cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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time.c (2300B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  linux/arch/arm/kernel/time.c
      4 *
      5 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
      6 *  Modifications for ARM (C) 1994-2001 Russell King
      7 *
      8 *  This file contains the ARM-specific time handling details:
      9 *  reading the RTC at bootup, etc...
     10 */
     11#include <linux/clockchips.h>
     12#include <linux/clocksource.h>
     13#include <linux/errno.h>
     14#include <linux/export.h>
     15#include <linux/init.h>
     16#include <linux/interrupt.h>
     17#include <linux/irq.h>
     18#include <linux/kernel.h>
     19#include <linux/of_clk.h>
     20#include <linux/profile.h>
     21#include <linux/sched.h>
     22#include <linux/sched_clock.h>
     23#include <linux/smp.h>
     24#include <linux/time.h>
     25#include <linux/timex.h>
     26#include <linux/timer.h>
     27
     28#include <asm/mach/arch.h>
     29#include <asm/mach/time.h>
     30#include <asm/stacktrace.h>
     31#include <asm/thread_info.h>
     32
     33#if defined(CONFIG_RTC_DRV_CMOS) || defined(CONFIG_RTC_DRV_CMOS_MODULE) || \
     34    defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE)
     35/* this needs a better home */
     36DEFINE_SPINLOCK(rtc_lock);
     37EXPORT_SYMBOL(rtc_lock);
     38#endif	/* pc-style 'CMOS' RTC support */
     39
     40/* change this if you have some constant time drift */
     41#define USECS_PER_JIFFY	(1000000/HZ)
     42
     43#ifdef CONFIG_SMP
     44unsigned long profile_pc(struct pt_regs *regs)
     45{
     46	struct stackframe frame;
     47
     48	if (!in_lock_functions(regs->ARM_pc))
     49		return regs->ARM_pc;
     50
     51	arm_get_current_stackframe(regs, &frame);
     52	do {
     53		int ret = unwind_frame(&frame);
     54		if (ret < 0)
     55			return 0;
     56	} while (in_lock_functions(frame.pc));
     57
     58	return frame.pc;
     59}
     60EXPORT_SYMBOL(profile_pc);
     61#endif
     62
     63static void dummy_clock_access(struct timespec64 *ts)
     64{
     65	ts->tv_sec = 0;
     66	ts->tv_nsec = 0;
     67}
     68
     69static clock_access_fn __read_persistent_clock = dummy_clock_access;
     70
     71void read_persistent_clock64(struct timespec64 *ts)
     72{
     73	__read_persistent_clock(ts);
     74}
     75
     76int __init register_persistent_clock(clock_access_fn read_persistent)
     77{
     78	/* Only allow the clockaccess functions to be registered once */
     79	if (__read_persistent_clock == dummy_clock_access) {
     80		if (read_persistent)
     81			__read_persistent_clock = read_persistent;
     82		return 0;
     83	}
     84
     85	return -EINVAL;
     86}
     87
     88void __init time_init(void)
     89{
     90	if (machine_desc->init_time) {
     91		machine_desc->init_time();
     92	} else {
     93#ifdef CONFIG_COMMON_CLK
     94		of_clk_init(NULL);
     95#endif
     96		timer_probe();
     97		tick_setup_hrtimer_broadcast();
     98	}
     99}