xref: /linux/include/linux/entry-common.h (revision b6be002bcd1dd1dedb926abf3c90c794eacb77dc)
1142781e1SThomas Gleixner /* SPDX-License-Identifier: GPL-2.0 */
2142781e1SThomas Gleixner #ifndef __LINUX_ENTRYCOMMON_H
3142781e1SThomas Gleixner #define __LINUX_ENTRYCOMMON_H
4142781e1SThomas Gleixner 
5142781e1SThomas Gleixner #include <linux/tracehook.h>
6142781e1SThomas Gleixner #include <linux/syscalls.h>
7142781e1SThomas Gleixner #include <linux/seccomp.h>
8142781e1SThomas Gleixner #include <linux/sched.h>
9142781e1SThomas Gleixner 
10142781e1SThomas Gleixner #include <asm/entry-common.h>
11142781e1SThomas Gleixner 
12142781e1SThomas Gleixner /*
13142781e1SThomas Gleixner  * Define dummy _TIF work flags if not defined by the architecture or for
14142781e1SThomas Gleixner  * disabled functionality.
15142781e1SThomas Gleixner  */
16142781e1SThomas Gleixner #ifndef _TIF_SYSCALL_EMU
17142781e1SThomas Gleixner # define _TIF_SYSCALL_EMU		(0)
18142781e1SThomas Gleixner #endif
19142781e1SThomas Gleixner 
20142781e1SThomas Gleixner #ifndef _TIF_SYSCALL_TRACEPOINT
21142781e1SThomas Gleixner # define _TIF_SYSCALL_TRACEPOINT	(0)
22142781e1SThomas Gleixner #endif
23142781e1SThomas Gleixner 
24142781e1SThomas Gleixner #ifndef _TIF_SECCOMP
25142781e1SThomas Gleixner # define _TIF_SECCOMP			(0)
26142781e1SThomas Gleixner #endif
27142781e1SThomas Gleixner 
28142781e1SThomas Gleixner #ifndef _TIF_SYSCALL_AUDIT
29142781e1SThomas Gleixner # define _TIF_SYSCALL_AUDIT		(0)
30142781e1SThomas Gleixner #endif
31142781e1SThomas Gleixner 
32a9f3a74aSThomas Gleixner #ifndef _TIF_PATCH_PENDING
33a9f3a74aSThomas Gleixner # define _TIF_PATCH_PENDING		(0)
34a9f3a74aSThomas Gleixner #endif
35a9f3a74aSThomas Gleixner 
36a9f3a74aSThomas Gleixner #ifndef _TIF_UPROBE
37a9f3a74aSThomas Gleixner # define _TIF_UPROBE			(0)
38a9f3a74aSThomas Gleixner #endif
39a9f3a74aSThomas Gleixner 
4012db8b69SJens Axboe #ifndef _TIF_NOTIFY_SIGNAL
4112db8b69SJens Axboe # define _TIF_NOTIFY_SIGNAL		(0)
4212db8b69SJens Axboe #endif
4312db8b69SJens Axboe 
44142781e1SThomas Gleixner /*
45900ffe39SKees Cook  * TIF flags handled in syscall_enter_from_user_mode()
46142781e1SThomas Gleixner  */
47142781e1SThomas Gleixner #ifndef ARCH_SYSCALL_ENTER_WORK
48142781e1SThomas Gleixner # define ARCH_SYSCALL_ENTER_WORK	(0)
49142781e1SThomas Gleixner #endif
50142781e1SThomas Gleixner 
51142781e1SThomas Gleixner #define SYSCALL_ENTER_WORK						\
52142781e1SThomas Gleixner 	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP |	\
53142781e1SThomas Gleixner 	 _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_EMU |			\
54142781e1SThomas Gleixner 	 ARCH_SYSCALL_ENTER_WORK)
55142781e1SThomas Gleixner 
56a9f3a74aSThomas Gleixner /*
57a9f3a74aSThomas Gleixner  * TIF flags handled in syscall_exit_to_user_mode()
58a9f3a74aSThomas Gleixner  */
59a9f3a74aSThomas Gleixner #ifndef ARCH_SYSCALL_EXIT_WORK
60a9f3a74aSThomas Gleixner # define ARCH_SYSCALL_EXIT_WORK		(0)
61a9f3a74aSThomas Gleixner #endif
62a9f3a74aSThomas Gleixner 
63a9f3a74aSThomas Gleixner #define SYSCALL_EXIT_WORK						\
64a9f3a74aSThomas Gleixner 	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT |			\
65a9f3a74aSThomas Gleixner 	 _TIF_SYSCALL_TRACEPOINT | ARCH_SYSCALL_EXIT_WORK)
66a9f3a74aSThomas Gleixner 
67a9f3a74aSThomas Gleixner /*
68a9f3a74aSThomas Gleixner  * TIF flags handled in exit_to_user_mode_loop()
69a9f3a74aSThomas Gleixner  */
70a9f3a74aSThomas Gleixner #ifndef ARCH_EXIT_TO_USER_MODE_WORK
71a9f3a74aSThomas Gleixner # define ARCH_EXIT_TO_USER_MODE_WORK		(0)
72a9f3a74aSThomas Gleixner #endif
73a9f3a74aSThomas Gleixner 
74a9f3a74aSThomas Gleixner #define EXIT_TO_USER_MODE_WORK						\
75a9f3a74aSThomas Gleixner 	(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE |		\
7612db8b69SJens Axboe 	 _TIF_NEED_RESCHED | _TIF_PATCH_PENDING | _TIF_NOTIFY_SIGNAL |	\
77a9f3a74aSThomas Gleixner 	 ARCH_EXIT_TO_USER_MODE_WORK)
78a9f3a74aSThomas Gleixner 
79142781e1SThomas Gleixner /**
80142781e1SThomas Gleixner  * arch_check_user_regs - Architecture specific sanity check for user mode regs
81142781e1SThomas Gleixner  * @regs:	Pointer to currents pt_regs
82142781e1SThomas Gleixner  *
83142781e1SThomas Gleixner  * Defaults to an empty implementation. Can be replaced by architecture
84142781e1SThomas Gleixner  * specific code.
85142781e1SThomas Gleixner  *
86142781e1SThomas Gleixner  * Invoked from syscall_enter_from_user_mode() in the non-instrumentable
87142781e1SThomas Gleixner  * section. Use __always_inline so the compiler cannot push it out of line
88142781e1SThomas Gleixner  * and make it instrumentable.
89142781e1SThomas Gleixner  */
90142781e1SThomas Gleixner static __always_inline void arch_check_user_regs(struct pt_regs *regs);
91142781e1SThomas Gleixner 
92142781e1SThomas Gleixner #ifndef arch_check_user_regs
93142781e1SThomas Gleixner static __always_inline void arch_check_user_regs(struct pt_regs *regs) {}
94142781e1SThomas Gleixner #endif
95142781e1SThomas Gleixner 
96142781e1SThomas Gleixner /**
97142781e1SThomas Gleixner  * arch_syscall_enter_tracehook - Wrapper around tracehook_report_syscall_entry()
98142781e1SThomas Gleixner  * @regs:	Pointer to currents pt_regs
99142781e1SThomas Gleixner  *
100142781e1SThomas Gleixner  * Returns: 0 on success or an error code to skip the syscall.
101142781e1SThomas Gleixner  *
102142781e1SThomas Gleixner  * Defaults to tracehook_report_syscall_entry(). Can be replaced by
103142781e1SThomas Gleixner  * architecture specific code.
104142781e1SThomas Gleixner  *
105142781e1SThomas Gleixner  * Invoked from syscall_enter_from_user_mode()
106142781e1SThomas Gleixner  */
107142781e1SThomas Gleixner static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs);
108142781e1SThomas Gleixner 
109142781e1SThomas Gleixner #ifndef arch_syscall_enter_tracehook
110142781e1SThomas Gleixner static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs)
111142781e1SThomas Gleixner {
112142781e1SThomas Gleixner 	return tracehook_report_syscall_entry(regs);
113142781e1SThomas Gleixner }
114142781e1SThomas Gleixner #endif
115142781e1SThomas Gleixner 
116142781e1SThomas Gleixner /**
1174facb95bSThomas Gleixner  * syscall_enter_from_user_mode_prepare - Establish state and enable interrupts
1184facb95bSThomas Gleixner  * @regs:	Pointer to currents pt_regs
1194facb95bSThomas Gleixner  *
1204facb95bSThomas Gleixner  * Invoked from architecture specific syscall entry code with interrupts
1214facb95bSThomas Gleixner  * disabled. The calling code has to be non-instrumentable. When the
1224facb95bSThomas Gleixner  * function returns all state is correct, interrupts are enabled and the
1234facb95bSThomas Gleixner  * subsequent functions can be instrumented.
1244facb95bSThomas Gleixner  *
1254facb95bSThomas Gleixner  * This handles lockdep, RCU (context tracking) and tracing state.
1264facb95bSThomas Gleixner  *
1274facb95bSThomas Gleixner  * This is invoked when there is extra architecture specific functionality
1284facb95bSThomas Gleixner  * to be done between establishing state and handling user mode entry work.
1294facb95bSThomas Gleixner  */
1304facb95bSThomas Gleixner void syscall_enter_from_user_mode_prepare(struct pt_regs *regs);
1314facb95bSThomas Gleixner 
1324facb95bSThomas Gleixner /**
1334facb95bSThomas Gleixner  * syscall_enter_from_user_mode_work - Check and handle work before invoking
134142781e1SThomas Gleixner  *				       a syscall
135142781e1SThomas Gleixner  * @regs:	Pointer to currents pt_regs
136142781e1SThomas Gleixner  * @syscall:	The syscall number
137142781e1SThomas Gleixner  *
138142781e1SThomas Gleixner  * Invoked from architecture specific syscall entry code with interrupts
1394facb95bSThomas Gleixner  * enabled after invoking syscall_enter_from_user_mode_prepare() and extra
1404facb95bSThomas Gleixner  * architecture specific work.
141142781e1SThomas Gleixner  *
142142781e1SThomas Gleixner  * Returns: The original or a modified syscall number
143142781e1SThomas Gleixner  *
144142781e1SThomas Gleixner  * If the returned syscall number is -1 then the syscall should be
145142781e1SThomas Gleixner  * skipped. In this case the caller may invoke syscall_set_error() or
146142781e1SThomas Gleixner  * syscall_set_return_value() first.  If neither of those are called and -1
147142781e1SThomas Gleixner  * is returned, then the syscall will fail with ENOSYS.
148142781e1SThomas Gleixner  *
1494facb95bSThomas Gleixner  * It handles the following work items:
150142781e1SThomas Gleixner  *
1514facb95bSThomas Gleixner  *  1) TIF flag dependent invocations of arch_syscall_enter_tracehook(),
152142781e1SThomas Gleixner  *     __secure_computing(), trace_sys_enter()
1534facb95bSThomas Gleixner  *  2) Invocation of audit_syscall_entry()
1544facb95bSThomas Gleixner  */
1554facb95bSThomas Gleixner long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall);
1564facb95bSThomas Gleixner 
1574facb95bSThomas Gleixner /**
1584facb95bSThomas Gleixner  * syscall_enter_from_user_mode - Establish state and check and handle work
1594facb95bSThomas Gleixner  *				  before invoking a syscall
1604facb95bSThomas Gleixner  * @regs:	Pointer to currents pt_regs
1614facb95bSThomas Gleixner  * @syscall:	The syscall number
1624facb95bSThomas Gleixner  *
1634facb95bSThomas Gleixner  * Invoked from architecture specific syscall entry code with interrupts
1644facb95bSThomas Gleixner  * disabled. The calling code has to be non-instrumentable. When the
1654facb95bSThomas Gleixner  * function returns all state is correct, interrupts are enabled and the
1664facb95bSThomas Gleixner  * subsequent functions can be instrumented.
1674facb95bSThomas Gleixner  *
1684facb95bSThomas Gleixner  * This is combination of syscall_enter_from_user_mode_prepare() and
1694facb95bSThomas Gleixner  * syscall_enter_from_user_mode_work().
1704facb95bSThomas Gleixner  *
1714facb95bSThomas Gleixner  * Returns: The original or a modified syscall number. See
1724facb95bSThomas Gleixner  * syscall_enter_from_user_mode_work() for further explanation.
173142781e1SThomas Gleixner  */
174142781e1SThomas Gleixner long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall);
175142781e1SThomas Gleixner 
176142781e1SThomas Gleixner /**
177a9f3a74aSThomas Gleixner  * local_irq_enable_exit_to_user - Exit to user variant of local_irq_enable()
178a9f3a74aSThomas Gleixner  * @ti_work:	Cached TIF flags gathered with interrupts disabled
179a9f3a74aSThomas Gleixner  *
180a9f3a74aSThomas Gleixner  * Defaults to local_irq_enable(). Can be supplied by architecture specific
181a9f3a74aSThomas Gleixner  * code.
182a9f3a74aSThomas Gleixner  */
183a9f3a74aSThomas Gleixner static inline void local_irq_enable_exit_to_user(unsigned long ti_work);
184a9f3a74aSThomas Gleixner 
185a9f3a74aSThomas Gleixner #ifndef local_irq_enable_exit_to_user
186a9f3a74aSThomas Gleixner static inline void local_irq_enable_exit_to_user(unsigned long ti_work)
187a9f3a74aSThomas Gleixner {
188a9f3a74aSThomas Gleixner 	local_irq_enable();
189a9f3a74aSThomas Gleixner }
190a9f3a74aSThomas Gleixner #endif
191a9f3a74aSThomas Gleixner 
192a9f3a74aSThomas Gleixner /**
193a9f3a74aSThomas Gleixner  * local_irq_disable_exit_to_user - Exit to user variant of local_irq_disable()
194a9f3a74aSThomas Gleixner  *
195a9f3a74aSThomas Gleixner  * Defaults to local_irq_disable(). Can be supplied by architecture specific
196a9f3a74aSThomas Gleixner  * code.
197a9f3a74aSThomas Gleixner  */
198a9f3a74aSThomas Gleixner static inline void local_irq_disable_exit_to_user(void);
199a9f3a74aSThomas Gleixner 
200a9f3a74aSThomas Gleixner #ifndef local_irq_disable_exit_to_user
201a9f3a74aSThomas Gleixner static inline void local_irq_disable_exit_to_user(void)
202a9f3a74aSThomas Gleixner {
203a9f3a74aSThomas Gleixner 	local_irq_disable();
204a9f3a74aSThomas Gleixner }
205a9f3a74aSThomas Gleixner #endif
206a9f3a74aSThomas Gleixner 
207a9f3a74aSThomas Gleixner /**
208a9f3a74aSThomas Gleixner  * arch_exit_to_user_mode_work - Architecture specific TIF work for exit
209a9f3a74aSThomas Gleixner  *				 to user mode.
210a9f3a74aSThomas Gleixner  * @regs:	Pointer to currents pt_regs
211a9f3a74aSThomas Gleixner  * @ti_work:	Cached TIF flags gathered with interrupts disabled
212a9f3a74aSThomas Gleixner  *
213a9f3a74aSThomas Gleixner  * Invoked from exit_to_user_mode_loop() with interrupt enabled
214a9f3a74aSThomas Gleixner  *
215a9f3a74aSThomas Gleixner  * Defaults to NOOP. Can be supplied by architecture specific code.
216a9f3a74aSThomas Gleixner  */
217a9f3a74aSThomas Gleixner static inline void arch_exit_to_user_mode_work(struct pt_regs *regs,
218a9f3a74aSThomas Gleixner 					       unsigned long ti_work);
219a9f3a74aSThomas Gleixner 
220a9f3a74aSThomas Gleixner #ifndef arch_exit_to_user_mode_work
221a9f3a74aSThomas Gleixner static inline void arch_exit_to_user_mode_work(struct pt_regs *regs,
222a9f3a74aSThomas Gleixner 					       unsigned long ti_work)
223a9f3a74aSThomas Gleixner {
224a9f3a74aSThomas Gleixner }
225a9f3a74aSThomas Gleixner #endif
226a9f3a74aSThomas Gleixner 
227a9f3a74aSThomas Gleixner /**
228a9f3a74aSThomas Gleixner  * arch_exit_to_user_mode_prepare - Architecture specific preparation for
229a9f3a74aSThomas Gleixner  *				    exit to user mode.
230a9f3a74aSThomas Gleixner  * @regs:	Pointer to currents pt_regs
231a9f3a74aSThomas Gleixner  * @ti_work:	Cached TIF flags gathered with interrupts disabled
232a9f3a74aSThomas Gleixner  *
233a9f3a74aSThomas Gleixner  * Invoked from exit_to_user_mode_prepare() with interrupt disabled as the last
234a9f3a74aSThomas Gleixner  * function before return. Defaults to NOOP.
235a9f3a74aSThomas Gleixner  */
236a9f3a74aSThomas Gleixner static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
237a9f3a74aSThomas Gleixner 						  unsigned long ti_work);
238a9f3a74aSThomas Gleixner 
239a9f3a74aSThomas Gleixner #ifndef arch_exit_to_user_mode_prepare
240a9f3a74aSThomas Gleixner static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,
241a9f3a74aSThomas Gleixner 						  unsigned long ti_work)
242a9f3a74aSThomas Gleixner {
243a9f3a74aSThomas Gleixner }
244a9f3a74aSThomas Gleixner #endif
245a9f3a74aSThomas Gleixner 
246a9f3a74aSThomas Gleixner /**
247a9f3a74aSThomas Gleixner  * arch_exit_to_user_mode - Architecture specific final work before
248a9f3a74aSThomas Gleixner  *			    exit to user mode.
249a9f3a74aSThomas Gleixner  *
250a9f3a74aSThomas Gleixner  * Invoked from exit_to_user_mode() with interrupt disabled as the last
251a9f3a74aSThomas Gleixner  * function before return. Defaults to NOOP.
252a9f3a74aSThomas Gleixner  *
253a9f3a74aSThomas Gleixner  * This needs to be __always_inline because it is non-instrumentable code
254a9f3a74aSThomas Gleixner  * invoked after context tracking switched to user mode.
255a9f3a74aSThomas Gleixner  *
256a9f3a74aSThomas Gleixner  * An architecture implementation must not do anything complex, no locking
257a9f3a74aSThomas Gleixner  * etc. The main purpose is for speculation mitigations.
258a9f3a74aSThomas Gleixner  */
259a9f3a74aSThomas Gleixner static __always_inline void arch_exit_to_user_mode(void);
260a9f3a74aSThomas Gleixner 
261a9f3a74aSThomas Gleixner #ifndef arch_exit_to_user_mode
262a9f3a74aSThomas Gleixner static __always_inline void arch_exit_to_user_mode(void) { }
263a9f3a74aSThomas Gleixner #endif
264a9f3a74aSThomas Gleixner 
265a9f3a74aSThomas Gleixner /**
26612db8b69SJens Axboe  * arch_do_signal_or_restart -  Architecture specific signal delivery function
267a9f3a74aSThomas Gleixner  * @regs:	Pointer to currents pt_regs
26812db8b69SJens Axboe  * @has_signal:	actual signal to handle
269a9f3a74aSThomas Gleixner  *
270a9f3a74aSThomas Gleixner  * Invoked from exit_to_user_mode_loop().
271a9f3a74aSThomas Gleixner  */
27212db8b69SJens Axboe void arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal);
273a9f3a74aSThomas Gleixner 
274a9f3a74aSThomas Gleixner /**
275a9f3a74aSThomas Gleixner  * arch_syscall_exit_tracehook - Wrapper around tracehook_report_syscall_exit()
276a9f3a74aSThomas Gleixner  * @regs:	Pointer to currents pt_regs
277a9f3a74aSThomas Gleixner  * @step:	Indicator for single step
278a9f3a74aSThomas Gleixner  *
279a9f3a74aSThomas Gleixner  * Defaults to tracehook_report_syscall_exit(). Can be replaced by
280a9f3a74aSThomas Gleixner  * architecture specific code.
281a9f3a74aSThomas Gleixner  *
282a9f3a74aSThomas Gleixner  * Invoked from syscall_exit_to_user_mode()
283a9f3a74aSThomas Gleixner  */
284a9f3a74aSThomas Gleixner static inline void arch_syscall_exit_tracehook(struct pt_regs *regs, bool step);
285a9f3a74aSThomas Gleixner 
286a9f3a74aSThomas Gleixner #ifndef arch_syscall_exit_tracehook
287a9f3a74aSThomas Gleixner static inline void arch_syscall_exit_tracehook(struct pt_regs *regs, bool step)
288a9f3a74aSThomas Gleixner {
289a9f3a74aSThomas Gleixner 	tracehook_report_syscall_exit(regs, step);
290a9f3a74aSThomas Gleixner }
291a9f3a74aSThomas Gleixner #endif
292a9f3a74aSThomas Gleixner 
293a9f3a74aSThomas Gleixner /**
294a9f3a74aSThomas Gleixner  * syscall_exit_to_user_mode - Handle work before returning to user mode
295a9f3a74aSThomas Gleixner  * @regs:	Pointer to currents pt_regs
296a9f3a74aSThomas Gleixner  *
297a9f3a74aSThomas Gleixner  * Invoked with interrupts enabled and fully valid regs. Returns with all
298a9f3a74aSThomas Gleixner  * work handled, interrupts disabled such that the caller can immediately
299a9f3a74aSThomas Gleixner  * switch to user mode. Called from architecture specific syscall and ret
300a9f3a74aSThomas Gleixner  * from fork code.
301a9f3a74aSThomas Gleixner  *
302a9f3a74aSThomas Gleixner  * The call order is:
303a9f3a74aSThomas Gleixner  *  1) One-time syscall exit work:
304a9f3a74aSThomas Gleixner  *	- rseq syscall exit
305a9f3a74aSThomas Gleixner  *      - audit
306a9f3a74aSThomas Gleixner  *	- syscall tracing
307a9f3a74aSThomas Gleixner  *	- tracehook (single stepping)
308a9f3a74aSThomas Gleixner  *
309a9f3a74aSThomas Gleixner  *  2) Preparatory work
310a9f3a74aSThomas Gleixner  *	- Exit to user mode loop (common TIF handling). Invokes
311a9f3a74aSThomas Gleixner  *	  arch_exit_to_user_mode_work() for architecture specific TIF work
312a9f3a74aSThomas Gleixner  *	- Architecture specific one time work arch_exit_to_user_mode_prepare()
313a9f3a74aSThomas Gleixner  *	- Address limit and lockdep checks
314a9f3a74aSThomas Gleixner  *
315a9f3a74aSThomas Gleixner  *  3) Final transition (lockdep, tracing, context tracking, RCU). Invokes
316a9f3a74aSThomas Gleixner  *     arch_exit_to_user_mode() to handle e.g. speculation mitigations
317a9f3a74aSThomas Gleixner  */
318a9f3a74aSThomas Gleixner void syscall_exit_to_user_mode(struct pt_regs *regs);
319a9f3a74aSThomas Gleixner 
320a9f3a74aSThomas Gleixner /**
321142781e1SThomas Gleixner  * irqentry_enter_from_user_mode - Establish state before invoking the irq handler
322142781e1SThomas Gleixner  * @regs:	Pointer to currents pt_regs
323142781e1SThomas Gleixner  *
324142781e1SThomas Gleixner  * Invoked from architecture specific entry code with interrupts disabled.
325142781e1SThomas Gleixner  * Can only be called when the interrupt entry came from user mode. The
326142781e1SThomas Gleixner  * calling code must be non-instrumentable.  When the function returns all
327142781e1SThomas Gleixner  * state is correct and the subsequent functions can be instrumented.
328142781e1SThomas Gleixner  *
329142781e1SThomas Gleixner  * The function establishes state (lockdep, RCU (context tracking), tracing)
330142781e1SThomas Gleixner  */
331142781e1SThomas Gleixner void irqentry_enter_from_user_mode(struct pt_regs *regs);
332142781e1SThomas Gleixner 
333a9f3a74aSThomas Gleixner /**
334a9f3a74aSThomas Gleixner  * irqentry_exit_to_user_mode - Interrupt exit work
335a9f3a74aSThomas Gleixner  * @regs:	Pointer to current's pt_regs
336a9f3a74aSThomas Gleixner  *
337a9f3a74aSThomas Gleixner  * Invoked with interrupts disbled and fully valid regs. Returns with all
338a9f3a74aSThomas Gleixner  * work handled, interrupts disabled such that the caller can immediately
339a9f3a74aSThomas Gleixner  * switch to user mode. Called from architecture specific interrupt
340a9f3a74aSThomas Gleixner  * handling code.
341a9f3a74aSThomas Gleixner  *
342a9f3a74aSThomas Gleixner  * The call order is #2 and #3 as described in syscall_exit_to_user_mode().
343a9f3a74aSThomas Gleixner  * Interrupt exit is not invoking #1 which is the syscall specific one time
344a9f3a74aSThomas Gleixner  * work.
345a9f3a74aSThomas Gleixner  */
346a9f3a74aSThomas Gleixner void irqentry_exit_to_user_mode(struct pt_regs *regs);
347a9f3a74aSThomas Gleixner 
348a5497babSThomas Gleixner #ifndef irqentry_state
349*b6be002bSThomas Gleixner /**
350*b6be002bSThomas Gleixner  * struct irqentry_state - Opaque object for exception state storage
351*b6be002bSThomas Gleixner  * @exit_rcu: Used exclusively in the irqentry_*() calls; signals whether the
352*b6be002bSThomas Gleixner  *            exit path has to invoke rcu_irq_exit().
353*b6be002bSThomas Gleixner  * @lockdep: Used exclusively in the irqentry_nmi_*() calls; ensures that
354*b6be002bSThomas Gleixner  *           lockdep state is restored correctly on exit from nmi.
355*b6be002bSThomas Gleixner  *
356*b6be002bSThomas Gleixner  * This opaque object is filled in by the irqentry_*_enter() functions and
357*b6be002bSThomas Gleixner  * must be passed back into the corresponding irqentry_*_exit() functions
358*b6be002bSThomas Gleixner  * when the exception is complete.
359*b6be002bSThomas Gleixner  *
360*b6be002bSThomas Gleixner  * Callers of irqentry_*_[enter|exit]() must consider this structure opaque
361*b6be002bSThomas Gleixner  * and all members private.  Descriptions of the members are provided to aid in
362*b6be002bSThomas Gleixner  * the maintenance of the irqentry_*() functions.
363*b6be002bSThomas Gleixner  */
364a5497babSThomas Gleixner typedef struct irqentry_state {
365*b6be002bSThomas Gleixner 	union {
366a5497babSThomas Gleixner 		bool	exit_rcu;
367*b6be002bSThomas Gleixner 		bool	lockdep;
368*b6be002bSThomas Gleixner 	};
369a5497babSThomas Gleixner } irqentry_state_t;
370a5497babSThomas Gleixner #endif
371a5497babSThomas Gleixner 
372a5497babSThomas Gleixner /**
373a5497babSThomas Gleixner  * irqentry_enter - Handle state tracking on ordinary interrupt entries
374a5497babSThomas Gleixner  * @regs:	Pointer to pt_regs of interrupted context
375a5497babSThomas Gleixner  *
376a5497babSThomas Gleixner  * Invokes:
377a5497babSThomas Gleixner  *  - lockdep irqflag state tracking as low level ASM entry disabled
378a5497babSThomas Gleixner  *    interrupts.
379a5497babSThomas Gleixner  *
380a5497babSThomas Gleixner  *  - Context tracking if the exception hit user mode.
381a5497babSThomas Gleixner  *
382a5497babSThomas Gleixner  *  - The hardirq tracer to keep the state consistent as low level ASM
383a5497babSThomas Gleixner  *    entry disabled interrupts.
384a5497babSThomas Gleixner  *
385a5497babSThomas Gleixner  * As a precondition, this requires that the entry came from user mode,
386a5497babSThomas Gleixner  * idle, or a kernel context in which RCU is watching.
387a5497babSThomas Gleixner  *
388a5497babSThomas Gleixner  * For kernel mode entries RCU handling is done conditional. If RCU is
389a5497babSThomas Gleixner  * watching then the only RCU requirement is to check whether the tick has
390a5497babSThomas Gleixner  * to be restarted. If RCU is not watching then rcu_irq_enter() has to be
391a5497babSThomas Gleixner  * invoked on entry and rcu_irq_exit() on exit.
392a5497babSThomas Gleixner  *
393a5497babSThomas Gleixner  * Avoiding the rcu_irq_enter/exit() calls is an optimization but also
394a5497babSThomas Gleixner  * solves the problem of kernel mode pagefaults which can schedule, which
395a5497babSThomas Gleixner  * is not possible after invoking rcu_irq_enter() without undoing it.
396a5497babSThomas Gleixner  *
397a5497babSThomas Gleixner  * For user mode entries irqentry_enter_from_user_mode() is invoked to
398a5497babSThomas Gleixner  * establish the proper context for NOHZ_FULL. Otherwise scheduling on exit
399a5497babSThomas Gleixner  * would not be possible.
400a5497babSThomas Gleixner  *
401a5497babSThomas Gleixner  * Returns: An opaque object that must be passed to idtentry_exit()
402a5497babSThomas Gleixner  */
403a5497babSThomas Gleixner irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs);
404a5497babSThomas Gleixner 
405a5497babSThomas Gleixner /**
406a5497babSThomas Gleixner  * irqentry_exit_cond_resched - Conditionally reschedule on return from interrupt
407a5497babSThomas Gleixner  *
408a5497babSThomas Gleixner  * Conditional reschedule with additional sanity checks.
409a5497babSThomas Gleixner  */
410a5497babSThomas Gleixner void irqentry_exit_cond_resched(void);
411a5497babSThomas Gleixner 
412a5497babSThomas Gleixner /**
413a5497babSThomas Gleixner  * irqentry_exit - Handle return from exception that used irqentry_enter()
414a5497babSThomas Gleixner  * @regs:	Pointer to pt_regs (exception entry regs)
415a5497babSThomas Gleixner  * @state:	Return value from matching call to irqentry_enter()
416a5497babSThomas Gleixner  *
417a5497babSThomas Gleixner  * Depending on the return target (kernel/user) this runs the necessary
418a5497babSThomas Gleixner  * preemption and work checks if possible and reguired and returns to
419a5497babSThomas Gleixner  * the caller with interrupts disabled and no further work pending.
420a5497babSThomas Gleixner  *
421a5497babSThomas Gleixner  * This is the last action before returning to the low level ASM code which
422a5497babSThomas Gleixner  * just needs to return to the appropriate context.
423a5497babSThomas Gleixner  *
424a5497babSThomas Gleixner  * Counterpart to irqentry_enter().
425a5497babSThomas Gleixner  */
426a5497babSThomas Gleixner void noinstr irqentry_exit(struct pt_regs *regs, irqentry_state_t state);
427a5497babSThomas Gleixner 
428*b6be002bSThomas Gleixner /**
429*b6be002bSThomas Gleixner  * irqentry_nmi_enter - Handle NMI entry
430*b6be002bSThomas Gleixner  * @regs:	Pointer to currents pt_regs
431*b6be002bSThomas Gleixner  *
432*b6be002bSThomas Gleixner  * Similar to irqentry_enter() but taking care of the NMI constraints.
433*b6be002bSThomas Gleixner  */
434*b6be002bSThomas Gleixner irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs);
435*b6be002bSThomas Gleixner 
436*b6be002bSThomas Gleixner /**
437*b6be002bSThomas Gleixner  * irqentry_nmi_exit - Handle return from NMI handling
438*b6be002bSThomas Gleixner  * @regs:	Pointer to pt_regs (NMI entry regs)
439*b6be002bSThomas Gleixner  * @irq_state:	Return value from matching call to irqentry_nmi_enter()
440*b6be002bSThomas Gleixner  *
441*b6be002bSThomas Gleixner  * Last action before returning to the low level assmenbly code.
442*b6be002bSThomas Gleixner  *
443*b6be002bSThomas Gleixner  * Counterpart to irqentry_nmi_enter().
444*b6be002bSThomas Gleixner  */
445*b6be002bSThomas Gleixner void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state);
446*b6be002bSThomas Gleixner 
447142781e1SThomas Gleixner #endif
448