From: changbin.du@intel.com
To: yamada.masahiro@socionext.com, michal.lkml@markovi.net,
tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org
Cc: x86@kernel.org, lgirdwood@gmail.com, broonie@kernel.org,
arnd@arndb.de, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
Changbin Du <changbin.du@intel.com>,
Steven Rostedt <rostedt@goodmis.org>
Subject: [PATCH 3/5] kernel hacking: new config NO_AUTO_INLINE to disable compiler atuo-inline optimizations
Date: Tue, 1 May 2018 21:00:12 +0800 [thread overview]
Message-ID: <1525179614-14571-4-git-send-email-changbin.du@intel.com> (raw)
In-Reply-To: <1525179614-14571-1-git-send-email-changbin.du@intel.com>
From: Changbin Du <changbin.du@intel.com>
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@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
---
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
next prev parent reply other threads:[~2018-05-01 13:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-01 13:00 [PATCH 0/5] kernel hacking: GCC optimization for debug experience (-Og) changbin.du
2018-05-01 13:00 ` [PATCH 1/5] x86/mm: surround level4_kernel_pgt with #ifdef CONFIG_X86_5LEVEL...#endif changbin.du
2018-05-01 13:00 ` [PATCH 2/5] regulator: add dummy of_find_regulator_by_node changbin.du
2018-05-01 20:40 ` Mark Brown
2018-05-02 9:24 ` Du, Changbin
2018-05-05 1:44 ` Applied "regulator: add dummy function of_find_regulator_by_node" to the regulator tree Mark Brown
2018-05-05 1:44 ` Mark Brown
2018-05-05 1:44 ` Mark Brown
2018-05-01 13:00 ` changbin.du [this message]
2018-05-01 14:54 ` [PATCH 3/5] kernel hacking: new config NO_AUTO_INLINE to disable compiler atuo-inline optimizations Steven Rostedt
2018-05-02 9:27 ` Du, Changbin
2018-05-01 13:00 ` [PATCH 4/5] kernel hacking: new config DEBUG_EXPERIENCE to apply GCC -Og optimization changbin.du
2018-05-01 15:25 ` Randy Dunlap
2018-05-02 9:24 ` Du, Changbin
2018-05-02 20:30 ` Arnd Bergmann
2018-05-01 13:00 ` [PATCH 5/5] asm-generic: fix build error in fix_to_virt with CONFIG_DEBUG_EXPERIENCE changbin.du
2018-05-02 7:33 ` [PATCH 0/5] kernel hacking: GCC optimization for debug experience (-Og) Ingo Molnar
2018-05-02 9:07 ` Du, Changbin
2018-05-02 11:09 ` Ingo Molnar
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