From 045812536e46b13d25f2d252819c20a4a7d2079a Mon Sep 17 00:00:00 2001 From: Mark Charlebois Date: Fri, 31 Mar 2017 22:38:13 +0200 Subject: kbuild, LLVMLinux: Add -Werror to cc-option to support clang MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit c3f0d0bc5b01ad90c45276952802455750444b4f upstream. Clang will warn about unknown warnings but will not return false unless -Werror is set. GCC will return false if an unknown warning is passed. Adding -Werror make both compiler behave the same. [arnd: it turns out we need the same patch for testing whether -ffunction-sections works right with gcc. I've build tested extensively with this patch applied, so let's just merge this one now.] Signed-off-by: Mark Charlebois Signed-off-by: Behan Webster Reviewed-by: Jan-Simon Möller Signed-off-by: Arnd Bergmann Acked-by: Kees Cook Signed-off-by: Masahiro Yamada [nc: Adjust context due to lack of d26e94149276f] Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman --- scripts/Kbuild.include | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'scripts/Kbuild.include') diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 5897fc3857a0..87ee353b8254 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -112,12 +112,12 @@ as-instr = $(call try-run,\ # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) cc-option = $(call try-run,\ - $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) + $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) # cc-option-yn # Usage: flag := $(call cc-option-yn,-march=winchip-c6) cc-option-yn = $(call try-run,\ - $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n) + $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n) # cc-option-align # Prefix align with either -falign or -malign @@ -127,7 +127,7 @@ cc-option-align = $(subst -functions=0,,\ # cc-disable-warning # Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable) cc-disable-warning = $(call try-run,\ - $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) + $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) # cc-name # Expands to either gcc or clang -- cgit v1.2.3 From 904ccb4cd1e5d4a46d96f008e00bf681b28150cb Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Mon, 6 Nov 2017 10:47:54 -0800 Subject: kbuild: fix linker feature test macros when cross compiling with Clang commit 86a9df597cdd564d2d29c65897bcad42519e3678 upstream. I was not seeing my linker flags getting added when using ld-option when cross compiling with Clang. Upon investigation, this seems to be due to a difference in how GCC vs Clang handle cross compilation. GCC is configured at build time to support one backend, that is implicit when compiling. Clang is explicit via the use of `-target ` and ships with all supported backends by default. GNU Make feature test macros that compile then link will always fail when cross compiling with Clang unless Clang's triple is passed along to the compiler. For example: $ clang -x c /dev/null -c -o temp.o $ aarch64-linux-android/bin/ld -E temp.o aarch64-linux-android/bin/ld: unknown architecture of input file `temp.o' is incompatible with aarch64 output aarch64-linux-android/bin/ld: warning: cannot find entry symbol _start; defaulting to 0000000000400078 $ echo $? 1 $ clang -target aarch64-linux-android- -x c /dev/null -c -o temp.o $ aarch64-linux-android/bin/ld -E temp.o aarch64-linux-android/bin/ld: warning: cannot find entry symbol _start; defaulting to 00000000004002e4 $ echo $? 0 This causes conditional checks that invoke $(CC) without the target triple, then $(LD) on the result, to always fail. Suggested-by: Masahiro Yamada Signed-off-by: Nick Desaulniers Reviewed-by: Matthias Kaehlcke Signed-off-by: Masahiro Yamada [nc: Fix conflicts due to lack of commit 3298b690b21cd in linux-4.4.y Use KBUILD_CFLAGS instead of CC_OPTION_FLAGS because commit d26e94149276f that introduced that variable isn't in 4.4 either] Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman --- scripts/Kbuild.include | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'scripts/Kbuild.include') diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 87ee353b8254..9f634b50e57b 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -147,12 +147,13 @@ cc-ifversion = $(shell [ $(cc-version) $(1) $(2) ] && echo $(3) || echo $(4)) # cc-ldoption # Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both) cc-ldoption = $(call try-run,\ - $(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) + $(CC) $(1) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2)) # ld-option # Usage: LDFLAGS += $(call ld-option, -X) ld-option = $(call try-run,\ - $(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2)) + $(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -x c /dev/null -c -o "$$TMPO"; \ + $(LD) $(LDFLAGS) $(1) "$$TMPO" -o "$$TMP",$(1),$(2)) # ar-option # Usage: KBUILD_ARFLAGS := $(call ar-option,D) -- cgit v1.2.3 From bf6401610af484e94afdd9534e706e9bef5fbe5c Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Wed, 21 Jun 2017 16:28:03 -0700 Subject: kbuild: Add __cc-option macro commit 9f3f1fd299768782465cb32cdf0dd4528d11f26b upstream. cc-option uses KBUILD_CFLAGS and KBUILD_CPPFLAGS when it determines whether an option is supported or not. This is fine for options used to build the kernel itself, however some components like the x86 boot code use a different set of flags. Add the new macro __cc-option which is a more generic version of cc-option with additional parameters. One parameter is the compiler with which the check should be performed, the other the compiler options to be used instead KBUILD_C*FLAGS. Refactor cc-option and hostcc-option to use __cc-option and move hostcc-option to scripts/Kbuild.include. Suggested-by: Arnd Bergmann Suggested-by: Masahiro Yamada Signed-off-by: Matthias Kaehlcke Acked-by: Arnd Bergmann Acked-by: Michal Marek Signed-off-by: Masahiro Yamada [nc: Fix conflicts due to lack of CC_OPTION_CFLAGS and hostcc-option wasn't added until v4.8 so no point including it in this tree] Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman --- Makefile | 2 +- scripts/Kbuild.include | 9 +++++++-- 2 files changed, 8 insertions(+), 3 deletions(-) (limited to 'scripts/Kbuild.include') diff --git a/Makefile b/Makefile index f3612502ff8b..cef9451148cc 100644 --- a/Makefile +++ b/Makefile @@ -303,7 +303,7 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \ HOSTCC = gcc HOSTCXX = g++ -HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89 +HOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89 HOSTCXXFLAGS = -O2 # Decide whether to build built-in, modular, or both. diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 9f634b50e57b..5e9cf7d146f0 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -108,11 +108,16 @@ as-option = $(call try-run,\ as-instr = $(call try-run,\ printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) +# __cc-option +# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586) +__cc-option = $(call try-run,\ + $(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4)) + # cc-option # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) -cc-option = $(call try-run,\ - $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) +cc-option = $(call __cc-option, $(CC),\ + $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS),$(1),$(2)) # cc-option-yn # Usage: flag := $(call cc-option-yn,-march=winchip-c6) -- cgit v1.2.3