From 989cea5c14be024e879c0055dc6d033680a52610 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Fri, 21 Oct 2016 01:13:33 +1100 Subject: kbuild: prevent lib-ksyms.o rebuilds Signed-off-by: Nicholas Piggin Reported-by: Russell King Tested-by: Russell King Signed-off-by: Michal Marek --- scripts/Makefile.build | 3 +++ 1 file changed, 3 insertions(+) (limited to 'scripts') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index de46ab03f063..e1f25d6d132e 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -430,6 +430,9 @@ cmd_export_list = $(OBJDUMP) -h $< | \ $(obj)/lib-ksyms.o: $(lib-target) FORCE $(call if_changed,export_list) + +targets += $(obj)/lib-ksyms.o + endif # -- cgit v1.2.3 From 4efca4ed05cbdfd13ec3e8cb623fb77d6e4ab187 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Tue, 1 Nov 2016 12:46:19 +1100 Subject: kbuild: modversions for EXPORT_SYMBOL() for asm Allow architectures to create asm/asm-prototypes.h file that provides C prototypes for exported asm functions, which enables proper CRC versions to be generated for them. Signed-off-by: Nicholas Piggin Signed-off-by: Michal Marek --- scripts/Makefile.build | 78 ++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 72 insertions(+), 6 deletions(-) (limited to 'scripts') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index e1f25d6d132e..3e223c264469 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -159,7 +159,8 @@ cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< $(obj)/%.i: $(src)/%.c FORCE $(call if_changed_dep,cpp_i_c) -cmd_gensymtypes = \ +# These mirror gensymtypes_S and co below, keep them in synch. +cmd_gensymtypes_c = \ $(CPP) -D__GENKSYMS__ $(c_flags) $< | \ $(GENKSYMS) $(if $(1), -T $(2)) \ $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \ @@ -169,7 +170,7 @@ cmd_gensymtypes = \ quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@ cmd_cc_symtypes_c = \ set -e; \ - $(call cmd_gensymtypes,true,$@) >/dev/null; \ + $(call cmd_gensymtypes_c,true,$@) >/dev/null; \ test -s $@ || rm -f $@ $(obj)/%.symtypes : $(src)/%.c FORCE @@ -198,9 +199,10 @@ else # the actual value of the checksum generated by genksyms cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $< -cmd_modversions = \ + +cmd_modversions_c = \ if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \ - $(call cmd_gensymtypes,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ + $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ > $(@D)/.tmp_$(@F:.o=.ver); \ \ $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \ @@ -268,13 +270,14 @@ endif # CONFIG_STACK_VALIDATION define rule_cc_o_c $(call echo-cmd,checksrc) $(cmd_checksrc) \ $(call cmd_and_fixdep,cc_o_c) \ - $(cmd_modversions) \ + $(cmd_modversions_c) \ $(cmd_objtool) \ $(call echo-cmd,record_mcount) $(cmd_record_mcount) endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) \ + $(cmd_modversions_S) \ $(cmd_objtool) endef @@ -314,6 +317,39 @@ modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) $(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) $(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) +# .S file exports must have their C prototypes defined in asm/asm-prototypes.h +# or a file that it includes, in order to get versioned symbols. We build a +# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from +# the .S file (with trailing ';'), and run genksyms on that, to extract vers. +# +# This is convoluted. The .S file must first be preprocessed to run guards and +# expand names, then the resulting exports must be constructed into plain +# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed +# to make the genksyms input. +# +# These mirror gensymtypes_c and co above, keep them in synch. +cmd_gensymtypes_S = \ + (echo "\#include " ; \ + echo "\#include " ; \ + $(CPP) $(a_flags) $< | \ + grep ^___EXPORT_SYMBOL | \ + sed 's/___EXPORT_SYMBOL \([a-zA-Z0-9_]*\),.*/EXPORT_SYMBOL(\1);/' ) | \ + $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ + $(GENKSYMS) $(if $(1), -T $(2)) \ + $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \ + $(if $(KBUILD_PRESERVE),-p) \ + -r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null)) + +quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@ +cmd_cc_symtypes_S = \ + set -e; \ + $(call cmd_gensymtypes_S,true,$@) >/dev/null; \ + test -s $@ || rm -f $@ + +$(obj)/%.symtypes : $(src)/%.S FORCE + $(call cmd,cc_symtypes_S) + + quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< @@ -321,7 +357,37 @@ $(obj)/%.s: $(src)/%.S FORCE $(call if_changed_dep,cpp_s_S) quiet_cmd_as_o_S = AS $(quiet_modtag) $@ -cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< + +ifndef CONFIG_MODVERSIONS +cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< + +else + +ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h) + +ifeq ($(ASM_PROTOTYPES),) +cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< + +else + +# versioning matches the C process described above, with difference that +# we parse asm-prototypes.h C header to get function definitions. + +cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $< + +cmd_modversions_S = \ + if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \ + $(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \ + > $(@D)/.tmp_$(@F:.o=.ver); \ + \ + $(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \ + -T $(@D)/.tmp_$(@F:.o=.ver); \ + rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \ + else \ + mv -f $(@D)/.tmp_$(@F) $@; \ + fi; +endif +endif $(obj)/%.o: $(src)/%.S $(objtool_obj) FORCE $(call if_changed_rule,as_o_S) -- cgit v1.2.3 From 82031ea29e454b574bc6f49a33683a693ca5d907 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Fri, 4 Nov 2016 19:39:39 +0100 Subject: scripts/has-stack-protector: add -fno-PIE Adding -no-PIE to the fstack protector check. -no-PIE was introduced before -fstack-protector so there is no need for a runtime check. Without it the build stops: |Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong available but compiler is broken due to -mcmodel=kernel + -fPIE if -fPIE is enabled by default. Tagging it stable so it is possible to compile recent stable kernels as well. Cc: stable@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Michal Marek --- scripts/gcc-x86_64-has-stack-protector.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/gcc-x86_64-has-stack-protector.sh b/scripts/gcc-x86_64-has-stack-protector.sh index 973e8c141567..17867e723a51 100755 --- a/scripts/gcc-x86_64-has-stack-protector.sh +++ b/scripts/gcc-x86_64-has-stack-protector.sh @@ -1,6 +1,6 @@ #!/bin/sh -echo "int foo(void) { char X[200]; return 3; }" | $* -S -x c -c -O0 -mcmodel=kernel -fstack-protector - -o - 2> /dev/null | grep -q "%gs" +echo "int foo(void) { char X[200]; return 3; }" | $* -S -x c -c -O0 -mcmodel=kernel -fno-PIE -fstack-protector - -o - 2> /dev/null | grep -q "%gs" if [ "$?" -eq "0" ] ; then echo y else -- cgit v1.2.3 From cc6acc11cad1eb1ae39707a3a6e4a97fafbeeabd Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Wed, 9 Nov 2016 15:34:05 +1100 Subject: kbuild: be more careful about matching preprocessed asm ___EXPORT_SYMBOL MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The CRC code for asm exports grabs the preprocessed asm, finds the ___EXPORT_SYMBOL and turns those into EXPORT_SYMBOL in a C program that can be preprocessed and parsed to create the CRC signatures from the type. The existing regex matching and replacement is too strict, and doesn't deal well with whitespace among other things. The line " EXPORT_SYMBOL(sym)" in a .S file would not match due to initial whitespace, for example, which resulted in x86's ___preempt_schedule failing to get CRCs. Reported-by: Philip Müller Signed-off-by: Nicholas Piggin Signed-off-by: Michal Marek --- scripts/Makefile.build | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 3e223c264469..7675d11ee65e 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -332,8 +332,8 @@ cmd_gensymtypes_S = \ (echo "\#include " ; \ echo "\#include " ; \ $(CPP) $(a_flags) $< | \ - grep ^___EXPORT_SYMBOL | \ - sed 's/___EXPORT_SYMBOL \([a-zA-Z0-9_]*\),.*/EXPORT_SYMBOL(\1);/' ) | \ + grep "\<___EXPORT_SYMBOL\>" | \ + sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \ $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \ $(GENKSYMS) $(if $(1), -T $(2)) \ $(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \ -- cgit v1.2.3 From eef06b82f16c78dc0197e3e9d5b2230647a890ff Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Thu, 10 Nov 2016 10:46:13 -0800 Subject: scripts/bloat-o-meter: fix SIGPIPE Fix piping output to a program which quickly exits (read: head -n1) $ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux | head -n1 add/remove: 0/0 grow/shrink: 9/60 up/down: 124/-305 (-181) close failed in file object destructor: sys.excepthook is missing lost sys.stderr Link: http://lkml.kernel.org/r/20161028204618.GA29923@avx2 Signed-off-by: Alexey Dobriyan Cc: Matt Mackall Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/bloat-o-meter | 3 +++ 1 file changed, 3 insertions(+) (limited to 'scripts') diff --git a/scripts/bloat-o-meter b/scripts/bloat-o-meter index 19f5adfd877d..d9ff038c1b28 100755 --- a/scripts/bloat-o-meter +++ b/scripts/bloat-o-meter @@ -8,6 +8,9 @@ # of the GNU General Public License, incorporated herein by reference. import sys, os, re +from signal import signal, SIGPIPE, SIG_DFL + +signal(SIGPIPE, SIG_DFL) if len(sys.argv) != 3: sys.stderr.write("usage: %s file1 file2\n" % sys.argv[0]) -- cgit v1.2.3 From a76bcf557ef408b368cf26f52a60865bfc27b632 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 10 Nov 2016 17:44:44 +0100 Subject: Kbuild: enable -Wmaybe-uninitialized warning for "make W=1" Traditionally, we have always had warnings about uninitialized variables enabled, as this is part of -Wall, and generally a good idea [1], but it also always produced false positives, mainly because this is a variation of the halting problem and provably impossible to get right in all cases [2]. Various people have identified cases that are particularly bad for false positives, and in commit e74fc973b6e5 ("Turn off -Wmaybe-uninitialized when building with -Os"), I turned off the warning for any build that was done with CC_OPTIMIZE_FOR_SIZE. This drastically reduced the number of false positive warnings in the default build but unfortunately had the side effect of turning the warning off completely in 'allmodconfig' builds, which in turn led to a lot of warnings (both actual bugs, and remaining false positives) to go in unnoticed. With commit 877417e6ffb9 ("Kbuild: change CC_OPTIMIZE_FOR_SIZE definition") enabled the warning again for allmodconfig builds in v4.7 and in v4.8-rc1, I had finally managed to address all warnings I get in an ARM allmodconfig build and most other maybe-uninitialized warnings for ARM randconfig builds. However, commit 6e8d666e9253 ("Disable "maybe-uninitialized" warning globally") was merged at the same time and disabled it completely for all configurations, because of false-positive warnings on x86 that I had not addressed until then. This caused a lot of actual bugs to get merged into mainline, and I sent several dozen patches for these during the v4.9 development cycle. Most of these are actual bugs, some are for correct code that is safe because it is only called under external constraints that make it impossible to run into the case that gcc sees, and in a few cases gcc is just stupid and finds something that can obviously never happen. I have now done a few thousand randconfig builds on x86 and collected all patches that I needed to address every single warning I got (I can provide the combined patch for the other warnings if anyone is interested), so I hope we can get the warning back and let people catch the actual bugs earlier. This reverts the change to disable the warning completely and for now brings it back at the "make W=1" level, so we can get it merged into mainline without introducing false positives. A follow-up patch enables it on all levels unless some configuration option turns it off because of false-positives. Link: https://rusty.ozlabs.org/?p=232 [1] Link: https://gcc.gnu.org/wiki/Better_Uninitialized_Warnings [2] Signed-off-by: Arnd Bergmann Signed-off-by: Linus Torvalds --- Makefile | 10 ++++++---- arch/arc/Makefile | 4 +++- scripts/Makefile.extrawarn | 3 +++ scripts/Makefile.ubsan | 4 ++++ 4 files changed, 16 insertions(+), 5 deletions(-) (limited to 'scripts') diff --git a/Makefile b/Makefile index f97f786de58d..06e2b73978e8 100644 --- a/Makefile +++ b/Makefile @@ -370,7 +370,7 @@ LDFLAGS_MODULE = CFLAGS_KERNEL = AFLAGS_KERNEL = LDFLAGS_vmlinux = -CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im +CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized CFLAGS_KCOV := $(call cc-option,-fsanitize-coverage=trace-pc,) @@ -620,7 +620,6 @@ ARCH_CFLAGS := include arch/$(SRCARCH)/Makefile KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,) -KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,) KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,) ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION @@ -629,15 +628,18 @@ KBUILD_CFLAGS += $(call cc-option,-fdata-sections,) endif ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE -KBUILD_CFLAGS += -Os +KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,) else ifdef CONFIG_PROFILE_ALL_BRANCHES -KBUILD_CFLAGS += -O2 +KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,) else KBUILD_CFLAGS += -O2 endif endif +KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \ + $(call cc-disable-warning,maybe-uninitialized,)) + # Tell gcc to never replace conditional load with a non-conditional one KBUILD_CFLAGS += $(call cc-option,--param=allow-store-data-races=0) diff --git a/arch/arc/Makefile b/arch/arc/Makefile index 864adad52280..25f81a1db9f9 100644 --- a/arch/arc/Makefile +++ b/arch/arc/Makefile @@ -68,7 +68,9 @@ cflags-$(CONFIG_ARC_DW2_UNWIND) += -fasynchronous-unwind-tables $(cfi) ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE # Generic build system uses -O2, we want -O3 # Note: No need to add to cflags-y as that happens anyways -ARCH_CFLAGS += -O3 +# +# Disable the false maybe-uninitialized warings gcc spits out at -O3 +ARCH_CFLAGS += -O3 $(call cc-disable-warning,maybe-uninitialized,) endif # small data is default for elf32 tool-chain. If not usable, disable it diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 53449a6ff6aa..7fc2c5a3dbbe 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -36,6 +36,7 @@ warning-2 += -Wshadow warning-2 += $(call cc-option, -Wlogical-op) warning-2 += $(call cc-option, -Wmissing-field-initializers) warning-2 += $(call cc-option, -Wsign-compare) +warning-2 += $(call cc-option, -Wmaybe-uninitialized) warning-3 := -Wbad-function-cast warning-3 += -Wcast-qual @@ -59,6 +60,8 @@ endif KBUILD_CFLAGS += $(warning) else +KBUILD_CFLAGS += $(call cc-disable-warning, maybe-uninitialized) + ifeq ($(cc-name),clang) KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides) KBUILD_CFLAGS += $(call cc-disable-warning, unused-value) diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan index dd779c40c8e6..3b1b13818d59 100644 --- a/scripts/Makefile.ubsan +++ b/scripts/Makefile.ubsan @@ -17,4 +17,8 @@ endif ifdef CONFIG_UBSAN_NULL CFLAGS_UBSAN += $(call cc-option, -fsanitize=null) endif + + # -fsanitize=* options makes GCC less smart than usual and + # increase number of 'maybe-uninitialized false-positives + CFLAGS_UBSAN += $(call cc-option, -Wno-maybe-uninitialized) endif -- cgit v1.2.3 From 4324cb23f4569edcf76e637cdb3c1dfe8e8a85e4 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 10 Nov 2016 17:44:54 +0100 Subject: Kbuild: enable -Wmaybe-uninitialized warnings by default Previously the warnings were added back at the W=1 level and above, this now turns them on again by default, assuming that we have addressed all warnings and again have a clean build for v4.10. I found a number of new warnings in linux-next already and submitted bugfixes for those. Hopefully they are caught by the 0day builder in the future as soon as this patch is merged. Signed-off-by: Arnd Bergmann Signed-off-by: Linus Torvalds --- scripts/Makefile.extrawarn | 2 -- 1 file changed, 2 deletions(-) (limited to 'scripts') diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 7fc2c5a3dbbe..7c321a603b07 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -60,8 +60,6 @@ endif KBUILD_CFLAGS += $(warning) else -KBUILD_CFLAGS += $(call cc-disable-warning, maybe-uninitialized) - ifeq ($(cc-name),clang) KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides) KBUILD_CFLAGS += $(call cc-disable-warning, unused-value) -- cgit v1.2.3