hw/intc/arm_gic: Fix NVIC assertion failure

Commit 40d225009ef accidentally changed the behaviour of
gic_acknowledge_irq() for the NVIC. The NVIC doesn't have SGIs,
so this meant we hit an assertion:
  gic_acknowledge_irq: Assertion `s->sgi_pending[irq][cpu] != 0' failed.

Return NVIC acknowledge-irq to its previous behaviour, like 11MPCore.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
target-arm: A64: Implement plain vector SIMD indexed element insns

Implement all the SIMD vector x indexed element instructions
in the subcategory which are not 'long' ops.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: Implement long vector x indexed insns

Implement the 'long' operations in the vector x indexed
element category.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: Implement SIMD scalar indexed instructions

Implement the SIMD scalar indexed instructions. The encoding
here is nearly identical to the vector indexed grouping, so
we combine the two.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: Implement scalar three different instructions

Implement the scalar three different instruction group:
it only has three instructions in it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: Implement SIMD FP compare and set insns

This adds all forms of the SIMD floating point and set instructions:

  FCM(GT|GE|EQ|LE|LT)

Most of the heavy lifting is done by either the existing neon helpers or
some new helpers for the 64bit double cases. Most of the code paths are
common although the 2misc versions are a little special as they compare
against zero.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
[PMM: fixed some minor bugs, added the 2-misc-scalar encoding]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: Implement floating point pairwise insns

Add support for the floating-point pairwise operations
FADDP, FMAXP, FMAXNMP, FMINP and FMINNMP. To do this we use the
code which was previously handling only integer pairwise operations,
and push the integer-specific decode and handling of unallocated
cases up one level in the call tree, so we can also call it from
the floating-point section of the decoder.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
softfloat: Support halving the result of muladd operation

The ARMv8 instruction set includes a fused floating point
reciprocal square root step instruction which demands an
"(x * y + z) / 2" fused operation. Support this by adding
a flag to the softfloat muladd operations which requests
that the result is halved before rounding.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: Implement remaining 3-same instructions

Implement the remaining instructions in the SIMD 3-reg-same
and scalar-3-reg-same groups: FMULX, FRECPS, FRSQRTS, FACGE,
FACGT, FMLA and FMLS.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm/kvm-consts.h: Define QEMU constants for known KVM CPUs

Extend the set of CPUs for which we provide a QEMU_KVM_ARM_TARGET_*
constant to include all the ones currently supported by the kernel
headers we are using.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: Define names for SCTLR bits

The SCTLR is full of bits for enabling or disabling various things, and so
there are many places in the code which check if certain bits are set.
Define some named constants for the SCTLR bits so these checks are easier
to read.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: Restrict check_ap() use of S and R bits to v6 and earlier

The SCTLR bits S and R (8 and 9) only exist in ARMv6 and earlier.
In ARMv7 these bits RAZ, and in ARMv8 they are reassigned. Guard
the use of them in check_ap() so that we don't get incorrect results
for ARMv8 CPUs.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
target-arm: Remove unused ARMCPUState sr substruct

Remove the 'struct sr' from ARMCPUState -- it isn't actually used and is
a hangover from the original separate system register implementation used
by the SuSE linux-user-mode-only AArch64 target.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
target-arm: Log bad system register accesses with LOG_UNIMP

Log guest attempts to access unimplemented system registers via
the LOG_UNIMP reporting mechanism (for both the 32 bit and 64 bit
instruction sets). This is particularly useful for debugging
problems where the guest is trying to use a system register that
QEMU doesn't implement.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
target-arm: Stop underdecoding ARM946 PRBS registers

The ARM946 has 8 PRBS (protection region base and size) registers.
Currently we implement these with a CP_ANY reginfo; however this
underdecodes (since there are 16 possible values of CRm but only
8 registers) and we catch the invalid values in the read and
write functions. However this causes issues with migration since
we only migrate the first of a wildcard register set, so we only
migrate c6_region[0]. It also makes it awkward to pull reginfo
access checks out into their own function.

Avoid all these problems by just defining separate reginfo structs
for each of the 8 registers; this also lets us avoid having any
read or write functions and will result in more efficient direct
field accesses from generated code.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: Split cpreg access checks out from read/write functions

Several of the system registers handled via the ARMCPRegInfo
mechanism have access trap control bits controlling whether the
registers are accessible to lower privilege levels. Replace
the existing mechanism (allowing the read and write functions
to return EXCP_UDEF if access is denied) with a dedicated
"check access rights" function pointer in the ARMCPRegInfo.
This will allow us to simplify some of the register definitions,
which no longer need read/write functions purely to handle
the access checks.

We take the opportunity to define the return value from the
access checking function in a way that allows us to set the
correct exception syndrome information for exceptions taken
to AArch64 (which may need to distinguish access failures due
to a configurable trap or enable from other kinds of access
failure).

This commit defines the new mechanism but does not move any
of the registers across to use it.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
target-arm: Convert performance monitor reginfo to accessfn

Convert the performance monitor reginfo definitions to use
an accessfn rather than returning EXCP_UDEF from read and
write functions. This also allows us to fix a couple of XXX
cases where we weren't imposing the access restrictions on
RAZ/WI or constant registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: Convert generic timer reginfo to accessfn

Convert the reginfo structs for the generic timer registers
to use access functions rather than returning EXCP_UDEF from
their read handlers. In some cases this allows us to remove
a read handler completely.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
target-arm: Convert miscellaneous reginfo structs to accessfn

Convert the remaining miscellaneous cases of reginfo read/write
functions returning EXCP_UDEF to use an accessfn instead:
TEEHBR, and the ATS address-translation operations.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: Drop success/fail return from cpreg read and write functions

All cpreg read and write functions now return 0, so we can clean up
their prototypes:
 * write functions return void
 * read functions return the value rather than taking a pointer
   to write the value to

This is a fairly mechanical change which makes only the bare
minimum set of changes to the callers of read and write functions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>