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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opal-tracepoints.c (1608B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/percpu.h>
      3#include <linux/jump_label.h>
      4#include <asm/trace.h>
      5
      6#ifdef CONFIG_JUMP_LABEL
      7struct static_key opal_tracepoint_key = STATIC_KEY_INIT;
      8
      9int opal_tracepoint_regfunc(void)
     10{
     11	static_key_slow_inc(&opal_tracepoint_key);
     12	return 0;
     13}
     14
     15void opal_tracepoint_unregfunc(void)
     16{
     17	static_key_slow_dec(&opal_tracepoint_key);
     18}
     19#else
     20/*
     21 * We optimise OPAL calls by placing opal_tracepoint_refcount
     22 * directly in the TOC so we can check if the opal tracepoints are
     23 * enabled via a single load.
     24 */
     25
     26/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
     27extern long opal_tracepoint_refcount;
     28
     29int opal_tracepoint_regfunc(void)
     30{
     31	opal_tracepoint_refcount++;
     32	return 0;
     33}
     34
     35void opal_tracepoint_unregfunc(void)
     36{
     37	opal_tracepoint_refcount--;
     38}
     39#endif
     40
     41/*
     42 * Since the tracing code might execute OPAL calls we need to guard against
     43 * recursion.
     44 */
     45static DEFINE_PER_CPU(unsigned int, opal_trace_depth);
     46
     47void __trace_opal_entry(unsigned long opcode, unsigned long *args)
     48{
     49	unsigned long flags;
     50	unsigned int *depth;
     51
     52	local_irq_save(flags);
     53
     54	depth = this_cpu_ptr(&opal_trace_depth);
     55
     56	if (*depth)
     57		goto out;
     58
     59	(*depth)++;
     60	preempt_disable();
     61	trace_opal_entry(opcode, args);
     62	(*depth)--;
     63
     64out:
     65	local_irq_restore(flags);
     66}
     67
     68void __trace_opal_exit(long opcode, unsigned long retval)
     69{
     70	unsigned long flags;
     71	unsigned int *depth;
     72
     73	local_irq_save(flags);
     74
     75	depth = this_cpu_ptr(&opal_trace_depth);
     76
     77	if (*depth)
     78		goto out;
     79
     80	(*depth)++;
     81	trace_opal_exit(opcode, retval);
     82	preempt_enable();
     83	(*depth)--;
     84
     85out:
     86	local_irq_restore(flags);
     87}