Add kexec support to ARM.

Improvements like commandline handling could be made but this patch gives
basic functional support. It uses the next available syscall number, 347.

Once the syscall number is known, userspace support will be
finalised/submitted to kexec-tools, various patches already exist.

Originally based on a patch by Maxim Syrchin but updated and forward
ported by various people.
Signed-off-by: NRichard Purdie <rpurdie@rpsys.net>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add:
  sys_unshare
  sys_set_robust_list
  sys_get_robust_list
  sys_splice
  sys_arm_sync_file_range
  sys_tee
  sys_vmsplice
  sys_move_pages
  sys_getcpu

Special note about sys_arm_sync_file_range(), which is implemented as:

asmlinkage long sys_arm_sync_file_range(int fd, unsigned int flags,
                                        loff_t offset, loff_t nbytes)
{
        return sys_sync_file_range(fd, offset, nbytes, flags);
}

We can't export sys_sync_file_range() directly on ARM because the
argument list someone picked does not fit in the available registers.
Would be nice if... there was an arch maintainer review mechanism for
new syscalls before they hit the kernel.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Later glibc requires the *at syscalls.  Add them.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

Commit 99595d02 forgot to intercept
sys_socketcall as well.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

struct sockaddr_un loses its padding with EABI.  Since the size of the
structure is used as a validation test in unix_mkname(), we need to
change the length argument to 110 whenever it is 112.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

ARM entry-common.S needs to know syscall table size; in itself that would
not be a problem, but there's an additional constraint - some of the
instructions using it want a constant that would be a multiple of 4.
So we have to pad syscall table with sys_ni_syscall and that's where
the trouble begins.  .rept pseudo-op wants a constant expression for
number of repetitions and subtraction of two labels (before and after
syscall table) doesn't always get simplified to constant early enough
for .rept.  If labels end up in different frags, we lose.  And while
the frag size is large enough (slightly below 4Kb), the syscall table
is about 1/3 of that.  We used to get away with that, but the recent
changes had been enough to trigger the breakage.

Proper fix is simple: have a macro (CALL(x)) to populate the table
instead of using explicit .long x and the first time we include calls.S
have it defined to .equ NR_syscalls,NR_syscalls+1.  Then we can find
the proper amount of padding on the first inclusion simply by looking
at NR_syscalls at that time.  And that will be constant, no matter what.

Moreover, the same trick kills the need of having an estimate of padded
NR_syscalls - it will be calculated for free at the same time.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

This patch adds the required code to support both user space ABIs at
the same time. A second syscall table is created to include legacy ABI
syscalls that need an ABI compat wrapper.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

struct statfs64 has extra padding with EABI growing its size from 84 to
88. This struct is now __attribute__((packed,aligned(4))) with a small
assembly wrapper to force the sz argument to 84 if it is 88 to avoid
copying the extra padding over user space memory unexpecting it.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Rather than providing more wrappers for 6-arg syscalls, arrange for
them to be supported as standard.  This just means that we always
store the 6th argument on the stack, rather than in the wrappers.

This means we eliminate the wrappers for:
* sys_futex
* sys_arm_fadvise64_64
* sys_mbind
* sys_ipc
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from George G. Davis

As pointed out be Matthew Klahn <MKLAHN@motorola.com>, some sys_ipc()
call options require six args, e.g. SEMTIMEDOP. This patch adds an ARM sys_ipc_wrapper to save the sys_ipc() 'fifth' arg on the stack.
Signed-off-by: NGeorge G. Davis <gdavis@mvista.com>
 arch/arm/kernel/calls.S        |    2 +-
 arch/arm/kernel/entry-common.S |    5 +++++
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

sys_mbind is a 6-arg syscall, hence needs wrapping to save the
sixth argument.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Add syscall numbers and syscall table entries for mbind,
set_mempolicy and get_mempolicy.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

The prototype for sys_fadvise64_64() is:
    long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
The argument list is therefore as follows on legacy ABI:
	fd: type int (r0)
	offset: type long long (r1-r2)
	len: type long long (r3-sp[0])
	advice: type int (sp[4])
With EABI this becomes:
	fd: type int (r0)
	offset: type long long (r2-r3)
	len: type long long (sp[0]-sp[4])
	advice: type int (sp[8])
Not only do we have ABI differences here, but the EABI version requires
one additional word on the syscall stack.
To avoid the ABI mismatch and the extra stack space required with EABI
this syscall is now defined with a different argument ordering
on ARM as follows:
    long sys_arm_fadvise64_64(int fd, int advice, loff_t offset, loff_t len)
This gives us the following ABI independent argument distribution:
	fd: type int (r0)
	advice: type int (r1)
	offset: type long long (r2-r3)
	len: type long long (sp[0]-sp[4])
Now, since the syscall entry code takes care of 5 registers only by
default including the store of r4 to the stack, we need a wrapper to
store r5 to the stack as well.  Because that wrapper was missing and was
always required this means that sys_fadvise64_64 never worked on ARM and
therefore we can safely reuse its syscall number for our new
sys_arm_fadvise64_64 interface.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NRobert Love <rml@novell.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

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!