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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smp_processor_id.c (1388B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * lib/smp_processor_id.c
      4 *
      5 * DEBUG_PREEMPT variant of smp_processor_id().
      6 */
      7#include <linux/export.h>
      8#include <linux/kprobes.h>
      9#include <linux/sched.h>
     10
     11noinstr static
     12unsigned int check_preemption_disabled(const char *what1, const char *what2)
     13{
     14	int this_cpu = raw_smp_processor_id();
     15
     16	if (likely(preempt_count()))
     17		goto out;
     18
     19	if (irqs_disabled())
     20		goto out;
     21
     22	if (is_percpu_thread())
     23		goto out;
     24
     25#ifdef CONFIG_SMP
     26	if (current->migration_disabled)
     27		goto out;
     28#endif
     29
     30	/*
     31	 * It is valid to assume CPU-locality during early bootup:
     32	 */
     33	if (system_state < SYSTEM_SCHEDULING)
     34		goto out;
     35
     36	/*
     37	 * Avoid recursion:
     38	 */
     39	preempt_disable_notrace();
     40
     41	instrumentation_begin();
     42	if (!printk_ratelimit())
     43		goto out_enable;
     44
     45	printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n",
     46		what1, what2, preempt_count() - 1, current->comm, current->pid);
     47
     48	printk("caller is %pS\n", __builtin_return_address(0));
     49	dump_stack();
     50	instrumentation_end();
     51
     52out_enable:
     53	preempt_enable_no_resched_notrace();
     54out:
     55	return this_cpu;
     56}
     57
     58noinstr unsigned int debug_smp_processor_id(void)
     59{
     60	return check_preemption_disabled("smp_processor_id", "");
     61}
     62EXPORT_SYMBOL(debug_smp_processor_id);
     63
     64noinstr void __this_cpu_preempt_check(const char *op)
     65{
     66	check_preemption_disabled("__this_cpu_", op);
     67}
     68EXPORT_SYMBOL(__this_cpu_preempt_check);