From: Jan-Simon Möller <[email protected]> This patch adds switches for -falign-jumps=1 and -falign-loops=1
Default is off by intention to allow seamless operation. Signed-off-by: Jan-Simon Möller <[email protected]> CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] CC: [email protected] --- arch/x86/Kconfig | 22 ++++++++++++++++++++++ arch/x86/Makefile | 4 ++++ 2 files changed, 26 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index b3a1a5d..ebd4b03 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -644,6 +644,28 @@ config SCHED_OMIT_FRAME_POINTER If in doubt, say "Y". +config ALIGN_JUMP_TARGETS_NONDEFAULT + bool "Align jump targets to 1 byte" + default n + ---help--- + Align jump targets to 1 byte, not the default 16 bytes. + This results in a smaller packaging of the Kernel + (around 300k in a usual configuration) by removing + noops that would otherwise be inserted for + alignment reasons. + The default is off to make sure all compilers work. + +config ALIGN_LOOPS_NONDEFAULT + bool "Pack loops tightly" + default n + ---help--- + Align loops to 1 byte, not the default 16 bytes. + This results in a smaller packaging of the Kernel + by removing noops that would otherwise be inserted for + alignment reasons. + The default is off to make sure all compilers work. + + menuconfig HYPERVISOR_GUEST bool "Linux guest support" ---help--- diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 118e6de..38c38f4 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -77,11 +77,15 @@ else KBUILD_AFLAGS += -m64 KBUILD_CFLAGS += -m64 +ifdef ALIGN_JUMP_TARGETS_NONDEFAULT # Align jump targets to 1 byte, not the default 16 bytes: KBUILD_CFLAGS += -falign-jumps=1 +endif +ifdef ALIGN_LOOPS_NONDEFAULT # Pack loops tightly as well: KBUILD_CFLAGS += -falign-loops=1 +endif # Don't autogenerate traditional x87 instructions KBUILD_CFLAGS += $(call cc-option,-mno-80387) -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
