linux/tools/objtool/Makefile
Josh Poimboeuf c1d45c3abd objtool: Support CROSS_COMPILE
When building with CONFIG_STACK_VALIDATION on a ppc64le host with an x86
cross-compiler, Stephen Rothwell saw the following objtool build errors:

    DESCEND  objtool
    CC       /home/sfr/next/x86_64_allmodconfig/tools/objtool/builtin-check.o
    CC       /home/sfr/next/x86_64_allmodconfig/tools/objtool/special.o
    CC       /home/sfr/next/x86_64_allmodconfig/tools/objtool/elf.o
    CC       /home/sfr/next/x86_64_allmodconfig/tools/objtool/objtool.o
    MKDIR    /home/sfr/next/x86_64_allmodconfig/tools/objtool/arch/x86/insn/
    CC       /home/sfr/next/x86_64_allmodconfig/tools/objtool/libstring.o
  elf.c:22:23: fatal error: sys/types.h: No such file or directory
  compilation terminated.
    CC       /home/sfr/next/x86_64_allmodconfig/tools/objtool/exec-cmd.o
    CC       /home/sfr/next/x86_64_allmodconfig/tools/objtool/help.o
  builtin-check.c:28:20: fatal error: string.h: No such file or directory
  compilation terminated.
  objtool.c:28:19: fatal error: stdio.h: No such file or directory
  compilation terminated.

It fails to build because it tries to compile objtool with the
cross-compiler instead of the host compiler.

Ensure that it always uses the host compiler by ignoring CROSS_COMPILE.

In order to do that properly, the libsubcmd.a library needs to be built
in tools/objtool/ rather than tools/lib/subcmd/.  The latter directory
contains the cross-compiled version which is needed for perf and
possibly other tools.

Note that cross-compiling for x86 on a _big_ endian system would result
in a bunch of false positive objtool warnings during the kernel build
because it isn't endian-aware.  But that's generally a rare edge case
and there haven't been any reports of anybody needing that.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/55b63eefc347f1bb28573f972d8d1adbf1f1c31d.1456962210.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-03 16:13:00 +01:00

64 lines
2.0 KiB
Makefile

include ../scripts/Makefile.include
ifndef ($(ARCH))
ARCH ?= $(shell uname -m)
ifeq ($(ARCH),x86_64)
ARCH := x86
endif
endif
# always use the host compiler
CC = gcc
LD = ld
AR = ar
ifeq ($(srctree),)
srctree := $(patsubst %/,%,$(dir $(shell pwd)))
srctree := $(patsubst %/,%,$(dir $(srctree)))
endif
SUBCMD_SRCDIR = $(srctree)/tools/lib/subcmd/
LIBSUBCMD_OUTPUT = $(if $(OUTPUT),$(OUTPUT),$(PWD)/)
LIBSUBCMD = $(LIBSUBCMD_OUTPUT)libsubcmd.a
OBJTOOL := $(OUTPUT)objtool
OBJTOOL_IN := $(OBJTOOL)-in.o
all: $(OBJTOOL)
INCLUDES := -I$(srctree)/tools/include
CFLAGS += -Wall -Werror $(EXTRA_WARNINGS) -fomit-frame-pointer -O2 $(INCLUDES)
LDFLAGS += -lelf $(LIBSUBCMD)
AWK = awk
export srctree OUTPUT CFLAGS ARCH AWK
include $(srctree)/tools/build/Makefile.include
$(OBJTOOL_IN): fixdep FORCE
@$(MAKE) $(build)=objtool
$(OBJTOOL): $(LIBSUBCMD) $(OBJTOOL_IN)
@(test -d ../../kernel -a -d ../../tools -a -d ../objtool && (( \
diff -I'^#include' arch/x86/insn/insn.c ../../arch/x86/lib/insn.c >/dev/null && \
diff -I'^#include' arch/x86/insn/inat.c ../../arch/x86/lib/inat.c >/dev/null && \
diff arch/x86/insn/x86-opcode-map.txt ../../arch/x86/lib/x86-opcode-map.txt >/dev/null && \
diff arch/x86/insn/gen-insn-attr-x86.awk ../../arch/x86/tools/gen-insn-attr-x86.awk >/dev/null && \
diff -I'^#include' arch/x86/insn/insn.h ../../arch/x86/include/asm/insn.h >/dev/null && \
diff -I'^#include' arch/x86/insn/inat.h ../../arch/x86/include/asm/inat.h >/dev/null && \
diff -I'^#include' arch/x86/insn/inat_types.h ../../arch/x86/include/asm/inat_types.h >/dev/null) \
|| echo "Warning: objtool: x86 instruction decoder differs from kernel" >&2 )) || true
$(QUIET_LINK)$(CC) $(OBJTOOL_IN) $(LDFLAGS) -o $@
$(LIBSUBCMD): fixdep FORCE
$(Q)$(MAKE) -C $(SUBCMD_SRCDIR) OUTPUT=$(LIBSUBCMD_OUTPUT)
clean:
$(call QUIET_CLEAN, objtool) $(RM) $(OBJTOOL)
$(Q)find $(OUTPUT) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
$(Q)$(RM) $(OUTPUT)arch/x86/insn/inat-tables.c $(OUTPUT)fixdep
FORCE:
.PHONY: clean FORCE