MFC 309589: Rework syscall structure lookups.

Avoid always using an O(n^2) loop over known syscall structures with
strcmp() on each system call. Instead, use a per-ABI cache indexed by
the system call number. The first 1024 system calls (which should cover
all of the normal system calls in currently-supported ABIs) use a flat array
indexed by the system call number to find system call structure. For other
system calls, a linked list of structures storing an integer to structure
mapping is stored in the ABI. The linked list isn't very smart, but it
should only be used by buggy applications invoking unknown system calls.

This also fixes handling of unknown system calls which currently trigger
a NULL pointer dereference.

MFC 307538,307948,308602,308603,311151: Move kdump's mksubr into libsysdecode.

307538:
Move mksubr from kdump into libsysdecode.

Restructure this script so that it generates a header of tables instead
of a source file. The tables are included in a flags.c source file which
provides functions to decode various system call arguments.

For functions that decode an enumeration, the function returns a pointer
to a string for known values and NULL for unknown values.

For functions that do more complex decoding (typically of a bitmask), the
function accepts a pointer to a FILE object (open_memstream() can be used
as a string builder) to which decoded values are written. If the
function operates on a bitmask, the function returns true if any bits
were decoded or false if the entire value was valid. Additionally, the
third argument accepts a pointer to a value to which any undecoded bits
are stored. This pointer can be NULL if the caller doesn't care about
remaining bits.

Convert kdump over to using decoder functions from libsysdecode instead of
mksubr. truss also uses decoders from libsysdecode instead of private
lookup tables, though lookup tables for objects not decoded by kdump remain
in truss for now. Eventually most of these tables should move into
libsysdecode as the automated table generation approach from mksubr is
less stale than the static tables in truss.

Some changes have been made to truss and kdump output:
- The flags passed to open() are now properly decoded in that one of
O_RDONLY, O_RDWR, O_WRONLY, or O_EXEC is always included in a decoded
mask.
- Optional arguments to open(), openat(), and fcntl() are only printed
in kdump if they exist (e.g. the mode is only printed for open() if
O_CREAT is set in the flags).
- Print argument to F_GETLK/SETLK/SETLKW in kdump as a pointer, not int.
- Include all procctl() commands.
- Correctly decode pipe2() flags in truss by not assuming full
open()-like flags with O_RDONLY, etc.
- Decode file flags passed to *chflags() as file flags (UF_* and SF_*)
rather than as a file mode.
- Fix decoding of quotactl() commands by splitting out the two command
components instead of assuming the raw command value matches the
primary command component.

In addition, truss and kdump now build without triggering any warnings.
All of the sysdecode manpages now include the required headers in the
synopsis.

307948:
Use binary and (&) instead of logical to extract the mask of a capability.

308602:
Generate and use a proper .depend file for tables.h.

308603:
Move libsysdecode-specific hack out of buildworld.

This should fix the lib32 build since it was not removing the generated
ioctl.c. This file is generated by a find(1) call, so cannot use normal
dependency tracking methods.

311151:
Update libsysdecode for getfsstat() 'flags' argument changing to 'mode'.

As a followup to r310638, update libsysdecode (and kdump) to decode the
'mode' argument to getfsstat(). sysdecode_getfsstat_flags() has been
renamed to sysdecode_getfsstat_mode() and now treats the argument as an
enumerated value rather than a mask of flags.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add a SYSDECODE_ABI_ prefix to the ABI enums to avoid potential collisions.

Suggested by: jmallett
Reviewed by: bdrewery, jmallett
Differential Revision: https://reviews.freebsd.org/D5123

Add support to libsysdecode for decoding system call names.

A new sysdecode_syscallname() function accepts a system call code and
returns a string of the corresponding name (or NULL if the code is
unknown). To support different process ABIs, the new function accepts a
value from a new sysdecode_abi enum as its first argument to select the
ABI in use. Current ABIs supported include FREEBSD (native binaries),
FREEBSD32, LINUX, LINUX32, and CLOUDABI64. Note that not all ABIs are
supported by all platforms. In general, a given ABI is only supported
if a platform can execute binaries for that ABI.

To simplify the implementation, libsysdecode's build reuses the
existing pre-generated files from the kernel source tree rather than
duplicating new copies of said files during the build.

kdump(1) and truss(1) now use these functions to map system call
identifiers to names. For kdump(1), a new 'syscallname()' function
consolidates duplicated code from ktrsyscall() and ktrsyscallret().
The Linux ABI no longer requires custom handling for ktrsyscall() and
linux_ktrsyscall() has been removed as a result.

Reviewed by: bdrewery
Differential Revision: https://reviews.freebsd.org/D4823

Simplify syscall generation and ABI source file handling for the build.

This is to make the Makefile more easily extendable for new ABIs.

This also makes several other subtle changes:
- The build now is given a list of ABIs to use based on the MACHINE_ARCH or
MACHINE_CPUARCH. These ABIs have a related path in sys/ that is used
to generate their syscalls. For each ABI to build check for a
ABI.c, MACHINE_ARCH-ABI.c, or a MACHINE_CPUARCH-ABI.c. This matches
the old behavior needed for archs such as powerpc* and mips*.
- The ABI source file selection allows for simpler assignment of common
ABIs such as "fbsd32" from sys/compat/freebsd32, or cloudabi64.
- Expand 'fbsd' to 'freebsd' everywhere for consistency.
- Split out the powerpc-fbsd.c file into a powerpc64-freebsd32.c to be more
like the amd64-freebsd32.c file and to more easily allow the auto-generation
of ABI handling to work.
- Rename 'syscalls.h' to 'fbsd_syscalls.h' to lessen the ambiguity and
avoid confusion with syscall.h (such as in r288997).
- For non-native syscall header files, they are now renamed to be
ABI_syscalls.h, where ABI is what ABI the Makefile is building.
- Remove all of the makesyscalls config files. The "native" one being
name i386.conf was a long outstanding bug. They were all the same
except for the data they generated, so now it is just auto-generated
as a build artifact.
- The syscalls array is now fixed to be static in the syscalls header to
remove the compiler warning about non-extern. This was worked around
in the aarch64-fbsd.c file but not the others.
- All syscall table names are now just 'syscallnames' since they don't
need to be different as they are all static in their own ABI files. The
alternative is to name them ABI_syscallnames which does not seem
necessary.

Reviewed by: ed, jhb
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D3851

Add aarch64 support to truss(1).

Reviewed by: jhb
Discussed with: emaste (license)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3750