Add a new program, create-klp-module, that, given a built module (.ko),
will create a patch module with klp rela sections, klp arch sections, and
klp symbols.
Introduce a common kpatch elf api by moving all functions and struct
declarations related to manipulating kpatch_elf objects from
create-diff-object to kpatch-elf.{h,c}. Move logging macros to a separate
file log.h, and have kpatch-elf.h include it. These changes will generalize
the kpatch-elf and logging api and make it available to other kpatch-build
tools.
Right now, the makefile has one target, create-diff-object, which
contains all the source/headers as one long list and all the source
files compiled in one command to make create-diff-object.
This doesn't scale well and doesn't accurately portray the dependencies
of each object that contribute to the final binary.
This commit renames create-diff-object.c to main.c so that it can be
compiled and linked seperately and cleanly in Make and autogenerates
dependencies for each .o. This should make it easier to add additional
object files, or refactor the very large main.o into seperate object
file, later.
Right now, we do three build passes: one to build the original tree
(full) build, one to build the patch tree (diff build), then one to
rebuild original objects that where changed by the patch (diff build).
This is going to be a problem when we try to support (near) full tree
rebuilds due to changes in commonly included header files.
This commit changes the build process to intercept calls to gcc by make
using the CROSS_COMPILE environment variable and, during the patched
build phase, copies the original object for any object that is about to
rebuilt due to a change.
This reduces the number of build passes to the minimum possible (two).
Signed-off-by: Seth Jennings <sjenning@redhat.com>
This adds dynamic linking support for the patch modules. It is the
first step toward supporting patching module code and relocatable
kernels.
Rela entries that reference non-included local and non-exported global
symbols are converted to "dynrelas". These dynrelas are relocations
that are done by the core module, not the kernel module linker. This
allows the core module to apply offsets to the base addresses found
in the base vmlinux or module.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
Conflicts:
kpatch-build/kpatch-build
In preparation for dynamic symbol linking, the symbol lookup logic
is going to move into create-diff-obj anyway. We might as well
minimize the code duplication and pull this into create-diff-obj.
This avoids having to re-parse the ELF file modify it in-place.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
Conflicts:
kpatch-build/kpatch-build
We merged PR #186 a little too hastily. It seg faults with the new
parainstructions-section.patch in the integration test suite. Reverting
it for now until we get it figured out.
This reverts commit e1177e3a03.
This reverts commit 880e271841.
This reverts commit 2de5f6cbfb.
This reverts commit 38b7ac74ad.
This reverts commit 108cd9f95e.
This adds dynamic linking support for the patch modules. It is the
first step toward supporting patching module code and relocatable
kernels.
Rela entries that reference non-included local and non-exported global
symbols are converted to "dynrelas". These dynrelas are relocations
that are done by the core module, not the kernel module linker. This
allows the core module to apply offsets to the base addresses found
in the base vmlinux or module.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
In preparation for dynamic symbol linking, the symbol lookup logic
is going to move into create-diff-obj anyway. We might as well
minimize the code duplication and pull this into create-diff-obj.
This avoids having to re-parse the ELF file modify it in-place.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
My apologies for the size of this commit. I combined these two features
(updating API and using a hash table) into a single commit because their
implementations are tightly coupled and I didn't want to have to add
support for the old kpatch_funcs array with the new API just for the
sake of splitting up the commit :-)
- Update the core module API to get a more clear separation between core
module and patch module. This is cleaner and will help our case for
getting the core module merged upstream into the kernel.
- Convert the old kpatch_funcs array into a hash table. This is so much
nicer performance-wise and everything-else-wise than that ugly old
array.
- Do the incremental patching in stop machine. This ensures that the
funcs hash is up to date and we don't miss anything.
- Disable preemption in the ftrace handler when accessing the func hash.
That way we don't get conflicts with the stop_machine handler updating
the hash.
kpatch-build is outgrowing the kpatch script and probably is a better
fit as its own utility instead of being wrapped by kpatch. Install
kpatch-build into /usr/local/bin, remove the kpatch wrapper around it,
and update the README accordingly.
- setup the makefiles to support "make" and "make install", which builds
the kpatch-build tools and installs everything in /usr/local.
- update kpatch-build to support new paths
- add "kpatch build" wrapper around kpatch-build
Jessica Yu
Chris J Arges
Josh Poimboeuf
Seth Jennings