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 8 struct static_key opal_tracepoint_key = STATIC_KEY_INIT; 9 opal_tracepoint_regfunc(void)10int opal_tracepoint_regfunc(void) 11 { 12 static_key_slow_inc(&opal_tracepoint_key); 13 return 0; 14 } 15 opal_tracepoint_unregfunc(void)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 */ 28 extern long opal_tracepoint_refcount; 29 opal_tracepoint_regfunc(void)30int opal_tracepoint_regfunc(void) 31 { 32 opal_tracepoint_refcount++; 33 return 0; 34 } 35 opal_tracepoint_unregfunc(void)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 */ 46 static DEFINE_PER_CPU(unsigned int, opal_trace_depth); 47 __trace_opal_entry(unsigned long opcode,unsigned long * args)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 65 out: 66 local_irq_restore(flags); 67 } 68 __trace_opal_exit(long opcode,unsigned long retval)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 86 out: 87 local_irq_restore(flags); 88 } 89