1// SPDX-License-Identifier: GPL-2.0 2#include <linux/percpu.h> 3#include <linux/jump_label.h> 4#include <asm/trace.h> 5#include <asm/asm-prototypes.h> 6 7#ifdef CONFIG_JUMP_LABEL 8struct static_key opal_tracepoint_key = STATIC_KEY_INIT; 9 10int opal_tracepoint_regfunc(void) 11{ 12 static_key_slow_inc(&opal_tracepoint_key); 13 return 0; 14} 15 16void opal_tracepoint_unregfunc(void) 17{ 18 static_key_slow_dec(&opal_tracepoint_key); 19} 20#else 21/* 22 * We optimise OPAL calls by placing opal_tracepoint_refcount 23 * directly in the TOC so we can check if the opal tracepoints are 24 * enabled via a single load. 25 */ 26 27/* NB: reg/unreg are called while guarded with the tracepoints_mutex */ 28extern long opal_tracepoint_refcount; 29 30int opal_tracepoint_regfunc(void) 31{ 32 opal_tracepoint_refcount++; 33 return 0; 34} 35 36void opal_tracepoint_unregfunc(void) 37{ 38 opal_tracepoint_refcount--; 39} 40#endif 41 42/* 43 * Since the tracing code might execute OPAL calls we need to guard against 44 * recursion. 45 */ 46static DEFINE_PER_CPU(unsigned int, opal_trace_depth); 47 48void __trace_opal_entry(unsigned long opcode, unsigned long *args) 49{ 50 unsigned long flags; 51 unsigned int *depth; 52 53 local_irq_save(flags); 54 55 depth = this_cpu_ptr(&opal_trace_depth); 56 57 if (*depth) 58 goto out; 59 60 (*depth)++; 61 preempt_disable(); 62 trace_opal_entry(opcode, args); 63 (*depth)--; 64 65out: 66 local_irq_restore(flags); 67} 68 69void __trace_opal_exit(long opcode, unsigned long retval) 70{ 71 unsigned long flags; 72 unsigned int *depth; 73 74 local_irq_save(flags); 75 76 depth = this_cpu_ptr(&opal_trace_depth); 77 78 if (*depth) 79 goto out; 80 81 (*depth)++; 82 trace_opal_exit(opcode, retval); 83 preempt_enable(); 84 (*depth)--; 85 86out: 87 local_irq_restore(flags); 88} 89