rtla: Simplify osnoise tracer option setting code

Each osnoise tracer option (in /sys/kernel/tracing/osnoise) used by RTLA
requires four functions to be defined:

- static osnoise_get_<opt>() - to get the current value of the option
  and save it into struct osnoise_context's orig_<opt> field,
- osnoise_set_<opt>() - to set the value of the option requested by the
  user after reading and saving the original with osnoise_get_<opt>(),
  and save it into <opt> field of struct osnoise_context,
- osnoise_restore_<opt>() - restore the value recorded in orig_<opt>,
- static osnoise_put_<opt>() - restore the value recorded in orig_<opt>
  and update <opt> to reflect that.

The logic is duplicated for all the options, except for cpus (which is
the only string option) and period/runtime (which are handled together
and feature extra checks).

Deduplicate by moving the common code in get/set/restore/put into common
helper functions local to osnoise.c. The original set/restore/put
functions are reduced to wrappers generated using a set of X macros:

- OSNOISE_LL_OPTIONS, which invokes the OSNOISE_LL_OPTION macro for all
  "long long" options,
- OSNOISE_FLAG_OPTIONS, which invokes the OSNOISE_FLAG_OPTION macro for
  all flag options (boolean values in osnoise/options file).

Those are also used to auto-generate the corresponding fields in struct
osnoise_context, plus initialization and restoration code for them.

There are a few minor changes in the refactored code:

- osnoise_set_<opt>() now distinguishes between -2 (option cannot be
  set) and -1 (option not present in kernel) for all options.
- OSNOISE_OPTION_INIT_VAL and OSNOISE_TIME_INIT_VAL are removed and
  replaced with a plain -1; all unsigned long long fields are changed to
  signed long long, consistent with pre-existing "%lld" format string in
  osnoise_write_ll_config().
- osnoise_restore_<opt>() now correctly resets the <opt> field (not
  orig_<opt>) for all options.

The change is intended to simplify adding and modifying tracer options.
It also makes the code shorter by a bit over 500 lines.

Assisted-by: Claude:claude-opus-4-6
Link: https://lore.kernel.org/r/20260929142944.1841462-1-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

tools/tracing/rtla/src/common.h

@@ -6,9 +6,42 @@
 #include "trace.h"
 #include "utils.h"
 
+/*
+ * OSNOISE_LL_OPTIONS - list of long long options backed by tracefs files.
+ *   OSNOISE_LL_OPTION(field_name, tracefs_path)
+ *
+ * OSNOISE_FLAG_OPTIONS - list of boolean options backed by osnoise/options.
+ *   OSNOISE_FLAG_OPTION(field_name, option_string)
+ *
+ * These X-macro lists are invoked in four places:
+ *  - struct osnoise_context field declarations (common.h),
+ *  - function declarations for osnoise_set_<opt>/osnoise_restore_<opt> (common.h),
+ *  - function definitions for set/restore/put (osnoise.c),
+ *  - context initialization and teardown in osnoise_context_alloc() and
+ *    osnoise_put_context() (osnoise.c).
+ */
+#define OSNOISE_LL_OPTIONS \
+	OSNOISE_LL_OPTION(stop_us,		"osnoise/stop_tracing_us")		\
+	OSNOISE_LL_OPTION(stop_total_us,	"osnoise/stop_tracing_total_us")	\
+	OSNOISE_LL_OPTION(print_stack,		"osnoise/print_stack")			\
+	OSNOISE_LL_OPTION(tracing_thresh,	"tracing_thresh")			\
+	OSNOISE_LL_OPTION(timerlat_period_us,	"osnoise/timerlat_period_us")		\
+	OSNOISE_LL_OPTION(timerlat_align_us,	"osnoise/timerlat_align_us")
+
+#define OSNOISE_FLAG_OPTIONS \
+	OSNOISE_FLAG_OPTION(irq_disable,	"OSNOISE_IRQ_DISABLE")	\
+	OSNOISE_FLAG_OPTION(workload,		"OSNOISE_WORKLOAD")	\
+	OSNOISE_FLAG_OPTION(timerlat_align,	"TIMERLAT_ALIGN")
+
 /*
  * osnoise_context - read, store, write, restore osnoise configs.
  */
+#define OSNOISE_LL_OPTION(name, path)			\
+	long long		orig_##name;		\
+	long long		name;
+#define OSNOISE_FLAG_OPTION(name, option_str)		\
+	int			orig_opt_##name;	\
+	int			opt_##name;
 struct osnoise_context {
 	int			flags;
 	int			ref;
@@ -16,50 +49,17 @@ struct osnoise_context {
 	char			*curr_cpus;
 	char			*orig_cpus;
 
-	/* 0 as init value */
-	unsigned long long	orig_runtime_us;
-	unsigned long long	runtime_us;
+	long long		orig_runtime_us;
+	long long		runtime_us;
 
-	/* 0 as init value */
-	unsigned long long	orig_period_us;
-	unsigned long long	period_us;
+	long long		orig_period_us;
+	long long		period_us;
 
-	/* 0 as init value */
-	long long		orig_timerlat_period_us;
-	long long		timerlat_period_us;
-
-	/* 0 as init value */
-	long long		orig_tracing_thresh;
-	long long		tracing_thresh;
-
-	/* -1 as init value because 0 is disabled */
-	long long		orig_stop_us;
-	long long		stop_us;
-
-	/* -1 as init value because 0 is disabled */
-	long long		orig_stop_total_us;
-	long long		stop_total_us;
-
-	/* -1 as init value because 0 is disabled */
-	long long		orig_print_stack;
-	long long		print_stack;
-
-	/* -1 as init value because 0 is off */
-	int			orig_opt_irq_disable;
-	int			opt_irq_disable;
-
-	/* -1 as init value because 0 is off */
-	int			orig_opt_workload;
-	int			opt_workload;
-
-	/* -1 as init value because 0 is off */
-	int			orig_opt_timerlat_align;
-	int			opt_timerlat_align;
-
-	/* 0 as init value */
-	unsigned long long	orig_timerlat_align_us;
-	unsigned long long	timerlat_align_us;
+	OSNOISE_LL_OPTIONS
+	OSNOISE_FLAG_OPTIONS
 };
+#undef OSNOISE_LL_OPTION
+#undef OSNOISE_FLAG_OPTION
 
 extern volatile int stop_tracing;
 
@@ -173,15 +173,21 @@ int osnoise_get_cpu_count(void);
 int osnoise_set_cpus(struct osnoise_context *context, char *cpus);
 void osnoise_restore_cpus(struct osnoise_context *context);
 
-int osnoise_set_workload(struct osnoise_context *context, bool onoff);
+#define OSNOISE_LL_OPTION(name, path)							\
+	int osnoise_set_##name(struct osnoise_context *context, long long name);	\
+	void osnoise_restore_##name(struct osnoise_context *context);
+#define OSNOISE_FLAG_OPTION(name, option_str)					\
+	int osnoise_set_##name(struct osnoise_context *context, bool onoff);	\
+	void osnoise_restore_##name(struct osnoise_context *context);
+OSNOISE_LL_OPTIONS
+OSNOISE_FLAG_OPTIONS
+#undef OSNOISE_LL_OPTION
+#undef OSNOISE_FLAG_OPTION
 
 void osnoise_destroy_tool(struct osnoise_tool *top);
 struct osnoise_tool *osnoise_init_tool(char *tool_name);
 struct osnoise_tool *osnoise_init_trace_tool(struct common_params *params, const char *tracer);
 bool osnoise_trace_is_off(struct osnoise_tool *tool, struct osnoise_tool *record);
-int osnoise_set_stop_us(struct osnoise_context *context, long long stop_us);
-int osnoise_set_stop_total_us(struct osnoise_context *context,
-			      long long stop_total_us);
 
 int common_apply_config(struct osnoise_tool *tool, struct common_params *params);
 int top_main_loop(struct osnoise_tool *tool);

tools/tracing/rtla/src/osnoise.h

@@ -18,45 +18,15 @@ struct osnoise_params {
 
 #define to_osnoise_params(ptr) container_of(ptr, struct osnoise_params, common)
 
-/*
- * *_INIT_VALs are also invalid values, they are used to
- * communicate errors.
- */
-#define OSNOISE_OPTION_INIT_VAL	(-1)
-#define OSNOISE_TIME_INIT_VAL	(0)
-
 struct osnoise_context *osnoise_context_alloc(void);
 int osnoise_get_context(struct osnoise_context *context);
 void osnoise_put_context(struct osnoise_context *context);
 
 int osnoise_set_runtime_period(struct osnoise_context *context,
-			       unsigned long long runtime,
-			       unsigned long long period);
+			       long long runtime,
+			       long long period);
 void osnoise_restore_runtime_period(struct osnoise_context *context);
 
-void osnoise_restore_stop_us(struct osnoise_context *context);
-void osnoise_restore_stop_total_us(struct osnoise_context *context);
-
-int osnoise_set_timerlat_period_us(struct osnoise_context *context,
-				   long long timerlat_period_us);
-void osnoise_restore_timerlat_period_us(struct osnoise_context *context);
-
-int osnoise_set_tracing_thresh(struct osnoise_context *context,
-			       long long tracing_thresh);
-void osnoise_restore_tracing_thresh(struct osnoise_context *context);
-
-void osnoise_restore_print_stack(struct osnoise_context *context);
-int osnoise_set_print_stack(struct osnoise_context *context,
-			    long long print_stack);
-
-int osnoise_set_timerlat_align_us(struct osnoise_context *context,
-				  long long timerlat_align_us);
-void osnoise_restore_timerlat_align_us(struct osnoise_context *context);
-
-int osnoise_set_timerlat_align(struct osnoise_context *context, bool onoff);
-
-int osnoise_set_irq_disable(struct osnoise_context *context, bool onoff);
-
 void osnoise_report_invalid_events(struct osnoise_tool *tool);
 void osnoise_report_missed_events(struct osnoise_tool *tool);
 int osnoise_apply_config(struct osnoise_tool *tool, struct osnoise_params *params);