Long ago, the kpatch_trampoline required being written in assembler, but
that's no longer needed now that it integrates nicely with ftrace.
Move it to a C function and rename it kpatch_ftrace_handler.
The current solution doesn't work because "$?" will always be 0, even if
there were no "CC" lines in the build log. Instead, just make sure the
changed_objs file isn't empty.
Add a patch testing step before compiling the kernel, so that users
don't have to wait for the kernel to compile before seeing if the patch
applies cleanly.
Also allow the printing of the patch command's stdout/stderr to make it
clear what files are being patched and whether there's any fuzz.
If the patch file fails to apply, it "corrupts" the cache by leaving the
old applied-patch file around. Fix that by always cleaning up after
ourselves.
Allow the user to supply a custom kernel source directory. This copies
the directory to ~/.kpatch/src instead of using it in place. Otherwise
the "make mrproper" (which is needed for compiling objects in a separate
tree) would modify the original source tree and remove its .config file.
There's currently no caching support for this option. If needed, we
could implement that pretty easily by calculating an md5sum of the
original source directory.
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.
For a local object or function symbol, we expect that
the section offset, sym.st_value, be 0 because we used
-ffunction-sections and -fdata-section during compile.
If value != 0, it undermines assumptions we make and
should return an error. Exceptions should be handled
on a case by case basis, like __ksymtab_strings.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
This commit introduces a simple automated testing system
with 3 simple testcase.
For each test case there is a .c, a .patch, and a .inventory
file. The .c is compiled, using the flags from the kflags file,
to create the original object. The .c file is then patched
with the .patch file and rebuilt to create the patched object.
The files are then analyzed by the differencing tool and an
output object is generated with a .inventory file that lists
the sections and symbol included in the output object. That
inventory file is then compared to the .inventory file for
that testcase. If they are the same, the test passes. If
not, the differences in the inventory files are displayed,
and the test fails.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
In preparation for adding an automated test framework,
add an ability to create-object-diff that will create
a human readable list of included sections and symbols
with type and bind information so that the test framework
can compare against a known-good reference list with the
expected set of sections and symbols.
The file is created when the -i/--inventory option is
used. The inventory filename is the user supplied output
file name suffixed by .inventory
Signed-off-by: Seth Jennings <sjenning@redhat.com>
I'm tired of setting CFLAGS and people shouldn't have to
recompile to get debug output. This lays the foundations
proper option handling and logging levels.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
- Fixup debug messages
- Remove dead code
- No more DEPENDENCY state
- Reachability test is now the "Inclusion tree" for determining
which syms/sections will be included in the output
- 'reachable' field is now and 'include' and is the sole
consideration in including sections/symbols (no more complex
conditional checks)
- Order LOCAL before GLOBAL in the symbol table. Apparently, after
a FILE sym, all LOCAL symbols should precede GLOBAL syms or readelf
shows <corrupt>
- Handle __ksymtab_strings section and __ksymtab_* syms
Signed-off-by: Seth Jennings <sjenning@redhat.com>
The kernel Makefile look for localversion in the source tree,
not the object tree. The absense from the source tree results
in a patch module that will not load because the kernel versions
don't match.
Signed-off-by: Seth Jennings <sjenning@redhat.com>
Setting KCFLAGS="-ffunction-sections -fdata-sections" causes make to
invalidate all the kernel objects, resulting in all the objects getting
rebuilt on the next pass, thus no build caching.
To fix that, build the objects in a separate directory (obj) for normal
builds, and another separate directory (obj2) for the builds with added
cflags.
