After restoring the existing code, make it work also when included in
kernelspace code (which isn't currently the case, but at least this will prevent
people from "fixing" it as just happened).
Whitespace is fixed in next patch - it cluttered the diff too much.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Commit 44456d37, between 2.6.13-rc3 and -rc4,
was a "nice cleanup" which broke something. Revert the offending part.

It broke because:
a) because this part doesn't fall under the description
b) the author didn't know what he was doing here
c) the author didn't try to compile the existing code and see that it worked
   perfectly.
d) the author didn't ask us what was happening
e) you didn't either, and somebody there should have learned that UML is a bit
   different.

In fact, UML is special in linking to host libc and using its includes.

In particular, since host includes always define both __BIG_ENDIAN and
__LITTLE_ENDIAN, ntohll() macros started thinking to be in a big-endian world;
and on-disk compatibility was broken.

Many thanks go to Nix for reporting the problem and correctly diagnosing an
endianness problem.

Btw, this patch restores the previous code, which worked; but the definitions
would be uncorrect if used in kernelspace files.

Next patch addresses that.

Cc: Nix <nix@esperi.org.uk>, Olaf Hering <olh@suse.de>
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

For files which need to include glibc headers (i.e. userspace files), we
specified the correct flags only for .o, not for .s/.lst/.i. Fix this.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Too many people were confused by skas0 and tried using "mode=skas0". And after
all, they are right - accept this.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add a missing $(Q) to a "ln" invocation.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The old code had the IP and SP coming from the registers in the thread
struct, which are completely wrong since those are the userspace
registers.  This fixes that by pulling the correct values from the
jmp_buf in which the kernel state of each thread is stored.
Signed-off-by: NAllan Graves <allan.graves@oracle.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Al's build tidying missed one bit from me - without this UML doesn't boot.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Acked-by: NAl Viro <viro@ftp.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Revert commit 12ebcd73, i.e.  [PATCH] uml: run
mconsole "sysrq" in process context on request from Jeff Dike.

a) sysrq may be run when the scheduler is non-functioning

b) the warning I wanted to fix actually came from the fault handler run in
   atomic context.  But I fixed that not to take the semaphore in a separate
   patch.

c) the fault handler is run because of a fault, and that fault was
   unaffected by this patch.
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>

SEGV_MAYBE_FIXABLE tests ptrace_faultinfo, and depends on it being 1 only in
SKAS3 mode, while currently when running with mode=tt it will be 1 anyway.
Fix this, and do the same for proc_mm.
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>

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>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.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>

User get *a lot* confused when consoles don't work but we don't report
anything.  And, as reported in the comment, using printk to report "your
console doesn't work" isn't likely to go that far.

Fix the problem on the base of this: stack consumption by host printf().  Use
kernel sprintf() and os_write_file, using a wild guess that one page will be
enough for the message, to preallocate the buffer with kmalloc().
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>

setup_initial_poll is only called with sigio_lock() held, so use appropriate
allocation.

Also, parse_chan() can also be called when holding a spinlock (see line_open()
 -> parse_chan_pair()).

I have sporadic problems (spinlock taken twice, with spinlock debugging on UP)
which could be caused by a sequence like "take spinlock, alloc and go to
sleep, take again the spinlock in the other thread".
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>

GFP_ATOMIC | GFP_KERNEL is meaningless and won't work.  Actually it never
worked, even in 2.4.
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>

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>

Things are breaking horribly with sysrq called in interrupt context.  I want
to try to fix it, but probably this is simpler.  To tell the truth, sysrq is
normally run in interrupt context, so there shouldn't be any problem.

There's also a warning from the fault handler because it's run in atomic
context (I have a patch for that, only I deferred it).  This is why I'm doing
this.
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>

Avoid setting w = 0 twice.  Spotted this (trivial) thing which is needed for
another patch.
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>

Simplify the code by using strlcat() instead of strncat() and manual
appending.
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>

Only remove the UML pidfile and management socket if we created them.
Currently in case two UMLs are started with the same umid, the second will
remove the first's ones.

Probably we should also panic() at that point, not sure however.
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 header declaring this function wasn't included, so the function declaration
was totally bogus wrt. the proto - even if this wasn't going to fail at all.

It was so bad that the compile warning I got was "control reaches end of
non-void function", i.e. missing return. Actually, this has been there for ages,
the consolidation patch just added the warning which was needed to clean it up.
Nice. Really.

Cc: Allan Graves <allan.graves@gmail.com>
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Explain why the casting we do to silence this warning is indeed safe.

It is because the field we're casting from, though being 64-bit wide, was filled
with a pointer in first place by ourselves.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Readd this header (deleted in 60d339f6). A
warning is spit out here about undeclared getpgrp().
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
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>

gcc is now complaining during link on some hosts - fix it as for other things.
Reported by Antoine Martin <antoine@nagafix.co.uk>.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Translate uname output taken from the host if needed.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I am a lamer :-(. Luckily, Luo Xin performed LTP testing and found this failure.
Btw, the fact that the patch in which I introduced this was merged shows that:

a) I'm really trusted by people
b) sometimes they're wrong about point a).
c) lack of time for reviewers.

CC: Luo Xin <luothing@sina.com>
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When removing verify_area, verify_area_{tt,skas} were forgotten.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Using native cmpxchg offers a slight performance improvement in uml/i386.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
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>

do_aio used to return -1 on error instead of errno.
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>

The serial UML OS-abstraction layer patch (um/kernel dir).

This joins mem_user.c and mem.c files.
Signed-off-by: NGennady Sharapov <Gennady.V.Sharapov@intel.com>
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>

The serial UML OS-abstraction layer patch (um/kernel dir).

This moves all system calls from mem_user.c and tempfile.c files under
os-Linux dir.
Signed-off-by: NGennady Sharapov <Gennady.V.Sharapov@intel.com>
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>

The poster child for this patch is the third tuntap_user hunk.  When an ioctl
fails, it properly closes the opened file descriptor and returns.  However,
the close resets errno to 0, and the 'return errno' that follows returns 0
rather than the value that ioctl set.  This caused the caller to believe that
the device open succeeded and had opened file descriptor 0, which caused no
end of interesting behavior.

The rest of this patch is a pass through the UML sources looking for places
where errno could be reset before being passed back out.  A common culprit is
printk, which could call write, being called before errno is returned.

In some cases, where the code ends up being much smaller, I just deleted the
printk.

There was another case where a caller of run_helper looked at errno after a
failure, rather than the return value of run_helper, which was the errno value
that it wanted.
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>

linux/inet.h isn't needed, and on my system, is empty.
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>

This removes a file which is no longer used.
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>

This patch implements a stack trace for a thread, not unlike sysrq-t does.
The advantage to this is that a break point can be placed on showreqs, so that
upon showing the stack, you jump immediately into the debugger.  While sysrq-t
does the same thing, sysrq-t shows *all* threads stacks.  It also doesn't work
right now.  In the future, I thought it might be acceptable to make this show
all pids stacks, but perhaps leaving well enough alone and just using sysrq-t
would be okay.  For now, upon receiving the stack command, UML switches
context to that thread, dumps its registers, and then switches context back to
the original thread.  Since UML compacts all threads into one of 4 host
threads, this sort of mechanism could be expanded in the future to include
other debugging helpers that sysrq does not cover.

Note by jdike - The main benefit to this is that it brings an arbitrary thread
back into context, where it can be examined by gdb.  The fact that it dumps it
stack is secondary.  This provides the capability to examine a sleeping
thread, which has existed in tt mode, but not in skas mode until now.

Also, the other threads, that sysrq doesn't cover, can be gdb-ed directly
anyway.

Signed-off-by: Allan Graves<allan.graves@gmail.com>
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>

This patch moves code that is in both switch_to_tt and switch_to_skas to the
top level _switch_to function, keeping us from duplicating code.  It is
required for the stack trace patch to work properly.
Signed-off-by: NAllan Graves <allan.graves@gmail.com>
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>