Messages in this thread | | | Subject | Re: [PATCH 3/3] objtool: Enable compilation of objtool for all architectures | From | Julien Thierry <> | Date | Wed, 20 May 2020 09:31:46 +0100 |
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On 5/19/20 9:55 PM, Matt Helsley wrote: > objtool currently only compiles for x86 architectures. This is > fine as it presently does not support tooling for other > architectures. However, we would like to be able to convert other > kernel tools to run as objtool sub commands because they too > process ELF object files. This will allow us to convert tools > such as recordmcount to use objtool's ELF code. > > Since much of recordmcount's ELF code is copy-paste code to/from > a variety of other kernel tools (look at modpost for example) this > means that if we can convert recordmcount we can convert more. > > We define "missing" weak definitions for subcommand entry functions > and other weak definitions for shared functions critical to > building existing subcommands. These return 127 when the command is > missing which signify tools that do not exist on all architectures. > In this case the "check" and "orc" tools do not exist on all > architectures so we only add them for x86. Future changes adding > support for "check", to arm64 for example, can then modify the > SUBCMD_CHECK variable when building for arm64. > > objtool is not currently wired in to KConfig to be built for other > architectures because it's not needed for those architectures and > there are no commands it supports other than those for x86. As more > command support is enabled on various architectures the necessary > KConfig changes can be made (e.g. adding "STACK_VALIDATION") to > trigger building objtool. > > Signed-off-by: Matt Helsley <mhelsley@vmware.com> > Cc: Julien Thierry <jthierry@redhat.com> > --- > tools/objtool/Build | 13 +++++++++---- > tools/objtool/Makefile | 11 ++++++++++- > tools/objtool/arch.h | 4 +++- > tools/objtool/builtin-check.c | 2 +- > tools/objtool/builtin-orc.c | 3 +-- > tools/objtool/check.c | 4 ++-- > tools/objtool/check.h | 4 ---- > tools/objtool/objtool.h | 14 ++++++++++++++ > tools/objtool/orc.h | 18 ------------------ > tools/objtool/orc_dump.c | 3 ++- > tools/objtool/orc_gen.c | 1 - > tools/objtool/weak.c | 35 +++++++++++++++++++++++++++++++++++ > 12 files changed, 77 insertions(+), 35 deletions(-) > delete mode 100644 tools/objtool/orc.h > create mode 100644 tools/objtool/weak.c > > diff --git a/tools/objtool/Build b/tools/objtool/Build > index 66f44f5cd2a6..b7222d5cc7bc 100644 > --- a/tools/objtool/Build > +++ b/tools/objtool/Build > @@ -1,11 +1,16 @@ > objtool-y += arch/$(SRCARCH)/ > + > +objtool-y += weak.o > + > +objtool-$(SUBCMD_CHECK) += check.o > +objtool-$(SUBCMD_CHECK) += special.o > +objtool-$(SUBCMD_ORC) += check.o > +objtool-$(SUBCMD_ORC) += orc_gen.o > +objtool-$(SUBCMD_ORC) += orc_dump.o > + > objtool-y += builtin-check.o > objtool-y += builtin-orc.o > -objtool-y += check.o > -objtool-y += orc_gen.o > -objtool-y += orc_dump.o > objtool-y += elf.o > -objtool-y += special.o > objtool-y += objtool.o > > objtool-y += libstring.o > diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile > index 6b91388aecbb..12686e2f1a56 100644 > --- a/tools/objtool/Makefile > +++ b/tools/objtool/Makefile > @@ -46,7 +46,16 @@ elfshdr := $(shell echo '$(pound)include <libelf.h>' | $(CC) $(CFLAGS) -x c -E - > CFLAGS += $(if $(elfshdr),,-DLIBELF_USE_DEPRECATED) > > AWK = awk > -export srctree OUTPUT CFLAGS SRCARCH AWK > + > +SUBCMD_CHECK := n > +SUBCMD_ORC := n > + > +ifeq ($(SRCARCH),x86) > + SUBCMD_CHECK := y > + SUBCMD_ORC := y > +endif > + > +export srctree OUTPUT CFLAGS SRCARCH AWK SUBCMD_CHECK SUBCMD_ORC
Nit: I was thinking, since the list of SUBCMD_* is only going to grow maybe it would be nicer to have a single export line for the SUBCMD_* variables and leave the export line of [srctree..AWK] untouched.
Just a suggestion, and only in case you respin this taking into account Josh's comment.
Otherwise things look good to me.
Cheers,
-- Julien Thierry
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