target/riscv: gdbstub: Check priv spec version before reporting CSR

target/riscv: gdbstub: Check priv spec version before reporting CSR

The gdbstub CSR XML is dynamically generated according to the result
of the CSR predicate() result. This has been working fine until
commit 7100fe6c2441 ("target/riscv: Enable privileged spec version 1.12")
introduced the privilege spec version check in riscv_csrrw_check().

When debugging the 'sifive_u' machine whose priv spec is at 1.10,
gdbstub reports priv spec 1.12 CSRs like menvcfg in the XML, hence
we see "remote failure reply 'E14'" message when examining all CSRs
via "info register system" from gdb.

Add the priv spec version check in the CSR XML generation logic to
fix this issue.

Fixes: 7100fe6c2441 ("target/riscv: Enable privileged spec version 1.12")
Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Weiwei Li <liweiwei@iscas.ac.cn>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Message-ID: <20230228104035.1879882-2-bmeng@tinylab.org>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>