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From:   Daniel Bristot de Oliveira <bristot@kernel.org>
To:     Daniel Bristot de Oliveira <bristot@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Jonathan Corbet <corbet@lwn.net>
Cc:     Juri Lelli <juri.lelli@redhat.com>,
        Clark Williams <williams@redhat.com>,
        linux-trace-devel@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 1/6] rtla/osnoise: Add helper functions to manipulate osnoise/options
Date:   Tue, 10 Jan 2023 21:08:02 +0100
Message-Id: <9bc53eae8804b4068a7e3f3e2b0b7c5a3e023c99.1673380089.git.bristot@kernel.org>
In-Reply-To: <cover.1673380089.git.bristot@kernel.org>
References: <cover.1673380089.git.bristot@kernel.org>
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Add some helper functions to read and set the on/off osnoise/options.
No usage in this patch.

In preparation for hwnoise tool.

Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jonathan Corbet <corbet@lwn.net>
---
 tools/tracing/rtla/src/osnoise.c | 108 +++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)

diff --git a/tools/tracing/rtla/src/osnoise.c b/tools/tracing/rtla/src/osnoise.c
index 4dee343909b1..050a9997191c 100644
--- a/tools/tracing/rtla/src/osnoise.c
+++ b/tools/tracing/rtla/src/osnoise.c
@@ -734,6 +734,114 @@ void osnoise_put_tracing_thresh(struct osnoise_context *context)
 	context->orig_tracing_thresh = OSNOISE_OPTION_INIT_VAL;
 }
 
+static int osnoise_options_get_option(char *option)
+{
+	char *options = tracefs_instance_file_read(NULL, "osnoise/options", NULL);
+	char no_option[128];
+	int retval = 0;
+	char *opt;
+
+	if (!options)
+		return OSNOISE_OPTION_INIT_VAL;
+
+	/*
+	 * Check first if the option is disabled.
+	 */
+	snprintf(no_option, sizeof(no_option), "NO_%s", option);
+
+	opt = strstr(options, no_option);
+	if (opt)
+		goto out_free;
+
+	/*
+	 * Now that it is not disabled, if the string is there, it is
+	 * enabled. If the string is not there, the option does not exist.
+	 */
+	opt = strstr(options, option);
+	if (opt)
+		retval = 1;
+	else
+		retval = OSNOISE_OPTION_INIT_VAL;
+
+out_free:
+	free(options);
+	return retval;
+}
+
+static int osnoise_options_set_option(char *option, bool onoff)
+{
+	char no_option[128];
+
+	if (onoff)
+		return tracefs_instance_file_write(NULL, "osnoise/options", option);
+
+	snprintf(no_option, sizeof(no_option), "NO_%s", option);
+
+	return tracefs_instance_file_write(NULL, "osnoise/options", no_option);
+}
+
+#define	OSNOISE_OPTION(name, option_str)						\
+static int osnoise_get_##name(struct osnoise_context *context)				\
+{											\
+	if (context->opt_##name != OSNOISE_OPTION_INIT_VAL)				\
+		return context->opt_##name;						\
+											\
+	if (context->orig_opt_##name != OSNOISE_OPTION_INIT_VAL)			\
+		return context->orig_opt_##name;					\
+											\
+	context->orig_opt_##name = osnoise_options_get_option(option_str);		\
+											\
+	return context->orig_opt_##name;						\
+}											\
+											\
+int osnoise_set_##name(struct osnoise_context *context, bool onoff)			\
+{											\
+	int opt_##name = osnoise_get_##name(context);					\
+	int retval;									\
+											\
+	if (opt_##name == OSNOISE_OPTION_INIT_VAL)					\
+		return -1;								\
+											\
+	if (opt_##name == onoff)							\
+		return 0;								\
+											\
+	retval = osnoise_options_set_option(option_str, onoff);				\
+	if (retval < 0)									\
+		return -1;								\
+											\
+	context->opt_##name = onoff;							\
+											\
+	return 0;									\
+}											\
+											\
+static void osnoise_restore_##name(struct osnoise_context *context)			\
+{											\
+	int retval;									\
+											\
+	if (context->orig_opt_##name == OSNOISE_OPTION_INIT_VAL)			\
+		return;									\
+											\
+	if (context->orig_opt_##name == context->opt_##name)				\
+		goto out_done;								\
+											\
+	retval = osnoise_options_set_option(option_str, context->orig_opt_##name);	\
+	if (retval < 0)									\
+		err_msg("Could not restore original osnoise " #option_str " option\n");	\
+											\
+out_done:										\
+	context->orig_opt_##name = OSNOISE_OPTION_INIT_VAL;				\
+}											\
+											\
+static void osnoise_put_##name(struct osnoise_context *context)				\
+{											\
+	osnoise_restore_##name(context);						\
+											\
+	if (context->orig_opt_##name == OSNOISE_OPTION_INIT_VAL)			\
+		return;									\
+											\
+	context->orig_opt_##name = OSNOISE_OPTION_INIT_VAL;				\
+}
+
 /*
  * enable_osnoise - enable osnoise tracer in the trace_instance
  */
-- 
2.38.1