target-arm: A64: add support for ld/st pair

This patch support the basic load and store pair instructions and
includes the generic helper functions:

  * do_gpr_st()
  * do_fp_st()
  * do_gpr_ld()
  * do_fp_ld()
  * read_cpu_reg_sp()
  * gen_check_sp_alignment()

The last function gen_check_sp_alignment() is a NULL op currently but
put in place to make it easy to add SP alignment checking later.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: A64: add support for ld/st unsigned imm

This adds support for the forms of ld/st with a 12 bit
unsigned immediate offset.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: A64: add support for ld/st with reg offset

This adds support for the load/store forms using a register offset.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: A64: add support for ld/st with index

This adds support for the pre/post-index ld/st forms with immediate
offsets as well as the un-scaled immediate form (which are all
variations on the same 9-bit immediate instruction form).

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: A64: add support for add, addi, sub, subi

Implement the non-carry forms of addition and subtraction
(immediate, extended register and shifted register).
This includes the code to calculate NZCV if the instruction
calls for setting the flags.

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>
target-arm: A64: add support for move wide instructions

This patch adds emulation for the mov wide instructions
(MOVN, MOVZ, MOVK).

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>
target-arm: A64: add support for 3 src data proc insns

This patch adds emulation for the "Data-processing (3 source)"
family of instructions, namely MADD, MSUB, SMADDL, SMSUBL, SMULH,
UMADDL, UMSUBL, UMULH.

Signed-off-by: Alexander Graf <agraf@suse.de>
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>
target-arm: A64: implement SVC, BRK

Add decoding for the exception generating instructions, and implement
SVC (syscalls) and BRK (software breakpoint).

Signed-off-by: Alexander Graf <agraf@suse.de>
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>
target-arm: A64: Add decoder skeleton for FP instructions

Add a top level decoder skeleton for FP instructions.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: implement FMOV

Implement FMOV, ie non-converting moves between general purpose
registers and floating point registers. This is a subtype of
the floating point <-> integer instruction class.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: Update generic cpreg code for AArch64

Update the generic cpreg support code to also handle AArch64:
AArch64-visible registers coexist in the same hash table with
AArch32-visible ones, with a bit in the hash key distinguishing
them.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: Remove ARMCPU/CPUARMState from cpregs APIs used by decoder

The cpregs APIs used by the decoder (get_arm_cp_reginfo() and
cp_access_ok()) currently take either a CPUARMState* or an ARMCPU*.
This is problematic for the A64 decoder, which doesn't pass the
environment pointer around everywhere the way the 32 bit decoder
does. Adjust the parameters these functions take so that we can
copy only the relevant info from the CPUARMState into the
DisasContext and then use that.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: A64: Implement MRS/MSR/SYS/SYSL

The AArch64 equivalent of the traditional AArch32
cp15 coprocessor registers is the set of instructions
MRS/MSR/SYS/SYSL, which cover between them both true
system registers and the "operations with side effects"
such as cache maintenance which in AArch32 are mixed
in with other cp15 registers. Implement these instructions
to look in the cpregs hashtable for the register or
operation.

Since we don't yet populate the cpregs hashtable with
any registers with the "AA64" bit set, everything will
still UNDEF at this point.

MSR/MRS is the first user of is_jmp = DISAS_UPDATE, so
fix an infelicity in its handling where the main loop
was requiring the caller to do the update of PC rather
than just doing it itself.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: Implement minimal set of EL0-visible sysregs

Implement an initial minimal set of EL0-visible system registers:
 * NZCV
 * FPCR
 * FPSR
 * CTR_EL0
 * DCZID_EL0

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: Widen thread-local register state fields to 64 bits

The common pattern for system registers in a 64-bit capable ARM
CPU is that when in AArch32 the cp15 register is a view of the
bottom 32 bits of the 64-bit AArch64 system register; writes in
AArch32 leave the top half unchanged. The most natural way to
model this is to have the state field in the CPU struct be a
64 bit value, and simply have the AArch32 TCG code operate on
a pointer to its lower half.

For aarch64-linux-user the only registers we need to share like
this are the thread-local-storage ones. Widen their fields to
64 bits and provide the 64 bit reginfo struct to make them
visible in AArch64 state.

Since we're touching almost every line in QEMU that uses the
c13_tls* fields in this patch anyway, we take the opportunity
to rename them in line with the standard ARM architectural names
for these registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: add support for add/sub with carry

This patch adds support for C3.5.3 Add/subtract (with carry):
instructions ADC, ADCS, SBC, SBCS.

Signed-off-by: Claudio Fontana <claudio.fontana@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
target-arm: A64: add support for conditional compare insns

this patch adds support for C3.5.4 - C3.5.5
Conditional compare (both immediate and register)

Signed-off-by: Claudio Fontana <claudio.fontana@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: aarch64: add support for ld lit

Adds support for Load Register (literal), both normal
and SIMD/FP forms.

Signed-off-by: Alexander Graf <agraf@suse.de>
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>
target-arm: Widen exclusive-access support struct fields to 64 bits

In preparation for adding support for A64 load/store exclusive instructions,
widen the fields in the CPU state struct that deal with address and data values
for exclusives from 32 to 64 bits. Although in practice AArch64 and AArch32
exclusive accesses will be generally separate there are some odd theoretical
corner cases (eg you should be able to do the exclusive load in AArch32, take
an exception to AArch64 and successfully do the store exclusive there), and it's
also easier to reason about.

The changes in semantics for the variables are:
 exclusive_addr  -> extended to 64 bits; -1ULL for "monitor lost",
   otherwise always < 2^32 for AArch32
 exclusive_val   -> extended to 64 bits. 64 bit exclusives in AArch32 now
   use the high half of exclusive_val instead of a separate exclusive_high
 exclusive_high  -> is no longer used in AArch32; extended to 64 bits as
   it will be needed for AArch64's pair-of-64-bit-values exclusives.
 exclusive_test  -> extended to 64 bits, as it is an address. Since this is
   a linux-user-only field, in arm-linux-user it will always have the top
   32 bits zero.
 exclusive_info  -> stays 32 bits, as it is neither data nor address, but
   simply holds register indexes etc. AArch64 will be able to fit all its
   information into 32 bits as well.

Note that the refactoring of gen_store_exclusive() coincidentally fixes
a minor bug where ldrexd would incorrectly update the first CPU register
even if the load for the second register faulted.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
target-arm: A64: support for ld/st/cl exclusive

This implement exclusive loads/stores for aarch64 along the lines of
arm32 and ppc implementations. The exclusive load remembers the address
and loaded value. The exclusive store throws an an exception which uses
those values to check for equality in a proper exclusive region.

This is not actually the architecture mandated semantics (for either
AArch32 or AArch64) but it is close enough for typical guest code
sequences to work correctly, and saves us from having to monitor all
guest stores. It's fairly easy to come up with test cases where we
don't behave like hardware - we don't for example model cache line
behaviour. However in the common patterns this works, and the existing
32 bit ARM exclusive access implementation has the same limitations.

AArch64 also implements new acquire/release loads/stores (which may be
either exclusive or non-exclusive). These imposes extra ordering
constraints on memory operations (ie they act as if they have an implicit
barrier built into them). As TCG is single-threaded all our barriers
are no-ops, so these just behave like normal loads and stores.

Signed-off-by: Michael Matz <matz@suse.de>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---

v3 -> v4 (ajb):
   - use new gpr_ld API

v4 -> v5 (ajb):
   - merge in later fixes from Matz
   - fix bug with using ZR for status
   - add sp alignment check
   - fixup bogus whitespace

v5 -> v6 (ajb):
   - better naming of goto fields
   - implement clrex
   - clear exclusive lock after strex
   - clear exclusive lock after exceptions
   - fix up checkpatch violations

PMM updates:
 * rebase on top of separate 'widen the exclusive fields' patch
 * rearrange code in main.c so we don't pointlessly jump from
   do_strex() to do_strex_a64()
 * use extract32 in do_strex_a64
 * put clearing of excl. monitor at bottom of cpu_loop which makes
   more conceptual sense since in hw it happens on exception return
 * use read_cpu_reg_sp() rather than explicit temp
 * minor tweaking
 * store the fault address in do_strex_a64 rather than forgetting it