tree bc5f6f1c069f7d4c03fdcb85f65c8f7aabc2c413
parent e9434cff87762255bc055e04a2695e70a53c41a2
author Ciro Santilli <ciro.santilli@arm.com> 1537368646 +0100
committer Ciro Santilli <ciro.santilli@arm.com> 1539961893 +0000

arm: update hint instruction decoding to match ARMv8.5

This fixes:

- unallocated hints that have since been allocated
- unallocated and unimplemented hint instructions being treated as
  Unknown instead of the correct NOP
- missing encoding for DBG on A32

Unallocated and unimplemented hints give a warning if executed.

The most important fix was for the CSDB Spectre mitigation
instruction, which was added recently and previously unallocated and
treated as Unknown.

The Linux kernel v4.18 ARMv7 uses CSDB it and boot would
fail with "undefined instruction" since Linux commit
1d4238c56f9816ce0f9c8dbe42d7f2ad81cb6613

Change-Id: I283da3f08a9af4148edc6fb3ca2930cbb97126b8
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13475
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>