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ftrace: add ftrace_bprintk()

PATCH In review Lai Jiangshan 1 participant 1 message Dec 31, 2008

Subsystems (4)
Tracing Generic include/asm header files ftrace Module support
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Lai Jiangshan

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PATCH 3/5 ftrace: add ftrace_bprintk()

Impact: Add a generic printk() for ftrace, like ftrace_printk()

ftrace_bprintk() use the infrastructure to record events on ring_buffer.

Signed-off-by Lai Jiangshan <[email protected]>
---
 include/asm-generic/vmlinux.lds.h |    3
 include/linux/ftrace.h            |   21 ++++++
 include/linux/module.h            |    5 +
 kernel/module.c                   |    6 +
 kernel/trace/trace.c              |   15 ++++
 kernel/trace/trace_bprintk.c      |  118 +++++++++++++++++++++++++++++++++++++-
 6 files changed, 167 insertions(+), 1 deletion(-)
include/asm-generic/vmlinux.lds.h +3 -0
index c61fab1..d5d5d42 100644
@@ -91,6 +91,9 @@
 		*(__vermagic)		/* Kernel version magic */	\
 		*(__markers_strings)	/* Markers: strings */		\
 		*(__tracepoints_strings)/* Tracepoints: strings */	\
+		VMLINUX_SYMBOL(__start___trace_bprintk_fmt) = .;	\
+		*(__trace_printk_fmt)	/* Trace_printk fmt' pointer */	\
+		VMLINUX_SYMBOL(__stop___trace_bprintk_fmt) = .;		\
 	}								\
 									\
 	.rodata1          : AT(ADDR(.rodata1) - LOAD_OFFSET) {		\
include/linux/ftrace.h +21 -0
index 0ec4752..9be4b3c 100644
@@ -183,6 +183,27 @@ extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 
 #ifdef CONFIG_TRACE_BPRINTK
 extern int trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
+extern int __ftrace_bprintk(unsigned long ip, const char *fmt, ...)
+		__attribute__ ((format (printf, 2, 3)));
+
+static inline void  ____ftrace_bprintk_check_format(const char *fmt, ...)
+		__attribute__ ((format (printf, 1, 2)));
+static inline void ____ftrace_bprintk_check_format(const char *fmt, ...) {}
+#define __ftrace_bprintk_check_format(fmt, args...)			\
+do {									\
+	if (0)								\
+		____ftrace_bprintk_check_format(fmt, ##args);		\
+} while (0)
+
+#define ftrace_bprintk(fmt, args...)					\
+do {									\
+	static char *__attribute__((section("__trace_bprintk_fmt")))	\
+			ftrace_bprintk_fmt = fmt;			\
+	__ftrace_bprintk_check_format(fmt, ##args);			\
+	__ftrace_bprintk(_THIS_IP_, ftrace_bprintk_fmt, ##args);	\
+} while (0)
+#else
+#define ftrace_bprintk ftrace_printk
 #endif
 
 /* May be defined in arch */
include/linux/module.h +5 -0
index 3bfed01..89fc51c 100644
@@ -337,6 +337,11 @@ struct module
 	unsigned int num_tracepoints;
 #endif
 
+#ifdef CONFIG_TRACE_BPRINTK
+	const char **trace_bprintk_fmt_start;
+	unsigned int num_trace_bprintk_fmt;
+#endif
+
 #ifdef CONFIG_MODULE_UNLOAD
 	/* What modules depend on me? */
 	struct list_head modules_which_use_me;
kernel/module.c +6 -0
index dd2a541..3a1e000 100644
@@ -2126,6 +2126,12 @@ static noinline struct module *load_module(void __user *umod,
 					&mod->num_tracepoints);
 #endif
 
+#ifdef CONFIG_TRACE_BPRINTK
+	mod->trace_bprintk_fmt_start = section_objs(hdr, sechdrs, secstrings,
+			"__trace_bprintk_fmt", sizeof(char *),
+			&mod->num_trace_bprintk_fmt);
+#endif
+
 #ifdef CONFIG_MODVERSIONS
 	if ((mod->num_syms && !mod->crcs)
 	    || (mod->num_gpl_syms && !mod->gpl_crcs)
kernel/trace/trace.c +15 -0
index 6e5c9df..61c9108 100644
@@ -3084,6 +3084,21 @@ out:
 }
 EXPORT_SYMBOL_GPL(trace_vbprintk);
 
+int __ftrace_bprintk(unsigned long ip, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+
+	if (!fmt)
+		return 0;
+
+	va_start(ap, fmt);
+	ret = trace_vbprintk(ip, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__ftrace_bprintk);
+
 static int trace_panic_handler(struct notifier_block *this,
 			       unsigned long event, void *unused)
 {
kernel/trace/trace_bprintk.c +117 -1

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