Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NRichard Weinberger <richard@nod.at>

Reusing the host's vDSO makes only sense on x86_32.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes a problem seen by a number of people running UML on newer host
kernels.  init would hang with an infinite segfault loop.

It turns out that the host kernel was providing a AT_SYSINFO_EHDR of
0xffffe000, which faked UML into believing that the host VDSO page could be
reused.  However, AT_SYSINFO pointed into the middle of the address space, and
was unmapped as a result.  Because UML was providing AT_SYSINFO_EHDR and
AT_SYSINFO to its own processes, these would branch to nowhere when trying to
use the VDSO.

The fix is to also check the location of AT_SYSINFO when deciding whether to
use the host's VDSO.
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>

Comment the lack of locking of the elf data extracted from the ELF headers
passed to UML.
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>

UML makefiles sanitized:
 - number of generated headers reduced to 2 (from user-offsets.c and
   kernel-offsets.c resp.).  The rest is made constant and simply
   includes those two.
 - mk_... helpers are gone now that we don't need to generate these
   headers
 - arch/um/include2 removed since everything under arch/um/include/sysdep
   is constant now and symlink can point straight to source tree.
 - dependencies seriously simplified.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Even if with a bit of misunderstanding, Al fixed this in commit
95608261.

Well, the symbol was intended to come from userspace (it exists there on normal
host), but since some hosts may miss that, using the kernel one is just as fine.
However, rename it to be named consistently with the rest.

Actually, he missed converting ELFCLASS32 to coming from kernel headers. For
consistence, add ELFCLASS64 too.

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

asm/elf.h is bad on x86_64, and i386 doesn't need it any more after Al's
cleanup.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

These ugly double-casts are the result of gdb complaining about size
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

elf_aux is userland code; it uses symbol (ELF_CLASS) that doesn't exist in
userland headers; pulled into kernel-offsets.h, switched elf_aux to using it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

asm/elf.h breaks the x86_64 build.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The #if/#ifdef cleanup exposed a bug in UML's ELF header processing.  With
this bug fixed, UML recognizes the vsyscall info coming from the host.  On
FC4, there is a vsyscall page low in the address space, which UML doesn't
provide.  This causes an infinite page fault loop and a hang on boot.

This patch works around that by making this look like a no-vsyscall system.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

turn many #if $undefined_string into #ifdef $undefined_string to fix some
warnings after -Wno-def was added to global CFLAGS
Signed-off-by: NOlaf Hering <olh@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is a bunch of compile fixes provoked by building UML with gcc 4.  There
are a bunch of signedness mismatches, a couple of uninitialized references,
and a botched C99 structure initialization which had somehow gone unnoticed.
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!