IOMMU: generalize and correct softirq processing during Dom0 device setup

c/s 21039:95f5a4ce8f24 ("VT-d: reduce default verbosity") having put a
call to process_pending_softirqs() in VT-d's domain_context_mapping()
was wrong in two ways: For one we shouldn't be doing this when setting
up a device during DomU assignment. And then - I didn't check whether
that was the case already back then - we shouldn't call that function
with the pcidevs_lock (or in fact any spin lock) held.

Move the "preemption" into generic code, at once dealing with further
actual (too much output elsewhere - particularly on systems with very
many host bridge like devices - having been observed to still cause the
watchdog to trigger when enabled) and potential (other IOMMU code may
also end up being too verbose) issues.

Do the "preemption" once per device actually being set up when in
verbose mode, and once per bus otherwise.

Note that dropping pcidevs_lock around the process_pending_softirqs()
invocation is specifically not a problem here: We're in an __init
function and aren't racing with potential additions/removals of PCI
devices. Not acquiring the lock in setup_dom0_pci_devices() otoh is not
an option, as there are too many places that assert the lock being
held.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Xiantao Zhang <xiantao.zhang@intel.com>
x86/time: cleanup

Eliminate effectively unused variables mistakenly left in place by
9539:08aede767c63 ("Rename update_dom_time() to
update_vcpu_system_time()").

Drop the pointless casts.

Use SECONDS() instead of open coding it.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
x86/time: avoid redundant this_cpu()

this_cpu() makes use of RELOC_HIDE() to prevent unsafe optimisations, forcing
a recalculation of the per-cpu data area.  Don't use it needlessly.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
x86: don't propagate acpi_skip_timer_override do Dom0

It's unclear why c/s 4850:923dd9975981 added this - Dom0 isn't
controlling the timer interrupt, and hence has no need to know.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
x86/AMD: re-use function wide variables in init_amd()

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
x86/ACPI: also print address space for PM1x fields

At least one vendor is in the process of making systems available where
these live in MMIO, not in I/O port space.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
correctly use gcc's -x option

In Linux the improper use was found to cause problems with certain
distributed build environments. Even if not directly affecting us, be
on the safe side.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
include: parallelize compat/xlat.h generation

Splitting this up into pieces signficantly speeds up building on multi-
CPU systems when making use of make's -j option.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
x86/crash: fix up declaration of do_nmi_crash()

... so it can correctly be annotated as noreturn.  Move the declaration of
nmi_crash() to be effectively private in crash.c

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Tim Deegan <tim@xen.org>
Acked-by: Keir Fraser <keir@xen.org>
compiler: replace opencoded __attribute__((noreturn))

Make a formal define for noreturn in compiler.h, and fix up opencoded uses of
__attribute__((noreturn)).  This includes removing redundant uses with
function definitions which have a public declaration.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
identify panic and reboot/halt functions as noreturn

On an x86 build (GCC Debian 4.7.2-5), this substantially reduces the size of
.text and .init.text sections.

Experimentally, even in a non-debug build, GCC uses `call` rather than `jmp`
so there should be no impact on any stack trace generation.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
misc cleanup as a result of the previous patches

This includes:
 * A stale comment in sh_skip_sync()
 * A dead for ever loop in __bug()
 * A prototype for machine_power_off() which unimplemented in any architecture
 * Replacing a for(;;); loop with unreachable()

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tim Deegan <tim@xen.org>
Acked-by: Keir Fraser <keir@xen.org>
x86: identify reset_stack_and_jump() as noreturn

reset_stack_and_jump() is actually a macro, but can effectivly become noreturn
by giving it an unreachable() declaration.

Propagate the 'noreturn-ness' up through the direct and indirect callers.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Tim Deegan <tim@xen.org>
Acked-by: Keir Fraser <keir@xen.org>