get_irqnr_preamble allows machines to take some action before entering the
get_irqnr_and_base loop.  On iop we enable cp6 access.

arch_ret_to_user is added to the userspace return path to allow individual
architectures to take actions, like disabling coprocessor access, before
the final return to userspace.

Per Nicolas Pitre's note, there is no need to cp_wait on the return to user
as the latency to return is sufficient.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

RETINSTR is a left-over from the days when we had 26-bit and
32-bit CPU support integrated into the same tree.  Since this
is no longer the case, we can now remove RETINSTR.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Paul Brook

The old-abi sys_syscall syscall is broken when called from Thumb mode. It
assumes the syscall number is an Arm syscall number (ie. starts from
__NR_OABI_SYSCALL_BASE).  In thumb mode syscall numbers start from zero.

The patch below fixes this by clearing the nigh bits of the syscall number
instead of inverting them. Technically this means we accept some invalid
syscall numbers, but I can't see how that could be a problem. The two sets of
numbers far apart that unimplemented syscalls should still be rejected.
Signed-off-by: NPaul Brook <paul@codesourcery.com>
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 is needed by strace to properly handle the tracing of some system
calls. It could be useful for other applications as well.

Based on an earlier patch from Daniel Jacobowitz.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NDaniel Jacobowitz <dan@debian.org>
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

The difference between EABI and the legacy ABI may affect either
structure member alignment and/or argument register selection.

The patch has the details.

Included are wrappers for the following syscalls:

  sys_stat64
  sys_lstat64
  sys_fstat64
  sys_fcntl64
  sys_epoll_ctl
  sys_epoll_wait
  sys_ipc
  sys_semop
  sys_semtimedop
  sys_pread64
  sys_pwrite64
  sys_truncate64
  sys_ftruncate64
  sys_readahead
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>

Patch from Nicolas Pitre

For a while we wanted to change the way syscalls were called on ARM.
Instead of encoding the syscall number in the swi instruction which
requires reading back the instruction from memory to extract that number
and polluting the data cache, it was decided that simply storing the
syscall number into r7 would be more efficient. Since this represents
an ABI change then making that change at the same time as EABI support
is the right thing to do.

It is now expected that EABI user space binaries put the syscall number
into r7 and use "swi 0" to call the kernel. Syscall register argument
are also expected to have "EABI arrangement" i.e. 64-bit arguments
should be put in a pair of registers from an even register number.

Example with long ftruncate64(unsigned int fd, loff_t length):

	legacy ABI:
	- put fd into r0
	- put length into r1-r2
	- use "swi #(0x900000 + 194)" to call the kernel

	new ARM EABI:
	- put fd into r0
	- put length into r2-r3 (skipping over r1)
	- put 194 into r7
	- use "swi 0" to call the kernel

Note that it is important to use 0 for the swi argument as backward
compatibility with legacy ABI user space relies on this.
The syscall macros in asm-arm/unistd.h were also updated to support
both ABIs and implement the right call method automatically.
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 Daniel Jacobowitz

After delivering a signal (creating its stack frame) we must check for
additional pending unblocked signals before returning to userspace.
Otherwise signals may be delayed past the next syscall or reschedule.

Once that was fixed it became obvious that the ARM signal mask manipulation
was broken.  It was a little bit broken before the recent SA_NODEFER
changes, and then very broken after them.  We must block the requested
signals before starting the handler or the same signal can be delivered
again before the handler even gets a chance to run.
Signed-off-by: NDaniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Nicolas Pitre

Either no one is using an ARM710 with recent kernels, or all ARM710s
still in use are not afflicted by this swi bug.  Nevertheless, the code
to work around the ARM710 swi bug is itself currently buggy since it
uses r8 as a pointer to S_PC while in fact it holds the spsr content
these days. Fix that, and simplify the code as well.
Signed-off-by: NNicolas Pitre <nico@cam.org>
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>

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>

Move common includes to entry-header, and file specific includes
to the relevant file.
Signed-off-by: NRussell King <rmk@arm.linux.org.uk>

Assembly macros are pointless if they're only used once.  Move
them inline.
Signed-off-by: NRussell King <rmk@arm.linux.org.uk>

Don't define our own local constants, but use those already defined
in asm/unistd.h instead.
Signed-off-by: NRussell King <rmk@arm.linux.org.uk>

Generate pt_regs S_xx offsets from the structure itself instead
of #defining them.
Signed-off-by: NRussell King <rmk@arm.linux.org.uk>

Since we do not require a register for these operations, we can
remove this unnecessary argument.
Signed-off-by: NRussell King <rmk@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!