On Thu, May 9, 2019 at 11:40 PM Joe Lawrence <joe.lawrence@xxxxxxxxxx> wrote: > > From: Joao Moreira <jmoreira@xxxxxxx> > > For automatic resolution of livepatch relocations, a file called > Symbols.list is used. This file maps symbols within every compiled > kernel object allowing the identification of symbols whose name is > unique, thus relocation can be automatically inferred, or providing > information that helps developers when code annotation is required for > solving the matter. > > Add support for creating Symbols.list in the main Makefile. First, > ensure that built-in is compiled when CONFIG_LIVEPATCH is enabled (as > required to achieve a complete Symbols.list file). Define the command to > build Symbols.list (cmd_klp_map) and hook it in the modules rule. > > As it is undesirable to have symbols from livepatch objects inside > Symbols.list, make livepatches discernible by modifying > scripts/Makefile.build to create a .livepatch file for each livepatch > in $(MODVERDIR). This file then used by cmd_klp_map to identify and > bypass livepatches. > > For identifying livepatches during the build process, a flag variable > LIVEPATCH_$(basetarget).o is considered in scripts/Makefile.build. This > way, set this flag for the livepatch sample Makefile in > samples/livepatch/Makefile. > > Finally, Add a clean rule to ensure that Symbols.list is removed during > clean. > > Notes: > > To achieve a correct Symbols.list file, all kernel objects must be > considered, thus, its construction require these objects to be priorly > built. On the other hand, invoking scripts/Makefile.modpost without > having a complete Symbols.list in place would occasionally lead to > in-tree livepatches being post-processed incorrectly. To prevent this > from becoming a circular dependency, the construction of Symbols.list > uses non-post-processed kernel objects and such does not cause harm as > the symbols normally referenced from within livepatches are visible at > this stage. Also due to these requirements, the spot in-between modules > compilation and the invocation of scripts/Makefile.modpost was picked > for hooking cmd_klp_map. > > The approach based on .livepatch files was proposed as an alternative > to using MODULE_INFO statements. This approach was originally > proposed by Miroslav Benes as a workaround for identifying livepathes > without depending on modinfo during the modpost stage. It was moved to > this patch as the approach also shown to be useful while building > Symbols.list. > > Signed-off-by: Joao Moreira <jmoreira@xxxxxxx> > Signed-off-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx> > --- > .gitignore | 1 + > Makefile | 30 ++++++++++++++++++++++++++---- > lib/livepatch/Makefile | 5 +++++ > samples/livepatch/Makefile | 4 ++++ > scripts/Makefile.build | 7 +++++++ > 5 files changed, 43 insertions(+), 4 deletions(-) > > diff --git a/.gitignore b/.gitignore > index a20ac26aa2f5..5cd5758f5ffe 100644 > --- a/.gitignore > +++ b/.gitignore > @@ -45,6 +45,7 @@ > *.xz > Module.symvers > modules.builtin > +Symbols.list Symbols.list is created only in the top directory. Please move this to # Top-level generic files section with a leading slash. Also, you need to add it to Documentation/dontdiff > # > # Top-level generic files > diff --git a/Makefile b/Makefile > index abe13538a8c0..98089f9d44fe 100644 > --- a/Makefile > +++ b/Makefile > @@ -574,10 +574,13 @@ KBUILD_BUILTIN := 1 > # If we have only "make modules", don't compile built-in objects. > # When we're building modules with modversions, we need to consider > # the built-in objects during the descend as well, in order to > -# make sure the checksums are up to date before we record them. > +# make sure the checksums are up to date before we record them. The > +# same applies for building livepatches, as built-in objects may hold > +# symbols which are referenced from livepatches and are required by > +# klp-convert post-processing tool for resolving these cases. > > ifeq ($(MAKECMDGOALS),modules) > - KBUILD_BUILTIN := $(if $(CONFIG_MODVERSIONS),1) > + KBUILD_BUILTIN := $(if $(or $(CONFIG_MODVERSIONS), $(CONFIG_LIVEPATCH)),1) > endif > > # If we have "make <whatever> modules", compile modules > @@ -1261,9 +1264,25 @@ all: modules > # duplicate lines in modules.order files. Those are removed > # using awk while concatenating to the final file. > > +quiet_cmd_klp_map = KLP Symbols.list > +SLIST = $(objtree)/Symbols.list Please do not define SLIST. Use Symbols.list directly. > + > +define cmd_klp_map > + $(shell echo "klp-convert-symbol-data.0.1" > $(SLIST)) \ > + $(shell echo "*vmlinux" >> $(SLIST)) \ > + $(shell nm -f posix $(objtree)/vmlinux | cut -d\ -f1 >> $(SLIST)) \ > + $(foreach m, $(wildcard $(MODVERDIR)/*.mod), \ > + $(eval mod = $(patsubst %.ko,%.o,$(shell head -n1 $(m)))) \ > + $(if $(wildcard $(MODVERDIR)/$(shell basename -s .o $(mod)).livepatch),,\ > + $(eval fmod = $(subst $(quote),_,$(subst -,_,$(mod)))) \ > + $(shell echo "*$(shell basename -s .o $(fmod))" >> $(SLIST)) \ > + $(shell nm -f posix $(mod) | cut -d\ -f1 >> $(SLIST)))) > +endef > + > PHONY += modules > modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin > $(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order > + $(if $(CONFIG_LIVEPATCH), $(call cmd,klp_map)) > @$(kecho) ' Building modules, stage 2.'; > $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost > > @@ -1350,7 +1369,7 @@ clean: rm-dirs := $(CLEAN_DIRS) > clean: rm-files := $(CLEAN_FILES) > clean-dirs := $(addprefix _clean_, . $(vmlinux-alldirs) Documentation samples) > > -PHONY += $(clean-dirs) clean archclean vmlinuxclean > +PHONY += $(clean-dirs) clean archclean vmlinuxclean klpclean > $(clean-dirs): > $(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@) > > @@ -1358,7 +1377,10 @@ vmlinuxclean: > $(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh clean > $(Q)$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) clean) > > -clean: archclean vmlinuxclean > +klpclean: > + $(Q) rm -f $(SLIST) klpclean is unneeded. Add it to CLEAN_FILES CLEAN_FILES += modules.builtin.modinfo Systems.list -- Best Regards Masahiro Yamada
