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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2015-09-29 09:43:30 -0400
committerSteven Rostedt <rostedt@goodmis.org>2015-09-29 13:23:57 -0400
commita3418a364ec3c8f0c29bf3f4cfc71dc6f240150e (patch)
tree419f836952e6d981d196aeecdcf21a1ac9dcd79e /kernel
parentce3fed628ecc86d81fdb2be5a5c336c636960bfe (diff)
downloadop-kernel-dev-a3418a364ec3c8f0c29bf3f4cfc71dc6f240150e.zip
op-kernel-dev-a3418a364ec3c8f0c29bf3f4cfc71dc6f240150e.tar.gz
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: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c36
-rw-r--r--kernel/trace/trace.h102
2 files changed, 55 insertions, 83 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f2fbf61..e80e380 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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
};
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 31d8395..d164845 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -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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