Convert cp15 crn=9 registers (mostly cache lockdown) to the new scheme.
Note that this change makes OMAPCP cores RAZ/WI the whole c9 space. This is
a change from previous behaviour, but a return to the behaviour of commit
c3d2689d when OMAP1 support was first added -- subsequent commits have
clearly accidentally relegated the OMAPCP RAZ condition to only a subset of
the crn=9 space when adding support for other cores.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Convert the cp15 crn=6 registers to the new scheme.
Note that this includes some minor tidyup: drop an unnecessary
underdecoding of op2 on OMAPCP cores, and only implement the
pre-v6 c6,c0,0,1 IFAR on the 1026 and not on the other ARMv5
cores, which didn't have it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Convert the cp15 crn=7 registers to the new scheme.
Note that to do this we have to distinguish some registers
used on the ARM9 and ARM10 from some which are ARM1176
only. This is because the old code returned a value of 0
but always set the Z flag (by clearing env->ZF, since we
store the Z flag in CPUState inverted). This is inconsistent
with actual ARM CPU behaviour, which only sets flags for
reads to r15 and sets them based on the top bits of the result.
However it happened to work for the two common use cases for
cp15 crn=7 reads:
* On ARM9 and ARM10 the cache clean-and-test operations are
typically done with a destination of r15 so that you can do
a "loop: mrc ... ; bne loop" to keep cleaning until the cache
is finally clean; always setting the Z flag means this loop
terminates immediately
* on ARM1176 the Cache Dirty Status Register reads as zero
if the cache is dirty; returning 0 means this is correctly
implemented for QEMU
Since the new coprocessor register framework does the right
thing of always setting flags based on the returned result
for reads to r15, we need to split these up so that we can
return (1<<30) for the ARM9/ARM10 registers but 0 for the
ARM1176 one.
This allows us to remove the nasty hack which always sets Z.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
We RAZ/WI the entire block of crn=10 registers. Note that this
actually covers not just the implementation-defined TLB
lockdown registers but also a number of v7 VMSA memory
attribute registers which we would need to implement to
support TEX remap. We retain the previous QEMU behaviour
in this conversion, though.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Convert the cp15 crn=13 registers (FCSEIDR, CONTEXTIDR,
and the ARM946 Trace Process Identifier Register).
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Convert the cp15 crn=2 registers (MMU page table control,
MPU cache control) to the new scheme.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Convert the cp15 c3 register (MMU domain access control
or MPU write buffer control). NB that this is horribly
underdecoded for modern cores (should be crn=3,crm=0,
opc1=0,opc2=0) but this change preserves the existing
QEMU behaviour.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Convert the various WFI and barrier instruction special cases to use
cp_reginfo infrastructure.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Add new function register_cp_regs_for_features() as a place to
register coprocessor registers dependent on feature flags.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
All the users of cpu_arm_set_cp_io have been converted, so we
can remove it and the infrastructure it used.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Initial infrastructure for data-driven registration of
coprocessor register implementations.
We still fall back to the old-style switch statements pending
complete conversion of all existing registers.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Make the 11MPCore report a valid value in its cache type register
(the previous value appears to have been incorrectly copied from
the 1136/1176). In particular, do not report that we have an
aliasing VIPT cache, because this causes Linux to attempt to use
the v6 block cache ops which the 11MPCore doesn't actually have.
(This causes no problems currently because we over-broadly provide
those ops on all cores, but prevents us correctly narrowing the
block ops down to those cores which actually implement them.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
In commit 1bba0dc932 cpu_reset()
was renamed to cpu_state_reset(), to allow introducing a new cpu_reset()
that would operate on QOM objects.
All callers have been updated except for one in target-mips, so drop all
implementations except for the one in target-mips and move the
declaration there until MIPSCPU reset can be fully QOM'ified.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Michael Walle <michael@walle.cc> (for lm32)
Acked-by: Max Filippov <jcmvbkbc@gmail.com> (for xtensa)
Acked-by: Edgar E. Iglesias <edgar.iglesias@gmail.com> (for mb + cris)
Acked-by: Alexander Graf <agraf@suse.de> (for ppc)
Acked-by: Blue Swirl <blauwirbel@gmail.com>
Commit 3c30dd5a68 (target-arm: Move reset
handling to arm_cpu_reset) QOM'ified CPU reset. Complete it by replacing
cpu_state_reset() with cpu_reset().
Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
The macro definition of cpu_init meant that if cpu_arm_init()
returned NULL this wouldn't result in cpu_init() itself returning
NULL. This had the effect that "-cpu foo" for some unknown CPU
name 'foo' would cause ARM targets to segfault rather than
generating a useful error message. Fix this by making cpu_init
a simple inline function.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
This patch fixes a bug affecting a variety of Neon instructions, such as
VQADD.
Signed-off-by: Matt Craighead <mjcraighead@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Make the SETEND instruction respect the setting of bswap_code,
so that in BE8 mode we UNDEF for attempts to switch into
little-endian mode and nop for attempts to stay in big-endian
mode. (This is the inverse of the existing handling of SETEND
in the more common little-endian setup, which we use since
we don't implement the architecturally-mandated dynamic
endianness switching.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Move the A9 config_base_address cp15 register reset value to
ARMCPU. This should become a QOM property so that the Highbank
board can set it without having to pull in cpu-qom.h, but at
least this avoids the implicit dependency on reset ordering
that the previous workaround had.
Cc: Mark Langsdorf <mark.langsdorf@calxeda.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Make cpu_arm_init() return a QOM ARMCPU, so that we don't need to
obtain an ARMCPU through arm_env_get_cpu() in machine init code.
This requires to adjust the inclusion site of cpu-qom.h and in turn,
forward-looking, to homogenize its include order.
cpu_init() must still return a CPUARMState for backwards and
cross-target compatibility, so adjust the cpu_init macro.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Now that cpu_reset_model_id() has gone we can move the
reset code over to the class reset function and have cpu_state_reset
simply do a reset on the CPU QOM object.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
cpu_reset_model_id() is now empty and we can remove it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Move cache ID register reset out of cpu_reset_model_id() by
creating a field for the reset value in ARMCPU and setting it
up in the cpu specific init functions.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Move the OMAP-specific cp15_i_{max,min} reset to cpu_state_reset;
since these registers are only accessible on CPUs with the
OMAPCP feature set there's no need to guard this reset with
either a CPUID or feature bit check.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Move feature register value setup to per-CPU init functions.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Move the iWMMXT wCID reset to cpu_state_reset(). Since
we use the same value for all CPUs with this feature
(with the major/minor revision fields set to the QEMU
specific 'Q' value) there's no need to create an ARMCPU
field just for this.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Andreas Färber <afaerber@suse.de>
None of the machines in QEMU offer a JTAG debug interface, so this info
was unused. Further, the PXA250 ID contradicts the February 2002
Developer's Manual, which has it as 0xn9264013 with n the MIDR Revision.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Move the reset value of SCTLR to ARMCPU, initialised in
the per-cpu init functions. It can then be reset by a
simple copy, and we can drop the code from cpu_reset_model_id().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Move CTR (cache type register) value to an ARMCPU field
set up by per-cpu init fns.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Move the MVFR* VFP feature register values to ARMCPU,
so they are set up by the implementation-specific instance
init functions rather than in cpu_reset_model_id().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Move the reset FPSID to the ARMCPU struct, and set it in the
per-implementation instance init function. At reset we then
just copy the reset value into the CPUARMState field.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Move the setting of the feature bits from cpu_reset_model_id()
to each CPU's instance init function. This requires us to move
the features field in CPUARMState so that it is not cleared
on reset.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Andreas Färber <afaerber@suse.de>
Register subclasses for each ARM CPU implementation.
Let arm_cpu_list() enumerate CPU subclasses in alphabetical order,
except for special value "any".
Replace cpu_arm_find_by_name()'s string -> CPUID lookup by storing the
CPUID (aka MIDR, Main ID Register) value in the class.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Use uintptr_t instead of void * or unsigned long in
several op related functions, env->mem_io_pc and
GETPC() macro.
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Add support for ARM BE8 userspace binaries.
i.e. big-endian data and little-endian code.
In principle LE8 mode is also possible, but AFAIK has never actually
been implemented/used.
System emulation doesn't have any useable big-endian board models,
but should in principle work once you fix that.
Dynamic endianness switching requires messing with data accesses,
preferably with TCG cooperation, and is orthogonal to BE8 support.
Signed-off-by: Paul Brook <paul@codesourcery.com>
[PMM: various changes, mostly as per my suggestions in code review:
* rebase
* use EF_ defines rather than hardcoded constants
* make bswap_code a bool for future VMSTATE macro compatibility
* update comment in cpu.h about TB flags bit field usage
* factor out load-code-and-swap into arm_ld*_code functions and
get_user_code* macros
* fix stray trailing space at end of line
* added braces in disas.c to satisfy checkpatch
]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
This patch replaces the ARM_FEATURE_VFP3 test when reading MVFR registers
with a test for a new feature flag ARM_FEATURE_MVFR, and sets this feature
for all ARMv6K cores (ARM1156 is not a v6K core, yet supports MVFR; qemu
does not support ARM1156 at this time.)
MVFR0 and MVFR1 were introduced in ARM1136JF-S r1p0 (ARMv6K, VFPv2) and are
present in ARM1156T2F-S (non-v6K), ARM1176JZF-S, ARM11MPCore and newer cores.
Reference: ARM DDI 0211H, 0290G, 0301H, 0360E.
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0211h/Ffbefjag.html
Without this change, the linux kernel will not boot with VFP support enabled
under ARM1176 system emulation, due to the unconditional use of MVFR1 at the
end of vfp_init() in arch/arm/vfp/vfpmodule.c:
VFP support v0.3: implemetor 41 architecture 1 part 20 variant b rev 5
Internal error: Oops - undefined instruction: 0 [#1]
Signed-off-by: Andrew Towers <atowers@gmail.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Introduce only one non-abstract type TYPE_ARM_CPU and do not touch
cp15 registers to not interfere with Peter's ongoing remodelling.
Embed CPUARMState as first (additional) field of ARMCPU.
Let CPUClass::reset() call cpu_state_reset() for now.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Decode the SETEND instruction correctly in Thumb mode,
rather than accidentally treating it like CPS. We don't
support BE8 mode, but this change brings the Thumb mode
in to line with behaviour in ARM mode: 'SETEND BE' is
not supported and will provoke an UNDEF exception, but
'SETEND LE' is correctly handled as a no-op.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reported-by: Daniel Forsgren <daniel.forsgren@enea.com>
Reviewed-by: Laurent Desnogues <laurent.desnogues@gmail.com>
When taking an exception for an M profile core, we must clear
the IT bits. Since the IT bits are cached in env->condexec_bits
we must clear them there: writing the bits in env->uncached_cpsr
has no effect. (Reported as LP:944645.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Fix a typo in handling of the ARM946 cp15 c5 c0 0 1 handling
(instruction access permission bits) that meant it would
return the data access permission bits by mistake.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Scripted conversion:
for file in *.[hc] hw/*.[hc] hw/kvm/*.[hc] linux-user/*.[hc] linux-user/m68k/*.[hc] bsd-user/*.[hc] darwin-user/*.[hc] tcg/*/*.[hc] target-*/cpu.h; do
sed -i "s/CPUState/CPUArchState/g" $file
done
All occurrences of CPUArchState are expected to be replaced by QOM CPUState,
once all targets are QOM'ified and common fields have been extracted.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Scripted conversion:
sed -i "s/CPUState/CPUARMState/g" target-arm/*.[hc]
sed -i "s/#define CPUARMState/#define CPUState/" target-arm/cpu.h
Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Anthony Liguori <aliguori@us.ibm.com>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
Frees the identifier cpu_reset for QOM CPUs (manual rename).
Don't hide the parameter type behind explicit casts, use static
functions with strongly typed argument to indirect.
Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Since target-arm has some CPUState fields for which we take the approach
of baking assumptions about them into translated code and then calling
tb_flush() when the fields change, we must also tb_flush on CPU reset,
because reset is a change of those fields.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andrzej Zaborowski <andrew.zaborowski@intel.com>
The correct FPSID for the Cortex-A9 (according to the TRM) is
0x41033090 for the r0p0 that we claim to model.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andrzej Zaborowski <andrew.zaborowski@intel.com>
Add a definition of a Cortex-A15 CPU. Note that for the moment we do
not implement any of:
* Large Physical Address Extensions (LPAE)
* Virtualization Extensions
* Generic Timer
* TrustZone (this is also true of our existing Cortex-A9 model, etc)
This CPU model is sufficient to boot a Linux kernel which has been
compiled for an A15 without LPAE enabled.
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Add a dummy implementation of the cp15 registers for the generic
timer (found in the Cortex-A15), just sufficient for Linux to
decide that it can't use it. This requires at least CNTP_CTL and
CNTFRQ to be implemented as RAZ/WI; we RAZ/WI all of c14.
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Long term, the config_base_register will be a QDM parameter. In the
meantime, models that use it need to be able to preserve it across
cpu_reset() calls.
Signed-off-by: Mark Langsdorf <mark.langsdorf@calxeda.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
In the helper routines for VCVT float-to-int conversions, add
an explicit cast rather than relying on the softfloat int32
type being exactly 32 bits wide (which it is not guaranteed to be).
Without this, if the softfloat type was 64 bits wide we would
get zero-extension of the 32 bit value from the ARM register
rather than sign-extension, since TCG i32 values are passed as
uint32_t.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Fix some bugs in the implementation of the TLB invalidate
operations on ARM:
* the 'invalidate all' op was not passing flush_global=1
to tlb_flush(); this doesn't have a practical effect since
tlb_flush() currently ignores that argument, but is
semantically incorrect
* 'invalidate by address for all ASIDs' was implemented as
flushing the whole TLB, which invalidates much more than
strictly necessary. Use tlb_flush_page() instead.
We also annotate the ops with the ARM ARM official acronyms.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Mark Langsdorf <mark.langsdorf@calxeda.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Fix errors in the decode of M profile CPS:
* the decode of the I (affects PRIMASK) and F (affects FAULTMASK)
bits was reversed
* the FAULTMASK system register number is 19, not 17
This fixes an issue reported as LP:913925.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Add dummy register support for the cp15, CRn=c15 registers.
config_base_register and power_control_register currently
default to 0, but may have improved support after the QOM
CPU patches are finished.
Signed-off-by: Mark Langsdorf <mark.langsdorf@calxeda.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Ignore attempts to set the CPSR mode field to an invalid value.
This is UNPREDICTABLE, but we should not cpu_abort() for things
a malicious guest (or a confused user on the gdbstub interface)
can provoke.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Avoid using cpu_single_env in bank_number() -- if we were
called via the gdb stub reading or writing the CPSR then
it is NULL and we will segfault if we take the cpu_abort().
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Return the correct value in the domain field in the cp15 DFSR
(C5) -- bug noticed during Xvisor development.
Signed-off-by: Jean-Christophe DUBOIS <jcd@tribudubois.net>
[Peter Maydell: reworded commit message]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Clarify some slightly misleading comments in the Thumb decoder's
handling of the memory hint space -- in particular one code path
marked as 'UNPREDICTABLE or unallocated hint' also includes some
legitimate preload instructions.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andrzej Zaborowski <andrew.zaborowski@intel.com>
env is allocated in cpu_arm_init() with g_malloc0(), so free with g_free().
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Fix the restoring of VFP registers on vmload.
Signed-off-by: Dmitry Koshelev <karaghiozis@gmail.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
[peter.maydell: improved commit message a little]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Implement the fused multiply-accumulate instructions (VFMA, VFMS,
VFNMA, VFNMS) which are new in VFPv4.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Add support for UDIV and SDIV in ARM mode. This is a new optional
feature for A profile cores (Thumb mode has had UDIV and SDIV for
M profile cores for some time).
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Rename the ARM_FEATURE_DIV feature bit to _THUMB_DIV, to
make room for a new feature switch enabling DIV in the ARM
encoding. (Cores may implement either (a) no divide insns
(b) divide insns in Thumb encodings only (c) divide insns
in both ARM and Thumb encodings.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Clean up the decoding of the v6 media multiply space so that we UNDEF
on unassigned encodings rather than randomly interpreting them as
some instruction in this space.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Indeed, the result is known to be always positive.
Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Fix a bug in bccd9ec5f0,
target-arm/op_helper.c missed a change unlike all other targets.
This lead to a NULL pointer dereferences.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
The command line option is called -kernel, not -kenrel.
Cc: Paul Brook <paul@codesourcery.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <andreas.faerber@web.de>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Parameter is_softmmu (and its evil mutant twin brother is_softmuu)
is not used in cpu_*_handle_mmu_fault() functions, remove them
and adjust callers.
Acked-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Move softmmu_exec.h include directives from target-*/exec.h to
target-*/op_helper.c. Move also various other stuff only used in
op_helper.c there.
Define global env in dyngen-exec.h.
For i386, move wrappers for segment and FPU helpers from user-exec.c
to op_helper.c. Implement raise_exception_err_env() to handle dynamic
CPUState. Move the function declarations to cpu.h since they can be
used outside of op_helper.c context.
LM32, s390x, UniCore32: remove unused cpu_halted(), regs_to_env() and
env_to_regs().
ARM: make raise_exception() static.
Convert
#include "exec.h"
to
#include "cpu.h"
#include "dyngen-exec.h"
and remove now unused target-*/exec.h.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Remove some stray printfs for cases which don't generally happen
(some VFP UNDEF cases, reads and writes to unknown cp14 registers);
we should simply generate an UNDEF when the instruction is executed.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
VCVTT/VCVTB with bit 8 set is UNPREDICTABLE; we choose to UNDEF.
This avoids a TCG assert later when the VCVTT/VCVTB code tries to
use a source register that wasn't ever set up.
We pull the check for the presence of the half-precision extension
up in to this common code as well.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
