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Message-Id: <1545062607-8599-10-git-send-email-yamada.masahiro@socionext.com>
Date: Tue, 18 Dec 2018 01:03:24 +0900
From: Masahiro Yamada <yamada.masahiro@...ionext.com>
To: x86@...nel.org, Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H . Peter Anvin" <hpa@...or.com>
Cc: Richard Biener <rguenther@...e.de>,
Segher Boessenkool <segher@...nel.crashing.org>,
Peter Zijlstra <peterz@...radead.org>,
Juergen Gross <jgross@...e.com>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Kees Cook <keescook@...omium.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Masahiro Yamada <yamada.masahiro@...ionext.com>,
Logan Gunthorpe <logang@...tatee.com>,
Nadav Amit <namit@...are.com>, linux-kbuild@...r.kernel.org,
linux-kernel@...r.kernel.org,
Michal Marek <michal.lkml@...kovi.net>
Subject: [PATCH v3 09/12] Revert "kbuild/Makefile: Prepare for using macros in inline assembly code to work around asm() related GCC inlining bugs"
This reverts commit 77b0bf55bc675233d22cd5df97605d516d64525e.
A few days after the patch set applied, discussion started to solve
the issue more elegantly with the help of compiler:
https://lkml.org/lkml/2018/10/7/92
The new syntax "asm inline" was implemented by Segher Boessenkool, and
now queued up for GCC 9. (People were positive even for back-porting it
to older compilers).
Since the in-kernel workarounds merged, some issues have been reported.
The current urgent issue is distro packages for module building. More
fundamentally, we cannot build external modules after 'make clean'
because *.s files are globally removed.
We could fix those in Makefiles, but I do not want to mess up the build
system any more.
Given that this issue will be solved in a cleaner way sooner or later,
let's revert the in-kernel workarounds, and wait for GCC 9.
Link: https://lkml.org/lkml/2018/11/15/467
Link: https://marc.info/?t=154212770600037&r=1&w=2
Reported-by: Sedat Dilek <sedat.dilek@...il.com> # deb/rpm package
Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc: Logan Gunthorpe <logang@...tatee.com>
Cc: Nadav Amit <namit@...are.com>
Cc: Segher Boessenkool <segher@...nel.crashing.org>
---
Makefile | 9 ++-------
arch/x86/Makefile | 7 -------
arch/x86/kernel/macros.S | 7 -------
scripts/Kbuild.include | 4 +---
scripts/mod/Makefile | 2 --
5 files changed, 3 insertions(+), 26 deletions(-)
delete mode 100644 arch/x86/kernel/macros.S
diff --git a/Makefile b/Makefile
index 56d5270..885c74b 100644
--- a/Makefile
+++ b/Makefile
@@ -1081,7 +1081,7 @@ scripts: scripts_basic scripts_dtc asm-generic gcc-plugins $(autoksyms_h)
# version.h and scripts_basic is processed / created.
# Listed in dependency order
-PHONY += prepare archprepare macroprepare prepare0 prepare1 prepare2 prepare3
+PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3
# prepare3 is used to check if we are building in a separate output directory,
# and if so do:
@@ -1104,9 +1104,7 @@ prepare2: prepare3 outputmakefile asm-generic
prepare1: prepare2 $(version_h) $(autoksyms_h) include/generated/utsrelease.h
$(cmd_crmodverdir)
-macroprepare: prepare1 archmacros
-
-archprepare: archheaders archscripts macroprepare scripts_basic
+archprepare: archheaders archscripts prepare1 scripts_basic
prepare0: archprepare gcc-plugins
$(Q)$(MAKE) $(build)=.
@@ -1174,9 +1172,6 @@ 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 75ef499..85a66c4 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -232,13 +232,6 @@ archscripts: scripts_basic
archheaders:
$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
-archmacros:
- $(Q)$(MAKE) $(build)=arch/x86/kernel arch/x86/kernel/macros.s
-
-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/macros.S b/arch/x86/kernel/macros.S
deleted file mode 100644
index cfc1c7d..0000000
--- a/arch/x86/kernel/macros.S
+++ /dev/null
@@ -1,7 +0,0 @@
-/* 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 bb01555..3d09844 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -115,9 +115,7 @@ __cc-option = $(call try-run,\
# 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.)
-# 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_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
# cc-option
# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
index a5b4af4..42c5d50 100644
--- a/scripts/mod/Makefile
+++ b/scripts/mod/Makefile
@@ -4,8 +4,6 @@ OBJECT_FILES_NON_STANDARD := y
hostprogs-y := modpost mk_elfconfig
always := $(hostprogs-y) empty.o
-CFLAGS_REMOVE_empty.o := $(ASM_MACRO_FLAGS)
-
modpost-objs := modpost.o file2alias.o sumversion.o
devicetable-offsets-file := devicetable-offsets.h
--
2.7.4
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