Commit graph

2183 commits

Author SHA1 Message Date
Peter Maydell 483da66139 target/arm: Implement MVE VQSHL (vector)
Implement the MVE VQSHL insn (encoding T4, which is the
vector-shift-by-vector version).

The DO_SQSHL_OP and DO_UQSHL_OP macros here are derived from
the neon_helper.c code for qshl_u{8,16,32} and qshl_s{8,16,32}.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-33-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell f741707bb3 target/arm: Implement MVE VQADD, VQSUB (vector)
Implement the vector forms of the MVE VQADD and VQSUB insns.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-32-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell 380caf6c07 target/arm: Implement MVE VQDMULH, VQRDMULH (vector)
Implement the vector forms of the MVE VQDMULH and VQRDMULH insns.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-31-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell a88903537d target/arm: Implement MVE VQDMULL scalar
Implement the MVE VQDMULL scalar insn. This multiplies the top or
bottom half of each element by the scalar, doubles and saturates
to a double-width result.

Note that this encoding overlaps with VQADD and VQSUB; it uses
what in VQADD and VQSUB would be the 'size=0b11' encoding.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-30-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell 66c0576754 target/arm: Implement MVE VQDMULH and VQRDMULH (scalar)
Implement the MVE VQDMULH and VQRDMULH scalar insns, which multiply
elements by the scalar, double, possibly round, take the high half
and saturate.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-29-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell 39f2ec8592 target/arm: Implement MVE VQADD and VQSUB
Implement the MVE VQADD and VQSUB insns, which perform saturating
addition of a scalar to each element.  Note that individual bytes of
each result element are used or discarded according to the predicate
mask, but FPSCR.QC is only set if the predicate mask for the lowest
byte of the element is set.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-28-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell 387debdb93 target/arm: Implement MVE VPST
Implement the MVE VPST insn, which sets the predicate mask
fields in the VPR to the immediate value encoded in the insn.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-27-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell b050543b68 target/arm: Implement MVE VBRSR
Implement the MVE VBRSR insn, which reverses a specified
number of bits in each element, setting the rest to zero.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-26-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell 644f717c35 target/arm: Implement MVE VHADD, VHSUB (scalar)
Implement the scalar variants of the MVE VHADD and VHSUB insns.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-25-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell 91a358fdfb target/arm: Implement MVE VSUB, VMUL (scalar)
Implement the scalar forms of the MVE VSUB and VMUL insns.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-24-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell e51896b386 target/arm: Implement MVE VADD (scalar)
Implement the scalar form of the MVE VADD insn. This takes the
scalar operand from a general purpose register.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-23-peter.maydell@linaro.org
2021-06-24 14:58:47 +01:00
Peter Maydell 3854874733 target/arm: Implement MVE VRMLALDAVH, VRMLSLDAVH
Implement the MVE VRMLALDAVH and VRMLSLDAVH insns, which accumulate
the results of a rounded multiply of pairs of elements into a 72-bit
accumulator, returning the top 64 bits in a pair of general purpose
registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-22-peter.maydell@linaro.org
2021-06-21 17:12:51 +01:00
Peter Maydell 181cd97143 target/arm: Implement MVE VMLSLDAV
Implement the MVE insn VMLSLDAV, which multiplies source elements,
alternately adding and subtracting them, and accumulates into a
64-bit result in a pair of general purpose registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-21-peter.maydell@linaro.org
2021-06-21 17:12:51 +01:00
Peter Maydell 1d2386f70a target/arm: Implement MVE VMLALDAV
Implement the MVE VMLALDAV insn, which multiplies pairs of integer
elements, accumulating them into a 64-bit result in a pair of
general-purpose registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-20-peter.maydell@linaro.org
2021-06-21 17:12:51 +01:00
Peter Maydell ac6ad1dca8 target/arm: Implement MVE VMULL
Implement the MVE VMULL insn, which multiplies two single
width integer elements to produce a double width result.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-19-peter.maydell@linaro.org
2021-06-21 17:12:51 +01:00
Peter Maydell abc48e310c target/arm: Implement MVE VHADD, VHSUB
Implement MVE VHADD and VHSUB insns, which perform an addition
or subtraction and then halve the result.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-18-peter.maydell@linaro.org
2021-06-21 17:12:51 +01:00
Peter Maydell bc67aa8d56 target/arm: Implement MVE VABD
Implement the MVE VABD insn.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-17-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell cd367ff391 target/arm: Implement MVE VMAX, VMIN
Implement the MVE VMAX and VMIN insns.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-16-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell fca87b78f3 target/arm: Implement MVE VRMULH
Implement the MVE VRMULH insn, which performs a rounding multiply
and then returns the high half.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-15-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell ba62cc56e8 target/arm: Implement MVE VMULH
Implement the MVE VMULH insn, which performs a vector
multiply and returns the high half of the result.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-14-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell 9333fe4dd3 target/arm: Implement MVE VADD, VSUB, VMUL
Implement the MVE VADD, VSUB and VMUL insns.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-13-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell 68245e442c target/arm: Implement MVE VAND, VBIC, VORR, VORN, VEOR
Implement the MVE vector logical operations operating
on two registers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-12-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell ab59362fca target/arm: Implement MVE VDUP
Implement the MVE VDUP insn, which duplicates a value from
a general-purpose register into every lane of a vector
register (subject to predication).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-11-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell 399a8c766c target/arm: Implement MVE VNEG
Implement the MVE VNEG insn (both integer and floating point forms).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-9-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell 59c9177338 target/arm: Implement MVE VABS
Implement the MVE VABS functions (both integer and floating point).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-8-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell 8abd3c80b1 target/arm: Implement MVE VMVN (register)
Implement the MVE VMVN(register) operation.  Note that for
predication this operation is byte-by-byte.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-7-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell 249b5309c4 target/arm: Implement MVE VREV16, VREV32, VREV64
Implement the MVE instructions VREV16, VREV32 and VREV64.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-6-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell 6437f1f77c target/arm: Implement MVE VCLS
Implement the MVE VCLS insn.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-5-peter.maydell@linaro.org
2021-06-21 17:12:50 +01:00
Peter Maydell 0f0f2bd548 target/arm: Implement MVE VCLZ
Implement the MVE VCLZ insn (and the necessary machinery
for MVE 1-input vector ops).

Note that for non-load instructions predication is always performed
at a byte level granularity regardless of element size (R_ZLSJ),
and so the masking logic here differs from that used in the VLDR
and VSTR helpers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-4-peter.maydell@linaro.org
2021-06-21 16:49:38 +01:00
Peter Maydell 2fc6b7510c target/arm: Implement widening/narrowing MVE VLDR/VSTR insns
Implement the variants of MVE VLDR (encodings T1, T2) which perform
"widening" loads where bytes or halfwords are loaded from memory and
zero or sign-extended into halfword or word length vector elements,
and the narrowing MVE VSTR (encodings T1, T2) where bytes or
halfwords are stored from halfword or word elements.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-3-peter.maydell@linaro.org
2021-06-21 16:49:38 +01:00
Peter Maydell 507b6a500c target/arm: Implement MVE VLDR/VSTR (non-widening forms)
Implement the forms of the MVE VLDR and VSTR insns which perform
non-widening loads of bytes, halfwords or words from memory into
vector elements of the same width (encodings T5, T6, T7).

(At the moment we know for MVE and M-profile in general that
vfp_access_check() can never return false, but we include the
conventional return-true-on-failure check for consistency
with non-M-profile translation code.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-2-peter.maydell@linaro.org
2021-06-21 16:49:38 +01:00
Peter Maydell 88137f787f target/arm: Handle FPU check for FPCXT_NS insns via vfp_access_check_m()
Instead of open-coding the "take NOCP exception if FPU disabled,
otherwise call gen_preserve_fp_state()" code in the accessors for
FPCXT_NS, add an argument to vfp_access_check_m() which tells it to
skip the gen_update_fp_context() call, so we can use it for the
FPCXT_NS case.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210618141019.10671-8-peter.maydell@linaro.org
2021-06-21 16:49:38 +01:00
Peter Maydell e8cedaf779 target/arm: Split vfp_access_check() into A and M versions
vfp_access_check and its helper routine full_vfp_access_check() has
gradually grown and is now an awkward mix of A-profile only and
M-profile only pieces.  Refactor it into an A-profile only and an
M-profile only version, taking advantage of the fact that now the
only direct call to full_vfp_access_check() is in A-profile-only
code.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210618141019.10671-7-peter.maydell@linaro.org
2021-06-21 16:49:38 +01:00
Peter Maydell 95aceeeac9 target/arm: Factor FP context update code out into helper function
Factor the code in full_vfp_access_check() which updates the
ownership of the FP context and creates a new FP context
out into its own function.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210618141019.10671-6-peter.maydell@linaro.org
2021-06-21 16:49:38 +01:00
Peter Maydell e494cd0a1a target/arm: Handle writeback in VLDR/VSTR sysreg with no memory access
A few subcases of VLDR/VSTR sysreg succeed but do not perform a
memory access:
 * VSTR of VPR when unprivileged
 * VLDR to VPR when unprivileged
 * VLDR to FPCXT_NS when fpInactive

In these cases, even though we don't do the memory access we should
still update the base register and perform the stack limit check if
the insn's addressing mode specifies writeback.  Our implementation
failed to do this, because we handle these side-effects inside the
memory_to_fp_sysreg() and fp_sysreg_to_memory() callback functions,
which are only called if there's something to load or store.

Fix this by adding an extra argument to the callbacks which is set to
true to actually perform the access and false to only do side effects
like writeback, and calling the callback with do_access = false
for the three cases listed above.

This produces slightly suboptimal code for the case of a write
to FPCXT_NS when the FPU is inactive and the insn didn't have
side effects (ie no writeback, or via VMSR), in which case we'll
generate a conditional branch over an unconditional branch.
But this doesn't seem to be important enough to merit requiring
the callback to report back whether it generated any code or not.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210618141019.10671-5-peter.maydell@linaro.org
2021-06-21 16:49:37 +01:00
Peter Maydell fa856736b6 target/arm: Don't NOCP fault for FPCXT_NS accesses
The M-profile architecture requires that accesses to FPCXT_NS when
there is no active FP state must not take a NOCP fault even if the
FPU is disabled. We were not implementing this correctly, because
in our decode we catch the NOCP faults early in m-nocp.decode.

Fix this bug by moving all the handling of M-profile FP system
register accesses from vfp.decode into m-nocp.decode and putting
it above the NOCP blocks. This provides the correct behaviour:
 * for accesses other than FPCXT_NS the trans functions call
   vfp_access_check(), which will check for FPU disabled and
   raise a NOCP exception if necessary
 * for FPCXT_NS we have the special case code that doesn't
   call vfp_access_check()
 * when these trans functions want to raise an UNDEF they return
   false, so the decoder will fall through into the NOCP blocks.
   This means that NOCP correctly takes precedence over UNDEF
   for these insns. (This is a difference from the other insns
   handled by m-nocp.decode, where UNDEF takes precedence and
   which we implement by having those trans functions call
   unallocated_encoding() in the appropriate places.)

[Note for backport to stable: this commit has a semantic dependency
on commit 9a486856e9, which was not marked as cc-stable because
we didn't know we'd need it for a for-stable bugfix.]

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210618141019.10671-4-peter.maydell@linaro.org
2021-06-21 16:49:37 +01:00
Peter Maydell 9931d9d84b target/arm: Handle FPU being disabled in FPCXT_NS accesses
If the guest makes an FPCXT_NS access when the FPU is disabled,
one of two things happens:
 * if there is no active FP context, then the insn behaves the
   same way as if the FPU was enabled: writes ignored, reads
   same value as FPDSCR_NS
 * if there is an active FP context, then we take a NOCP
   exception

Add code to the sysreg read/write functions which emits
code to take the NOCP exception in the latter case.

At the moment this will never be used, because the NOCP checks in
m-nocp.decode happen first, and so the trans functions are never
called when the FPU is disabled.  The code will be needed when we
move the sysreg access insns to before the NOCP patterns in the
following commit.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210618141019.10671-3-peter.maydell@linaro.org
2021-06-21 16:49:37 +01:00
Peter Maydell 41b3ffc599 target/arm/translate-vfp.c: Whitespace fixes
In the code for handling VFP system register accesses there is some
stray whitespace after a unary '-' operator, and also some incorrect
indent in a couple of function prototypes.  We're about to move this
code to another file, so fix the code style issues first so
checkpatch doesn't complain about the code-movement patch.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210618141019.10671-2-peter.maydell@linaro.org
2021-06-21 16:49:37 +01:00
Peter Maydell 15613357ba target/arm: Use acpi_ghes_present() to see if we report ACPI memory errors
The virt_is_acpi_enabled() function is specific to the virt board, as
is the check for its 'ras' property.  Use the new acpi_ghes_present()
function to check whether we should report memory errors via
acpi_ghes_record_errors().

This avoids a link error if QEMU was built without support for the
virt board, and provides a mechanism that can be used by any future
board models that want to add ACPI memory error reporting support
(they only need to call acpi_ghes_add_fw_cfg()).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Dongjiu Geng <gengdongjiu1@gmail.com>
Message-id: 20210603171259.27962-4-peter.maydell@linaro.org
2021-06-21 16:49:37 +01:00
Peter Maydell dbcf6f9367 bitops.h: Provide hswap32(), hswap64(), wswap64() swapping operations
Currently the ARM SVE helper code defines locally some utility
functions for swapping 16-bit halfwords within 32-bit or 64-bit
values and for swapping 32-bit words within 64-bit values,
parallel to the byte-swapping bswap16/32/64 functions.

We want these also for the ARM MVE code, and they're potentially
generally useful for other targets, so move them to bitops.h.
(We don't put them in bswap.h with the bswap* functions because
they are implemented in terms of the rotate operations also
defined in bitops.h, and including bitops.h from bswap.h seems
better avoided.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210614151007.4545-17-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell 77f96148f3 target/arm: Move expand_pred_b() data to vec_helper.c
For MVE, we want to re-use the large data table from expand_pred_b().
Move the data table to vec_helper.c so it is no longer in an SVE
specific source file.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-14-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell 6390eed45c target/arm: Add framework for MVE decode
Add the framework for decoding MVE insns, with the necessary new
files and the meson.build rules, but no actual content yet.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-11-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell a454ea1e6d target/arm: Implement MVE LETP insn
Implement the MVE LETP insn.  This is like the existing LE loop-end
insn, but it must perform an FPU-enabled check, and on loop-exit it
resets LTPSIZE to 4.

To accommodate the requirement to do something on loop-exit, we drop
the use of condlabel and instead manage both the TB exits manually,
in the same way we already do in trans_WLS().

The other MVE-specific change to the LE insn is that we must raise an
INVSTATE UsageFault insn if LTPSIZE is not 4.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-10-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell 40a36f003c target/arm: Implement MVE DLSTP
Implement the MVE DLSTP insn; this is like the existing DLS
insn, except that it must do an FPU access check and it
sets LTPSIZE to the value specified in the insn.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-9-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell 6822abfdf8 target/arm: Implement MVE WLSTP insn
Implement the MVE WLSTP insn; this is like the existing WLS insn,
except that it specifies a size value which is used to set
FPSCR.LTPSIZE.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-8-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell 76c32d721d target/arm: Implement MVE LCTP
Implement the MVE LCTP instruction.

We put its decode and implementation with the other
low-overhead-branch insns because although it is only present if MVE
is implemented it is logically in the same group as the other LOB
insns.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-7-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell 9a486856e9 target/arm: Let vfp_access_check() handle late NOCP checks
In commit a3494d4671 we reworked the M-profile handling of its
checks for when the NOCP exception should be raised because the FPU
is disabled, so that (in line with the architecture) the NOCP check
is done early over a large range of the encoding space, and takes
precedence over UNDEF exceptions.  As part of this, we removed the
code from full_vfp_access_check() which raised an exception there for
M-profile with the FPU disabled, because it was no longer reachable.

For MVE, some instructions which are outside the "coprocessor space"
region of the encoding space must nonetheless do "is the FPU enabled"
checks and possibly raise a NOCP exception.  (In particular this
covers the MVE-specific low-overhead branch insns LCTP, DLSTP and
WLSTP.) To support these insns, reinstate the code in
full_vfp_access_check(), so that their trans functions can call
vfp_access_check() and get the correct behaviour.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-6-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell 5138bd0143 target/arm: Add handling for PSR.ECI/ICI
On A-profile, PSR bits [15:10][26:25] are always the IT state bits.
On M-profile, some of the reserved encodings of the IT state are used
to instead indicate partial progress through instructions that were
interrupted partway through by an exception and can be resumed.

These resumable instructions fall into two categories:

(1) load/store multiple instructions, where these bits are called
"ICI" and specify the register in the ldm/stm list where execution
should resume.  (Specifically: LDM, STM, VLDM, VSTM, VLLDM, VLSTM,
CLRM, VSCCLRM.)

(2) MVE instructions subject to beatwise execution, where these bits
are called "ECI" and specify which beats in this and possibly also
the following MVE insn have been executed.

There are also a few insns (LE, LETP, and BKPT) which do not use the
ICI/ECI bits but must leave them alone.

Otherwise, we should raise an INVSTATE UsageFault for any attempt to
execute an insn with non-zero ICI/ECI bits.

So far we have been able to ignore ECI/ICI, because the architecture
allows the IMPDEF choice of "always restart load/store multiple from
the beginning regardless of ICI state", so the only thing we have
been missing is that we don't raise the INVSTATE fault for bad guest
code.  However, MVE requires that we honour ECI bits and do not
rexecute beats of an insn that have already been executed.

Add the support in the decoder for handling ECI/ICI:
 * identify the ECI/ICI case in the CONDEXEC TB flags
 * when a load/store multiple insn succeeds, it updates the ECI/ICI
   state (both in DisasContext and in the CPU state), and sets a flag
   to say that the ECI/ICI state was handled
 * if we find that the insn we just decoded did not handle the
   ECI/ICI state, we delete all the code that we just generated for
   it and instead emit the code to raise the INVFAULT.  This allows
   us to avoid having to update every non-MVE non-LDM/STM insn to
   make it check for "is ECI/ICI set?".

We continue with our existing IMPDEF choice of not caring about the
ICI state for the load/store multiples and simply restarting them
from the beginning.  Because we don't allow interrupts in the middle
of an insn, the only way we would see this state is if the guest set
ICI manually on return from an exception handler, so it's a corner
case which doesn't merit optimisation.

ICI update for LDM/STM is simple -- it always zeroes the state.  ECI
update for MVE beatwise insns will be a little more complex, since
the ECI state may include information for the following insn.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-5-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell 375256a846 target/arm: Handle VPR semantics in existing code
When MVE is supported, the VPR register has a place on the exception
stack frame in a previously reserved slot just above the FPSCR.
It must also be zeroed in various situations when we invalidate
FPU context.

Update the code which handles the stack frames (exception entry and
exit code, VLLDM, and VLSTM) to save/restore VPR.

Update code which invalidates FP registers (mostly also exception
entry and exit code, but also VSCCLRM and the code in
full_vfp_access_check() that corresponds to the ExecuteFPCheck()
pseudocode) to zero VPR.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-4-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00
Peter Maydell c485ce2c49 target/arm: Enable FPSCR.QC bit for MVE
MVE has an FPSCR.QC bit similar to the A-profile Neon one; when MVE
is implemented make the bit writeable, both in the generic "load and
store FPSCR" helper functions and in the code for handling the NZCVQC
sysreg which we had previously left as "TODO when we implement MVE".

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210614151007.4545-3-peter.maydell@linaro.org
2021-06-16 14:33:52 +01:00