[PATCH] riscv: signal: protect regs->status RMW from concurrent preemption

[Guobin Zhang]

Hi Andy,

Thanks for the review and the suggested approach. I'll send a v2 that
disables preemption at the fstate_save()/fstate_restore() level and
adds the fstate_{save,restore}_preempt_off() variants for the scheduler
and kernel_mode_fpu.

Thanks,
Guobin