[PATCH 3/3] tracing/stack-tracer: introduce CONFIG_USER_STACKTRACE_SUPPORT

["Török Edwin" <edwintorok@gmail.com>]

User stack tracing is just implemented for x86, but it is not x86 specific.
Introduce a generic config flag, that is currently enabled only for x86.
When other arches implements it, they will have to SELECT USER_STACKTRACE_SUPPORT

Signed-off-by: Török Edwin <edwintorok@gmail.com>
---
 arch/x86/Kconfig           |    1 +
 include/linux/stacktrace.h |    2 +-
 kernel/trace/Kconfig       |    3 +++
 3 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7a146ba..e49a4fd 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -36,6 +36,7 @@ config X86
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_GENERIC_DMA_COHERENT if X86_32
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
+	select USER_STACKTRACE_SUPPORT
 
 config ARCH_DEFCONFIG
 	string
diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
index fd42d68..1a8cecc 100644
--- a/include/linux/stacktrace.h
+++ b/include/linux/stacktrace.h
@@ -16,7 +16,7 @@ extern void save_stack_trace_tsk(struct task_struct *tsk,
 
 extern void print_stack_trace(struct stack_trace *trace, int spaces);
 
-#ifdef CONFIG_X86
+#ifdef CONFIG_USER_STACKTRACE_SUPPORT
 extern void save_stack_trace_user(struct stack_trace *trace);
 #else
 # define save_stack_trace_user(trace)              do { } while (0)
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index b8378fa..87fc34a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -3,6 +3,9 @@
 #  select HAVE_FUNCTION_TRACER:
 #
 
+config USER_STACKTRACE_SUPPORT
+	bool
+
 config NOP_TRACER
 	bool
 
-- 
1.5.6.5