Skip to content

Commit 4efca4e

Browse files
npigginMichal Marek
npiggin
authored and
Michal Marek
committed
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 <npiggin@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.com>
1 parent 989cea5 commit 4efca4e

1 file changed

Lines changed: 72 additions & 6 deletions

File tree

‎scripts/Makefile.build‎

Lines changed: 72 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -159,7 +159,8 @@ cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
159159
$(obj)/%.i: $(src)/%.c FORCE
160160
$(call if_changed_dep,cpp_i_c)
161161

162-
cmd_gensymtypes = \
162+
# These mirror gensymtypes_S and co below, keep them in synch.
163+
cmd_gensymtypes_c = \
163164
$(CPP) -D__GENKSYMS__ $(c_flags) $< | \
164165
$(GENKSYMS) $(if $(1), -T $(2)) \
165166
$(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
@@ -169,7 +170,7 @@ cmd_gensymtypes = \
169170
quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
170171
cmd_cc_symtypes_c = \
171172
set -e; \
172-
$(call cmd_gensymtypes,true,$@) >/dev/null; \
173+
$(call cmd_gensymtypes_c,true,$@) >/dev/null; \
173174
test -s $@ || rm -f $@
174175

175176
$(obj)/%.symtypes : $(src)/%.c FORCE
@@ -198,9 +199,10 @@ else
198199
# the actual value of the checksum generated by genksyms
199200

200201
cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<
201-
cmd_modversions = \
202+
203+
cmd_modversions_c = \
202204
if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
203-
$(call cmd_gensymtypes,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
205+
$(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
204206
> $(@D)/.tmp_$(@F:.o=.ver); \
205207
\
206208
$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
@@ -268,13 +270,14 @@ endif # CONFIG_STACK_VALIDATION
268270
define rule_cc_o_c
269271
$(call echo-cmd,checksrc) $(cmd_checksrc) \
270272
$(call cmd_and_fixdep,cc_o_c) \
271-
$(cmd_modversions) \
273+
$(cmd_modversions_c) \
272274
$(cmd_objtool) \
273275
$(call echo-cmd,record_mcount) $(cmd_record_mcount)
274276
endef
275277

276278
define rule_as_o_S
277279
$(call cmd_and_fixdep,as_o_S) \
280+
$(cmd_modversions_S) \
278281
$(cmd_objtool)
279282
endef
280283

@@ -314,14 +317,77 @@ modkern_aflags := $(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL)
314317
$(real-objs-m) : modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
315318
$(real-objs-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
316319

320+
# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
321+
# or a file that it includes, in order to get versioned symbols. We build a
322+
# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
323+
# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
324+
#
325+
# This is convoluted. The .S file must first be preprocessed to run guards and
326+
# expand names, then the resulting exports must be constructed into plain
327+
# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
328+
# to make the genksyms input.
329+
#
330+
# These mirror gensymtypes_c and co above, keep them in synch.
331+
cmd_gensymtypes_S = \
332+
(echo "\#include <linux/kernel.h>" ; \
333+
echo "\#include <asm/asm-prototypes.h>" ; \
334+
$(CPP) $(a_flags) $< | \
335+
grep ^___EXPORT_SYMBOL | \
336+
sed 's/___EXPORT_SYMBOL \([a-zA-Z0-9_]*\),.*/EXPORT_SYMBOL(\1);/' ) | \
337+
$(CPP) -D__GENKSYMS__ $(c_flags) -xc - | \
338+
$(GENKSYMS) $(if $(1), -T $(2)) \
339+
$(patsubst y,-s _,$(CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX)) \
340+
$(if $(KBUILD_PRESERVE),-p) \
341+
-r $(firstword $(wildcard $(2:.symtypes=.symref) /dev/null))
342+
343+
quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
344+
cmd_cc_symtypes_S = \
345+
set -e; \
346+
$(call cmd_gensymtypes_S,true,$@) >/dev/null; \
347+
test -s $@ || rm -f $@
348+
349+
$(obj)/%.symtypes : $(src)/%.S FORCE
350+
$(call cmd,cc_symtypes_S)
351+
352+
317353
quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
318354
cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
319355

320356
$(obj)/%.s: $(src)/%.S FORCE
321357
$(call if_changed_dep,cpp_s_S)
322358

323359
quiet_cmd_as_o_S = AS $(quiet_modtag) $@
324-
cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
360+
361+
ifndef CONFIG_MODVERSIONS
362+
cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
363+
364+
else
365+
366+
ASM_PROTOTYPES := $(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/asm-prototypes.h)
367+
368+
ifeq ($(ASM_PROTOTYPES),)
369+
cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $<
370+
371+
else
372+
373+
# versioning matches the C process described above, with difference that
374+
# we parse asm-prototypes.h C header to get function definitions.
375+
376+
cmd_as_o_S = $(CC) $(a_flags) -c -o $(@D)/.tmp_$(@F) $<
377+
378+
cmd_modversions_S = \
379+
if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then \
380+
$(call cmd_gensymtypes_S,$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
381+
> $(@D)/.tmp_$(@F:.o=.ver); \
382+
\
383+
$(LD) $(LDFLAGS) -r -o $@ $(@D)/.tmp_$(@F) \
384+
-T $(@D)/.tmp_$(@F:.o=.ver); \
385+
rm -f $(@D)/.tmp_$(@F) $(@D)/.tmp_$(@F:.o=.ver); \
386+
else \
387+
mv -f $(@D)/.tmp_$(@F) $@; \
388+
fi;
389+
endif
390+
endif
325391

326392
$(obj)/%.o: $(src)/%.S $(objtool_obj) FORCE
327393
$(call if_changed_rule,as_o_S)

0 commit comments

Comments
 (0)