linux/tools
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
..
arch
build tools build: Add BPF feature check to test-all 2016-01-11 19:22:21 -03:00
cgroup
firewire
hv tools: hv: vss: fix the write()'s argument: error -> vss_msg 2015-12-14 19:15:05 -08:00
iio iio: generic_buffer: be helpful about enabling channels 2015-08-16 10:51:26 +01:00
include tools: Make list.h self-sufficient 2016-01-12 12:42:07 -03:00
laptop/freefall Move freefall program from Documentation/ to tools/ 2015-06-08 16:42:07 -06:00
lguest tools/lguest: Clean up include dir 2015-08-26 06:12:35 +02:00
lib objtool: Support CROSS_COMPILE 2016-03-03 16:13:00 +01:00
net tools/net: Use include/uapi with __EXPORTED_HEADERS__ 2015-11-15 17:24:33 -05:00
nfsd
objtool objtool: Support CROSS_COMPILE 2016-03-03 16:13:00 +01:00
perf x86/asm/decoder: Use explicitly signed chars 2016-03-03 16:13:00 +01:00
power Merge branch 'pm-tools' 2016-01-21 00:43:29 +01:00
scripts tools: Move Makefile.arch from perf/config to tools/scripts 2016-01-11 19:22:20 -03:00
spi spi: spidev_test: Fix typo in error message 2015-12-08 17:58:56 +00:00
testing Merge branch 'x86/debug' into core/objtool, to pick up frame pointer fixes 2016-02-25 09:00:38 +01:00
thermal/tmon tools/thermal: tmon: use pkg-config also for CFLAGS 2015-10-10 11:32:31 +08:00
time
usb usb: patches for v4.4 merge window 2015-10-22 17:19:33 -07:00
virtio tools/virtio: add ringtest utilities 2016-01-26 10:18:30 +02:00
vm tools/vm/page-types.c: support KPF_IDLE 2015-11-20 16:17:32 -08:00
Makefile objtool: Add tool to perform compile-time stack metadata validation 2016-02-29 08:35:12 +01:00