1142781e1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0 2142781e1SThomas Gleixner 3142781e1SThomas Gleixner #include <linux/context_tracking.h> 4142781e1SThomas Gleixner #include <linux/entry-common.h> 5a9f3a74aSThomas Gleixner #include <linux/livepatch.h> 6a9f3a74aSThomas Gleixner #include <linux/audit.h> 7142781e1SThomas Gleixner 811894468SGabriel Krisman Bertazi #include "common.h" 911894468SGabriel Krisman Bertazi 10142781e1SThomas Gleixner #define CREATE_TRACE_POINTS 11142781e1SThomas Gleixner #include <trace/events/syscalls.h> 12142781e1SThomas Gleixner 1396e2fbccSSven Schnelle /* See comment for enter_from_user_mode() in entry-common.h */ 146666bb71SSven Schnelle static __always_inline void __enter_from_user_mode(struct pt_regs *regs) 15142781e1SThomas Gleixner { 16142781e1SThomas Gleixner arch_check_user_regs(regs); 17142781e1SThomas Gleixner lockdep_hardirqs_off(CALLER_ADDR0); 18142781e1SThomas Gleixner 19142781e1SThomas Gleixner CT_WARN_ON(ct_state() != CONTEXT_USER); 20142781e1SThomas Gleixner user_exit_irqoff(); 21142781e1SThomas Gleixner 22142781e1SThomas Gleixner instrumentation_begin(); 23142781e1SThomas Gleixner trace_hardirqs_off_finish(); 24142781e1SThomas Gleixner instrumentation_end(); 25142781e1SThomas Gleixner } 26142781e1SThomas Gleixner 2796e2fbccSSven Schnelle void noinstr enter_from_user_mode(struct pt_regs *regs) 2896e2fbccSSven Schnelle { 2996e2fbccSSven Schnelle __enter_from_user_mode(regs); 3096e2fbccSSven Schnelle } 3196e2fbccSSven Schnelle 32142781e1SThomas Gleixner static inline void syscall_enter_audit(struct pt_regs *regs, long syscall) 33142781e1SThomas Gleixner { 34142781e1SThomas Gleixner if (unlikely(audit_context())) { 35142781e1SThomas Gleixner unsigned long args[6]; 36142781e1SThomas Gleixner 37142781e1SThomas Gleixner syscall_get_arguments(current, regs, args); 38142781e1SThomas Gleixner audit_syscall_entry(syscall, args[0], args[1], args[2], args[3]); 39142781e1SThomas Gleixner } 40142781e1SThomas Gleixner } 41142781e1SThomas Gleixner 42142781e1SThomas Gleixner static long syscall_trace_enter(struct pt_regs *regs, long syscall, 4329915524SGabriel Krisman Bertazi unsigned long work) 44142781e1SThomas Gleixner { 45142781e1SThomas Gleixner long ret = 0; 46142781e1SThomas Gleixner 4711894468SGabriel Krisman Bertazi /* 4811894468SGabriel Krisman Bertazi * Handle Syscall User Dispatch. This must comes first, since 4911894468SGabriel Krisman Bertazi * the ABI here can be something that doesn't make sense for 5011894468SGabriel Krisman Bertazi * other syscall_work features. 5111894468SGabriel Krisman Bertazi */ 5211894468SGabriel Krisman Bertazi if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) { 5311894468SGabriel Krisman Bertazi if (syscall_user_dispatch(regs)) 5411894468SGabriel Krisman Bertazi return -1L; 5511894468SGabriel Krisman Bertazi } 5611894468SGabriel Krisman Bertazi 57142781e1SThomas Gleixner /* Handle ptrace */ 5864eb35f7SGabriel Krisman Bertazi if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) { 59142781e1SThomas Gleixner ret = arch_syscall_enter_tracehook(regs); 6064eb35f7SGabriel Krisman Bertazi if (ret || (work & SYSCALL_WORK_SYSCALL_EMU)) 61142781e1SThomas Gleixner return -1L; 62142781e1SThomas Gleixner } 63142781e1SThomas Gleixner 64142781e1SThomas Gleixner /* Do seccomp after ptrace, to catch any tracer changes. */ 6523d67a54SGabriel Krisman Bertazi if (work & SYSCALL_WORK_SECCOMP) { 66142781e1SThomas Gleixner ret = __secure_computing(NULL); 67142781e1SThomas Gleixner if (ret == -1L) 68142781e1SThomas Gleixner return ret; 69142781e1SThomas Gleixner } 70142781e1SThomas Gleixner 71b6ec4134SKees Cook /* Either of the above might have changed the syscall number */ 72b6ec4134SKees Cook syscall = syscall_get_nr(current, regs); 73b6ec4134SKees Cook 74524666cbSGabriel Krisman Bertazi if (unlikely(work & SYSCALL_WORK_SYSCALL_TRACEPOINT)) 75142781e1SThomas Gleixner trace_sys_enter(regs, syscall); 76142781e1SThomas Gleixner 77142781e1SThomas Gleixner syscall_enter_audit(regs, syscall); 78142781e1SThomas Gleixner 79142781e1SThomas Gleixner return ret ? : syscall; 80142781e1SThomas Gleixner } 81142781e1SThomas Gleixner 824facb95bSThomas Gleixner static __always_inline long 834facb95bSThomas Gleixner __syscall_enter_from_user_work(struct pt_regs *regs, long syscall) 84142781e1SThomas Gleixner { 85b86678cfSGabriel Krisman Bertazi unsigned long work = READ_ONCE(current_thread_info()->syscall_work); 86142781e1SThomas Gleixner 8729915524SGabriel Krisman Bertazi if (work & SYSCALL_WORK_ENTER) 8829915524SGabriel Krisman Bertazi syscall = syscall_trace_enter(regs, syscall, work); 89142781e1SThomas Gleixner 90142781e1SThomas Gleixner return syscall; 91142781e1SThomas Gleixner } 92142781e1SThomas Gleixner 934facb95bSThomas Gleixner long syscall_enter_from_user_mode_work(struct pt_regs *regs, long syscall) 944facb95bSThomas Gleixner { 954facb95bSThomas Gleixner return __syscall_enter_from_user_work(regs, syscall); 964facb95bSThomas Gleixner } 974facb95bSThomas Gleixner 984facb95bSThomas Gleixner noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall) 994facb95bSThomas Gleixner { 1004facb95bSThomas Gleixner long ret; 1014facb95bSThomas Gleixner 1026666bb71SSven Schnelle __enter_from_user_mode(regs); 1034facb95bSThomas Gleixner 1044facb95bSThomas Gleixner instrumentation_begin(); 1054facb95bSThomas Gleixner local_irq_enable(); 1064facb95bSThomas Gleixner ret = __syscall_enter_from_user_work(regs, syscall); 1074facb95bSThomas Gleixner instrumentation_end(); 1084facb95bSThomas Gleixner 1094facb95bSThomas Gleixner return ret; 1104facb95bSThomas Gleixner } 1114facb95bSThomas Gleixner 1124facb95bSThomas Gleixner noinstr void syscall_enter_from_user_mode_prepare(struct pt_regs *regs) 1134facb95bSThomas Gleixner { 1146666bb71SSven Schnelle __enter_from_user_mode(regs); 1154facb95bSThomas Gleixner instrumentation_begin(); 1164facb95bSThomas Gleixner local_irq_enable(); 1174facb95bSThomas Gleixner instrumentation_end(); 1184facb95bSThomas Gleixner } 1194facb95bSThomas Gleixner 120310de1a6SSven Schnelle /* See comment for exit_to_user_mode() in entry-common.h */ 121bb793562SSven Schnelle static __always_inline void __exit_to_user_mode(void) 122a9f3a74aSThomas Gleixner { 123a9f3a74aSThomas Gleixner instrumentation_begin(); 124a9f3a74aSThomas Gleixner trace_hardirqs_on_prepare(); 125a9f3a74aSThomas Gleixner lockdep_hardirqs_on_prepare(CALLER_ADDR0); 126a9f3a74aSThomas Gleixner instrumentation_end(); 127a9f3a74aSThomas Gleixner 128a9f3a74aSThomas Gleixner user_enter_irqoff(); 129a9f3a74aSThomas Gleixner arch_exit_to_user_mode(); 130a9f3a74aSThomas Gleixner lockdep_hardirqs_on(CALLER_ADDR0); 131a9f3a74aSThomas Gleixner } 132a9f3a74aSThomas Gleixner 133310de1a6SSven Schnelle void noinstr exit_to_user_mode(void) 134310de1a6SSven Schnelle { 135310de1a6SSven Schnelle __exit_to_user_mode(); 136310de1a6SSven Schnelle } 137310de1a6SSven Schnelle 138a9f3a74aSThomas Gleixner /* Workaround to allow gradual conversion of architecture code */ 13912db8b69SJens Axboe void __weak arch_do_signal_or_restart(struct pt_regs *regs, bool has_signal) { } 14012db8b69SJens Axboe 14112db8b69SJens Axboe static void handle_signal_work(struct pt_regs *regs, unsigned long ti_work) 14212db8b69SJens Axboe { 14312db8b69SJens Axboe if (ti_work & _TIF_NOTIFY_SIGNAL) 14412db8b69SJens Axboe tracehook_notify_signal(); 14512db8b69SJens Axboe 14612db8b69SJens Axboe arch_do_signal_or_restart(regs, ti_work & _TIF_SIGPENDING); 14712db8b69SJens Axboe } 148a9f3a74aSThomas Gleixner 149a9f3a74aSThomas Gleixner static unsigned long exit_to_user_mode_loop(struct pt_regs *regs, 150a9f3a74aSThomas Gleixner unsigned long ti_work) 151a9f3a74aSThomas Gleixner { 152a9f3a74aSThomas Gleixner /* 153a9f3a74aSThomas Gleixner * Before returning to user space ensure that all pending work 154a9f3a74aSThomas Gleixner * items have been completed. 155a9f3a74aSThomas Gleixner */ 156a9f3a74aSThomas Gleixner while (ti_work & EXIT_TO_USER_MODE_WORK) { 157a9f3a74aSThomas Gleixner 158a9f3a74aSThomas Gleixner local_irq_enable_exit_to_user(ti_work); 159a9f3a74aSThomas Gleixner 160a9f3a74aSThomas Gleixner if (ti_work & _TIF_NEED_RESCHED) 161a9f3a74aSThomas Gleixner schedule(); 162a9f3a74aSThomas Gleixner 163a9f3a74aSThomas Gleixner if (ti_work & _TIF_UPROBE) 164a9f3a74aSThomas Gleixner uprobe_notify_resume(regs); 165a9f3a74aSThomas Gleixner 166a9f3a74aSThomas Gleixner if (ti_work & _TIF_PATCH_PENDING) 167a9f3a74aSThomas Gleixner klp_update_patch_state(current); 168a9f3a74aSThomas Gleixner 16912db8b69SJens Axboe if (ti_work & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) 17012db8b69SJens Axboe handle_signal_work(regs, ti_work); 171a9f3a74aSThomas Gleixner 172a9f3a74aSThomas Gleixner if (ti_work & _TIF_NOTIFY_RESUME) { 173a9f3a74aSThomas Gleixner tracehook_notify_resume(regs); 174a9f3a74aSThomas Gleixner rseq_handle_notify_resume(NULL, regs); 175a9f3a74aSThomas Gleixner } 176a9f3a74aSThomas Gleixner 177a9f3a74aSThomas Gleixner /* Architecture specific TIF work */ 178a9f3a74aSThomas Gleixner arch_exit_to_user_mode_work(regs, ti_work); 179a9f3a74aSThomas Gleixner 180a9f3a74aSThomas Gleixner /* 181a9f3a74aSThomas Gleixner * Disable interrupts and reevaluate the work flags as they 182a9f3a74aSThomas Gleixner * might have changed while interrupts and preemption was 183a9f3a74aSThomas Gleixner * enabled above. 184a9f3a74aSThomas Gleixner */ 185a9f3a74aSThomas Gleixner local_irq_disable_exit_to_user(); 186a9f3a74aSThomas Gleixner ti_work = READ_ONCE(current_thread_info()->flags); 187a9f3a74aSThomas Gleixner } 188a9f3a74aSThomas Gleixner 189a9f3a74aSThomas Gleixner /* Return the latest work state for arch_exit_to_user_mode() */ 190a9f3a74aSThomas Gleixner return ti_work; 191a9f3a74aSThomas Gleixner } 192a9f3a74aSThomas Gleixner 193a9f3a74aSThomas Gleixner static void exit_to_user_mode_prepare(struct pt_regs *regs) 194a9f3a74aSThomas Gleixner { 195a9f3a74aSThomas Gleixner unsigned long ti_work = READ_ONCE(current_thread_info()->flags); 196a9f3a74aSThomas Gleixner 197a9f3a74aSThomas Gleixner lockdep_assert_irqs_disabled(); 198a9f3a74aSThomas Gleixner 199a9f3a74aSThomas Gleixner if (unlikely(ti_work & EXIT_TO_USER_MODE_WORK)) 200a9f3a74aSThomas Gleixner ti_work = exit_to_user_mode_loop(regs, ti_work); 201a9f3a74aSThomas Gleixner 202a9f3a74aSThomas Gleixner arch_exit_to_user_mode_prepare(regs, ti_work); 203a9f3a74aSThomas Gleixner 204a9f3a74aSThomas Gleixner /* Ensure that the address limit is intact and no locks are held */ 205a9f3a74aSThomas Gleixner addr_limit_user_check(); 206a9f3a74aSThomas Gleixner lockdep_assert_irqs_disabled(); 207a9f3a74aSThomas Gleixner lockdep_sys_exit(); 208a9f3a74aSThomas Gleixner } 209a9f3a74aSThomas Gleixner 210a9f3a74aSThomas Gleixner #ifndef _TIF_SINGLESTEP 21164eb35f7SGabriel Krisman Bertazi static inline bool report_single_step(unsigned long work) 212a9f3a74aSThomas Gleixner { 213a9f3a74aSThomas Gleixner return false; 214a9f3a74aSThomas Gleixner } 215a9f3a74aSThomas Gleixner #else 216a9f3a74aSThomas Gleixner /* 21764eb35f7SGabriel Krisman Bertazi * If SYSCALL_EMU is set, then the only reason to report is when 218a9f3a74aSThomas Gleixner * TIF_SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP). This syscall 219900ffe39SKees Cook * instruction has been already reported in syscall_enter_from_user_mode(). 220a9f3a74aSThomas Gleixner */ 22164eb35f7SGabriel Krisman Bertazi static inline bool report_single_step(unsigned long work) 222a9f3a74aSThomas Gleixner { 22364eb35f7SGabriel Krisman Bertazi if (!(work & SYSCALL_WORK_SYSCALL_EMU)) 22464eb35f7SGabriel Krisman Bertazi return false; 22564eb35f7SGabriel Krisman Bertazi 22664eb35f7SGabriel Krisman Bertazi return !!(current_thread_info()->flags & _TIF_SINGLESTEP); 227a9f3a74aSThomas Gleixner } 228a9f3a74aSThomas Gleixner #endif 229a9f3a74aSThomas Gleixner 23029915524SGabriel Krisman Bertazi 23129915524SGabriel Krisman Bertazi static void syscall_exit_work(struct pt_regs *regs, unsigned long work) 232a9f3a74aSThomas Gleixner { 233a9f3a74aSThomas Gleixner bool step; 234a9f3a74aSThomas Gleixner 23511894468SGabriel Krisman Bertazi /* 23611894468SGabriel Krisman Bertazi * If the syscall was rolled back due to syscall user dispatching, 23711894468SGabriel Krisman Bertazi * then the tracers below are not invoked for the same reason as 23811894468SGabriel Krisman Bertazi * the entry side was not invoked in syscall_trace_enter(): The ABI 23911894468SGabriel Krisman Bertazi * of these syscalls is unknown. 24011894468SGabriel Krisman Bertazi */ 24111894468SGabriel Krisman Bertazi if (work & SYSCALL_WORK_SYSCALL_USER_DISPATCH) { 24211894468SGabriel Krisman Bertazi if (unlikely(current->syscall_dispatch.on_dispatch)) { 24311894468SGabriel Krisman Bertazi current->syscall_dispatch.on_dispatch = false; 24411894468SGabriel Krisman Bertazi return; 24511894468SGabriel Krisman Bertazi } 24611894468SGabriel Krisman Bertazi } 24711894468SGabriel Krisman Bertazi 248a9f3a74aSThomas Gleixner audit_syscall_exit(regs); 249a9f3a74aSThomas Gleixner 250524666cbSGabriel Krisman Bertazi if (work & SYSCALL_WORK_SYSCALL_TRACEPOINT) 251a9f3a74aSThomas Gleixner trace_sys_exit(regs, syscall_get_return_value(current, regs)); 252a9f3a74aSThomas Gleixner 25364eb35f7SGabriel Krisman Bertazi step = report_single_step(work); 25464c19ba2SGabriel Krisman Bertazi if (step || work & SYSCALL_WORK_SYSCALL_TRACE) 255a9f3a74aSThomas Gleixner arch_syscall_exit_tracehook(regs, step); 256a9f3a74aSThomas Gleixner } 257a9f3a74aSThomas Gleixner 258a9f3a74aSThomas Gleixner /* 259a9f3a74aSThomas Gleixner * Syscall specific exit to user mode preparation. Runs with interrupts 260a9f3a74aSThomas Gleixner * enabled. 261a9f3a74aSThomas Gleixner */ 262a9f3a74aSThomas Gleixner static void syscall_exit_to_user_mode_prepare(struct pt_regs *regs) 263a9f3a74aSThomas Gleixner { 264b86678cfSGabriel Krisman Bertazi unsigned long work = READ_ONCE(current_thread_info()->syscall_work); 265a9f3a74aSThomas Gleixner unsigned long nr = syscall_get_nr(current, regs); 266a9f3a74aSThomas Gleixner 267a9f3a74aSThomas Gleixner CT_WARN_ON(ct_state() != CONTEXT_KERNEL); 268a9f3a74aSThomas Gleixner 269a9f3a74aSThomas Gleixner if (IS_ENABLED(CONFIG_PROVE_LOCKING)) { 270a9f3a74aSThomas Gleixner if (WARN(irqs_disabled(), "syscall %lu left IRQs disabled", nr)) 271a9f3a74aSThomas Gleixner local_irq_enable(); 272a9f3a74aSThomas Gleixner } 273a9f3a74aSThomas Gleixner 274a9f3a74aSThomas Gleixner rseq_syscall(regs); 275a9f3a74aSThomas Gleixner 276a9f3a74aSThomas Gleixner /* 277a9f3a74aSThomas Gleixner * Do one-time syscall specific work. If these work items are 278a9f3a74aSThomas Gleixner * enabled, we want to run them exactly once per syscall exit with 279a9f3a74aSThomas Gleixner * interrupts enabled. 280a9f3a74aSThomas Gleixner */ 28129915524SGabriel Krisman Bertazi if (unlikely(work & SYSCALL_WORK_EXIT)) 28229915524SGabriel Krisman Bertazi syscall_exit_work(regs, work); 283a9f3a74aSThomas Gleixner } 284a9f3a74aSThomas Gleixner 285*c6156e1dSSven Schnelle static __always_inline void __syscall_exit_to_user_mode_work(struct pt_regs *regs) 286a9f3a74aSThomas Gleixner { 287a9f3a74aSThomas Gleixner syscall_exit_to_user_mode_prepare(regs); 288a9f3a74aSThomas Gleixner local_irq_disable_exit_to_user(); 289a9f3a74aSThomas Gleixner exit_to_user_mode_prepare(regs); 290*c6156e1dSSven Schnelle } 291*c6156e1dSSven Schnelle 292*c6156e1dSSven Schnelle void syscall_exit_to_user_mode_work(struct pt_regs *regs) 293*c6156e1dSSven Schnelle { 294*c6156e1dSSven Schnelle __syscall_exit_to_user_mode_work(regs); 295*c6156e1dSSven Schnelle } 296*c6156e1dSSven Schnelle 297*c6156e1dSSven Schnelle __visible noinstr void syscall_exit_to_user_mode(struct pt_regs *regs) 298*c6156e1dSSven Schnelle { 299*c6156e1dSSven Schnelle instrumentation_begin(); 300*c6156e1dSSven Schnelle __syscall_exit_to_user_mode_work(regs); 301a9f3a74aSThomas Gleixner instrumentation_end(); 302bb793562SSven Schnelle __exit_to_user_mode(); 303a9f3a74aSThomas Gleixner } 304a9f3a74aSThomas Gleixner 305142781e1SThomas Gleixner noinstr void irqentry_enter_from_user_mode(struct pt_regs *regs) 306142781e1SThomas Gleixner { 3076666bb71SSven Schnelle __enter_from_user_mode(regs); 308142781e1SThomas Gleixner } 309a9f3a74aSThomas Gleixner 310a9f3a74aSThomas Gleixner noinstr void irqentry_exit_to_user_mode(struct pt_regs *regs) 311a9f3a74aSThomas Gleixner { 312a9f3a74aSThomas Gleixner instrumentation_begin(); 313a9f3a74aSThomas Gleixner exit_to_user_mode_prepare(regs); 314a9f3a74aSThomas Gleixner instrumentation_end(); 315bb793562SSven Schnelle __exit_to_user_mode(); 316a9f3a74aSThomas Gleixner } 317a5497babSThomas Gleixner 318aadfc2f9SIngo Molnar noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs) 319a5497babSThomas Gleixner { 320a5497babSThomas Gleixner irqentry_state_t ret = { 321a5497babSThomas Gleixner .exit_rcu = false, 322a5497babSThomas Gleixner }; 323a5497babSThomas Gleixner 324a5497babSThomas Gleixner if (user_mode(regs)) { 325a5497babSThomas Gleixner irqentry_enter_from_user_mode(regs); 326a5497babSThomas Gleixner return ret; 327a5497babSThomas Gleixner } 328a5497babSThomas Gleixner 329a5497babSThomas Gleixner /* 330a5497babSThomas Gleixner * If this entry hit the idle task invoke rcu_irq_enter() whether 331a5497babSThomas Gleixner * RCU is watching or not. 332a5497babSThomas Gleixner * 33378a56e04SIra Weiny * Interrupts can nest when the first interrupt invokes softirq 334a5497babSThomas Gleixner * processing on return which enables interrupts. 335a5497babSThomas Gleixner * 336a5497babSThomas Gleixner * Scheduler ticks in the idle task can mark quiescent state and 337a5497babSThomas Gleixner * terminate a grace period, if and only if the timer interrupt is 338a5497babSThomas Gleixner * not nested into another interrupt. 339a5497babSThomas Gleixner * 3407f2a53c2SPaul E. McKenney * Checking for rcu_is_watching() here would prevent the nesting 341a5497babSThomas Gleixner * interrupt to invoke rcu_irq_enter(). If that nested interrupt is 342a5497babSThomas Gleixner * the tick then rcu_flavor_sched_clock_irq() would wrongfully 343a5497babSThomas Gleixner * assume that it is the first interupt and eventually claim 34478a56e04SIra Weiny * quiescent state and end grace periods prematurely. 345a5497babSThomas Gleixner * 346a5497babSThomas Gleixner * Unconditionally invoke rcu_irq_enter() so RCU state stays 347a5497babSThomas Gleixner * consistent. 348a5497babSThomas Gleixner * 349a5497babSThomas Gleixner * TINY_RCU does not support EQS, so let the compiler eliminate 350a5497babSThomas Gleixner * this part when enabled. 351a5497babSThomas Gleixner */ 352a5497babSThomas Gleixner if (!IS_ENABLED(CONFIG_TINY_RCU) && is_idle_task(current)) { 353a5497babSThomas Gleixner /* 354a5497babSThomas Gleixner * If RCU is not watching then the same careful 355a5497babSThomas Gleixner * sequence vs. lockdep and tracing is required 35645ff5105SIra Weiny * as in irqentry_enter_from_user_mode(). 357a5497babSThomas Gleixner */ 358a5497babSThomas Gleixner lockdep_hardirqs_off(CALLER_ADDR0); 359a5497babSThomas Gleixner rcu_irq_enter(); 360a5497babSThomas Gleixner instrumentation_begin(); 361a5497babSThomas Gleixner trace_hardirqs_off_finish(); 362a5497babSThomas Gleixner instrumentation_end(); 363a5497babSThomas Gleixner 364a5497babSThomas Gleixner ret.exit_rcu = true; 365a5497babSThomas Gleixner return ret; 366a5497babSThomas Gleixner } 367a5497babSThomas Gleixner 368a5497babSThomas Gleixner /* 369a5497babSThomas Gleixner * If RCU is watching then RCU only wants to check whether it needs 370a5497babSThomas Gleixner * to restart the tick in NOHZ mode. rcu_irq_enter_check_tick() 371a5497babSThomas Gleixner * already contains a warning when RCU is not watching, so no point 372a5497babSThomas Gleixner * in having another one here. 373a5497babSThomas Gleixner */ 3749d820f68SThomas Gleixner lockdep_hardirqs_off(CALLER_ADDR0); 375a5497babSThomas Gleixner instrumentation_begin(); 376a5497babSThomas Gleixner rcu_irq_enter_check_tick(); 3779d820f68SThomas Gleixner trace_hardirqs_off_finish(); 378a5497babSThomas Gleixner instrumentation_end(); 379a5497babSThomas Gleixner 380a5497babSThomas Gleixner return ret; 381a5497babSThomas Gleixner } 382a5497babSThomas Gleixner 383a5497babSThomas Gleixner void irqentry_exit_cond_resched(void) 384a5497babSThomas Gleixner { 385a5497babSThomas Gleixner if (!preempt_count()) { 386a5497babSThomas Gleixner /* Sanity check RCU and thread stack */ 387a5497babSThomas Gleixner rcu_irq_exit_check_preempt(); 388a5497babSThomas Gleixner if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) 389a5497babSThomas Gleixner WARN_ON_ONCE(!on_thread_stack()); 390a5497babSThomas Gleixner if (need_resched()) 391a5497babSThomas Gleixner preempt_schedule_irq(); 392a5497babSThomas Gleixner } 393a5497babSThomas Gleixner } 394a5497babSThomas Gleixner 395aadfc2f9SIngo Molnar noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) 396a5497babSThomas Gleixner { 397a5497babSThomas Gleixner lockdep_assert_irqs_disabled(); 398a5497babSThomas Gleixner 399a5497babSThomas Gleixner /* Check whether this returns to user mode */ 400a5497babSThomas Gleixner if (user_mode(regs)) { 401a5497babSThomas Gleixner irqentry_exit_to_user_mode(regs); 402a5497babSThomas Gleixner } else if (!regs_irqs_disabled(regs)) { 403a5497babSThomas Gleixner /* 404a5497babSThomas Gleixner * If RCU was not watching on entry this needs to be done 405a5497babSThomas Gleixner * carefully and needs the same ordering of lockdep/tracing 406a5497babSThomas Gleixner * and RCU as the return to user mode path. 407a5497babSThomas Gleixner */ 408a5497babSThomas Gleixner if (state.exit_rcu) { 409a5497babSThomas Gleixner instrumentation_begin(); 410a5497babSThomas Gleixner /* Tell the tracer that IRET will enable interrupts */ 411a5497babSThomas Gleixner trace_hardirqs_on_prepare(); 412a5497babSThomas Gleixner lockdep_hardirqs_on_prepare(CALLER_ADDR0); 413a5497babSThomas Gleixner instrumentation_end(); 414a5497babSThomas Gleixner rcu_irq_exit(); 415a5497babSThomas Gleixner lockdep_hardirqs_on(CALLER_ADDR0); 416a5497babSThomas Gleixner return; 417a5497babSThomas Gleixner } 418a5497babSThomas Gleixner 419a5497babSThomas Gleixner instrumentation_begin(); 420a5497babSThomas Gleixner if (IS_ENABLED(CONFIG_PREEMPTION)) 421a5497babSThomas Gleixner irqentry_exit_cond_resched(); 422a5497babSThomas Gleixner /* Covers both tracing and lockdep */ 423a5497babSThomas Gleixner trace_hardirqs_on(); 424a5497babSThomas Gleixner instrumentation_end(); 425a5497babSThomas Gleixner } else { 426a5497babSThomas Gleixner /* 427a5497babSThomas Gleixner * IRQ flags state is correct already. Just tell RCU if it 428a5497babSThomas Gleixner * was not watching on entry. 429a5497babSThomas Gleixner */ 430a5497babSThomas Gleixner if (state.exit_rcu) 431a5497babSThomas Gleixner rcu_irq_exit(); 432a5497babSThomas Gleixner } 433a5497babSThomas Gleixner } 434b6be002bSThomas Gleixner 435b6be002bSThomas Gleixner irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs) 436b6be002bSThomas Gleixner { 437b6be002bSThomas Gleixner irqentry_state_t irq_state; 438b6be002bSThomas Gleixner 439b6be002bSThomas Gleixner irq_state.lockdep = lockdep_hardirqs_enabled(); 440b6be002bSThomas Gleixner 441b6be002bSThomas Gleixner __nmi_enter(); 442b6be002bSThomas Gleixner lockdep_hardirqs_off(CALLER_ADDR0); 443b6be002bSThomas Gleixner lockdep_hardirq_enter(); 444b6be002bSThomas Gleixner rcu_nmi_enter(); 445b6be002bSThomas Gleixner 446b6be002bSThomas Gleixner instrumentation_begin(); 447b6be002bSThomas Gleixner trace_hardirqs_off_finish(); 448b6be002bSThomas Gleixner ftrace_nmi_enter(); 449b6be002bSThomas Gleixner instrumentation_end(); 450b6be002bSThomas Gleixner 451b6be002bSThomas Gleixner return irq_state; 452b6be002bSThomas Gleixner } 453b6be002bSThomas Gleixner 454b6be002bSThomas Gleixner void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state) 455b6be002bSThomas Gleixner { 456b6be002bSThomas Gleixner instrumentation_begin(); 457b6be002bSThomas Gleixner ftrace_nmi_exit(); 458b6be002bSThomas Gleixner if (irq_state.lockdep) { 459b6be002bSThomas Gleixner trace_hardirqs_on_prepare(); 460b6be002bSThomas Gleixner lockdep_hardirqs_on_prepare(CALLER_ADDR0); 461b6be002bSThomas Gleixner } 462b6be002bSThomas Gleixner instrumentation_end(); 463b6be002bSThomas Gleixner 464b6be002bSThomas Gleixner rcu_nmi_exit(); 465b6be002bSThomas Gleixner lockdep_hardirq_exit(); 466b6be002bSThomas Gleixner if (irq_state.lockdep) 467b6be002bSThomas Gleixner lockdep_hardirqs_on(CALLER_ADDR0); 468b6be002bSThomas Gleixner __nmi_exit(); 469b6be002bSThomas Gleixner } 470