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| author | Andi Kleen <ak@suse.de> | 2006-09-26 10:52:30 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-09-26 10:52:30 +0200 |
| commit | e2414910f212c52d9d7c64c99a22863488ac5b48 (patch) | |
| tree | 5a7e55191ace4aa755c0684bcefc9cf1b124128c | |
| parent | fe7414a2882c953788af13a7f2c9d570ed8f71c5 (diff) | |
| download | lwn-e2414910f212c52d9d7c64c99a22863488ac5b48.tar.gz lwn-e2414910f212c52d9d7c64c99a22863488ac5b48.zip | |
[PATCH] x86: Detect CFI support in the assembler at runtime
... instead of using a CONFIG option. The config option still controls
if the resulting executable actually has unwind information.
This is useful to prevent compilation errors when users select
CONFIG_STACK_UNWIND on old binutils and also allows to use
CFI in the future for non kernel debugging applications.
Cc: jbeulich@novell.com
Cc: sam@ravnborg.org
Signed-off-by: Andi Kleen <ak@suse.de>
| -rw-r--r-- | Documentation/kbuild/makefiles.txt | 5 | ||||
| -rw-r--r-- | arch/i386/Makefile | 4 | ||||
| -rw-r--r-- | arch/x86_64/Makefile | 3 | ||||
| -rw-r--r-- | include/asm-x86_64/dwarf2.h | 2 | ||||
| -rw-r--r-- | scripts/Kbuild.include | 7 |
5 files changed, 20 insertions, 1 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index b7d6abb501a6..e2cbd59cf2d0 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -421,6 +421,11 @@ more details, with real examples. The second argument is optional, and if supplied will be used if first argument is not supported. + as-instr + as-instr checks if the assembler reports a specific instruction + and then outputs either option1 or option2 + C escapes are supported in the test instruction + cc-option cc-option is used to check if $(CC) supports a given option, and not supported to use an optional second option. diff --git a/arch/i386/Makefile b/arch/i386/Makefile index 3e4adb1e2244..508cdbeb3a09 100644 --- a/arch/i386/Makefile +++ b/arch/i386/Makefile @@ -46,6 +46,10 @@ cflags-y += -ffreestanding # a lot more stack due to the lack of sharing of stacklots: CFLAGS += $(shell if [ $(call cc-version) -lt 0400 ] ; then echo $(call cc-option,-fno-unit-at-a-time); fi ;) +# do binutils support CFI? +cflags-y += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,) +AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,) + CFLAGS += $(cflags-y) # Default subarch .c files diff --git a/arch/x86_64/Makefile b/arch/x86_64/Makefile index 431bb4bc36cd..d6472ddf5f6e 100644 --- a/arch/x86_64/Makefile +++ b/arch/x86_64/Makefile @@ -54,6 +54,9 @@ endif cflags-y += $(call cc-option,-funit-at-a-time) # prevent gcc from generating any FP code by mistake cflags-y += $(call cc-option,-mno-sse -mno-mmx -mno-sse2 -mno-3dnow,) +# do binutils support CFI? +cflags-y += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,) +AFLAGS += $(call as-instr,.cfi_startproc\n.cfi_endproc,-DCONFIG_AS_CFI=1,) CFLAGS += $(cflags-y) CFLAGS_KERNEL += $(cflags-kernel-y) diff --git a/include/asm-x86_64/dwarf2.h b/include/asm-x86_64/dwarf2.h index 0744db777676..2b9368365fad 100644 --- a/include/asm-x86_64/dwarf2.h +++ b/include/asm-x86_64/dwarf2.h @@ -13,7 +13,7 @@ away for older version. */ -#ifdef CONFIG_UNWIND_INFO +#ifdef CONFIG_AS_CFI #define CFI_STARTPROC .cfi_startproc #define CFI_ENDPROC .cfi_endproc diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 3d523899fdc0..7adef12a0c26 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -63,6 +63,13 @@ as-option = $(shell if $(CC) $(CFLAGS) $(1) -Wa,-Z -c -o /dev/null \ -xassembler /dev/null > /dev/null 2>&1; then echo "$(1)"; \ else echo "$(2)"; fi ;) +# as-instr +# Usage: cflags-y += $(call as-instr, instr, option1, option2) + +as-instr = $(shell if echo -e "$(1)" | $(AS) -Z -o astest$$$$.out \ + 2>&1 >/dev/null ; then echo "$(2)"; else echo "$(3)"; fi; \ + rm -f astest$$$$.out) + # cc-option # Usage: cflags-y += $(call cc-option, -march=winchip-c6, -march=i586) |