Kbuild people - for the lack of a way to doing toolchain dependencies in
Kconfig I'm doing this right now for x32 support. I am a little unclear
if this is the right thing to do, especially if I should be using := or
= here.
-hpa
-------- Original Message --------
Subject: [tip:x86/x32] x32: Warn and disable rather than error if
binutils too old
Date: Mon, 27 Feb 2012 14:21:55 -0800
From: tip-bot for H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Reply-To: mingo@xxxxxxxxxx, hpa@xxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx,
tglx@xxxxxxxxxxxxx, hpa@xxxxxxxxxxxxxxx, mingo@xxxxxxx,
hjl.tools@xxxxxxxxx
To: linux-tip-commits@xxxxxxxxxxxxxxx
CC: linux-kernel@xxxxxxxxxxxxxxx, hpa@xxxxxxxxx, mingo@xxxxxxxxxx,
tglx@xxxxxxxxxxxxx, hpa@xxxxxxxxxxxxxxx, hjl.tools@xxxxxxxxx,
mingo@xxxxxxx
Commit-ID: 0bf6276392e990dd0da0ccd8e10f42597d503f29
Gitweb:
http://git.kernel.org/tip/0bf6276392e990dd0da0ccd8e10f42597d503f29
Author: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 27 Feb 2012 14:09:10 -0800
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Mon, 27 Feb 2012 14:09:10 -0800
x32: Warn and disable rather than error if binutils too old
If X32 is enabled in .config, but the binutils can't build it, issue a
warning and disable the feature rather than erroring out.
In order to support this, have CONFIG_X86_X32 be the option set in
Kconfig, and CONFIG_X86_X32_ABI be the option set by the Makefile when
it is enabled and binutils has been found to be functional.
Requested-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Cc: H. J. Lu <hjl.tools@xxxxxxxxx>
Link:
http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@xxxxxxxxx
---
arch/x86/Kconfig | 4 ++--
arch/x86/Makefile | 16 ++++++++++++++++
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c9d6c9e..e2b38b4 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2175,7 +2175,7 @@ config IA32_AOUT
---help---
Support old a.out binaries in the 32bit emulation.
-config X86_X32_ABI
+config X86_X32
bool "x32 ABI for 64-bit mode (EXPERIMENTAL)"
depends on X86_64 && IA32_EMULATION && EXPERIMENTAL
---help---
@@ -2190,7 +2190,7 @@ config X86_X32_ABI
config COMPAT
def_bool y
- depends on IA32_EMULATION || X86_X32_ABI
+ depends on IA32_EMULATION || X86_X32
config COMPAT_FOR_U64_ALIGNMENT
def_bool COMPAT
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 209ba12..31bb1eb 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -82,6 +82,22 @@ ifdef CONFIG_CC_STACKPROTECTOR
endif
endif
+ifdef CONFIG_X86_X32
+ x32_ld_ok := $(call try-run,\
+ /bin/echo -e '1: .quad 1b' | \
+ $(CC) $(KBUILD_AFLAGS) -c -xassembler -o "$$TMP" - && \
+ $(OBJCOPY) -O elf32-x86-64 "$$TMP" "$$TMPO" && \
+ $(LD) -m elf32_x86_64 "$$TMPO" -o "$$TMP",y,n)
+ ifeq ($(x32_ld_ok),y)
+ CONFIG_X86_X32_ABI := y
+ KBUILD_AFLAGS += -DCONFIG_X86_X32_ABI
+ KBUILD_CFLAGS += -DCONFIG_X86_X32_ABI
+ else
+ $(warning CONFIG_X86_X32 enabled but no binutils support)
+ endif
+endif
+export CONFIG_X86_X32_ABI
+
# Don't unroll struct assignments with kmemcheck enabled
ifeq ($(CONFIG_KMEMCHECK),y)
KBUILD_CFLAGS += $(call cc-option,-fno-builtin-memcpy)
--
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