csr_read_allowed/csr_read_allowed requires trap.case to detect the results,
but if no exception occurs, the value of trap.case will remain unchanged,
which makes the detection results unreliable. Add code to initialize
trap.case to 0.
Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
As RISC-V ISA allows many CSRs such as pmp, s/mcounteren to be optional
in hardware, OpenSBI should provide an option to dynamically detect
these csr access capability at run time.
Implement a csr read/write access check helper macros.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Jonathan Balkind <jbalkind@cs.princeton.edu>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
