For various reasons its often necessary to generate certain
complex data structures at build-time by separate tools outside
of the C compiler. Data is populated to these tools by way of
special binary sections not intended to be included in the final
binary. We currently do this to generate interrupt tables, forthcoming
work will also use this to generate MMU page tables.
The way we have been doing this is to generatea "kernel_prebuilt.elf",
extract the metadata sections with objcopy, run the tool, and then
re-link the kernel with the extra data *and* use objcopy to pull
out the unwanted sections.
This doesn't scale well if multiple post-build steps are needed.
Now this is much simpler; in any Makefile, a special
GENERATED_KERNEL_OBJECT_FILES variable may be appended to containing
the filenames to the generated object files, which will be generated
by Make in the usual fashion.
Instead of using objcopy to pull out, we now create a linker-pass2.cmd
which additionally defines LINKER_PASS2. The source linker script
can #ifdef around this to use the special /DISCARD/ section target
to not include metadata sections in the final binary.
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This is a new mechanism for generating interrupt tables which will
be useful on many architectures. It replaces the old linker-based
mechanism for creating these tables and has a couple advantages:
1) It is now possible to use enums as the IRQ line argument to
IRQ_CONNECT(), which should ease CMSIS integration.
2) The vector table itself is now generated, which lets us place
interrupts directly into the vector table without having to
hard-code them. This is a feature we have long enjoyed on x86
and will enable 'direct' interrupts.
3) More code is common, requiring less arch-specific code to
support.
This patch introduces the common code for this mechanism. Follow-up
patches will enable it on various arches.
Issue: ZEP-1038, ZEP-1165
Change-Id: I9acd6e0de8b438fa9293f2e00563628f7510168a
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
Andrew Boie