While adding proper linker script option my previous patch left the
linker script in the list of source files (on pre-4.20 kernels) for
ld somehow breaking kpatch callback sections. For this to work
properly kpatch.lds needs to be added to 'extra-y' instead of objs. And
for kbuild to process this option properly we need to call make without
the .ko target, i.e. let kbuild decide what to build.
Fixes: 17a97b4 ("kmod/patch: fix patch linking with 4.20")
Signed-off-by: Artem Savkov <asavkov@redhat.com>
4.20 includes commit 69ea912fda74 "kbuild: remove unneeded link_multi_deps"
which changes kbuild so that only '.o' files are given to ld as targets
for linking, leaving out our linker script. Even before this commit we
were still doing this wrong and were succeeding just because ld is smart
enough to detect the script, it even throws a warning:
ld: warning: kpatch.lds contains output sections; did you forget -T?
The right thing to do is to add the script to ldflags either through
kbuilds 'ldflags-y' or by adding it to LDFLAGS/KPATCH_LDFLAGS directly.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Use kpatch-<modname>.ko or livepatch-<modname>.ko depending on the type
of module we're building.
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
This patch adds support for livepatch hook based module
creation for PPC64le. It introduces PPC64le architecture
bits:
- Add relocation type of R_PPC64_ADDR64 while parsing powerpc ELF.
- Introduce .toc sections mainpulation.
- Skip kpatch specific details for livepatch hook.
Also remove the definition of rela_insn() for powerpc. The only
call site is been guarded by #ifdef x86.
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Introduce a second phase in the kpatch-build process that creates kpatch
modules or livepatch modules that use the new klp rela sections depending on
the kernel version being worked on. This change uses the two new programs to
either create a patch module that uses dynrelas (create-kpatch-module) or a
patch module that uses klp rela and arch sections + klp symbols marked with the
correct Elf flags (create-klp-module).
For klp patch modules, the --unique flag for ld is needed to prevent
.parainstructions and .altinstructions sections from different objects
from being merged, as arch_klp_init_object_loaded() applies these sections
per-object.
Adds a new patch module scaffold for use when building against a kernel
with CONFIG_LIVE_PATCHING=y.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
Build and install the kpatch core module with make and make install,
rather than building it every time with kpatch build.
The only downside to this approach is that the user has to make and make
install kpatch every time they get a new kernel. But this is only
temporary, until the kpatch module is delivered in an RPM.
Artem Savkov
Joe Lawrence
Simon Ruderich
Josh Poimboeuf
Kamalesh Babulal
Jessica Yu
Seth Jennings