From b334e19ae9381f12a7521976883022385d2b7eef Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Fri, 13 Jan 2017 16:40:01 +0100 Subject: Kbuild: use cc-disable-warning consistently for maybe-uninitialized In commit a76bcf557ef4 ("Kbuild: enable -Wmaybe-uninitialized warning for "make W=1""), I reverted another change that happened to fix a problem with old compilers, and now we get this report again with old compilers (prior to gcc-4.8) and GCOV enabled: cc1: warnings being treated as errors drivers/gpu/drm/i915/intel_ringbuffer.c: In function 'intel_ring_setup_status_page': drivers/gpu/drm/i915/intel_ringbuffer.c:438: error: 'mmio.reg' may be used uninitialized in this function At top level: >> cc1: error: unrecognized command line option "-Wno-maybe-uninitialized" The problem is that we turn off the warning conditionally in a number of places as we should, but one of them does it unconditionally. Instead, change it to call cc-disable-warning as we do elsewhere. The original patch that caused it was merged into linux-4.7, then 4.8 removed the change and 4.9 brought it back, so we probably want a backport to 4.9 once this is merged. Use a ':=' assignment instead of '=' to force the cc-disable-warning call to only be evaluated once instead of every time. Cc: stable@vger.kernel.org Fixes: a76bcf557ef4 ("Kbuild: enable -Wmaybe-uninitialized warning for "make W=1"") Fixes: e72e2dfe7c16 ("gcov: disable -Wmaybe-uninitialized warning") Reported-by: kbuild test robot Signed-off-by: Arnd Bergmann Signed-off-by: Masahiro Yamada --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index 165cf9783a5d..b8a6b862ed73 100644 --- a/Makefile +++ b/Makefile @@ -372,7 +372,7 @@ LDFLAGS_MODULE = CFLAGS_KERNEL = AFLAGS_KERNEL = LDFLAGS_vmlinux = -CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized +CFLAGS_GCOV := -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,) CFLAGS_KCOV := $(call cc-option,-fsanitize-coverage=trace-pc,) -- cgit From 7292ae3d5a18fb922be496e6bb687647193569b4 Mon Sep 17 00:00:00 2001 From: Gleb Fotengauer-Malinovskiy Date: Mon, 20 Mar 2017 20:15:53 +0300 Subject: jump label: fix passing kbuild_cflags when checking for asm goto support The latest change of asm goto support check added passing of KBUILD_CFLAGS to compiler. When these flags reference gcc plugins that are not built yet, the check fails. When one runs "make bzImage" followed by "make modules", the kernel is always built with HAVE_JUMP_LABEL disabled, while the modules are built depending on CONFIG_JUMP_LABEL. If HAVE_JUMP_LABEL macro happens to be different, modules are built with undefined references, e.g.: ERROR: "static_key_slow_inc" [net/netfilter/xt_TEE.ko] undefined! ERROR: "static_key_slow_dec" [net/netfilter/xt_TEE.ko] undefined! ERROR: "static_key_slow_dec" [net/netfilter/nft_meta.ko] undefined! ERROR: "static_key_slow_inc" [net/netfilter/nft_meta.ko] undefined! ERROR: "nf_hooks_needed" [net/netfilter/ipvs/ip_vs.ko] undefined! ERROR: "nf_hooks_needed" [net/ipv6/ipv6.ko] undefined! ERROR: "static_key_count" [net/ipv6/ipv6.ko] undefined! ERROR: "static_key_slow_inc" [net/ipv6/ipv6.ko] undefined! This change moves the check before all these references are added to KBUILD_CFLAGS. This is correct because subsequent KBUILD_CFLAGS modifications are not relevant to this check. Reported-by: Anton V. Boyarshinov Fixes: 35f860f9ba6a ("jump label: pass kbuild_cflags when checking for asm goto support") Cc: stable@vger.kernel.org # v4.10 Signed-off-by: Gleb Fotengauer-Malinovskiy Signed-off-by: Dmitry V. Levin Acked-by: Steven Rostedt (VMware) Acked-by: David Lin Signed-off-by: Masahiro Yamada --- Makefile | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'Makefile') diff --git a/Makefile b/Makefile index b8a6b862ed73..74d69f241543 100644 --- a/Makefile +++ b/Makefile @@ -653,6 +653,12 @@ KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \ # Tell gcc to never replace conditional load with a non-conditional one KBUILD_CFLAGS += $(call cc-option,--param=allow-store-data-races=0) +# check for 'asm goto' +ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y) + KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO + KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO +endif + include scripts/Makefile.gcc-plugins ifdef CONFIG_READABLE_ASM @@ -798,12 +804,6 @@ KBUILD_CFLAGS += $(call cc-option,-Werror=incompatible-pointer-types) # use the deterministic mode of AR if available KBUILD_ARFLAGS := $(call ar-option,D) -# check for 'asm goto' -ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y) - KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO - KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO -endif - include scripts/Makefile.kasan include scripts/Makefile.extrawarn include scripts/Makefile.ubsan -- cgit