arch-arm: Implement ARMv8.1-PAN, Privileged access never

ARMv8.1-PAN adds a new bit to PSTATE. When the value of this PAN state
bit is 1, any privileged data access from EL1 or EL2 to a virtual memory
address that is accessible at EL0 generates a Permission fault.
This feature is mandatory in ARMv8.1 implementations.
This feature is supported in AArch64 and AArch32 states.
The ID_AA64MMFR1_EL1.PAN, ID_MMFR3_EL1.PAN, and ID_MMFR3.PAN fields
identify the support for ARMv8.1-PAN.

Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Change-Id: I94a76311711739dd2394c72944d88ba9321fd159
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19729
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

arch-arm: Add HPD bit for TCR_EL2/EL3

This is controlling Hierarchical Permissions for EL3 and for EL2 when
HCR_EL2.E2H = 0.

Change-Id: I9d6615ff4980cc56a28dc32088cf1524155f0fa4
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Ciro Santilli <ciro.santilli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19609
Tested-by: kokoro <noreply+kokoro@google.com>

arch-arm,cpu: Add initial support for Arm SVE

This changeset adds initial support for the Arm Scalable Vector Extension
(SVE) by implementing:
- support for most data-processing instructions (no loads/stores yet);
- basic system-level support.

Additional authors:
- Javier Setoain <javier.setoain@arm.com>
- Gabor Dozsa <gabor.dozsa@arm.com>
- Giacomo Travaglini <giacomo.travaglini@arm.com>

Thanks to Pau Cabre for his contribution of bugfixes.

Change-Id: I1808b5ff55b401777eeb9b99c9a1129e0d527709
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/13515
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: Additional bits in misc ARM registers to use with the TLB and page walker

Change-Id: I71a6360709b35ad788d8c88fba1a7a2761233dbd
Reviewed-on: https://gem5-review.googlesource.com/c/14555
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: Remove SCTLR.VE bit

ARMv8 has removed SCTLR.VE bit which is now hardcoded to 0. We are
removing it from gem5 since we were not handling it anyway.

Change-Id: Ibde2db45c7f8add4a3188f2cb8c23701a6088d03
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13998
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: Add FP16 support and other primitives to fplib

This changeset:
- extends fplib to support emulation of half-precision floating-point
(FP16) operations;
- extends fplib to support additional primitives introduced by the Arm
Scalable Vector Extension (SVE) (fplibExpa, fplibScale,
fplibTrigMAdd, fplibTrigSMul, fplibTrigSSel);
- adds the FZ16 bit to FPSCR;
- cleans up fplib code by replacing constants with preprocessor macros
and by adding inline functions to recognise NaNs and infinities.

Change-Id: If8fdb2a5824b478c8310bbc126ec60cc1105f135
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/13044
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: Implement AArch64 ID regs as bitunions

This patch is implementing the following AArch64 ID registers as
bitunions, so that it is easier to query for feature availability:

- ID_AA64DFR0_EL1
- ID_AA64ISAR0_EL1
- ID_AA64ISAR1_EL1
- ID_AA64MMFR1_EL1
- ID_AA64MMFR2_EL1
- ID_AA64PFR0_EL1

They are updated to the latest Armv8.5 arch release version.
RES0 only ID registers like ID_AA64AFR1_EL1 haven't been added.

Change-Id: Ied037abe3757421bcfc2834d397a8cf9a2b9f0a7
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/13067
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

arch-arm: Move MiscReg BitUnions into a separate header file

As the number of MiscRegs increases there is the need of a cleaner
header file; this patch is separating miscreg.[cc,hh] where the miscreg
decoding/utility functions are defined/declared from the MiscReg
register types (BitUnion).

Change-Id: I815f53b117b50e47f93aa13d78356ef09d2a2541
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/13065
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>