From 22c8542d7b220ffc53816d47b371b1fe34341d4a Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Fri, 25 Sep 2020 16:43:53 -0700 Subject: [PATCH] tracing: add support for objtool mcount This change adds build support for using objtool to generate __mcount_loc sections. Signed-off-by: Sami Tolvanen --- Makefile | 7 +++++++ kernel/trace/Kconfig | 13 +++++++++++++ scripts/Makefile.build | 3 +++ 3 files changed, 23 insertions(+) diff --git a/Makefile b/Makefile index 2233951666f7..3189eacf3185 100644 --- a/Makefile +++ b/Makefile @@ -860,6 +860,9 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_CC endif endif endif +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL + CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT +endif ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT ifdef CONFIG_HAVE_C_RECORDMCOUNT BUILD_C_RECORDMCOUNT := y @@ -1236,6 +1239,10 @@ uapi-asm-generic: PHONY += prepare-objtool prepare-resolve_btfids prepare-objtool: $(objtool_target) ifeq ($(SKIP_STACK_VALIDATION),1) +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL + @echo "error: Cannot generate __mcount_loc for CONFIG_DYNAMIC_FTRACE=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2 + @false +endif ifdef CONFIG_UNWINDER_ORC @echo "error: Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2 @false diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 3985a31a49b7..936ccab1b938 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -60,6 +60,11 @@ config HAVE_NOP_MCOUNT help Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount +config HAVE_OBJTOOL_MCOUNT + bool + help + Arch supports objtool --mcount + config HAVE_C_RECORDMCOUNT bool help @@ -612,10 +617,18 @@ config FTRACE_MCOUNT_USE_CC depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY depends on FTRACE_MCOUNT_RECORD +config FTRACE_MCOUNT_USE_OBJTOOL + def_bool y + depends on HAVE_OBJTOOL_MCOUNT + depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY + depends on !FTRACE_MCOUNT_USE_CC + 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_USE_OBJTOOL depends on FTRACE_MCOUNT_RECORD config TRACING_MAP diff --git a/scripts/Makefile.build b/scripts/Makefile.build index d94fc9ab819d..59fabd9685ee 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -238,6 +238,9 @@ endif ifdef CONFIG_X86_SMAP objtool_args += --uaccess endif +ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL + objtool_args += --mcount +endif # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file