More trimming of the page fault path.

Permissions are passed around in a single int rather than one bit per
int.  The permission values are copied from libc so that they can be
passed to mmap and mprotect without any further conversion.

The register sets used by do_syscall_stub and copy_context_skas0 are
initialized once, at boot time, rather than once per call.

wait_stub_done checks whether it is getting the signals it expects by
comparing the wait status to a mask containing bits for the signals of
interest rather than comparing individually to the signal numbers.  It
also has one check for a wait failure instead of two.  The caller is
expected to do the initial continue of the stub.  This gets rid of an
argument and some logic.  The fname argument is gone, as that can be
had from a stack trace.

user_signal() is collapsed into userspace() as it is basically one or
two lines of code afterwards.

The physical memory remapping stuff is gone, as it is unused.

flush_tlb_page is inlined.
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>

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>

Rename os_{read_write}_file_k back to os_{read_write}_file, delete
the originals and their bogus infrastructure, and fix all the callers.
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>

Dump core after a panic.  This will provide better debugging information than
is currently available.
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>

This patch starts the removal of a very old, very broken piece of code.  This
stems from the problem of passing a userspace buffer into read() or write() on
the host.  If that buffer had not yet been faulted in, read and write will
return -EFAULT.

To avoid this problem, the solution was to fault the buffer in before the
system call by touching the pages that hold the buffer by doing a copy-user of
a byte to each page.  This is obviously bogus, but it does usually work, in tt
mode, since the kernel and process are in the same address space and userspace
addresses can be accessed directly in the kernel.

In skas mode, where the kernel and process are in separate address spaces, it
is completely bogus because the userspace address, which is invalid in the
kernel, is passed into the system call instead of the corresponding physical
address, which would be valid.  Here, it appears that this code, on every host
read() or write(), tries to fault in a random process page.  This doesn't seem
to cause any correctness problems, but there is a performance impact.  This
patch, and the ones following, result in a 10-15% performance gain on a kernel
build.

This code can't be immediately tossed out because when it is, you can't log
in.  Apparently, there is some code in the console driver which depends on
this somehow.

However, we can start removing it by switching the code which does I/O using
kernel addresses to using plain read() and write().  This patch introduces
os_read_file_k and os_write_file_k for use with kernel buffers and converts
all call locations which use obvious kernel buffers to use them.  These
include I/O using buffers which are local variables which are on the stack or
kmalloc-ed.  Later patches will handle the less obvious cases, followed by a
mass conversion back to the original interface.
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>

If there's a segfault inside the kernel, we want a dump of the registers at
the point of the segfault, not the registers at the point of calling panic or
the last userspace registers.

sig_handler_common_skas now uses a static register set in the case of a
SIGSEGV to avoid messing up the process registers if the segfault turns out to
be non-fatal.

The architecture sigcontext-to-pt_regs copying code was repurposed to copy
data out of the SEGV stack frame.
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>

Tidying in preparation for the segfault register dumping patch which follows.

void * pointers are changed to union uml_pt_regs *.  This makes the types
match reality, except in arch_fixup, which is changed to operate on a union
uml_pt_regs.  This fixes a bug in the call from segv_handler, which passes a
union uml_pt_regs, to segv, which expects to pass a struct sigcontext to
arch_fixup.

Whitespace and other style fixes.

There's also a errno printk fix.
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>

userspace code used to have to call the kernelspace function page_size() in
order to determine the value of the kernel's PAGE_SIZE.  Since this is now
available directly from kern_constants.h as UM_KERN_PAGE_SIZE, page_size() can
be deleted and calls changed to use the constant.
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>

Clean up arch/um/kernel/process.c:

- lots of return(x); -> return x; conversions

- a number of the small functions are either unused, in which case they are
  gone, along any declarations in a header, or could be made static.

- current_pid is ifdefed on CONFIG_MODE_TT and its declaration is ifdefed on
  both CONFIG_MODE_TT and UML_CONFIG_MODE_TT because we don't know whether
  it's being used in a userspace or kernel file.
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>

To look at users I did:
$ find arch/um/ include/asm-um -name '*.[ch]'|xargs grep -r 'net_kern\.h'
+-l|xargs grep '\<user\>'

Most users just cast user to the appropriate pointer, the remaining ones are
fixed here.  In net_kern.c, I'm almost sure that save trick is not needed
anymore, but I've not verified it.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
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>

user_util.h isn't needed any more, so delete it and remove all includes of it.
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>

Rescue the useful contents of the soon-to-be-gone user-util.h.

pty.c now gets ptsname from stdlib.h like it should have always done.

CATCH_EINTR is now in os.h, although perhaps all usage should be under
os-Linux at some point.

get_pty is also in os.h.

This patch restores the old definition of ARRAY_SIZE in user.h.  This file is
included only in userspace files, so there will be no conflict with the
kernel's new ARRAY_SIZE.  The copy of the kernel's ARRAY_SIZE and associated
infrastructure is now gone.
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>

This patch moves all the the symbols defined in um_arch.c, which are mostly
boundaries between different parts of the UML kernel address space, to a new
header, as-layout.h.  There are also a few things here which aren't really
related to address space layout, but which don't really have a better place to
go.
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>

This patch moves the declarations of the architecture hooks from user_util.h
to a new header, arch.c, and adds the necessary includes to files which need
those declarations.
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>

This patch narrows the sigio interface.  The boot-time SIGIO testing used to
be in start_up.c, which meant that pty_output_sigio and pty_close_sigio needed
to be global.  By moving that code here, those can become static and the
declarations moved from user_util.h.

os_check_bugs is also here because it only does the SIGIO checking.  If it
does more, it'll probably move back to start_up.c.
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>

We can use a gcc extension to ensure that ARRAY_SIZE() is handed an array,
not a pointer.  This is especially important when code is changed from a
fixed array to a pointer.  I assume the Intel compiler doesn't support
__builtin_types_compatible_p.

[jdike@addtoit.com: uml: update UML definition of ARRAY_SIZE]
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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 fixes a number of problems associated with network interface hotplug.

The userspace initialization function can fail in some cases, but the
failure was never passed back to eth_configure, which proceeded with the
configuration.  This results in a zombie device that is present, but can't
work.  This is fixed by allowing the initialization routines to return an
error, which is checked, and the configuration aborted on failure.

eth_configure failed to check for many failures.  Even when it did check,
it didn't undo whatever initializations has already happened, so a present,
but partially initialized and non-working device could result.  It now
checks everything that can fail, and bails out, undoing whatever had been
done.

The return value of eth_configure was always ignored, so it is now just
void.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the host_info string from util.c to um_arch.c, where it is
actually initialized and used.  Also document its lack of locking.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Get rid of a bunch of unused stuff -
	cpu_feature had no users
	linux_prog is little-used, so its declaration is moved to the
user for easy deletion when the whole file goes away
	a long-unused debugging aid in helper.c is gone
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Fix a few miscellaneous compilation problems -
	an assignment with mismatched types in ldt.c
	a missing include in mconsole.h which needs a definition of uml_pt_regs
	I missed removing an include of user_util.h in hostfs
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>

This patch uses MAX_REG_NR consistently to refer to the register file size.
 FRAME_SIZE isn't sufficient because on x86_64, it is smaller than the
ptrace register file size.  MAX_REG_NR was introduced as a consistent way
to get the number of registers, but wasn't used everywhere it should be.

When this causes a problem, it makes PTRACE_SETREGS fail on x86_64 because
of a corrupted segment register value in the known-good register file.  The
patch also adds a register dump at that point in case there are any future
problems here.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

os_usr1_signal() is totally unused, os_usr1_process() is used only by TT mode.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove in-source externs, linux/init.h is included in all cases.
This is a fixups for "Dynamic kernel command-line" patch.

It also includes some uml __init fixups so that we can __initdata also its
command_line.
Signed-off-by: NAlon Bar-Lev <alon.barlev@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

1. Rename saved_command_line into boot_command_line.
2. Set command_line as __initdata.
Signed-off-by: NAlon Bar-Lev <alon.barlev@gmail.com>
Cc: Jeff Dike <jdike@addtoit.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>

x86_64 needs some TLS fixes.  What was missing was remembering the child
thread id during clone and stuffing it into the child during each context
switch.

The %fs value is stored separately in the thread structure since the host
controls what effect it has on the actual register file.  The host also needs
to store it in its own thread struct, so we need the value kept outside the
register file.

arch_prctl_skas was fixed to call PTRACE_ARCH_PRCTL appropriately.  There is
some saving and restoring of registers in the ARCH_SET_* cases so that the
correct set of registers are changed on the host and restored to the process
when it runs again.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Add an error message when two umids are put on the command line.

umid.h is kind of pointless since it only declares one thing, and that
is already declared in os.h.

Commented the lack of locking of some data in os-Linux/umid.h.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Fix formatting in the sigio code.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

We shouldn't be using the os wrappers from os code - we can use libc directly.
This patch replaces wrapper calls with libc calls.

It turns out that os_sigio_async had only one caller, which was in startup.c,
so that function is moved there and its name changed.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Locking comments and emacs comment removal in the low-level memory and
temp file code.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

A bunch of the signal handlers can be made static.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

syscall_index and next_syscall_index turn out not to be used.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Eliminate the open_mutex after complaints from Blaisorblade.  It turns out
that the tty count provides the information needed to tell whether we are the
first opener or last closer.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Remove the last vestiges of devfs from console registration.  Change the name
of the function, plus remove a couple of unused fields from the line_driver
structure.

struct lines is no longer needed, all traces of it are gone.

The only way that I can see to mark a structure as being almost-const is to
individually const the fields.  This is the case for the line_driver
structure, which has only one modifiable field - a list_head in a
sub-structure.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Whitespace fixes and emacs comment removal.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

The chan_opts structure is mostly const, and needs no locking.  Comment the
lack of locking on the one field that can change.

Make all the other fields const.  It turned out that console_open_chan didn't
use its chan_opts argument, so that is deleted from the function and its
callers.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Some whitespace and coding style cleanups in the network driver code.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Garzik <jeff@garzik.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The registration of host network transports needed some locking.  The
transport list itself is locked, but calls to the registration routines are
not.  This is compensated for by checking that a transport structure is not
yet on any list.

I also took the opportunity to const all fields in the transport structure
except the list, which obviously can be modified.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Some comment and whitespace cleanups in the console and mconsole code.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

I noticed that errors happening while hotplugging devices from the host were
never returned back to the mconsole client.  In some cases, success was
returned instead of even an information-free error.

This patch cleans that up by having the low-level configuration code pass back
an error string along with an error code.  At the top level, which knows
whether it is early boot time or responding to an mconsole request, the string
is printk'd or returned to the mconsole client.

There are also whitespace and trivial code cleanups in the surrounding code.
Signed-off-by: NJeff Dike <jdike@addtoit.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>

Clean up the console driver locking.  There are various problems here,
including sleeping under a spinlock and spinlock recursion, some of which are
fixed here.  This patch deals with the locking involved with opens and closes.
 The problem is that an mconsole request to change a console's configuration
can race with an open.  Changing a configuration should only be done when a
console isn't opened.  Also, an open must be looking at a stable
configuration.  In addition, a get configuration request must observe the same
locking since it must also see a stable configuration.  With the old locking,
it was possible for this to hang indefinitely in some cases because open would
block for a long time waiting for a connection from the host while holding the
lock needed by the mconsole request.

As explained in the long comment, this is fixed by adding a spinlock for the
use count and configuration and a mutex for the actual open and close.
Signed-off-by: NJeff Dike <jdike@addtoit.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>