tracing: Remove ksym tracer

The ksym (breakpoint) ftrace plugin has been superseded by perf
tools that are much more poweful to use the cpu breakpoints.
This tracer doesn't bring more feature. It has been deprecated
for a while now, lets remove it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>

kernel/trace/Kconfig

@@ -308,28 +308,6 @@ config BRANCH_TRACER
 
 	  Say N if unsure.
 
-config KSYM_TRACER
-	bool "Trace read and write access on kernel memory locations"
-	depends on HAVE_HW_BREAKPOINT
-	select TRACING
-	help
-	  This tracer helps find read and write operations on any given kernel
-	  symbol i.e. /proc/kallsyms.
-
-config PROFILE_KSYM_TRACER
-	bool "Profile all kernel memory accesses on 'watched' variables"
-	depends on KSYM_TRACER
-	help
-	  This tracer profiles kernel accesses on variables watched through the
-	  ksym tracer ftrace plugin. Depending upon the hardware, all read
-	  and write operations on kernel variables can be monitored for
-	  accesses.
-
-	  The results will be displayed in:
-	  /debugfs/tracing/profile_ksym
-
-	  Say N if unsure.
-
 config STACK_TRACER
 	bool "Trace max stack"
 	depends on HAVE_FUNCTION_TRACER

kernel/trace/Makefile

@@ -53,7 +53,6 @@ obj-$(CONFIG_EVENT_TRACING) += trace_event_perf.o
 endif
 obj-$(CONFIG_EVENT_TRACING) += trace_events_filter.o
 obj-$(CONFIG_KPROBE_EVENT) += trace_kprobe.o
-obj-$(CONFIG_KSYM_TRACER) += trace_ksym.o
 obj-$(CONFIG_EVENT_TRACING) += power-traces.o
 
 libftrace-y := ftrace.o

kernel/trace/trace.h

@@ -30,7 +30,6 @@ enum trace_type {
 	TRACE_GRAPH_ENT,
 	TRACE_USER_STACK,
 	TRACE_BLK,
-	TRACE_KSYM,
 
 	__TRACE_LAST_TYPE,
 };
@@ -200,7 +199,6 @@ extern void __ftrace_bad_type(void);
 			  TRACE_GRAPH_ENT);		\
 		IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,	\
 			  TRACE_GRAPH_RET);		\
-		IF_ASSIGN(var, ent, struct ksym_trace_entry, TRACE_KSYM);\
 		__ftrace_bad_type();					\
 	} while (0)
 
@@ -361,8 +359,6 @@ int register_tracer(struct tracer *type);
 void unregister_tracer(struct tracer *type);
 int is_tracing_stopped(void);
 
-extern int process_new_ksym_entry(char *ksymname, int op, unsigned long addr);
-
 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
 
 extern unsigned long tracing_thresh;
@@ -436,8 +432,6 @@ extern int trace_selftest_startup_sysprof(struct tracer *trace,
 					       struct trace_array *tr);
 extern int trace_selftest_startup_branch(struct tracer *trace,
 					 struct trace_array *tr);
-extern int trace_selftest_startup_ksym(struct tracer *trace,
-					 struct trace_array *tr);
 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 
 extern void *head_page(struct trace_array_cpu *data);

kernel/trace/trace_entries.h

@@ -291,18 +291,3 @@ FTRACE_ENTRY(branch, trace_branch,
 		 __entry->func, __entry->file, __entry->correct)
 );
 
-FTRACE_ENTRY(ksym_trace, ksym_trace_entry,
-
-	TRACE_KSYM,
-
-	F_STRUCT(
-		__field(	unsigned long,	ip			  )
-		__field(	unsigned char,	type			  )
-		__array(	char	     ,	cmd,	   TASK_COMM_LEN  )
-		__field(	unsigned long,  addr			  )
-	),
-
-	F_printk("ip: %pF type: %d ksym_name: %pS cmd: %s",
-		(void *)__entry->ip, (unsigned int)__entry->type,
-		(void *)__entry->addr,  __entry->cmd)
-);

kernel/trace/trace_selftest.c

@@ -17,7 +17,6 @@ static inline int trace_valid_entry(struct trace_entry *entry)
 	case TRACE_BRANCH:
 	case TRACE_GRAPH_ENT:
 	case TRACE_GRAPH_RET:
-	case TRACE_KSYM:
 		return 1;
 	}
 	return 0;
@@ -755,56 +754,3 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
 }
 #endif /* CONFIG_BRANCH_TRACER */
 
-#ifdef CONFIG_KSYM_TRACER
-static int ksym_selftest_dummy;
-
-int
-trace_selftest_startup_ksym(struct tracer *trace, struct trace_array *tr)
-{
-	unsigned long count;
-	int ret;
-
-	/* start the tracing */
-	ret = tracer_init(trace, tr);
-	if (ret) {
-		warn_failed_init_tracer(trace, ret);
-		return ret;
-	}
-
-	ksym_selftest_dummy = 0;
-	/* Register the read-write tracing request */
-
-	ret = process_new_ksym_entry("ksym_selftest_dummy",
-				     HW_BREAKPOINT_R | HW_BREAKPOINT_W,
-					(unsigned long)(&ksym_selftest_dummy));
-
-	if (ret < 0) {
-		printk(KERN_CONT "ksym_trace read-write startup test failed\n");
-		goto ret_path;
-	}
-	/* Perform a read and a write operation over the dummy variable to
-	 * trigger the tracer
-	 */
-	if (ksym_selftest_dummy == 0)
-		ksym_selftest_dummy++;
-
-	/* stop the tracing. */
-	tracing_stop();
-	/* check the trace buffer */
-	ret = trace_test_buffer(tr, &count);
-	trace->reset(tr);
-	tracing_start();
-
-	/* read & write operations - one each is performed on the dummy variable
-	 * triggering two entries in the trace buffer
-	 */
-	if (!ret && count != 2) {
-		printk(KERN_CONT "Ksym tracer startup test failed");
-		ret = -1;
-	}
-
-ret_path:
-	return ret;
-}
-#endif /* CONFIG_KSYM_TRACER */
-