Commit 9c3681f9 authored by Sami Tolvanen's avatar Sami Tolvanen Committed by Masahiro Yamada
Browse files

kbuild: Add gendwarfksyms as an alternative to genksyms 



When MODVERSIONS is enabled, allow selecting gendwarfksyms as the
implementation, but default to genksyms.

Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
Signed-off-by: default avatarMasahiro Yamada <masahiroy@kernel.org>
parent d7476f24

kernel/module/Kconfig

+22 −0
Original line number Diff line number Diff line
@@ -169,6 +169,22 @@ config MODVERSIONS 
	  make them incompatible with the kernel you are running.  If

	  unsure, say N.



choice

	prompt "Module versioning implementation"

	depends on MODVERSIONS

	help

	  Select the tool used to calculate symbol versions for modules.



	  If unsure, select GENKSYMS.



config GENKSYMS

	bool "genksyms (from source code)"

	help

	  Calculate symbol versions from pre-processed source code using

	  genksyms.



	  If unsure, say Y.



config GENDWARFKSYMS

	bool "gendwarfksyms (from debugging information)"

	depends on DEBUG_INFO
@@ -176,6 +192,12 @@ config GENDWARFKSYMS 
	depends on !DEBUG_INFO_REDUCED && !DEBUG_INFO_SPLIT

	# Requires ELF object files.

	depends on !LTO

	help

	  Calculate symbol versions from DWARF debugging information using

	  gendwarfksyms. Requires DEBUG_INFO to be enabled.



	  If unsure, say N.

endchoice



config ASM_MODVERSIONS

	bool

scripts/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ hostprogs += unifdef 
targets += module.lds



subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins

subdir-$(CONFIG_MODVERSIONS) += genksyms

subdir-$(CONFIG_GENKSYMS) += genksyms

subdir-$(CONFIG_GENDWARFKSYMS) += gendwarfksyms

subdir-$(CONFIG_SECURITY_SELINUX) += selinux

subdir-$(CONFIG_SECURITY_IPE) += ipe

scripts/Makefile.build

+29 −6
Original line number Diff line number Diff line
@@ -107,13 +107,24 @@ cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $< 
$(obj)/%.i: $(obj)/%.c FORCE

	$(call if_changed_dep,cpp_i_c)



getexportsymbols = $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/$(1)/p'



gendwarfksyms = $(objtree)/scripts/gendwarfksyms/gendwarfksyms	\

	$(if $(KBUILD_SYMTYPES), --symtypes $(@:.o=.symtypes))	\

	$(if $(KBUILD_GENDWARFKSYMS_STABLE), --stable)



genksyms = $(objtree)/scripts/genksyms/genksyms		\

	$(if $(KBUILD_SYMTYPES), -T $(@:.o=.symtypes))	\

	$(if $(KBUILD_PRESERVE), -p)			\

	$(addprefix -r , $(wildcard $(@:.o=.symref)))



# These mirror gensymtypes_S and co below, keep them in synch.

ifdef CONFIG_GENDWARFKSYMS

cmd_gensymtypes_c = $(if $(skip_gendwarfksyms),,	\

	$(call getexportsymbols,\1) | $(gendwarfksyms) $@)

else

cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms)

endif # CONFIG_GENDWARFKSYMS



# LLVM assembly

# Generate .ll files from .c
@@ -286,14 +297,26 @@ $(obj)/%.rs: $(obj)/%.rs.S FORCE 
# 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.

# to make the genksyms input or compiled into an object for gendwarfksyms.

#

# These mirror gensymtypes_c and co above, keep them in synch.

cmd_gensymtypes_S =                                                         \

getasmexports =								\

   { echo "\#include <linux/kernel.h>" ;				\

     echo "\#include <linux/string.h>" ;				\

     echo "\#include <asm/asm-prototypes.h>" ;				\

     $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \

     $(call getexportsymbols,EXPORT_SYMBOL(\1);) ; }



ifdef CONFIG_GENDWARFKSYMS

cmd_gensymtypes_S =							\

	$(getasmexports) |						\

	$(CC) $(c_flags) -c -o $(@:.o=.gendwarfksyms.o) -xc -;		\

	$(call getexportsymbols,\1) |					\

	$(gendwarfksyms) $(@:.o=.gendwarfksyms.o)

else

cmd_gensymtypes_S =							\

	$(getasmexports) |						\

	$(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms)

endif # CONFIG_GENDWARFKSYMS



quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@

cmd_cpp_s_S       = $(CPP) $(a_flags) -o $@ $<