From c1d45c3abd49b5bf9447e435099c1b000dcde752 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 2 Mar 2016 18:39:37 -0600 Subject: 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 Signed-off-by: Josh Poimboeuf Cc: Adrian Hunter Cc: Linus Torvalds Cc: Masami Hiramatsu Cc: Michael Ellerman Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/55b63eefc347f1bb28573f972d8d1adbf1f1c31d.1456962210.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- tools/lib/subcmd/Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'tools/lib/subcmd/Makefile') diff --git a/tools/lib/subcmd/Makefile b/tools/lib/subcmd/Makefile index 629cf8c14e68..1faecb82ad42 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 -- cgit