This patchset throws out tt mode, which has been non-functional for a while.

This is done in phases, interspersed with code cleanups on the affected files.

The removal is done as follows:
	remove all code, config options, and files which depend on
CONFIG_MODE_TT
	get rid of the CHOOSE_MODE macro, which decided whether to
call tt-mode or skas-mode code, and replace invocations with their
skas portions
	replace all now-trivial procedures with their skas equivalents

There are now a bunch of now-redundant pieces of data structures, including
mode-specific pieces of the thread structure, pt_regs, and mm_context.  These
are all replaced with their skas-specific contents.

As part of the ongoing style compliance project, I made a style pass over all
files that were changed.  There are three such patches, one for each phase,
covering the files affected by that phase but no later ones.

I noticed that we weren't freeing the LDT state associated with a process when
it exited, so that's fixed in one of the later patches.

The last patch is a tidying patch which I've had for a while, but which caused
inexplicable crashes under tt mode.  Since that is no longer a problem, this
can now go in.

This patch:

Start getting rid of tt mode support.

This patch throws out CONFIG_MODE_TT and all config options, code, and files
which depend on it.

CONFIG_MODE_SKAS is gone and everything that depends on it is included
unconditionally.

The few changed lines are in re-written Kconfig help, lines which needed
something skas-related removed from them, and a few more which weren't
strictly deletions.
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 completes Linus's wish that the fault return codes be made into
bit flags, which I agree makes everything nicer.  This requires requires
all handle_mm_fault callers to be modified (possibly the modifications
should go further and do things like fault accounting in handle_mm_fault --
however that would be for another patch).

[akpm@linux-foundation.org: fix alpha build]
[akpm@linux-foundation.org: fix s390 build]
[akpm@linux-foundation.org: fix sparc build]
[akpm@linux-foundation.org: fix sparc64 build]
[akpm@linux-foundation.org: fix ia64 build]
Signed-off-by: NNick Piggin <npiggin@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: NKyle McMartin <kyle@mcmartin.ca>
Acked-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NRalf Baechle <ralf@linux-mips.org>
Acked-by: NAndi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
[ Still apparently needs some ARM and PPC loving - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It turns out that the message complaining about a lack of tmpfs space
on the host can be misunderstood as referring to the UML.
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>

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>

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>

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>

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

This is an updated version of Eric Biederman's is_init() patch.
(http://lkml.org/lkml/2006/2/6/280).  It applies cleanly to 2.6.18-rc3 and
replaces a few more instances of ->pid == 1 with is_init().

Further, is_init() checks pid and thus removes dependency on Eric's other
patches for now.

Eric's original description:

	There are a lot of places in the kernel where we test for init
	because we give it special properties.  Most  significantly init
	must not die.  This results in code all over the kernel test
	->pid == 1.

	Introduce is_init to capture this case.

	With multiple pid spaces for all of the cases affected we are
	looking for only the first process on the system, not some other
	process that has pid == 1.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NSukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: <lxc-devel@lists.sourceforge.net>
Acked-by: NPaul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

BB noticed that we had the wrong bus error handler.
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>

Make lots of structures const in order to make it obvious that they need no
locking.
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>

UML can get a SIGBUS anywhere if the tmpfs mount being used for its memory
runs out of space.  This patch adds a printk before the panic to provide a
clue as to what likely went wrong.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Move most *_kern.c files in arch/um/kernel to *.c.  This makes UML somewhat
more closely resemble the other arches.

[akpm@osdl.org: use the new INTF_* flags]
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>

misc sparse annotations
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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 joins trap_user.c and trap_kernel.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 all systemcalls from trap_user.c file under os-Linux dir
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 below warning was added in place of pte_mkyoung(); if (is_write)
pte_mkdirty();

In fact, if the PTE is not marked young/dirty, our dirty/accessed bit
emulation would cause the TLB permission not to be changed, and so we'd loop,
and given we don't support preemption yet, we'd busy-hang here.

However, I've seen this warning trigger without crashes during a loop of
concurrent kernel builds, at random times (i.e. like a race condition), and I
realized that two concurrent faults on the same page, one on read and one on
write, can trigger it. The read fault gets serviced and the PTE gets marked
writable but clean (it's possible on a shared-writable mapping), while the
generic code sees the PTE was already installed and returns without action. In
this case, we'll see another fault and service it normally.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I hadn't been running a SKAS3 host when testing the "uml: fix hang in TT mode
on fault" patch (commit 546fe1cb), and I
didn't think enough to the missing trap_no in SKAS3 mode.

In fact, the resulting kernel doesn't work at all in SKAS3 mode.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Following i386, we should maybe refuse trying to fault in pages when we're
doing atomic operations, because to handle the fault we could need to take
already taken spinlocks.

Also, if we're doing an atomic operation (in the sense of in_atomic()) we're
surely in kernel mode and we're surely going to handle adequately the failed
fault, so it's safe to behave this way.

Currently, on UML SMP is rarely used, and we don't support PREEMPT, so this is
unlikely to create problems right now, but it might in the future.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The current code doesn't handle well general protection faults on the host -
it thinks that cr2 is always the address of a page fault.  While actually, on
general protection faults, that address is not accessible, so we'd better
assume we couldn't satisfy the fault.  Currently instead we think we've fixed
it, so we go back, retry the instruction and fault again endlessly.

This leads to the kernel hanging when doing copy_from_user(dest, -1, ...) in
TT mode, since reading *(-1) causes a GFP, and we don't support kernel
preemption.

Thanks to Luo Xin for testing UML with LTP and reporting the failures he got.

Cc: Luo Xin <luothing@sina.com>
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The PTE returned from handle_mm_fault is already marked as dirty and accessed
if needed.

Also, since this is not set with set_pte() (which sets NEWPAGE and NEWPROT as
needed), this wouldn't work anyway.

This version has been updated and fixed, thanks to some feedback from Jeff Dike.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The UML fault handler was recently changed to enforce PROT_NONE protections,
by requiring VM_READ or VM_EXEC on VMA's.

However, by mistake, things were changed such that VM_READ is always checked,
also on write faults; so a VMA mapped with only PROT_WRITE is not readable
(unless it's prefaulted with MAP_POPULATE or with a write), which is different
from i386.

Discovered while testing remap_file_pages protection support.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Avoid chomping low bits of address for functions doing it by themselves,
fix whitespace, add a correctness checking.

I did this for remap-file-pages protection support, it was useful on its
own too.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This eliminates the segfault info ring buffer, which added a system call to
each page fault, and which hadn't been useful for debugging in ages.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove old useless header that was used in Ye Olde Times during 2.4->2.5
porting to abstract differences.  It's definitions are no more used anyway, so
let's finally kill it.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Finally rip out the ubd-mmap code, which turned out to be broken by design.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Any access to a PROT_NONE page should segfault the process.  A JVM seems to do
this on purpose.  Also, Al noticed some bogus code, which is now deleted.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This fixes some x86_64 bugs -

- maybe_map returns -1 on error instead of 0, which is interpreted as
  physical address 0

- removed an include of ipc.h, which isn't needed

- fixed the calculation of signal frame location

- the signal delivery code is now immune to the stack expansion check

- added a missing include
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 patch removes the arch-specific fault/trap-infos from thread and
skas-regs.

It adds a new struct faultinfo, that is arch-specific defined in
sysdep/faultinfo.h.

The structure is inserted in thread.arch and thread.regs.skas and
thread.regs.tt

Now, segv and other trap-handlers can copy the contents from regs.X.faultinfo
to thread.arch.faultinfo with one simple assignment.

Also, the number of macros necessary is reduced to

FAULT_ADDRESS(struct faultinfo)
    extracts the faulting address from faultinfo

FAULT_WRITE(struct faultinfo)
    extracts the "is_write" flag

SEGV_IS_FIXABLE(struct faultinfo)
    is true for the fixable segvs, i.e. (TRAP == 14)
    on i386

UPT_FAULTINFO(regs)
    result is (struct faultinfo *) to the faultinfo
    in regs->skas.faultinfo

GET_FAULTINFO_FROM_SC(struct faultinfo, struct sigcontext *)
    copies the relevant parts of the sigcontext to
    struct faultinfo.

On SIGSEGV, call user_signal() instead of handle_segv(), if the architecture
provides the information needed in PTRACE_FAULTINFO, or if PTRACE_FAULTINFO is
missing, because segv-stub will provide the info.

The benefit of the change is, that in case of a non-fixable SIGSEGV, we can
give user processes a SIGSEGV, instead of possibly looping on pagefault
handling.

Since handle_segv() sikked arch_fixup() implicitly by passing ip==0 to segv(),
I changed segv() to call arch_fixup() only, if !is_user.
Signed-off-by: NBodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!