Commit 04e36857 authored by Linus Torvalds's avatar Linus Torvalds

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
parents aad931a3 c6a38553
......@@ -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 $(srctree)/scripts/module-common.lds
......
......@@ -16,6 +16,7 @@ KCOV_INSTRUMENT := n
KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -MD -Os -mcmodel=large
KBUILD_CFLAGS += -m$(BITS)
KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
$(call if_changed,ld)
......
......@@ -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
#
......
#!/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
......
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