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Message-ID: <20180402095033.nfzcrmxvpm46dhbl@gmail.com>
Date: Mon, 2 Apr 2018 11:50:33 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/build changes for v4.17
Linus,
Please pull the latest x86-build-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-build-for-linus
# HEAD: d6289f36aa7d5893d091a7a0c67eee7798719f03 x86/build: Don't pass in -D__KERNEL__ multiple times
The biggest change is the forcing of asm-goto support on x86, which effectively
increases the GCC minimum supported version to gcc-4.5 (on x86).
There's also some Makefile and linker script cleanups.
out-of-topic modifications in x86-build-for-linus:
----------------------------------------------------
Makefile # e501ce957a78: x86: Force asm-goto
Thanks,
Ingo
------------------>
Cao jin (2):
x86/build: Drop superfluous ALIGN from the linker script
x86/build: Don't pass in -D__KERNEL__ multiple times
Peter Zijlstra (2):
x86: Force asm-goto
x86: Remove FAST_FEATURE_TESTS
Makefile | 13 +++++++------
arch/x86/Kconfig | 11 -----------
arch/x86/Makefile | 7 +++++--
arch/x86/boot/compressed/Makefile | 2 +-
arch/x86/include/asm/cpufeature.h | 8 --------
arch/x86/kernel/vmlinux.lds.S | 7 +++----
6 files changed, 16 insertions(+), 32 deletions(-)
diff --git a/Makefile b/Makefile
index d65e2e229017..6fb6fd28a124 100644
--- a/Makefile
+++ b/Makefile
@@ -494,6 +494,13 @@ RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG)))
export RETPOLINE_CFLAGS
+# check for 'asm goto'
+ifeq ($(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
+ CC_HAVE_ASM_GOTO := 1
+ KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
+ KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
+endif
+
ifeq ($(config-targets),1)
# ===========================================================================
# *config targets only - make sure prerequisites are updated, and descend
@@ -658,12 +665,6 @@ KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \
# Tell gcc to never replace conditional load with a non-conditional one
KBUILD_CFLAGS += $(call cc-option,--param=allow-store-data-races=0)
-# check for 'asm goto'
-ifeq ($(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
- KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
- KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
-endif
-
include scripts/Makefile.kcov
include scripts/Makefile.gcc-plugins
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 0fa71a78ec99..cb5b5907dbd6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -393,17 +393,6 @@ config X86_FEATURE_NAMES
If in doubt, say Y.
-config X86_FAST_FEATURE_TESTS
- bool "Fast CPU feature tests" if EMBEDDED
- default y
- ---help---
- Some fast-paths in the kernel depend on the capabilities of the CPU.
- Say Y here for the kernel to patch in the appropriate code at runtime
- based on the capabilities of the CPU. The infrastructure for patching
- code at runtime takes up some additional space; space-constrained
- embedded systems may wish to say N here to produce smaller, slightly
- slower code.
-
config X86_X2APIC
bool "Support x2apic"
depends on X86_LOCAL_APIC && X86_64 && (IRQ_REMAP || HYPERVISOR_GUEST)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 498c1b812300..a517852dad55 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -31,8 +31,7 @@ endif
CODE16GCC_CFLAGS := -m32 -Wa,$(srctree)/arch/x86/boot/code16gcc.h
M16_CFLAGS := $(call cc-option, -m16, $(CODE16GCC_CFLAGS))
-REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -D__KERNEL__ \
- -DDISABLE_BRANCH_PROFILING \
+REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -DDISABLE_BRANCH_PROFILING \
-Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
-fno-strict-aliasing -fomit-frame-pointer -fno-pic \
-mno-mmx -mno-sse
@@ -181,6 +180,10 @@ ifdef CONFIG_FUNCTION_GRAPH_TRACER
endif
endif
+ifndef CC_HAVE_ASM_GOTO
+ $(error Compiler lacks asm-goto support.)
+endif
+
#
# Jump labels need '-maccumulate-outgoing-args' for gcc < 4.5.2 to prevent a
# GCC bug (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226). There's no way
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index f25e1530e064..f484ae0ece93 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -26,7 +26,7 @@ KCOV_INSTRUMENT := n
targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4
-KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ -O2
+KBUILD_CFLAGS := -m$(BITS) -O2
KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC)
KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
cflags-$(CONFIG_X86_32) := -march=i386
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 736771c9822e..b27da9602a6d 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -140,7 +140,6 @@ extern void clear_cpu_cap(struct cpuinfo_x86 *c, unsigned int bit);
#define setup_force_cpu_bug(bit) setup_force_cpu_cap(bit)
-#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_X86_FAST_FEATURE_TESTS)
/*
* Static testing of CPU features. Used the same as boot_cpu_has().
* These will statically patch the target code for additional
@@ -196,13 +195,6 @@ static __always_inline __pure bool _static_cpu_has(u16 bit)
boot_cpu_has(bit) : \
_static_cpu_has(bit) \
)
-#else
-/*
- * Fall back to dynamic for gcc versions which don't support asm goto. Should be
- * a minority now anyway.
- */
-#define static_cpu_has(bit) boot_cpu_has(bit)
-#endif
#define cpu_has_bug(c, bit) cpu_has(c, (bit))
#define set_cpu_bug(c, bit) set_cpu_cap(c, (bit))
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index b854ebf5851b..795f3a80e576 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -102,7 +102,6 @@ SECTIONS
_stext = .;
/* bootstrapping code */
HEAD_TEXT
- . = ALIGN(8);
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
@@ -200,7 +199,7 @@ SECTIONS
. = __vvar_beginning_hack + PAGE_SIZE;
} :data
- . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
+ . = ALIGN(__vvar_page + PAGE_SIZE, PAGE_SIZE);
/* Init code and data - will be freed after init */
. = ALIGN(PAGE_SIZE);
@@ -368,8 +367,8 @@ SECTIONS
. = ALIGN(PAGE_SIZE); /* keep VO_INIT_SIZE page aligned */
_end = .;
- STABS_DEBUG
- DWARF_DEBUG
+ STABS_DEBUG
+ DWARF_DEBUG
/* Sections to be discarded */
DISCARDS
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