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a7e89326b4
Commitf51246efee("MIPS: Get rid of finish_arch_switch().") moved the __restore_watch() call from finish_arch_switch() (i.e. after resume() returns) to before the resume() call in switch_to(). This results in watchpoints only being restored when a task is descheduled, preventing the watchpoints from being effective most of the time, except due to chance before the watchpoints are lazily removed. Fix the call sequence from switch_to() through to mips_install_watch_registers() to pass the task_struct pointer of the next task, instead of using current. This allows the watchpoints for the next (non-current) task to be restored without reintroducing finish_arch_switch(). Fixes:f51246efee("MIPS: Get rid of finish_arch_switch().") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: <stable@vger.kernel.org> # 4.3.x- Patchwork: https://patchwork.linux-mips.org/patch/12726/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
100 lines
2.2 KiB
C
100 lines
2.2 KiB
C
/*
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* Copyright (C) 2014 Imagination Technologies Ltd.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* CPU PM notifiers for saving/restoring general CPU state.
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*/
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#include <linux/cpu_pm.h>
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#include <linux/init.h>
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#include <asm/dsp.h>
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#include <asm/fpu.h>
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#include <asm/mmu_context.h>
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#include <asm/pm.h>
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#include <asm/watch.h>
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/* Used by PM helper macros in asm/pm.h */
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struct mips_static_suspend_state mips_static_suspend_state;
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/**
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* mips_cpu_save() - Save general CPU state.
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* Ensures that general CPU context is saved, notably FPU and DSP.
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*/
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static int mips_cpu_save(void)
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{
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/* Save FPU state */
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lose_fpu(1);
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/* Save DSP state */
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save_dsp(current);
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return 0;
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}
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/**
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* mips_cpu_restore() - Restore general CPU state.
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* Restores important CPU context.
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*/
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static void mips_cpu_restore(void)
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{
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unsigned int cpu = smp_processor_id();
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/* Restore ASID */
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if (current->mm)
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write_c0_entryhi(cpu_asid(cpu, current->mm));
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/* Restore DSP state */
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restore_dsp(current);
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/* Restore UserLocal */
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if (cpu_has_userlocal)
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write_c0_userlocal(current_thread_info()->tp_value);
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/* Restore watch registers */
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__restore_watch(current);
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}
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/**
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* mips_pm_notifier() - Notifier for preserving general CPU context.
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* @self: Notifier block.
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* @cmd: CPU PM event.
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* @v: Private data (unused).
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*
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* This is called when a CPU power management event occurs, and is used to
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* ensure that important CPU context is preserved across a CPU power down.
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*/
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static int mips_pm_notifier(struct notifier_block *self, unsigned long cmd,
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void *v)
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{
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int ret;
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switch (cmd) {
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case CPU_PM_ENTER:
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ret = mips_cpu_save();
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if (ret)
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return NOTIFY_STOP;
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break;
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case CPU_PM_ENTER_FAILED:
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case CPU_PM_EXIT:
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mips_cpu_restore();
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break;
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}
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return NOTIFY_OK;
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}
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static struct notifier_block mips_pm_notifier_block = {
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.notifier_call = mips_pm_notifier,
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};
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static int __init mips_pm_init(void)
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{
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return cpu_pm_register_notifier(&mips_pm_notifier_block);
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}
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arch_initcall(mips_pm_init);
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