diff mbox series

[v4,06/29] tracing: move function tracer options to Kconfig

Message ID 20200929214631.3516445-7-samitolvanen@google.com
State New, archived
Headers show
Series Add support for Clang LTO | expand

Commit Message

Sami Tolvanen Sept. 29, 2020, 9:46 p.m. UTC
Move function tracer options to Kconfig to make it easier to add
new methods for generating __mcount_loc, and to make the options
available also when building kernel modules.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 Makefile               | 20 ++++++++------------
 kernel/trace/Kconfig   | 16 ++++++++++++++++
 scripts/Makefile.build |  6 ++----
 3 files changed, 26 insertions(+), 16 deletions(-)

Comments

Steven Rostedt Sept. 30, 2020, 12:12 a.m. UTC | #1
On Tue, 29 Sep 2020 14:46:08 -0700
Sami Tolvanen <samitolvanen@google.com> wrote:

> +++ b/kernel/trace/Kconfig
> @@ -595,6 +595,22 @@ config FTRACE_MCOUNT_RECORD
>  	depends on DYNAMIC_FTRACE
>  	depends on HAVE_FTRACE_MCOUNT_RECORD
>  
> +config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
> +	bool
> +	depends on FTRACE_MCOUNT_RECORD
> +
> +config FTRACE_MCOUNT_USE_CC
> +	def_bool y
> +	depends on $(cc-option,-mrecord-mcount)

Does the above get executed at every build? Or does a make *config need
to be done? If someone were to pass a .config to someone else that had
a compiler that didn't support this, would it be changed if the person
just did a make?

-- Steve


> +	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
> +	depends on FTRACE_MCOUNT_RECORD
> +
> +config FTRACE_MCOUNT_USE_RECORDMCOUNT
> +	def_bool y
> +	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
> +	depends on !FTRACE_MCOUNT_USE_CC
> +	depends on FTRACE_MCOUNT_RECORD
> +
>  config TRACING_MAP
>  	bool
>  	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
Sami Tolvanen Sept. 30, 2020, 4:05 p.m. UTC | #2
On Tue, Sep 29, 2020 at 5:13 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Tue, 29 Sep 2020 14:46:08 -0700
> Sami Tolvanen <samitolvanen@google.com> wrote:
>
> > +++ b/kernel/trace/Kconfig
> > @@ -595,6 +595,22 @@ config FTRACE_MCOUNT_RECORD
> >       depends on DYNAMIC_FTRACE
> >       depends on HAVE_FTRACE_MCOUNT_RECORD
> >
> > +config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
> > +     bool
> > +     depends on FTRACE_MCOUNT_RECORD
> > +
> > +config FTRACE_MCOUNT_USE_CC
> > +     def_bool y
> > +     depends on $(cc-option,-mrecord-mcount)
>
> Does the above get executed at every build? Or does a make *config need
> to be done? If someone were to pass a .config to someone else that had
> a compiler that didn't support this, would it be changed if the person
> just did a make?

Yes, it's updated if you copy a .config and just run make. For
example, here's what happens when I create a config with gcc and then
build it with Clang:

$ make defconfig
...
$ ./scripts/config -e FUNCTION_TRACER -e DYNAMIC_FTRACE
$ make olddefconfig
...
$ grep MCOUNT_USE .config
CONFIG_FTRACE_MCOUNT_USE_CC=y
$ make CC=clang
scripts/kconfig/conf  --syncconfig Kconfig
...
^C
$ grep MCOUNT_USE .config
CONFIG_FTRACE_MCOUNT_USE_OBJTOOL=y

Sami
diff mbox series

Patch

diff --git a/Makefile b/Makefile
index 476f19ccac17..77e4f0a9495e 100644
--- a/Makefile
+++ b/Makefile
@@ -841,12 +841,8 @@  KBUILD_CFLAGS += $(DEBUG_CFLAGS)
 export DEBUG_CFLAGS
 
 ifdef CONFIG_FUNCTION_TRACER
-ifdef CONFIG_FTRACE_MCOUNT_RECORD
-  # gcc 5 supports generating the mcount tables directly
-  ifeq ($(call cc-option-yn,-mrecord-mcount),y)
-    CC_FLAGS_FTRACE	+= -mrecord-mcount
-    export CC_USING_RECORD_MCOUNT := 1
-  endif
+ifdef CONFIG_FTRACE_MCOUNT_USE_CC
+  CC_FLAGS_FTRACE	+= -mrecord-mcount
   ifdef CONFIG_HAVE_NOP_MCOUNT
     ifeq ($(call cc-option-yn, -mnop-mcount),y)
       CC_FLAGS_FTRACE	+= -mnop-mcount
@@ -854,6 +850,12 @@  ifdef CONFIG_FTRACE_MCOUNT_RECORD
     endif
   endif
 endif
+ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
+  ifdef CONFIG_HAVE_C_RECORDMCOUNT
+    BUILD_C_RECORDMCOUNT := y
+    export BUILD_C_RECORDMCOUNT
+  endif
+endif
 ifdef CONFIG_HAVE_FENTRY
   ifeq ($(call cc-option-yn, -mfentry),y)
     CC_FLAGS_FTRACE	+= -mfentry
@@ -863,12 +865,6 @@  endif
 export CC_FLAGS_FTRACE
 KBUILD_CFLAGS	+= $(CC_FLAGS_FTRACE) $(CC_FLAGS_USING)
 KBUILD_AFLAGS	+= $(CC_FLAGS_USING)
-ifdef CONFIG_DYNAMIC_FTRACE
-	ifdef CONFIG_HAVE_C_RECORDMCOUNT
-		BUILD_C_RECORDMCOUNT := y
-		export BUILD_C_RECORDMCOUNT
-	endif
-endif
 endif
 
 # We trigger additional mismatches with less inlining
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index a4020c0b4508..927ad004888a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -595,6 +595,22 @@  config FTRACE_MCOUNT_RECORD
 	depends on DYNAMIC_FTRACE
 	depends on HAVE_FTRACE_MCOUNT_RECORD
 
+config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	bool
+	depends on FTRACE_MCOUNT_RECORD
+
+config FTRACE_MCOUNT_USE_CC
+	def_bool y
+	depends on $(cc-option,-mrecord-mcount)
+	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	depends on FTRACE_MCOUNT_RECORD
+
+config FTRACE_MCOUNT_USE_RECORDMCOUNT
+	def_bool y
+	depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
+	depends on !FTRACE_MCOUNT_USE_CC
+	depends on FTRACE_MCOUNT_RECORD
+
 config TRACING_MAP
 	bool
 	depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a467b9323442..a4634aae1506 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -178,8 +178,7 @@  cmd_modversions_c =								\
 	fi
 endif
 
-ifdef CONFIG_FTRACE_MCOUNT_RECORD
-ifndef CC_USING_RECORD_MCOUNT
+ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
 # compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
 ifdef BUILD_C_RECORDMCOUNT
 ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
@@ -206,8 +205,7 @@  recordmcount_source := $(srctree)/scripts/recordmcount.pl
 endif # BUILD_C_RECORDMCOUNT
 cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),	\
 	$(sub_cmd_record_mcount))
-endif # CC_USING_RECORD_MCOUNT
-endif # CONFIG_FTRACE_MCOUNT_RECORD
+endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
 
 ifdef CONFIG_STACK_VALIDATION
 ifneq ($(SKIP_STACK_VALIDATION),1)