zicsr extension issue

[quickflow]

Hi - encountering the below - any help appreciated

arch/riscv/cpu/cpu.c: Assembler messages:
arch/riscv/cpu/cpu.c:94: Error: unrecognized opcode csrs sstatus,a5', extension zicsr' required
arch/riscv/cpu/cpu.c:95: Error: unrecognized opcode csrw 0x003,0', extension zicsr' required

[Omeg8051]

Seemed to have something to do with the fact that some CSR instructions had been moved out of the base ISA. So the included arch attribute rv64imac is no longer sufficient to inform the assembler to include zicsr extension.
Adding
-save-temps
to line
KCFLAGS='-v -save-temps -O1 -gno-column-info' \
and comment out the
# .attribute arch, "rv64i2p1_m2p0_a2p1_c2p0"
in the "cpu.s" generated in u-boot/arch/riscv/cpu/
allow the -march=rv64imac_zicsr to take effect and assemble successfully out side the make file.

Still trying to figure out how to let it include the zicsr extension during compile phase to make it work.