- Make some variables and functions static, since they don't need to be
  global.

- Remove an unused function - arch/um/kernel/time.c::sched_clock().

- Clean the style a bit as complained by checkpatch.pl.

Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: NWANG Cong <wangcong@zeuux.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Robert Day noticed a few unused headers in UML, so this gets rid of them.

Cc: "Robert P. J. Day" <rpjday@crashcourse.ca>
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch folds mmu_context_skas into struct mm_context, changing all users
of these structures as needed.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Formatting changes in the files which have been changed in the course
of folding foo_skas functions into their callers.  These include:
	copyright updates
	header file trimming
	style fixes
	adding severity to printks

These changes should be entirely non-functional.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch makes a number of simplifications enabled by the removal of
CHOOSE_MODE.  There were lots of functions that looked like

	int foo(args){
		foo_skas(args);
	}

The bodies of foo_skas are now folded into foo, and their declarations (and
sometimes entire header files) are deleted.

In addition, the union uml_pt_regs, which was a union between the tt and skas
register formats, is now a struct, with the tt-mode arm of the union being
removed.

It turns out that usr2_handler was unused, so it is gone.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The next stage after removing code which depends on CONFIG_MODE_TT is removing
the CHOOSE_MODE abstraction, which provided both compile-time and run-time
branching to either tt-mode or skas-mode code.

This patch removes choose-mode.h and all inclusions of it, and replaces all
CHOOSE_MODE invocations with the skas branch.  This leaves a number of trivial
functions which will be dealt with in a later patch.

There are some changes in the uaccess and tls support which go somewhat beyond
this and eliminate some of the now-redundant functions.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Tidying of the UML physical memory system.  These are mostly style fixes,
however the includes were cleaned as well.  This uncovered a need for
mem_user.h to be included in mode_kern_skas.h.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Throw out a lot of code dealing with saving and restoring floating-point
state.  In skas mode, where processes run in a restoring floating-point state
on kernel entry and exit is pointless.

This eliminates most of arch/um/os-Linux/sys-{i386,x86_64}/registers.c.  Most
of what remained is now arch-indpendent, and can be moved up to
arch/um/os-Linux/registers.c.  Both arches need the jmp_buf accessor
get_thread_reg, and i386 needs {save,restore}_fp_regs because it cheats during
sigreturn by getting the fp state using ptrace rather than copying it out of
the process sigcontext.

After this, it turns out that arch/um/include/skas/mode-skas.h is almost
completely unneeded.  The declarations in it are variables which either don't
exist or which don't have global scope.  The one exception is
kill_off_processes_skas.  If that's removed, this header can be deleted.

This uncovered a bug in user.h, which wasn't correctly making sure that a
size_t definition was available to both userspace and kernelspace files.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Give the page fault code a specialized path.  There is only one page to look
at, so there's no point in going into the general page table walking code.
There's only going to be one host operation, so there are no opportunities for
merging.  So, we go straight to the pte we want, figure out what needs doing,
and do it.

While I was in here, I fixed the wart where the address passed to unmap was a
void *, but an unsigned long to map and protect.

This gives me just under 10% on a kernel build.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kbuild explicitly includes this at build time.
Signed-off-by: NDave Jones <davej@redhat.com>

fork on UML has always somewhat subtle.  The underlying cause has been the
need to initialize a stack for the new process.  The only portable way to
initialize a new stack is to set it as the alternate signal stack and take a
signal.  The signal handler does whatever initialization is needed and jumps
back to the original stack, where the fork processing is finished.  The basic
context switching mechanism is a jmp_buf for each process.  You switch to a
new process by longjmping to its jmp_buf.

Now that UML has its own implementation of setjmp and longjmp, and I can poke
around inside a jmp_buf without fear that libc will change the structure, a
much simpler mechanism is possible.  The jmpbuf can simply be initialized by
hand.

This eliminates -
	the need to set up and remove the alternate signal stack
	sending and handling a signal
	the signal blocking needed around the stack switching, since
there is no stack switching
	setting up the jmp_buf needed to jump back to the original
stack after the new one is set up

In addition, since jmp_buf is now defined by UML, and not by libc, it can be
embedded in the thread struct.  This makes it unnecessary to have it exist on
the stack, where it used to be.  It also simplifies interfaces, since the
switch jmp_buf used to be a void * inside the thread struct, and functions
which took it as an argument needed to define a jmp_buf variable and assign it
from the void *.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When UML is built as a static binary, it segfaults when run.  The reason is
that a memory hole that is present in dynamic binaries isn't there in static
binaries, and it contains essential stuff.

This fix removes the code which maps some anonymous memory into that hole and
cleans up some related code.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I was looking at the code of the UML and more precisely at the functions
set_task_sizes_tt and set_task_sizes_skas.  I noticed that these 2 functions
take a paramater (arg) which is not used : the function is always called with
the value 0.

I suppose that this value might change in the future (or even can be
configured), so I added a constant in mem_user.h file.

Also, I rounded CONFIG_HOST_TASk_SIZE to a 4M.
Signed-off-by: NTyler <tyler@agat.net>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This rearranges the OS declarations by moving some declarations into os.h.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The serial UML OS-abstraction layer patch (um/kernel/skas dir).

This moves all systemcalls from skas/process.c file under os-Linux dir and
join skas/process.c and skas/process_kern.c files.
Signed-off-by: NGennady Sharapov <gennady.v.sharapov@intel.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The serial UML OS-abstraction layer patch (um/kernel/skas dir).

This moves all systemcalls from skas/mem_user.c file under os-Linux dir and
join skas/mem_user.c and skas/mem.c files.
Signed-off-by: NGennady Sharapov <gennady.v.sharapov@intel.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The serial UML OS-abstraction layer patch (um/kernel dir).

This moves skas headers to arch/um/include.
Signed-off-by: NGennady Sharapov <Gennady.V.Sharapov@intel.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>