sys: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

riscv: always include frame pointer

Specifically it is missing in kernel modules, meaning a proper backtrace
can't be constructed.

Reviewed by: jhb
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D37657

riscv: Add the device-tree path to the include path

Simplify the RISC-V kernel linker invocation

Remove our custom SYSTEM_LD definition. This generates program headers
that are more consistent with other architectures, and more importantly,
are in line with what loader(8) expects when loading a kernel.

As noted in https://reviews.freebsd.org/D22920, there is no apparent
reason why the kernel would need a writable text segment, so removal of
the -N flag isn't likely to cause issue.

Reviewed by: kp, br
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D24909

Retire the GENERICSF kernel config.

Now that hw.machine_arch handles soft-float vs hard-float there is no
longer a reason for this config.

Submitted by: mhorne (kern.mk hunk)
Reviewed by: imp (earlier version), kp
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D24544

Better check for floating point type.

Use __riscv_flen instead of __riscv_float_abi_soft. While the latter works for
userland (and one could argue it's more correct), it fails for the kernel. We
compile the kernel with -mabi=lp64 (eg soft float abi) to avoid floating point
instructions in the kernel. We also compile the kernel -march=rv64imafdc for
hard float kernels (eg those with options FPE), but with -march=rv64imac for
softfloat kernels (eg those with FPE). Since we do this, in the kernel (as in
userland) __riscv_flen will be defined for 'riscv64' and not for 'riscv64sf'.

This also removes the -DMACHINE_ARCH hack now that it's no longer needed.

Longer term, we should return the ABI from the sysctl hw.machine_arch like on
amd64 for i386 binaries.

Suggested by: mhorne@
Differential Revision: https://reviews.freebsd.org/D23813

Add a soft-float riscv kernel config

GENERICSF is just like GENERIC, only creates a soft-float kernel. Omit it from the
universe build for now.

Reviewed by: philip
Differential Revision: https://reviews.freebsd.org/D23812

Use MACHINE_ARCH instead of TARGET_ARCH

TARGET_ARCH is only for use in Makefile.inc1 contexts. MACHINE_ARCH is the
preferred thing to set. Makefile.inc1 sets MACHINE_ARCH in the cross build
case, and make sets it in the native build case. This will fix anybody doing a
native build. Add a comment for why we have to do this dance so when/if the
problem with CFLAGS is fixed for the kernel this workaround can be removed.

riscv: Set MACHINE_ARCH correctly

MACHINE_ARCH sets the hw.machine_arch sysctl in the kernel. In userspace
it sets MACHINE_ARCH in bmake, which bsd.cpu.mk uses to configure the
target ABI for ports.

For riscv64sf builds (i.e. soft-float) that needs to be riscv64sf, but
the sysctl didn't reflect that. It is static.

Set the define from the riscv makefile so that we correctly reflect our
actual build (i.e. riscv64 or riscv64sf), depending on what TARGET_ARCH
we were built with.

That still doesn't satisfy userspace builds (e.g. bmake), so check if
we're building with a software-floating point toolchain there. That
check doesn't work in the kernel, because it never uses floating point.

Reviewed by: philip (previous version), mhorne
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D23741

Set the LMA of the riscv kernel to the OpenSBI jump target by default

This allows us to boot FreeBSD RISCV on QEMU using the -kernel command line
options. When using that option, QEMU maps the kernel ELF file to the
addresses specified in the LMAs in the program headers.

Since version 4.2 QEMU ships with OpenSBI fw_jump by default so this allows
booting FreeBSD using the following command line:
qemu-system-riscv64 -bios default -kernel /.../boot/kernel/kernel -nographic -M virt

Without this change the -kernel option cannot be used since the LMAs start
at address zero and QEMU already maps a ROM to these low physical addresses.

For targets that require a different kernel LMA the make variable
KERNEL_LMA can be overwritten in the config file. For example, adding
`makeoptions KERNEL_LMA=0xc0200000` will create an ELF file that will be
loaded at 0xc0200000.

Before:
There are 4 program headers, starting at offset 64

Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x001000 0xffffffc000000000 0x0000000000000000 0x75e598 0x8be318 RWE 0x1000
DYNAMIC 0x71fb20 0xffffffc00071eb20 0x000000000071eb20 0x000100 0x000100 RW 0x8
GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RW 0x0
NOTE 0x693400 0xffffffc000692400 0x0000000000692400 0x000024 0x000024 R 0x4

After:

There are 4 program headers, starting at offset 64

Program Headers:
Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
LOAD 0x001000 0xffffffc000000000 0x0000000080200000 0x734198 0x893e18 RWE 0x1000
DYNAMIC 0x6f7810 0xffffffc0006f6810 0x00000000808f6810 0x000100 0x000100 RW 0x8
GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RW 0x0
NOTE 0x66ca70 0xffffffc00066ba70 0x000000008086ba70 0x000024 0x000024 R 0x4

Reviewed By: br, mhorne (earlier version)
Differential Revision: https://reviews.freebsd.org/D23436

Revert r356077, apparently the change doesn't work after all (failed to
build in CI).

For riscv kernel builds, add -N to LDFLAGS instead of replacing the
SYSTEM_LD variable. This avoids duplicating the contents of SYSTEM_LD
from kern.pre.mk just to add the -N flag to it. If the basic linker command
ever needs to be changed, this will be one less place that has to be found
and fixed.

Some testing by kp@ indicates that the -N flag may not be needed at all,
so a comment to that effect is also added, and the -N flag may be removed
in a followup commit.

Differential Revision: https://reviews.freebsd.org/D22920

Revert r336353 completely based on protest; compatibility shims incoming

Revert 336358 and step away fron machine for the day...

VERSREQ < 7.+ physically will not work with new config(8) due to major bump,
which is why I bumped it in the first place... Back to the original version

Partially revert r336353: sys/conf/* %VERSREQ bumps

The changes made in r335998 don't strictly require a newer config(8),
though it is advised. The %VERSREQ bumps were premature.

config(8): Bump major version after r335998

config-generated hints.c/env.c from r335998 and later are incompatible with
earlier kernels due to no longer setting envmode/hintmode. A minor bump for
this is insufficient, as matching major version with a later minor version
is still viewed as backwards-compatible.

This was an MI kernel change, soo all VERSREQ's are bumped.

Support for v1.10 (latest) of RISC-V privilege specification.

New version is not compatible on supervisor mode with v1.9.1
(previous version).

Highlights:
o BBL (Berkeley Boot Loader) provides no initial page tables
anymore allowing us to choose VM, to build page tables manually
and enable MMU in S-mode.
o SBI interface changed.
o GENERIC kernel.
FDT is now chosen standard for RISC-V hardware description.
DTB is now provided by Spike (golden model simulator). This
allows us to introduce GENERIC kernel. However, description
for console and timer devices is not provided in DTB, so move
these devices temporary to nexus bus.
o Supervisor can't access userspace by default. Solution is to
set SUM (permit Supervisor User Memory access) bit in sstatus
register.
o Compressed extension is now turned on by default.
o External GCC 7.1 compiler used.
o _gp renamed to __global_pointer$
o Compiler -march= string is now in use allowing us to choose
required extensions (compressed, FPU, atomic, etc).

Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D11800

Set dependencies for genassym.c.
This fixes non-parallel build.

Add support for ddb(4).

Sponsored by: DARPA, AFRL
Sponsored by: HEIF5

Welcome the RISC-V 64-bit kernel.

This is the final step required allowing to compile and to run RISC-V
kernel and userland from HEAD.

RISC-V is a completely open ISA that is freely available to academia
and industry.

Thanks to all the people involved! Special thanks to Andrew Turner,
David Chisnall, Ed Maste, Konstantin Belousov, John Baldwin and
Arun Thomas for their help.
Thanks to Robert Watson for organizing this project.

This project sponsored by UK Higher Education Innovation Fund (HEIF5) and
DARPA CTSRD project at the University of Cambridge Computer Laboratory.

FreeBSD/RISC-V project home: https://wiki.freebsd.org/riscv

Reviewed by: andrew, emaste, kib
Relnotes: Yes
Sponsored by: DARPA, AFRL
Sponsored by: HEIF5
Differential Revision: https://reviews.freebsd.org/D4982