Messages in this thread | | | From | Matt Helsley <> | Subject | [RFC][PATCH 0/5] Enable objtool multiarch build | Date | Mon, 11 May 2020 10:35:08 -0700 |
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My previous RFC[1] tried to add recordmcount as the mcount subcommand of objtool. As a necessary first step that required enabling building of objtool for more than the x86 architecture.
Some folks have been working on enabling objtool checking functionality for arm64. Rather than repeat that work here I aim to show a minimal set which ensures that objtool builds for any architecture. This will allow for not only building the check and ORC subcommands but also incorporating more subcommands -- such as recordmcount.
I changed the Makefile to use the SRCARCH to determine which subcommands should be available and set the appropriate SUBCMD_ variables. Those variables then get used in the Build file to conditionally build them into objtool. When the files are missing suitable empty definitions are located in arch/missing so that the compilation will succeed while also allowing objtool to report that the command is unavailable on the architecture.
Since the series does not add support for stack validation or checking to any new architectures there's no reason to make KConfig or Makefile changes which would normally be used to test this. So I've been forcing builds of objtool with:
make O=build-ARCH ARCH=foo CROSS_COMPILE=foo-linux-gnu- defconfig make O=build-ARCH ARCH=foo CROSS_COMPILE=foo-linux-gnu- tools/objtool
And running the resulting binary in qemu-static to verify that it shows all objtool subcommands are supported on x86 and unsupported on another arch.
[1] https://lore.kernel.org/lkml/cover.1586468801.git.mhelsley@vmware.com/
Matt Helsley (5): objtool: Exit successfully when requesting help objtool: Move struct objtool_file into arch-independent header objtool: Add support for relocations without addends objtool: Enable compilation of objtool for all architectures objtool: Report missing support for subcommands
tools/objtool/Build | 10 +++-- tools/objtool/Makefile | 11 +++++- tools/objtool/arch.h | 40 +++++++++++++++++++ tools/objtool/arch/missing/Build | 3 ++ tools/objtool/arch/missing/check.c | 16 ++++++++ tools/objtool/arch/missing/orc_dump.c | 13 ++++++ tools/objtool/arch/missing/orc_gen.c | 16 ++++++++ tools/objtool/arch/x86/Build | 1 + tools/objtool/{ => arch/x86}/special.c | 4 +- tools/objtool/{ => arch/x86}/special.h | 2 +- tools/objtool/builtin-check.c | 5 +++ tools/objtool/builtin-orc.c | 9 ++++- tools/objtool/builtin.h | 2 + tools/objtool/check.c | 5 ++- tools/objtool/check.h | 48 +--------------------- tools/objtool/elf.c | 55 +++++++++++++++++++++----- tools/objtool/elf.h | 5 ++- tools/objtool/objtool.c | 39 +++++++++++++++--- tools/objtool/objtool.h | 20 ++++++++++ tools/objtool/orc.h | 3 +- tools/objtool/orc_dump.c | 1 + tools/objtool/orc_gen.c | 3 ++ 22 files changed, 235 insertions(+), 76 deletions(-) create mode 100644 tools/objtool/arch/missing/Build create mode 100644 tools/objtool/arch/missing/check.c create mode 100644 tools/objtool/arch/missing/orc_dump.c create mode 100644 tools/objtool/arch/missing/orc_gen.c rename tools/objtool/{ => arch/x86}/special.c (98%) rename tools/objtool/{ => arch/x86}/special.h (95%) create mode 100644 tools/objtool/objtool.h
base-commit: 6e7f2eacf09811d092c1b41263108ac7fe0d089d -- 2.20.1
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