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authorLinus Torvalds <torvalds@linux-foundation.org>2016-11-18 16:45:21 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-11-18 16:45:21 -0800
commit04e36857d6747e4525e68c4292c081b795b48366 (patch)
tree7683cb1959467bba420926167bbc99ab1ab39842
parentaad931a30fd88c5319868c6891396d04ad6bfb3e (diff)
parentc6a385539175ebc603da53aafb7753d39089f32e (diff)
Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild fixes from Michal Marek: "Here are some regression fixes for kbuild: - modversion support for exported asm symbols (Nick Piggin). The affected architectures need separate patches adding asm-prototypes.h. - fix rebuilds of lib-ksyms.o (Nick Piggin) - -fno-PIE builds (Sebastian Siewior and Borislav Petkov). This is not a kernel regression, but one of the Debian gcc package. Nevertheless, it's quite annoying, so I think it should go into mainline and stable now" * 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: kbuild: Steal gcc's pie from the very beginning kbuild: be more careful about matching preprocessed asm ___EXPORT_SYMBOL x86/kexec: add -fno-PIE scripts/has-stack-protector: add -fno-PIE kbuild: add -fno-PIE kbuild: modversions for EXPORT_SYMBOL() for asm kbuild: prevent lib-ksyms.o rebuilds
-rw-r--r--Makefile5
-rw-r--r--arch/x86/purgatory/Makefile1
-rw-r--r--scripts/Makefile.build81
-rwxr-xr-xscripts/gcc-x86_64-has-stack-protector.sh2
4 files changed, 80 insertions, 9 deletions
diff --git a/Makefile b/Makefile
index 247430abfc73..9bc877d073d7 100644
--- a/Makefile
+++ b/Makefile
@@ -399,11 +399,12 @@ KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-fno-strict-aliasing -fno-common \
-Werror-implicit-function-declaration \
-Wno-format-security \
- -std=gnu89
+ -std=gnu89 $(call cc-option,-fno-PIE)
+
KBUILD_AFLAGS_KERNEL :=
KBUILD_CFLAGS_KERNEL :=
-KBUILD_AFLAGS := -D__ASSEMBLY__
+KBUILD_AFLAGS := -D__ASSEMBLY__ $(call cc-option,-fno-PIE)
KBUILD_AFLAGS_MODULE := -DMODULE
KBUILD_CFLAGS_MODULE := -DMODULE
KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index ac58c1616408..555b9fa0ad43 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -16,6 +16,7 @@ KCOV_INSTRUMENT := n
KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -MD -Os -mcmodel=large
KBUILD_CFLAGS += -m$(BITS)
+KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
$(call if_changed,ld)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index de46ab03f063..7675d11ee65e 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 <linux/kernel.h>" ; \
+ echo "\#include <asm/asm-prototypes.h>" ; \
+ $(CPP) $(a_flags) $< | \
+ 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)) \
+ $(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)
@@ -430,6 +496,9 @@ cmd_export_list = $(OBJDUMP) -h $< | \
$(obj)/lib-ksyms.o: $(lib-target) FORCE
$(call if_changed,export_list)
+
+targets += $(obj)/lib-ksyms.o
+
endif
#
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