Stop UML crashing when trying to dump a process core on x86_64.  This is the
minimal fix to stop the crash - more things are broken here, and patches are
forthcoming.

The immediate thing to do is define ELF_CORE_COPY_REGS and
ELF_CORE_COPY_FPREGS.  Defining ELF_CORE_COPY_FPREGS allows dump_fpu to go
away.  It is defined in terms of save_fp_registers, so that needs to be added.
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 fixes some missing ptrace bits on x86_64.  PTRACE_ARCH_PRCTL is
hooked up and implemented.  This required generalizing arch_prctl_skas
slightly to take a task_struct to modify.  Previously, it always operated on
current.

Reading and writing the debug registers is also enabled by un-ifdefing the
code that implements that.  It turns out that x86_64 is identical to i386, so
the same code can 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>

For security reasons, UML in is_syscall() needs to have access to code in
vsyscall-page.  The current implementation grants this access by explicitly
allowing access to vsyscall in access_ok_skas().  With this change,
copy_from_user() may be used to read the code.  Ptrace access to vsyscall-page
for debugging already was implemented in get_user_pages() by mainline.  In
i386, copy_from_user can't access vsyscall-page, but returns EFAULT.

To make UML behave as i386 does, I changed is_syscall to use
access_process_vm(current) to read the code from vsyscall-page.  This doesn't
hurt security, but simplifies the code and prepares implementation of
stub-vmas.
Signed-off-by: NBodo Stroesser <bstroesser@fujitsu-siemens.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>

Some changes that I sent in didn't make 2.6.12-rc4 for some reason.  This
adds them back.  We have
	an x86_64 definition of TOP_ADDR
	a reimplementation of the x86_64 csum_partial_copy_from_user
	some syntax fixes in arch/um/kernel/ptrace.c
	removal of a CFLAGS definition in the x86_64 Makefile
	some include changes in the x86_64 ptrace.c and user-offsets.h
	a syntax fix in elf-x86_64.h
Also moved an include in the i386 and x86_64 Makefiles to make the symlinks
work, and some small fixes from Al Viro.
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>

s390 needs to change some parts of arch/um/kernel/ptrace.c.  Thus, the code
regarding PEEKUSER and POKEUSER are shifted to arch/um/sys-<subarch>/ptrace.c.

Also s390 debug registers need to be updated, when singlestepping is switched
on / off.  Thus, setting/resetting of singlestepping is centralized in the new
function set_singlestep(), which also inserts the macro
SUBARCH_SET_SINGLESTEP(mode), if defined.

Finally, s390 has the "ieee_instruction_pointer" in its
registers, which also is allowed to be read via

  ptrace( PTRACE_PEEKUSER, getpid(), PT_IEEE_IP, 0);

To implement this feature, sys_ptrace inserts the macro
SUBARCH_PTRACE_SPECIAL, if defined.
Signed-off-by: NBodo Stroesser <bstroesser@fujitsu-siemens.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>

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!