path: root/lib
diff options
authorPeter Oberparleiter <oberpar@linux.vnet.ibm.com>2014-02-06 15:58:20 +0100
committerH. Peter Anvin <hpa@zytor.com>2014-02-06 07:15:20 -0800
commit6583327c4dd55acbbf2a6f25e775b28b3abf9a42 (patch)
tree867fe6fc63d4c1e322802ee56ecec4793cf383fc /lib
parent85fc73a2cdf10cf42bc36fb3bca3896b2095a1c2 (diff)
x86, hweight: Fix BUG when booting with CONFIG_GCOV_PROFILE_ALL=y
Commit d61931d89b, "x86: Add optimized popcnt variants" introduced compile flag -fcall-saved-rdi for lib/hweight.c. When combined with options -fprofile-arcs and -O2, this flag causes gcc to generate broken constructor code. As a result, a 64 bit x86 kernel compiled with CONFIG_GCOV_PROFILE_ALL=y prints message "gcov: could not create file" and runs into sproadic BUGs during boot. The gcc people indicate that these kinds of problems are endemic when using ad hoc calling conventions. It is therefore best to treat any file compiled with ad hoc calling conventions as an isolated environment and avoid things like profiling or coverage analysis, since those subsystems assume a "normal" calling conventions. This patch avoids the bug by excluding lib/hweight.o from coverage profiling. Reported-by: Meelis Roos <mroos@linux.ee> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/52F3A30C.7050205@linux.vnet.ibm.com Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: <stable@vger.kernel.org>
Diffstat (limited to 'lib')
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/Makefile b/lib/Makefile
index a459c31e8c6b..04944e9993ed 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_HAS_IOMEM) += iomap_copy.o devres.o
obj-$(CONFIG_CHECK_SIGNATURE) += check_signature.o
obj-$(CONFIG_DEBUG_LOCKING_API_SELFTESTS) += locking-selftest.o
+GCOV_PROFILE_hweight.o := n
CFLAGS_hweight.o = $(subst $(quote),,$(CONFIG_ARCH_HWEIGHT_CFLAGS))
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o