From: Nadav Amit <namit@vmware.com>
To: <linux-kernel@vger.kernel.org>, <x86@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Subject: [PATCH v2 1/9] Makefile: Prepare for using macros for inline asm
Date: Mon, 4 Jun 2018 04:21:23 -0700 [thread overview]
Message-ID: <20180604112131.59100-2-namit@vmware.com> (raw)
In-Reply-To: <20180604112131.59100-1-namit@vmware.com>
Using macros for inline assembly improves both readability and
compilation decisions that are distorted by big assembly blocks that use
alternative sections. Compile macros.S and use it to assemble all C
files. Currently, only x86 will use it.
Signed-off-by: Nadav Amit <namit@vmware.com>
---
Makefile | 9 +++++++--
arch/x86/Makefile | 11 +++++++++--
arch/x86/kernel/Makefile | 6 ++++++
arch/x86/kernel/macros.S | 7 +++++++
scripts/Kbuild.include | 4 +++-
5 files changed, 32 insertions(+), 5 deletions(-)
create mode 100644 arch/x86/kernel/macros.S
diff --git a/Makefile b/Makefile
index 619a85ad716b..c255ed4841d5 100644
--- a/Makefile
+++ b/Makefile
@@ -1082,7 +1082,7 @@ scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \
# version.h and scripts_basic is processed / created.
# Listed in dependency order
-PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3
+PHONY += prepare archprepare macroprepare prepare0 prepare1 prepare2 prepare3
# prepare3 is used to check if we are building in a separate output directory,
# and if so do:
@@ -1106,7 +1106,9 @@ prepare1: prepare2 $(version_h) $(autoksyms_h) include/generated/utsrelease.h \
include/config/auto.conf
$(cmd_crmodverdir)
-archprepare: archheaders archscripts prepare1 scripts_basic
+macroprepare: prepare1 archmacros
+
+archprepare: archheaders archscripts macroprepare scripts_basic
prepare0: archprepare gcc-plugins
$(Q)$(MAKE) $(build)=.
@@ -1211,6 +1213,9 @@ archheaders:
PHONY += archscripts
archscripts:
+PHONY += archmacros
+archmacros:
+
PHONY += __headers
__headers: $(version_h) scripts_basic uapi-asm-generic archheaders archscripts
$(Q)$(MAKE) $(build)=scripts build_unifdef
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 60135cbd905c..6b82314776fd 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -235,8 +235,8 @@ ifdef CONFIG_X86_64
LDFLAGS += $(call ld-option, -z max-page-size=0x200000)
endif
-# Speed up the build
-KBUILD_CFLAGS += -pipe
+# We cannot use -pipe flag since we give an additional .s file to the compiler
+#KBUILD_CFLAGS += -pipe
# Workaround for a gcc prelease that unfortunately was shipped in a suse release
KBUILD_CFLAGS += -Wno-sign-compare
#
@@ -258,11 +258,18 @@ archscripts: scripts_basic
archheaders:
$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
+archmacros:
+ $(Q)$(MAKE) $(build)=arch/x86/kernel macros
+
archprepare:
ifeq ($(CONFIG_KEXEC_FILE),y)
$(Q)$(MAKE) $(build)=arch/x86/purgatory arch/x86/purgatory/kexec-purgatory.c
endif
+ASM_MACRO_FLAGS = -Wa,arch/x86/kernel/macros.s
+export ASM_MACRO_FLAGS
+KBUILD_CFLAGS += $(ASM_MACRO_FLAGS)
+
###
# Kernel objects
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 02d6f5cf4e70..fdb6c5b2a922 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -9,6 +9,12 @@ extra-y += ebda.o
extra-y += platform-quirks.o
extra-y += vmlinux.lds
+$(obj)/macros.s: $(obj)/macros.S FORCE
+ $(call if_changed_dep,cpp_s_S)
+
+macros: $(obj)/macros.s
+ @:
+
CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
ifdef CONFIG_FUNCTION_TRACER
diff --git a/arch/x86/kernel/macros.S b/arch/x86/kernel/macros.S
new file mode 100644
index 000000000000..cfc1c7d1a6eb
--- /dev/null
+++ b/arch/x86/kernel/macros.S
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * This file includes headers whose assembly part includes macros which are
+ * commonly used. The macros are precompiled into assmebly file which is later
+ * assembled together with each compiled file.
+ */
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 50cee534fd64..ad2c02062aa4 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -189,7 +189,9 @@ __cc-option = $(call try-run-cached,\
# Do not attempt to build with gcc plugins during cc-option tests.
# (And this uses delayed resolution so the flags will be up to date.)
-CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
+# In addition, do not include the asm macros which are built later.
+CC_OPTION_FILTERED = $(GCC_PLUGINS_CFLAGS) $(ASM_MACRO_FLAGS)
+CC_OPTION_CFLAGS = $(filter-out $(CC_OPTION_FILTERED),$(KBUILD_CFLAGS))
# cc-option
# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
--
2.17.0
next prev parent reply other threads:[~2018-06-04 18:36 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-04 11:21 [PATCH v2 0/9] x86: macrofying inline asm for better compilation Nadav Amit
2018-06-04 11:21 ` Nadav Amit [this message]
2018-06-04 11:21 ` [PATCH v2 2/9] x86: objtool: use asm macro for better compiler decisions Nadav Amit
2018-06-04 19:04 ` Josh Poimboeuf
2018-06-05 5:41 ` kbuild test robot
2018-06-04 11:21 ` [PATCH v2 3/9] x86: refcount: prevent gcc distortions Nadav Amit
2018-06-04 22:06 ` Kees Cook
2018-06-04 22:20 ` Nadav Amit
2018-06-05 8:26 ` kbuild test robot
2018-06-04 11:21 ` [PATCH v2 4/9] x86: alternatives: macrofy locks for better inlining Nadav Amit
2018-06-05 5:36 ` kbuild test robot
2018-06-05 14:07 ` kbuild test robot
2018-06-07 3:05 ` [lkp-robot] [x86] 1a39381d70: WARNING:at_kernel/locking/mutex.c:#__mutex_unlock_slowpath kernel test robot
2018-06-04 11:21 ` [PATCH v2 5/9] x86: bug: prevent gcc distortions Nadav Amit
2018-06-05 7:34 ` kbuild test robot
2018-06-04 11:21 ` [PATCH v2 6/9] x86: prevent inline distortion by paravirt ops Nadav Amit
2018-06-04 11:21 ` [PATCH v2 7/9] x86: extable: use macros instead of inline assembly Nadav Amit
2018-06-04 11:21 ` [PATCH v2 8/9] x86: cpufeature: " Nadav Amit
2018-06-04 11:21 ` [PATCH v2 9/9] x86: jump-labels: " Nadav Amit
2018-06-04 19:05 ` [PATCH v2 0/9] x86: macrofying inline asm for better compilation Josh Poimboeuf
2018-06-04 19:56 ` Nadav Amit
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