mirror of https://gitee.com/openkylin/linux.git
87 lines
2.1 KiB
C
87 lines
2.1 KiB
C
/*
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* Based on arch/arm/kernel/time.c
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*
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* Copyright (C) 1991, 1992, 1995 Linus Torvalds
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* Modifications for ARM (C) 1994-2001 Russell King
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/smp.h>
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#include <linux/timex.h>
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#include <linux/errno.h>
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#include <linux/profile.h>
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#include <linux/syscore_ops.h>
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#include <linux/timer.h>
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#include <linux/irq.h>
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#include <linux/delay.h>
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#include <linux/clocksource.h>
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#include <clocksource/arm_arch_timer.h>
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#include <asm/thread_info.h>
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#include <asm/stacktrace.h>
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#ifdef CONFIG_SMP
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unsigned long profile_pc(struct pt_regs *regs)
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{
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struct stackframe frame;
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if (!in_lock_functions(regs->pc))
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return regs->pc;
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frame.fp = regs->regs[29];
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frame.sp = regs->sp;
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frame.pc = regs->pc;
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do {
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int ret = unwind_frame(&frame);
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if (ret < 0)
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return 0;
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} while (in_lock_functions(frame.pc));
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return frame.pc;
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}
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EXPORT_SYMBOL(profile_pc);
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#endif
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static u64 sched_clock_mult __read_mostly;
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unsigned long long notrace sched_clock(void)
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{
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return arch_timer_read_counter() * sched_clock_mult;
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}
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void __init time_init(void)
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{
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u32 arch_timer_rate;
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clocksource_of_init();
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arch_timer_rate = arch_timer_get_rate();
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if (!arch_timer_rate)
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panic("Unable to initialise architected timer.\n");
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/* Cache the sched_clock multiplier to save a divide in the hot path. */
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sched_clock_mult = NSEC_PER_SEC / arch_timer_rate;
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/* Calibrate the delay loop directly */
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lpj_fine = arch_timer_rate / HZ;
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}
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