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