arch-riscv: fix load reserved store conditional

  * According to the manual, load reservations must be cleared on a
    failed or a successful SC attempt.
  * A load reservation can be arbitrarily large. The current
    implementation was reserving something different than cacheBlockSize
    which could lead to problems if snoop addresses are cache block
    aligned. This patch implementation assumes a cacheBlock granularity.
  * Load reservations should also be cleared on faults

Change-Id: I64513534710b5f269260fcb204f717801913e2f5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/71520
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
4 files changed