tracing: move function tracer options to Kconfig

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.

Note that FTRACE_MCOUNT_USE_* options are updated on rebuild and
therefore, work even if the .config was generated in a different
environment.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-2-samitolvanen@google.com

diff --git a/Makefile b/Makefile
index 8b2c3f88ee5ea6c711f3d859d45817de325ab707..b434c342080bc5f47e38d356cb55e6c383fd6e9a 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -851,12 +851,8 @@ 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
@@ -864,6 +860,12 @@ 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
@@ -873,12 +875,6 @@ 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 d5a19413d4f8a3945cdb53cd64c2fd887773730d..3985a31a49b7f1355d4632af760ce98d611c8b67 100644 (file)
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -602,6 +602,22 @@ 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 4c058f12dd73cb6d2d3832788f25daa9d2b413d6..22654a463ad817fa3959adb67080d71672c16714 100644 (file)
--- 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)