| From foo@baz Wed Nov 21 18:50:25 CET 2018 |
| From: Matthias Kaehlcke <mka@chromium.org> |
| Date: Thu, 13 Apr 2017 10:26:09 -0700 |
| Subject: x86/kbuild: Use cc-option to enable -falign-{jumps/loops} |
| |
| From: Matthias Kaehlcke <mka@chromium.org> |
| |
| commit 2c4fd1ac3ff167c91272dc43c7bfd2269ef61557 upstream. |
| |
| clang currently does not support these optimizations, only enable them |
| when they are available. |
| |
| Signed-off-by: Matthias Kaehlcke <mka@chromium.org> |
| Cc: Greg Hackmann <ghackmann@google.com> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Masahiro Yamada <yamada.masahiro@socionext.com> |
| Cc: Michael Davidson <md@google.com> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Cc: grundler@chromium.org |
| Link: http://lkml.kernel.org/r/20170413172609.118122-1-mka@chromium.org |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/x86/Makefile | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/arch/x86/Makefile |
| +++ b/arch/x86/Makefile |
| @@ -88,10 +88,10 @@ else |
| KBUILD_CFLAGS += -m64 |
| |
| # Align jump targets to 1 byte, not the default 16 bytes: |
| - KBUILD_CFLAGS += -falign-jumps=1 |
| + KBUILD_CFLAGS += $(call cc-option,-falign-jumps=1) |
| |
| # Pack loops tightly as well: |
| - KBUILD_CFLAGS += -falign-loops=1 |
| + KBUILD_CFLAGS += $(call cc-option,-falign-loops=1) |
| |
| # Don't autogenerate traditional x87 instructions |
| KBUILD_CFLAGS += $(call cc-option,-mno-80387) |
