tree d230b106cca136fba2b559ceb8f17843798eaa69
parent 76e7aec54256696dfdc9567c7ea325fb07c48ef1
author Alec Roelke <alec.roelke@gmail.com> 1528670494 -0400
committer Alec Roelke <alec.roelke@gmail.com> 1532803756 +0000

arch-riscv: Add xret instructions

This patch adds the uret, sret, and mret instructions for use with
returning from user-, supervisor-, and machine-level code, respectively.
These instructions read the STATUS register to determine the previous
privilege level and modify it to re-enable interrupts at the old
privilege level. These instructions can only be executed at the
corresponding privilege level or higher.

Change-Id: I6125c31cb2fdcc3f83eca86910519e81ffbbbfc9
Reviewed-on: https://gem5-review.googlesource.com/11136
Maintainer: Alec Roelke <alec.roelke@gmail.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Robert Scheffel <robert.scheffel1@tu-dresden.de>