1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk}) 4 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de) 5 * Copyright (C) 2012-2014 Cisco Systems 6 * Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com) 7 */ 8 9 #include <stddef.h> 10 #include <unistd.h> 11 #include <errno.h> 12 #include <signal.h> 13 #include <time.h> 14 #include <sys/signalfd.h> 15 #include <sys/time.h> 16 #include <kern_util.h> 17 #include <os.h> 18 #include <smp.h> 19 #include <string.h> 20 #include "internal.h" 21 22 static timer_t event_high_res_timer[CONFIG_NR_CPUS] = { 0 }; 23 24 static inline long long timespec_to_ns(const struct timespec *ts) 25 { 26 return ((long long) ts->tv_sec * UM_NSEC_PER_SEC) + ts->tv_nsec; 27 } 28 29 long long os_persistent_clock_emulation(void) 30 { 31 struct timespec realtime_tp; 32 33 clock_gettime(CLOCK_REALTIME, &realtime_tp); 34 return timespec_to_ns(&realtime_tp); 35 } 36 37 #ifndef sigev_notify_thread_id 38 #define sigev_notify_thread_id _sigev_un._tid 39 #endif 40 41 /** 42 * os_timer_create() - create an new posix (interval) timer 43 */ 44 int os_timer_create(void) 45 { 46 int cpu = uml_curr_cpu(); 47 timer_t *t = &event_high_res_timer[cpu]; 48 struct sigevent sev = { 49 .sigev_notify = SIGEV_THREAD_ID, 50 .sigev_signo = SIGALRM, 51 .sigev_value.sival_ptr = t, 52 .sigev_notify_thread_id = gettid(), 53 }; 54 55 if (timer_create(CLOCK_MONOTONIC, &sev, t) == -1) 56 return -1; 57 58 return 0; 59 } 60 61 int os_timer_set_interval(int cpu, unsigned long long nsecs) 62 { 63 struct itimerspec its; 64 65 its.it_value.tv_sec = nsecs / UM_NSEC_PER_SEC; 66 its.it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC; 67 68 its.it_interval.tv_sec = nsecs / UM_NSEC_PER_SEC; 69 its.it_interval.tv_nsec = nsecs % UM_NSEC_PER_SEC; 70 71 if (timer_settime(event_high_res_timer[cpu], 0, &its, NULL) == -1) 72 return -errno; 73 74 return 0; 75 } 76 77 int os_timer_one_shot(int cpu, unsigned long long nsecs) 78 { 79 struct itimerspec its = { 80 .it_value.tv_sec = nsecs / UM_NSEC_PER_SEC, 81 .it_value.tv_nsec = nsecs % UM_NSEC_PER_SEC, 82 83 .it_interval.tv_sec = 0, 84 .it_interval.tv_nsec = 0, // we cheat here 85 }; 86 87 timer_settime(event_high_res_timer[cpu], 0, &its, NULL); 88 return 0; 89 } 90 91 /** 92 * os_timer_disable() - disable the posix (interval) timer 93 * @cpu: the CPU for which the timer is to be disabled 94 */ 95 void os_timer_disable(int cpu) 96 { 97 struct itimerspec its; 98 99 memset(&its, 0, sizeof(struct itimerspec)); 100 timer_settime(event_high_res_timer[cpu], 0, &its, NULL); 101 } 102 103 long long os_nsecs(void) 104 { 105 struct timespec ts; 106 107 clock_gettime(CLOCK_MONOTONIC,&ts); 108 return timespec_to_ns(&ts); 109 } 110 111 static __thread int wake_signals; 112 113 void os_idle_prepare(void) 114 { 115 sigset_t set; 116 117 sigemptyset(&set); 118 sigaddset(&set, SIGALRM); 119 sigaddset(&set, IPI_SIGNAL); 120 121 /* 122 * We need to use signalfd rather than sigsuspend in idle sleep 123 * because the IPI signal is a real-time signal that carries data, 124 * and unlike handling SIGALRM, we cannot simply flag it in 125 * signals_pending. 126 */ 127 wake_signals = signalfd(-1, &set, SFD_CLOEXEC); 128 if (wake_signals < 0) 129 panic("Failed to create signal FD, errno = %d", errno); 130 } 131 132 /** 133 * os_idle_sleep() - sleep until interrupted 134 */ 135 void os_idle_sleep(void) 136 { 137 sigset_t set; 138 139 /* 140 * Block SIGALRM while performing the need_resched check. 141 * Note that, because IRQs are disabled, the IPI signal is 142 * already blocked. 143 */ 144 sigemptyset(&set); 145 sigaddset(&set, SIGALRM); 146 sigprocmask(SIG_BLOCK, &set, NULL); 147 148 /* 149 * Because disabling IRQs does not block SIGALRM, it is also 150 * necessary to check for any pending timer alarms. 151 */ 152 if (!uml_need_resched() && !timer_alarm_pending()) 153 os_poll(1, &wake_signals); 154 155 /* Restore the signal mask. */ 156 sigprocmask(SIG_UNBLOCK, &set, NULL); 157 } 158