Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by: rwatson
Approved by: re (bz)

Revert r210451, and the similar part of the r210431. The forward-declaration
for the enum tag when enum definition is not complete is not allowed by
C99, and is gcc extension.

Requested by: stefanf
MFC after: 28 days

Remove the linux_exec_copyin_args(), freebsd32_exec_copyin_args() may
server as well. COMPAT_FREEBSD32 is a prerequisite for COMPAT_LINUX32.

Reviewed by: alc
MFC after: 3 weeks

Extract the code to copy-out struct rusage32 from struct rusage
into the new function.

Reviewed by: jhb
MFC after: 1 week

Introduce SYSCALL_INIT_HELPER and SYSCALL32_INIT_HELPER macros and
neccessary support functions to allow registering dynamically loaded
syscalls from the MOD_LOAD handlers. Helpers handle registration
failures semi-automatically.

Reviewed by: jhb
MFC after: 2 weeks

FOr SYSCALL_MODULE_HELPER, use "sys/<syscallname>" module name.
FOr SYSCALL32_MODULE_HELPER, use "sys32/<syscallname>" module name.
This avoids modules name conflict when compat32 syscall does not
need shims.

Note that SYSCALL_MODULE_HELPER is going to be unused in the tree by
several next commits.

Suggested by: jhb
MFC after: 2 weeks

Make freebsd32_copyiniov() available outside of freebsd32_misc.

MFC after: 2 weeks

Provide groundwork for 32-bit binary compatibility on non-x86 platforms,
for upcoming 64-bit PowerPC and MIPS support. This renames the COMPAT_IA32
option to COMPAT_FREEBSD32, removes some IA32-specific code from MI parts
of the kernel and enhances the freebsd32 compatibility code to support
big-endian platforms.

Reviewed by: kib, jhb

Add support for installing 32-bit system calls from kernel modules. This
includes syscall32_{de,}register() routines as well as a module handler
and wrapper macros similar to the support for native syscalls in
<sys/sysent.h>.

MFC after: 1 month

Sort includes and add multiple include guards.

- Change the commented out freebsd32_xxx() example to use kern_xxx() along
with a single copyin() + translate and translate + copyout() rather than
using the stackgap.
- Remove implementation of the stackgap for freebsd32 since it is no longer
used for that compat ABI.

Approved by: re (scottl)

Eliminate stackgap usage for the (woefully incomplete) path translations
since it isn't needed here anymore.
Use standard open(2)/access(2) and chflags(2) syscalls now.

Switch to using the emulator in the common compat area.
Still work-in-progress.

Initial sweep to de-i386-ify this

Deal with the user VM space expanding. 32 bit applications do not like
having their stack at the 512GB mark. Give 4GB of user VM space for 32
bit apps. Note that this is significantly more than on i386 which gives
only about 2.9GB of user VM to a process (1GB for kernel, plus page
table pages which eat user VM space).

Approved by: re (blanket)

Add BASIC i386 binary support for the amd64 kernel. This is largely
stolen from the ia64/ia32 code (indeed there was a repocopy), but I've
redone the MD parts and added and fixed a few essential syscalls. It
is sufficient to run i386 binaries like /bin/ls, /usr/bin/id (dynamic)
and p4. The ia64 code has not implemented signal delivery, so I had
to do that.

Before you say it, yes, this does need to go in a common place. But
we're in a freeze at the moment and I didn't want to risk breaking ia64.
I will sort this out after the freeze so that the common code is in a
common place.

On the AMD64 side, this required adding segment selector context switch
support and some other support infrastructure. The %fs/%gs etc code
is hairy because loading %gs will clobber the kernel's current MSR_GSBASE
setting. The segment selectors are not used by the kernel, so they're only
changed at context switch time or when changing modes. This still needs
to be optimized.

Approved by: re (amd64/* blanket)

SCARGS removal take II.

Backout removal SCARGS, the code freeze is only "selectively" over.

Remove SCARGS.

Reviewed by: md5

Infrastructure tweaks to allow having both an Elf32 and an Elf64 executable
handler in the kernel at the same time. Also, allow for the
exec_new_vmspace() code to build a different sized vmspace depending on
the executable environment. This is a big help for execing i386 binaries
on ia64. The ELF exec code grows the ability to map partial pages when
there is a page size difference, eg: emulating 4K pages on 8K or 16K
hardware pages.

Flesh out the i386 emulation support for ia64. At this point, the only
binary that I know of that fails is cvsup, because the cvsup runtime
tries to execute code in pages not marked executable.

Obtained from: dfr (mostly, many tweaks from me).