lkml.org 
[lkml]   [2016]   [Mar]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:core/objtool] objtool: Detect and warn if libelf is missing anddon't break the build
Commit-ID:  d3a325df8e6636d912436ef4a2d16accf3b1fe7f
Gitweb: http://git.kernel.org/tip/d3a325df8e6636d912436ef4a2d16accf3b1fe7f
Author: Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Thu, 3 Mar 2016 11:39:30 -0600
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 4 Mar 2016 12:18:23 +0100

objtool: Detect and warn if libelf is missing anddon't break the build

With CONFIG_STACK_VALIDATION enabled, if the host system doesn't have
a development version of libelf installed, the build fails with errors
like:

elf.h:22:18: fatal error: gelf.h: No such file or directory compilation terminated.

Instead of failing to build, instead just print a warning and disable
stack validation.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-next@vger.kernel.org
Cc: linux@roeck-us.net
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/8c27fe00face60f42e888ddb3142c97e45223165.1457026550.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
Makefile | 13 ++++++++++++-
scripts/Makefile.build | 2 ++
2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 2c27a01..60b7295 100644
--- a/Makefile
+++ b/Makefile
@@ -995,8 +995,19 @@ prepare0: archprepare FORCE
# All the preparing..
prepare: prepare0 prepare-objtool

+ifdef CONFIG_STACK_VALIDATION
+ has_libelf := $(shell echo "int main() {}" | $(HOSTCC) -xc -o /dev/null -lelf - &> /dev/null && echo 1 || echo 0)
+ ifeq ($(has_libelf),1)
+ objtool_target := tools/objtool FORCE
+ else
+ $(warning "Cannot use CONFIG_STACK_VALIDATION, please install libelf-dev or elfutils-libelf-devel")
+ SKIP_STACK_VALIDATION := 1
+ export SKIP_STACK_VALIDATION
+ endif
+endif
+
PHONY += prepare-objtool
-prepare-objtool: $(if $(CONFIG_STACK_VALIDATION), tools/objtool FORCE)
+prepare-objtool: $(objtool_target)

# Generate some files
# ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 130a452..e1bc190 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -242,6 +242,7 @@ cmd_record_mcount = \
endif

ifdef CONFIG_STACK_VALIDATION
+ifneq ($(SKIP_STACK_VALIDATION),1)

__objtool_obj := $(objtree)/tools/objtool/objtool

@@ -260,6 +261,7 @@ objtool_obj = $(if $(patsubst y%,, \
$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
$(__objtool_obj))

+endif # SKIP_STACK_VALIDATION
endif # CONFIG_STACK_VALIDATION

define rule_cc_o_c
\
 
 \ /
  Last update: 2016-03-04 13:01    [W:0.081 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site