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    SubjectRe: [PATCH v7 00/10] livepatch: klp-convert tool
    On Mon, Mar 06, 2023 at 09:08:14AM -0500, Joe Lawrence wrote:
    > Summary
    > -------
    >
    > Livepatches may use symbols which are not contained in its own scope,
    > and, because of that, may end up compiled with relocations that will
    > only be resolved during module load. Yet, when the referenced symbols
    > are not exported, solving this relocation requires information on the
    > object that holds the symbol (either vmlinux or modules) and its
    > position inside the object, as an object may contain multiple symbols
    > with the same name. Providing such information must be done accordingly
    > to what is specified in Documentation/livepatch/module-elf-format.txt.
    >
    > Currently, there is no trivial way to embed the required information as
    > requested in the final livepatch elf object. klp-convert solves this
    > problem in two different forms: (i) by relying on a symbol map, which is
    > built during kernel compilation, to automatically infer the relocation
    > targeted symbol, and, when such inference is not possible (ii) by using
    > annotations in the elf object to convert the relocation accordingly to
    > the specification, enabling it to be handled by the livepatch loader.
    >
    > Given the above, add support for symbol mapping in the form of a
    > symbols.klp file; add klp-convert tool; integrate klp-convert tool into
    > kbuild; make livepatch modules discernible during kernel compilation
    > pipeline; add data-structure and macros to enable users to annotate
    > livepatch source code; make modpost stage compatible with livepatches;
    > update livepatch-sample and update documentation.
    >
    > The patch was tested under three use-cases:
    >
    > use-case 1: There is a relocation in the lp that can be automatically
    > resolved by klp-convert. For example. see the saved_command_line
    > variable in lib/livepatch/test_klp_convert2.c.
    >
    > use-case 2: There is a relocation in the lp that cannot be automatically
    > resolved, as the name of the respective symbol appears in multiple
    > objects. The livepatch contains an annotation to enable a correct
    > relocation. See the KLP_MODULE_RELOC / KLP_SYMPOS annotation sections
    > in lib/livepatch/test_klp_convert{1,2}.c.
    >
    > use-case 3: There is a relocation in the lp that cannot be automatically
    > resolved similarly as 2, but no annotation was provided in the
    > livepatch, triggering an error during compilation. Reproducible by
    > removing the KLP_MODULE_RELOC / KLP_SYMPOS annotation sections in
    > lib/livepatch/test_klp_convert{1,2}.c.
    >
    > Selftests have been added to exercise these klp-convert use-cases
    > through several tests.
    >
    >
    > Testing
    > -------
    >
    > The patchset selftests build and execute on x86_64, s390x, and ppc64le
    > for both default config (with added livepatch dependencies) and a larger
    > RHEL-9-ish config.
    >
    > Using the Intel's Linux Kernel Performance tests's make.cross,
    > klp-convert builds and processes livepatch .ko's for x86_64 ppc64le
    > ppc32 s390 arm64 arches.
    >
    >
    > Summary of changes in v7
    > ------------------------
    >
    > - rebase for v6.2
    > - combine ("livepatch: Add klp-convert tool") with ("livepatch: Add
    > klp-convert annotation helpers")
    > - combine ("kbuild: Support for symbols.klp creation") with ("modpost:
    > Integrate klp-convert") to simplify Kbuild magic [Petr, Nicolas]
    > - klp-convert: add safe_snprintf() (-Wsign-compare)
    > - klp-convert: fix -Wsign-compare warnings
    > - klp-convert: use calloc() where appropriate
    > - klp-convert: copy ELF e_flags
    > - selftests: fix various build warnings
    > - klp-convert: WARN msg simplification, failed sanity checks, and sympos
    > comment [Marcos]
    > - klp-convert: fix elf_write_file() error paths [Petr]

    Thanks for the new version Joe. I've run the ksefltests on my x86 laptop, and it
    succeed as expected, so

    Tested-by: Marcos Paulo de Souza <mpdesouza@suse.com>

    >
    >
    > Previous versions
    > -----------------
    >
    > RFC:
    > https://lore.kernel.org/lkml/cover.1477578530.git.jpoimboe@redhat.com/
    > v2:
    > https://lore.kernel.org/lkml/f52d29f7-7d1b-ad3d-050b-a9fa8878faf2@redhat.com/
    > v3:
    > https://lore.kernel.org/lkml/20190410155058.9437-1-joe.lawrence@redhat.com/
    > v4:
    > https://lore.kernel.org/lkml/20190509143859.9050-1-joe.lawrence@redhat.com/
    > v5:
    > (not posted)
    > https://github.com/joe-lawrence/klp-convert-tree/tree/klp-convert-v5-devel
    > v6:
    > https://lore.kernel.org/live-patching/20220216163940.228309-1-joe.lawrence@redhat.com/
    >
    >
    > Joe Lawrence (10):
    > livepatch: Create and include UAPI headers
    > livepatch: Add klp-convert tool
    > kbuild/modpost: create symbols.klp and integrate klp-convert
    > livepatch: Add sample livepatch module
    > documentation: Update on livepatch elf format
    > livepatch/selftests: add klp-convert
    > livepatch/selftests: test multiple sections
    > livepatch/selftests: add __asm__ symbol renaming examples
    > livepatch/selftests: add data relocations test
    > livepatch/selftests: add static keys test
    >
    > .gitignore | 2 +
    > Documentation/dontdiff | 1 +
    > Documentation/livepatch/livepatch.rst | 3 +
    > Documentation/livepatch/module-elf-format.rst | 42 +-
    > MAINTAINERS | 2 +
    > Makefile | 16 +-
    > include/linux/livepatch.h | 13 +
    > include/uapi/linux/livepatch.h | 25 +
    > kernel/livepatch/core.c | 4 +-
    > lib/livepatch/Makefile | 12 +
    > lib/livepatch/test_klp_convert.h | 45 +
    > lib/livepatch/test_klp_convert1.c | 121 +++
    > lib/livepatch/test_klp_convert2.c | 110 +++
    > lib/livepatch/test_klp_convert_data.c | 190 ++++
    > lib/livepatch/test_klp_convert_keys.c | 91 ++
    > lib/livepatch/test_klp_convert_keys_mod.c | 52 +
    > lib/livepatch/test_klp_convert_mod_a.c | 31 +
    > lib/livepatch/test_klp_convert_mod_b.c | 19 +
    > lib/livepatch/test_klp_convert_mod_c.c | 36 +
    > lib/livepatch/test_klp_convert_sections.c | 120 +++
    > samples/livepatch/Makefile | 1 +
    > .../livepatch/livepatch-annotated-sample.c | 93 ++
    > scripts/Makefile | 1 +
    > scripts/Makefile.modfinal | 33 +
    > scripts/Makefile.modpost | 5 +
    > scripts/livepatch/.gitignore | 1 +
    > scripts/livepatch/Makefile | 5 +
    > scripts/livepatch/elf.c | 817 ++++++++++++++++
    > scripts/livepatch/elf.h | 74 ++
    > scripts/livepatch/klp-convert.c | 893 ++++++++++++++++++
    > scripts/livepatch/klp-convert.h | 47 +
    > scripts/livepatch/list.h | 391 ++++++++
    > scripts/mod/modpost.c | 28 +-
    > scripts/mod/modpost.h | 1 +
    > .../selftests/livepatch/test-livepatch.sh | 403 ++++++++
    > 35 files changed, 3716 insertions(+), 12 deletions(-)
    > create mode 100644 include/uapi/linux/livepatch.h
    > create mode 100644 lib/livepatch/test_klp_convert.h
    > create mode 100644 lib/livepatch/test_klp_convert1.c
    > create mode 100644 lib/livepatch/test_klp_convert2.c
    > create mode 100644 lib/livepatch/test_klp_convert_data.c
    > create mode 100644 lib/livepatch/test_klp_convert_keys.c
    > create mode 100644 lib/livepatch/test_klp_convert_keys_mod.c
    > create mode 100644 lib/livepatch/test_klp_convert_mod_a.c
    > create mode 100644 lib/livepatch/test_klp_convert_mod_b.c
    > create mode 100644 lib/livepatch/test_klp_convert_mod_c.c
    > create mode 100644 lib/livepatch/test_klp_convert_sections.c
    > create mode 100644 samples/livepatch/livepatch-annotated-sample.c
    > create mode 100644 scripts/livepatch/.gitignore
    > create mode 100644 scripts/livepatch/Makefile
    > create mode 100644 scripts/livepatch/elf.c
    > create mode 100644 scripts/livepatch/elf.h
    > create mode 100644 scripts/livepatch/klp-convert.c
    > create mode 100644 scripts/livepatch/klp-convert.h
    > create mode 100644 scripts/livepatch/list.h
    >
    > --
    > 2.39.2
    >

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