[PATCH] x86/build: Move max-page-size option to LDFLAGS_vmlinux

[PATCH] x86/build: Move max-page-size option to LDFLAGS_vmlinux

[Arvind Sankar]

This option is only required for vmlinux on 64-bit, to enforce 2MiB
alignment, so set it in LDFLAGS_vmlinux instead of KBUILD_LDFLAGS. Also
drop the ld-option check: this option was added in binutils-2.18 and all
the other places that use it already don't have the check.

This reduces the size of the intermediate ELF files
arch/x86/boot/setup.elf and arch/x86/realmode/rm/realmode.elf by about
2MiB each. The binary versions are unchanged.

Move the LDFLAGS settings to all be together and just after CFLAGS
settings are done.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
---
 arch/x86/Makefile | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 00e378de8bc0..1e634d7ee6eb 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -47,10 +47,6 @@ export REALMODE_CFLAGS
 # e.g.: obj-y += foo_$(BITS).o
 export BITS
 
-ifdef CONFIG_X86_NEED_RELOCS
-        LDFLAGS_vmlinux := --emit-relocs --discard-none
-endif
-
 #
 # Prevent GCC from generating any FP code by mistake.
 #
@@ -177,17 +173,6 @@ ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
 	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
 endif
 
-KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
-
-#
-# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
-# the linker to force 2MB page size regardless of the default page size used
-# by the linker.
-#
-ifdef CONFIG_X86_64
-KBUILD_LDFLAGS += $(call ld-option, -z max-page-size=0x200000)
-endif
-
 # Workaround for a gcc prelease that unfortunately was shipped in a suse release
 KBUILD_CFLAGS += -Wno-sign-compare
 #
@@ -207,6 +192,23 @@ ifdef CONFIG_RETPOLINE
   endif
 endif
 
+KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
+
+ifdef CONFIG_X86_NEED_RELOCS
+LDFLAGS_vmlinux := --emit-relocs --discard-none
+else
+LDFLAGS_vmlinux :=
+endif
+
+#
+# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
+# the linker to force 2MB page size regardless of the default page size used
+# by the linker.
+#
+ifdef CONFIG_X86_64
+LDFLAGS_vmlinux += -z max-page-size=0x200000
+endif
+
 archscripts: scripts_basic
 	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
 
-- 
2.26.2

[tip: x86/build] x86/build: Move max-page-size option to LDFLAGS_vmlinux

[tip-bot2 for Arvind Sankar]

The following commit has been merged into the x86/build branch of tip:

Commit-ID:     587af649bcc04eb016822f209a975005c0092151
Gitweb:        https://git.kernel.org/tip/587af649bcc04eb016822f209a975005c0092151
Author:        Arvind Sankar <nivedita@alum.mit.edu>
AuthorDate:    Wed, 22 Jul 2020 14:43:34 -04:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Fri, 24 Jul 2020 16:39:27 +02:00

x86/build: Move max-page-size option to LDFLAGS_vmlinux

This option is only required for vmlinux on 64-bit, to enforce 2MiB
alignment, so set it in LDFLAGS_vmlinux instead of KBUILD_LDFLAGS. Also
drop the ld-option check: this option was added in binutils-2.18 and all
the other places that use it already don't have the check.

This reduces the size of the intermediate ELF files
arch/x86/boot/setup.elf and arch/x86/realmode/rm/realmode.elf by about
2MiB each. The binary versions are unchanged.

Move the LDFLAGS settings to all be together and just after CFLAGS
settings are done.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Link: https://lore.kernel.org/r/20200722184334.3785418-1-nivedita@alum.mit.edu
---
 arch/x86/Makefile | 32 +++++++++++++++++---------------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 00e378d..1e634d7 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -47,10 +47,6 @@ export REALMODE_CFLAGS
 # e.g.: obj-y += foo_$(BITS).o
 export BITS
 
-ifdef CONFIG_X86_NEED_RELOCS
-        LDFLAGS_vmlinux := --emit-relocs --discard-none
-endif
-
 #
 # Prevent GCC from generating any FP code by mistake.
 #
@@ -177,17 +173,6 @@ ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
 	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
 endif
 
-KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
-
-#
-# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
-# the linker to force 2MB page size regardless of the default page size used
-# by the linker.
-#
-ifdef CONFIG_X86_64
-KBUILD_LDFLAGS += $(call ld-option, -z max-page-size=0x200000)
-endif
-
 # Workaround for a gcc prelease that unfortunately was shipped in a suse release
 KBUILD_CFLAGS += -Wno-sign-compare
 #
@@ -207,6 +192,23 @@ ifdef CONFIG_RETPOLINE
   endif
 endif
 
+KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
+
+ifdef CONFIG_X86_NEED_RELOCS
+LDFLAGS_vmlinux := --emit-relocs --discard-none
+else
+LDFLAGS_vmlinux :=
+endif
+
+#
+# The 64-bit kernel must be aligned to 2MB.  Pass -z max-page-size=0x200000 to
+# the linker to force 2MB page size regardless of the default page size used
+# by the linker.
+#
+ifdef CONFIG_X86_64
+LDFLAGS_vmlinux += -z max-page-size=0x200000
+endif
+
 archscripts: scripts_basic
 	$(Q)$(MAKE) $(build)=arch/x86/tools relocs