os_dump_core() uses abort() to terminate UML in case of an fatal error.

glibc's abort() calls raise(SIGABRT) which makes use of tgkill().
tgkill() has no effect within UML's kernel threads because they are not
pthreads.  As fallback abort() executes an invalid instruction to
terminate the process.  Therefore UML gets killed by SIGSEGV and leaves a
ugly log entry in the host's kernel ring buffer.

To get rid of this we use our own abort routine.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In some cases gcc >= 4.5.2 will optimize away current_thread_info().  To
prevent gcc from doing so the stack address has to be obtained via inline
asm.

Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Make HoneyPot ProcFS depend on CONFIG_PROC_FS so that it will build.
Recommended by Christoph Hellwig.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=33692

Reported-by: Simon Danner <danner.simon@gmail.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This adds support for 64 bit atomic operations on 32 bit UML systems.  XFS
needs them since 2.6.38.

  $ make ARCH=um SUBARCH=i386
  ...
    LD      .tmp_vmlinux1
  fs/built-in.o: In function `xlog_regrant_reserve_log_space':
  xfs_log.c:(.text+0xd8584): undefined reference to `atomic64_read_386'
  xfs_log.c:(.text+0xd85ac): undefined reference to `cmpxchg8b_emu'
  ...

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=32812

Reported-by: Martin Walch <walch.martin@web.de>
Tested-by: Martin Walch <walch.martin@web.de>
Cc: Martin Walch <walch.martin@web.de>
Cc: <stable@kernel.org> [2.6.38.x 084189a: um: disable CONFIG_CMPXCHG_LOCAL]
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 8a5ec0ba "Lockless (and preemptless) fastpaths for slub" makes use
of this_cpu_cmpxchg_double() which needs this_cpu_cmpxchg16b_emu() on
x86_64.  Implementing cmpxchg16b emulation for UML would introduce too
much complexity.  So just disable it.

Signed-off-by: Richard Weinberger <richard@nod.at>
Reported-by: Sergei Trofimovich <slyich@gmail.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 1de1502c ("x86, um: now we can get rid of trivial uml headers")
removed accidentally bug.h which broke UML's call tracer and bug
handler.

Without asm-generic/bug.h UML uses BUG() from arch/x86/ which makes use
of ud2.  UML cannot use ud2, it raises SIGILL in user mode.  As UML has
a different stack for handling signals the call trace will be cut off.

Signed-off-by: Richard Weinberger <richard@nod.at>
Reported-by: Sergei Trofimovich <slyich@gmail.com>
Tested-by: Sergei Trofimovich <slyich@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Scripted with coccinelle.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>