1
2
3#include <linux/context_tracking.h>
4#include <linux/entry-common.h>
5#include <linux/highmem.h>
6#include <linux/livepatch.h>
7#include <linux/audit.h>
8
9#include "common.h"
10
11#define CREATE_TRACE_POINTS
12#include <trace/events/syscalls.h>
13
14
15static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
16{
17 arch_check_user_regs(regs);
18 lockdep_hardirqs_off(CALLER_ADDR0);
19
20 CT_WARN_ON(ct_state() != CONTEXT_USER);
21 user_exit_irqoff();
22
23 instrumentation_begin();
24 trace_hardirqs_off_finish();
25 instrumentation_end();
26}
27
28void noinstr enter_from_user_mode(struct pt_regs *regs)
29{
30 __enter_from_user_mode(regs);
31}
32
33static inline void syscall_enter_audit(struct pt_regs *regs, long syscall)
34{
35 if (unlikely(audit_context())) {
36 unsigned long args[6];
37
38 syscall_get_arguments(current, regs, args);
39 audit_syscall_entry(syscall, args[0], args[1], args[2], args[3]);
40 }
41}
42
43static long syscall_trace_enter(struct pt_regs *regs, long syscall,
44 unsigned long work)
45{
46 long ret = 0;
47
48
49
50
51
52
53 if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
54 if (syscall_user_dispatch(regs))
55 return -1L;
56 }
57
58
59 if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
60 ret = arch_syscall_enter_tracehook(regs);
61 if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
62 return -1L;
63 }
64
65
66 if (work & SYSCALL_WORK_SECCOMP) {
67 ret = __secure_computing(NULL);
68 if (ret == -1L)
69 return ret;
70 }
71
72
73 syscall = syscall_get_nr(current, regs);
74
75 if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT))
76 trace_sys_enter(regs, syscall);
77
78 syscall_enter_audit(regs, syscall);
79
80 return ret ? : syscall;
81}
82
83static __always_inline long
84__syscall_enter_from_user_work(struct pt_regs *regs, long syscall)
85{
86 unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
87
88 if (work & SYSCALL_WORK_ENTER)
89 syscall = syscall_trace_enter(regs, syscall, work);
90
91 return syscall;
92}
93
94long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall)
95{
96 return __syscall_enter_from_user_work(regs, syscall);
97}
98
99noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
100{
101 long ret;
102
103 __enter_from_user_mode(regs);
104
105 instrumentation_begin();
106 local_irq_enable();
107 ret = __syscall_enter_from_user_work(regs, syscall);
108 instrumentation_end();
109
110 return ret;
111}
112
113noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs)
114{
115 __enter_from_user_mode(regs);
116 instrumentation_begin();
117 local_irq_enable();
118 instrumentation_end();
119}
120
121
122static __always_inline void __exit_to_user_mode(void)
123{
124 instrumentation_begin();
125 trace_hardirqs_on_prepare();
126 lockdep_hardirqs_on_prepare(CALLER_ADDR0);
127 instrumentation_end();
128
129 user_enter_irqoff();
130 arch_exit_to_user_mode();
131 lockdep_hardirqs_on(CALLER_ADDR0);
132}
133
134void noinstr exit_to_user_mode(void)
135{
136 __exit_to_user_mode();
137}
138
139
140void __weak arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) { }
141
142static void handle_signal_work(struct pt_regs *regs, unsigned long ti_work)
143{
144 if (ti_work & _TIF_NOTIFY_SIGNAL)
145 tracehook_notify_signal();
146
147 arch_do_signal_or_restart(regs, ti_work & _TIF_SIGPENDING);
148}
149
150static unsigned long exit_to_user_mode_loop(struct pt_regs *regs,
151 unsigned long ti_work)
152{
153
154
155
156
157 while (ti_work & EXIT_TO_USER_MODE_WORK) {
158
159 local_irq_enable_exit_to_user(ti_work);
160
161 if (ti_work & _TIF_NEED_RESCHED)
162 schedule();
163
164 if (ti_work & _TIF_UPROBE)
165 uprobe_notify_resume(regs);
166
167 if (ti_work & _TIF_PATCH_PENDING)
168 klp_update_patch_state(current);
169
170 if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
171 handle_signal_work(regs, ti_work);
172
173 if (ti_work & _TIF_NOTIFY_RESUME) {
174 tracehook_notify_resume(regs);
175 rseq_handle_notify_resume(NULL, regs);
176 }
177
178
179 arch_exit_to_user_mode_work(regs, ti_work);
180
181
182
183
184
185
186 local_irq_disable_exit_to_user();
187
188
189 rcu_nocb_flush_deferred_wakeup();
190
191 ti_work = READ_ONCE(current_thread_info()->flags);
192 }
193
194
195 return ti_work;
196}
197
198static void exit_to_user_mode_prepare(struct pt_regs *regs)
199{
200 unsigned long ti_work = READ_ONCE(current_thread_info()->flags);
201
202 lockdep_assert_irqs_disabled();
203
204
205 rcu_nocb_flush_deferred_wakeup();
206
207 if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK))
208 ti_work = exit_to_user_mode_loop(regs, ti_work);
209
210 arch_exit_to_user_mode_prepare(regs, ti_work);
211
212
213 addr_limit_user_check();
214 kmap_assert_nomap();
215 lockdep_assert_irqs_disabled();
216 lockdep_sys_exit();
217}
218
219
220
221
222
223
224static inline bool report_single_step(unsigned long work)
225{
226 if (work & SYSCALL_WORK_SYSCALL_EMU)
227 return false;
228
229 return work & SYSCALL_WORK_SYSCALL_EXIT_TRAP;
230}
231
232static void syscall_exit_work(struct pt_regs *regs, unsigned long work)
233{
234 bool step;
235
236
237
238
239
240
241
242 if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) {
243 if (unlikely(current->syscall_dispatch.on_dispatch)) {
244 current->syscall_dispatch.on_dispatch = false;
245 return;
246 }
247 }
248
249 audit_syscall_exit(regs);
250
251 if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT)
252 trace_sys_exit(regs, syscall_get_return_value(current, regs));
253
254 step = report_single_step(work);
255 if (step || work & SYSCALL_WORK_SYSCALL_TRACE)
256 arch_syscall_exit_tracehook(regs, step);
257}
258
259
260
261
262
263static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs)
264{
265 unsigned long work = READ_ONCE(current_thread_info()->syscall_work);
266 unsigned long nr = syscall_get_nr(current, regs);
267
268 CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
269
270 if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
271 if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr))
272 local_irq_enable();
273 }
274
275 rseq_syscall(regs);
276
277
278
279
280
281
282 if (unlikely(work & SYSCALL_WORK_EXIT))
283 syscall_exit_work(regs, work);
284}
285
286static __always_inline void __syscall_exit_to_user_mode_work(struct pt_regs *regs)
287{
288 syscall_exit_to_user_mode_prepare(regs);
289 local_irq_disable_exit_to_user();
290 exit_to_user_mode_prepare(regs);
291}
292
293void syscall_exit_to_user_mode_work(struct pt_regs *regs)
294{
295 __syscall_exit_to_user_mode_work(regs);
296}
297
298__visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs)
299{
300 instrumentation_begin();
301 __syscall_exit_to_user_mode_work(regs);
302 instrumentation_end();
303 __exit_to_user_mode();
304}
305
306noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs)
307{
308 __enter_from_user_mode(regs);
309}
310
311noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs)
312{
313 instrumentation_begin();
314 exit_to_user_mode_prepare(regs);
315 instrumentation_end();
316 __exit_to_user_mode();
317}
318
319noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
320{
321 irqentry_state_t ret = {
322 .exit_rcu = false,
323 };
324
325 if (user_mode(regs)) {
326 irqentry_enter_from_user_mode(regs);
327 return ret;
328 }
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353 if (!IS_ENABLED(CONFIG_TINY_RCU) && is_idle_task(current)) {
354
355
356
357
358
359 lockdep_hardirqs_off(CALLER_ADDR0);
360 rcu_irq_enter();
361 instrumentation_begin();
362 trace_hardirqs_off_finish();
363 instrumentation_end();
364
365 ret.exit_rcu = true;
366 return ret;
367 }
368
369
370
371
372
373
374
375 lockdep_hardirqs_off(CALLER_ADDR0);
376 instrumentation_begin();
377 rcu_irq_enter_check_tick();
378 trace_hardirqs_off_finish();
379 instrumentation_end();
380
381 return ret;
382}
383
384void irqentry_exit_cond_resched(void)
385{
386 if (!preempt_count()) {
387
388 rcu_irq_exit_check_preempt();
389 if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
390 WARN_ON_ONCE(!on_thread_stack());
391 if (need_resched())
392 preempt_schedule_irq();
393 }
394}
395#ifdef CONFIG_PREEMPT_DYNAMIC
396DEFINE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched);
397#endif
398
399noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
400{
401 lockdep_assert_irqs_disabled();
402
403
404 if (user_mode(regs)) {
405 irqentry_exit_to_user_mode(regs);
406 } else if (!regs_irqs_disabled(regs)) {
407
408
409
410
411
412 if (state.exit_rcu) {
413 instrumentation_begin();
414
415 trace_hardirqs_on_prepare();
416 lockdep_hardirqs_on_prepare(CALLER_ADDR0);
417 instrumentation_end();
418 rcu_irq_exit();
419 lockdep_hardirqs_on(CALLER_ADDR0);
420 return;
421 }
422
423 instrumentation_begin();
424 if (IS_ENABLED(CONFIG_PREEMPTION)) {
425#ifdef CONFIG_PREEMPT_DYNAMIC
426 static_call(irqentry_exit_cond_resched)();
427#else
428 irqentry_exit_cond_resched();
429#endif
430 }
431
432 trace_hardirqs_on();
433 instrumentation_end();
434 } else {
435
436
437
438
439 if (state.exit_rcu)
440 rcu_irq_exit();
441 }
442}
443
444irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs)
445{
446 irqentry_state_t irq_state;
447
448 irq_state.lockdep = lockdep_hardirqs_enabled();
449
450 __nmi_enter();
451 lockdep_hardirqs_off(CALLER_ADDR0);
452 lockdep_hardirq_enter();
453 rcu_nmi_enter();
454
455 instrumentation_begin();
456 trace_hardirqs_off_finish();
457 ftrace_nmi_enter();
458 instrumentation_end();
459
460 return irq_state;
461}
462
463void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state)
464{
465 instrumentation_begin();
466 ftrace_nmi_exit();
467 if (irq_state.lockdep) {
468 trace_hardirqs_on_prepare();
469 lockdep_hardirqs_on_prepare(CALLER_ADDR0);
470 }
471 instrumentation_end();
472
473 rcu_nmi_exit();
474 lockdep_hardirq_exit();
475 if (irq_state.lockdep)
476 lockdep_hardirqs_on(CALLER_ADDR0);
477 __nmi_exit();
478}
479