87 MODULE_AUTHOR("Nam Cao <namcao@linutronix.de>");
88 MODULE_DESCRIPTION("pagefault: Monitor that RT tasks do not raise page faults");
89