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 <s...@canb.auug.org.au>
Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
---
tools/lib/subcmd/Makefile | 6 ++++--
tools/objtool/Makefile | 17 ++++++++++-------
2 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/tools/lib/subcmd/Makefile b/tools/lib/subcmd/Makefile
index 629cf8c..1faecb8 100644
--- a/tools/lib/subcmd/Makefile
+++ b/tools/lib/subcmd/Makefile
@@ -8,8 +8,10 @@ srctree := $(patsubst %/,%,$(dir $(srctree)))
#$(info Determined 'srctree' to be $(srctree))
endif
-CC = $(CROSS_COMPILE)gcc
-AR = $(CROSS_COMPILE)ar
+CC ?= $(CROSS_COMPILE)gcc
+LD ?= $(CROSS_COMPILE)ld
+AR ?= $(CROSS_COMPILE)ar
+
RM = rm -f
MAKEFLAGS += --no-print-directory
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index c4f0713..e4a6bd5 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -7,13 +7,19 @@ ARCH := x86
endif
endif
+# always use the host compiler
+CC = gcc
+LD = ld
+AR = ar
+
ifeq ($(srctree),)
srctree := $(patsubst %/,%,$(dir $(shell pwd)))
srctree := $(patsubst %/,%,$(dir $(srctree)))
endif
-SUBCMD_SRCDIR = $(srctree)/tools/lib/subcmd/
-LIBSUBCMD = $(if $(OUTPUT),$(OUTPUT),$(SUBCMD_SRCDIR))libsubcmd.a
+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
@@ -45,12 +51,9 @@ $(OBJTOOL): $(LIBSUBCMD) $(OBJTOOL_IN)
$(LIBSUBCMD): fixdep FORCE
- $(Q)$(MAKE) -C $(SUBCMD_SRCDIR)
-
-$(LIBSUBCMD)-clean:
- $(Q)$(MAKE) -C $(SUBCMD_SRCDIR) clean > /dev/null
+ $(Q)$(MAKE) -C $(SUBCMD_SRCDIR) OUTPUT=$(LIBSUBCMD_OUTPUT)
-clean: $(LIBSUBCMD)-clean
+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
--
2.4.3
