symbols from the linked kernel.
The main thrust of this change is to generate a kernel that has the arm
"marker" symbols stripped. Marker symbols start with $a, $d, $t or $x, and
are emitted by the compiler to tell other toolchain components about the
locations of data embedded in the instruction stream (literal-pool
stuff). They are used for generating mixed-endian binaries (which we don't
support). The linked kernel has approximately 21,000 such symbols in it,
wasting space (500K in kernel.full, 190K in the final linked kernel), and
sometimes obscuring function names in stack tracebacks.
This change also simplifies the way the kernel is linked. Instead of using
sed to generate two different ldscript files to generate both an elf kernel
and a binary (elf headers stripped) kernel, we now use a single ldscript
that refers to a "text_start" symbol, and we provide the value for that
symbol using --defsym on the linker command line.
After our migration (of certain architectures) to lld the kernel is built
with a unique build-ID. Make it available via a sysctl and uname(1) to
allow the user to identify their running kernel.
Submitted by: Ali Mashtizadeh <ali_mashtizadeh.com>
MFC after: 2 weeks
Relnotes: Yes
Event: Waterloo Hackathon 2019
Differential Revision: https://reviews.freebsd.org/D20326
The linker script CONSTRUCTORS keyword is only meaningful "when linking
object file formats which do not support arbitrary sections, such as
ECOFF and XCOFF"[1] and is ignored for other object file formats.
LLVM's lld does not yet accept (and ignore) CONSTRUCTORS, so just remove
CONSTRUCTORS from the linker scripts as it has no effect.
[1] https://sourceware.org/binutils/docs/ld/Output-Section-Keywords.html
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D7343
This is only the minimum set of files needed to boot in qemu. As such it is
missing a few things.
The bus_dma code is currently only stub functions with a full implementation
from the development tree to follow.
The gic driver has been copied as the interrupt framework is different. It
is expected the two drivers will be merged by the arm intrng project,
however this will need to be imported into the tree and support for arm64
would need to be added.
This includes code developed by myself, SemiHalf, Ed Maste, and Robin
Randhawa from ARM. This has been funded by the FreeBSD Foundation, with
early development by myself in my spare time with assistance from Robin.
Differential Revision: https://reviews.freebsd.org/D2199
Reviewed by: emaste, imp
Relnotes: yes
Sponsored by: The FreeBSD Foundation
