88 строки
1.8 KiB
C
88 строки
1.8 KiB
C
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/*
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* ICSWX and ACOP/PID Management
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*
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* Copyright (C) 2011 Anton Blanchard, IBM Corp. <anton@samba.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/spinlock.h>
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#include <linux/idr.h>
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#include <linux/module.h>
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#include "icswx.h"
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#define COP_PID_MIN (COP_PID_NONE + 1)
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#define COP_PID_MAX (0xFFFF)
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static DEFINE_SPINLOCK(mmu_context_acop_lock);
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static DEFINE_IDA(cop_ida);
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static int new_cop_pid(struct ida *ida, int min_id, int max_id,
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spinlock_t *lock)
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{
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int index;
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int err;
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again:
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if (!ida_pre_get(ida, GFP_KERNEL))
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return -ENOMEM;
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spin_lock(lock);
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err = ida_get_new_above(ida, min_id, &index);
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spin_unlock(lock);
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if (err == -EAGAIN)
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goto again;
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else if (err)
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return err;
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if (index > max_id) {
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spin_lock(lock);
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ida_remove(ida, index);
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spin_unlock(lock);
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return -ENOMEM;
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}
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return index;
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}
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int get_cop_pid(struct mm_struct *mm)
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{
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int pid;
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if (mm->context.cop_pid == COP_PID_NONE) {
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pid = new_cop_pid(&cop_ida, COP_PID_MIN, COP_PID_MAX,
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&mmu_context_acop_lock);
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if (pid >= 0)
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mm->context.cop_pid = pid;
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}
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return mm->context.cop_pid;
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}
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int disable_cop_pid(struct mm_struct *mm)
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{
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int free_pid = COP_PID_NONE;
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if ((!mm->context.acop) && (mm->context.cop_pid != COP_PID_NONE)) {
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free_pid = mm->context.cop_pid;
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mm->context.cop_pid = COP_PID_NONE;
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}
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return free_pid;
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}
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void free_cop_pid(int free_pid)
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{
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spin_lock(&mmu_context_acop_lock);
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ida_remove(&cop_ida, free_pid);
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spin_unlock(&mmu_context_acop_lock);
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}
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