From: Changbin Du <changbin.du@xxxxxxxxx> This patch add a new kernel hacking option NO_AUTO_INLINE. Selecting this option will make compiler not auto-inline kernel functions. By enabling this option, all the kernel functions (including static ones) will not be optimized out except those marked as inline or always_inline. This is useful when you are using ftrace to understand the control flow of kernel code or tracing some static functions. Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> --- Makefile | 6 ++++++ lib/Kconfig.debug | 13 +++++++++++++ 2 files changed, 19 insertions(+) diff --git a/Makefile b/Makefile index 619a85a..eb694f6 100644 --- a/Makefile +++ b/Makefile @@ -775,6 +775,12 @@ KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \ $(call cc-option,-fno-var-tracking) endif +ifdef CONFIG_NO_AUTO_INLINE +KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions) \ + $(call cc-option, -fno-inline-small-functions) \ + $(call cc-option, -fno-inline-functions-called-once) +endif + ifdef CONFIG_FUNCTION_TRACER ifndef CC_FLAGS_FTRACE CC_FLAGS_FTRACE := -pg diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c40c7b7..90f35ad 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -198,6 +198,19 @@ config GDB_SCRIPTS instance. See Documentation/dev-tools/gdb-kernel-debugging.rst for further details. +config NO_AUTO_INLINE + bool "Disable compiler atuo-inline optimizations" + default n + help + This will make compiler not auto-inline kernel functions for + optimization. By enabling this option, all the kernel functions + (including static ones) will not be optimized out except those + marked as inline or always_inline. This is useful when you are + using ftrace to understand the control flow of kernel code or + tracing some static functions. + + Use only if you want to debug the kernel. + config ENABLE_WARN_DEPRECATED bool "Enable __deprecated logic" default y -- 2.7.4
