Commit a3418a36 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Use TRACE_FLAGS macro to keep enums and strings matched 



Use a cute little macro trick to keep the names of the trace flags file
guaranteed to match the corresponding masks.

The macro TRACE_FLAGS is defined as a serious of enum names followed by
the string name of the file that matches it. For example:

 #define TRACE_FLAGS						\
		C(PRINT_PARENT,		"print-parent"),	\
		C(SYM_OFFSET,		"sym-offset"),		\
		C(SYM_ADDR,		"sym-addr"),		\
		C(VERBOSE,		"verbose"),

Now we can define the following:

 #undef C
 #define C(a, b) TRACE_ITER_##a##_BIT
 enum trace_iterator_bits { TRACE_FLAGS };

The above creates:

 enum trace_iterator_bits {
	TRACE_ITER_PRINT_PARENT_BIT,
	TRACE_ITER_SYM_OFFSET_BIT,
	TRACE_ITER_SYM_ADDR_BIT,
	TRACE_ITER_VERBOSE_BIT,
 };

Then we can redefine C as:

 #undef C
 #define C(a, b) TRACE_ITER_##a = (1 << TRACE_ITER_##a##_BIT)
 enum trace_iterator_flags { TRACE_FLAGS };

Which creates:

 enum trace_iterator_flags {
	TRACE_ITER_PRINT_PARENT	= (1 << TRACE_ITER_PRINT_PARENT_BIT),
	TRACE_ITER_SYM_OFFSET	= (1 << TRACE_ITER_SYM_OFFSET_BIT),
	TRACE_ITER_SYM_ADDR	= (1 << TRACE_ITER_SYM_ADDR_BIT),
	TRACE_ITER_VERBOSE	= (1 << TRACE_ITER_VERBOSE_BIT),
 };

Then finally we can create the list of file names:

 #undef C
 #define C(a, b) b
 static const char *trace_options[] = {
	TRACE_FLAGS
	NULL
 };

Which creates:
 static const char *trace_options[] = {
	"print-parent",
	"sym-offset",
	"sym-addr",
	"verbose",
	NULL
 };

The importance of this is that the strings match the bit index.

	trace_options[TRACE_ITER_SYM_ADDR_BIT] == "sym-addr"

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent ce3fed62

kernel/trace/trace.c

+10 −26
Original line number Diff line number Diff line
@@ -854,34 +854,18 @@ unsigned long nsecs_to_usecs(unsigned long nsecs) 
	return nsecs / 1000;

}



/*

 * TRACE_FLAGS is defined as a tuple matching bit masks with strings.

 * It uses C(a, b) where 'a' is the enum name and 'b' is the string that

 * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list

 * of strings in the order that the enums were defined.

 */

#undef C

#define C(a, b) b



/* These must match the bit postions in trace_iterator_flags */

static const char *trace_options[] = {

	"print-parent",

	"sym-offset",

	"sym-addr",

	"verbose",

	"raw",

	"hex",

	"bin",

	"block",

	"stacktrace",

	"trace_printk",

	"branch",

	"annotate",

	"userstacktrace",

	"sym-userobj",

	"printk-msg-only",

	"context-info",

	"latency-format",

	"sleep-time",

	"graph-time",

	"record-cmd",

	"overwrite",

	"disable_on_free",

	"irq-info",

	"markers",

	"function-trace",

	"display-graph",

	TRACE_FLAGS

	NULL

};

kernel/trace/trace.h

+45 −57
Original line number Diff line number Diff line
@@ -884,65 +884,53 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf, 
 * positions into trace_flags that controls the output.

 *

 * NOTE: These bits must match the trace_options array in

 *       trace.c.

 *       trace.c (this macro guarantees it).

 */

enum trace_iterator_bits {

	TRACE_ITER_PRINT_PARENT_BIT	= 0,

	TRACE_ITER_SYM_OFFSET_BIT,

	TRACE_ITER_SYM_ADDR_BIT,

	TRACE_ITER_VERBOSE_BIT,

	TRACE_ITER_RAW_BIT,

	TRACE_ITER_HEX_BIT,

	TRACE_ITER_BIN_BIT,

	TRACE_ITER_BLOCK_BIT,

	TRACE_ITER_STACKTRACE_BIT,

	TRACE_ITER_PRINTK_BIT,

	TRACE_ITER_BRANCH_BIT,

	TRACE_ITER_ANNOTATE_BIT,

	TRACE_ITER_USERSTACKTRACE_BIT,

	TRACE_ITER_SYM_USEROBJ_BIT,

	TRACE_ITER_PRINTK_MSGONLY_BIT,

	TRACE_ITER_CONTEXT_INFO_BIT,	/* Print pid/cpu/time */

	TRACE_ITER_LATENCY_FMT_BIT,

	TRACE_ITER_SLEEP_TIME_BIT,

	TRACE_ITER_GRAPH_TIME_BIT,

	TRACE_ITER_RECORD_CMD_BIT,

	TRACE_ITER_OVERWRITE_BIT,

	TRACE_ITER_STOP_ON_FREE_BIT,

	TRACE_ITER_IRQ_INFO_BIT,

	TRACE_ITER_MARKERS_BIT,

	TRACE_ITER_FUNCTION_BIT,

	TRACE_ITER_DISPLAY_GRAPH_BIT,

};

#define TRACE_FLAGS						\

		C(PRINT_PARENT,		"print-parent"),	\

		C(SYM_OFFSET,		"sym-offset"),		\

		C(SYM_ADDR,		"sym-addr"),		\

		C(VERBOSE,		"verbose"),		\

		C(RAW,			"raw"),			\

		C(HEX,			"hex"),			\

		C(BIN,			"bin"),			\

		C(BLOCK,		"block"),		\

		C(STACKTRACE,		"stacktrace"),		\

		C(PRINTK,		"trace_printk"),	\

		C(BRANCH,		"branch"),		\

		C(ANNOTATE,		"annotate"),		\

		C(USERSTACKTRACE,	"userstacktrace"),	\

		C(SYM_USEROBJ,		"sym-userobj"),		\

		C(PRINTK_MSGONLY,	"printk-msg-only"),	\

		C(CONTEXT_INFO,		"context-info"),   /* Print pid/cpu/time */ \

		C(LATENCY_FMT,		"latency-format"),	\

		C(SLEEP_TIME,		"sleep-time"),		\

		C(GRAPH_TIME,		"graph-time"),		\

		C(RECORD_CMD,		"record-cmd"),		\

		C(OVERWRITE,		"overwrite"),		\

		C(STOP_ON_FREE,		"disable_on_free"),	\

		C(IRQ_INFO,		"irq-info"),		\

		C(MARKERS,		"markers"),		\

		C(FUNCTION,		"function-trace"),	\

		C(DISPLAY_GRAPH,	"display-graph"),



enum trace_iterator_flags {

	TRACE_ITER_PRINT_PARENT		= (1 << TRACE_ITER_PRINT_PARENT_BIT),

	TRACE_ITER_SYM_OFFSET		= (1 << TRACE_ITER_SYM_OFFSET_BIT),

	TRACE_ITER_SYM_ADDR		= (1 << TRACE_ITER_SYM_ADDR_BIT),

	TRACE_ITER_VERBOSE		= (1 << TRACE_ITER_VERBOSE_BIT),

	TRACE_ITER_RAW			= (1 << TRACE_ITER_RAW_BIT),

	TRACE_ITER_HEX			= (1 << TRACE_ITER_HEX_BIT),

	TRACE_ITER_BIN			= (1 << TRACE_ITER_BIN_BIT),

	TRACE_ITER_BLOCK		= (1 << TRACE_ITER_BLOCK_BIT),

	TRACE_ITER_STACKTRACE		= (1 << TRACE_ITER_STACKTRACE_BIT),

	TRACE_ITER_PRINTK		= (1 << TRACE_ITER_PRINTK_BIT),

	TRACE_ITER_BRANCH		= (1 << TRACE_ITER_BRANCH_BIT),

	TRACE_ITER_ANNOTATE		= (1 << TRACE_ITER_ANNOTATE_BIT),

	TRACE_ITER_USERSTACKTRACE       = (1 << TRACE_ITER_USERSTACKTRACE_BIT),

	TRACE_ITER_SYM_USEROBJ          = (1 << TRACE_ITER_SYM_USEROBJ_BIT),

	TRACE_ITER_PRINTK_MSGONLY	= (1 << TRACE_ITER_PRINTK_MSGONLY_BIT),

	TRACE_ITER_CONTEXT_INFO		= (1 << TRACE_ITER_CONTEXT_INFO_BIT),

	TRACE_ITER_LATENCY_FMT		= (1 << TRACE_ITER_LATENCY_FMT_BIT),

	TRACE_ITER_SLEEP_TIME		= (1 << TRACE_ITER_SLEEP_TIME_BIT),

	TRACE_ITER_GRAPH_TIME		= (1 << TRACE_ITER_GRAPH_TIME_BIT),

	TRACE_ITER_RECORD_CMD		= (1 << TRACE_ITER_RECORD_CMD_BIT),

	TRACE_ITER_OVERWRITE		= (1 << TRACE_ITER_OVERWRITE_BIT),

	TRACE_ITER_STOP_ON_FREE		= (1 << TRACE_ITER_STOP_ON_FREE_BIT),

	TRACE_ITER_IRQ_INFO		= (1 << TRACE_ITER_IRQ_INFO_BIT),

	TRACE_ITER_MARKERS		= (1 << TRACE_ITER_MARKERS_BIT),

	TRACE_ITER_FUNCTION		= (1 << TRACE_ITER_FUNCTION_BIT),

	TRACE_ITER_DISPLAY_GRAPH	= (1 << TRACE_ITER_DISPLAY_GRAPH_BIT),

};

/*

 * By defining C, we can make TRACE_FLAGS a list of bit names

 * that will define the bits for the flag masks.

 */

#undef C

#define C(a, b) TRACE_ITER_##a##_BIT



enum trace_iterator_bits { TRACE_FLAGS };



/*

 * By redefining C, we can make TRACE_FLAGS a list of masks that

 * use the bits as defined above.

 */

#undef C

#define C(a, b) TRACE_ITER_##a = (1 << TRACE_ITER_##a##_BIT)



enum trace_iterator_flags { TRACE_FLAGS };



/*

 * TRACE_ITER_SYM_MASK masks the options in trace_flags that

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