Recently a new dm_op[1] hypercall was added to Xen to provide a mechanism
for restricting device emulators (such as QEMU) to a limited set of
hypervisor operations, and being able to audit those operations in the
kernel of the domain in which they run.

This patch adds IOCTL_PRIVCMD_DM_OP as gateway for __HYPERVISOR_dm_op.

NOTE: There is no requirement for user-space code to bounce data through
      locked memory buffers (as with IOCTL_PRIVCMD_HYPERCALL) since
      privcmd has enough information to lock the original buffers
      directly.

[1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=524a98c2Signed-off-by: NPaul Durrant <paul.durrant@citrix.com>
Acked-by: NStefano Stabellini <sstabellini@kernel.org>
Signed-off-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>

Split asm-only parts of arm64 uaccess.h into a new header and use that
from *.S.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Privcmd calls are issued by the userspace. The kernel needs to enable
access to TTBR0_EL1 as the hypervisor would issue stage 1 translations
to user memory via AT instructions. Since AT instructions are not
affected by the PAN bit (ARMv8.1), we only need the explicit
uaccess_enable/disable if the TTBR0 PAN option is enabled.
Reviewed-by: NJulien Grall <julien.grall@arm.com>
Acked-by: NStefano Stabellini <sstabellini@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

Add support for the Xen HYPERVISOR_vm_assist hypercall.
Signed-off-by: NJuergen Gross <jgross@suse.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: NJulien Grall <julien.grall@arm.com>
Reviewed-by: NStefano Stabellini <sstabellini@kernel.org>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

As part of this make the usual change to xen_ulong_t in place of unsigned long.
This change has no impact on x86.

The Linux definition of struct multicall_entry.result differs from the Xen
definition, I think for good reasons, and used a long rather than an unsigned
long. Therefore introduce a xen_long_t, which is a long on x86 architectures
and a signed 64-bit integer on ARM.

Use uint32_t nr_calls on x86 for consistency with the ARM definition.

Build tested on amd64 and i386 builds. Runtime tested on ARM.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>

Introduce CONFIG_XEN and the implementation of hypercall.S (that is
the only ARMv8 specific code in Xen support for ARM).

Compile enlighten.c and grant_table.c from arch/arm.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: NIan Campbell <ian.campbell@citrix.com>

Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NIan Campbell <ian.campbell@citrix.com>

Use the new __HVC macro in hypercall.S.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Use r12 to pass the hypercall number to the hypervisor.

We need a register to pass the hypercall number because we might not
know it at compile time and HVC only takes an immediate argument.

Among the available registers r12 seems to be the best choice because it
is defined as "intra-procedure call scratch register".

Use the ISS to pass an hypervisor specific tag.


Changes in v2:
- define an HYPERCALL macro for 5 arguments hypercall wrappers, even if
at the moment is unused;
- use ldm instead of pop;
- fix up comments.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>