forked from Qortal/Brooklyn
2a709f28fa
* 0day explit mitigation * Memory corruption prevention * Privilege escalation prevention * Buffer over flow prevention * File System corruption defense * Thread escape prevention This may very well be the most intensive inclusion to BrooklynR. This will not be part of an x86 suite nor it will be released as tool kit. The security core toolkit will remain part of kernel base.
101 lines
2.2 KiB
C
101 lines
2.2 KiB
C
/* Copyright (c) 2016 Facebook
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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 version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include "percpu_freelist.h"
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int pcpu_freelist_init(struct pcpu_freelist *s)
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{
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int cpu;
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s->freelist = alloc_percpu(struct pcpu_freelist_head);
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if (!s->freelist)
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return -ENOMEM;
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for_each_possible_cpu(cpu) {
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struct pcpu_freelist_head *head = per_cpu_ptr(s->freelist, cpu);
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raw_spin_lock_init(&head->lock);
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head->first = NULL;
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}
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return 0;
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}
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void pcpu_freelist_destroy(struct pcpu_freelist *s)
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{
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free_percpu(s->freelist);
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}
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static inline void __pcpu_freelist_push(struct pcpu_freelist_head *head,
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struct pcpu_freelist_node *node)
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{
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raw_spin_lock(&head->lock);
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node->next = head->first;
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head->first = node;
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raw_spin_unlock(&head->lock);
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}
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void pcpu_freelist_push(struct pcpu_freelist *s,
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struct pcpu_freelist_node *node)
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{
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struct pcpu_freelist_head *head = this_cpu_ptr(s->freelist);
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__pcpu_freelist_push(head, node);
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}
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void pcpu_freelist_populate(struct pcpu_freelist *s, void *buf, u32 elem_size,
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u32 nr_elems)
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{
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struct pcpu_freelist_head *head;
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unsigned long flags;
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int i, cpu, pcpu_entries;
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pcpu_entries = nr_elems / num_possible_cpus() + 1;
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i = 0;
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/* disable irq to workaround lockdep false positive
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* in bpf usage pcpu_freelist_populate() will never race
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* with pcpu_freelist_push()
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*/
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local_irq_save(flags);
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for_each_possible_cpu(cpu) {
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again:
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head = per_cpu_ptr(s->freelist, cpu);
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__pcpu_freelist_push(head, buf);
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i++;
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buf += elem_size;
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if (i == nr_elems)
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break;
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if (i % pcpu_entries)
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goto again;
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}
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local_irq_restore(flags);
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}
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struct pcpu_freelist_node *pcpu_freelist_pop(struct pcpu_freelist *s)
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{
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struct pcpu_freelist_head *head;
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struct pcpu_freelist_node *node;
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int orig_cpu, cpu;
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orig_cpu = cpu = raw_smp_processor_id();
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while (1) {
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head = per_cpu_ptr(s->freelist, cpu);
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raw_spin_lock(&head->lock);
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node = head->first;
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if (node) {
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head->first = node->next;
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raw_spin_unlock(&head->lock);
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return node;
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}
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raw_spin_unlock(&head->lock);
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cpu = cpumask_next(cpu, cpu_possible_mask);
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if (cpu >= nr_cpu_ids)
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cpu = 0;
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if (cpu == orig_cpu)
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return NULL;
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}
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}
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