__riscv_ctx_hdr
struct __riscv_ctx_hdr hdr;
struct __riscv_ctx_hdr __user *head = sc_ext_ptr;
total_context_size += sizeof(struct __riscv_ctx_hdr);
struct __riscv_ctx_hdr __user *sc_ext_ptr = &sc->sc_extdesc.hdr;
riscv_v_sc_size = sizeof(struct __riscv_ctx_hdr) +
riscv_zicfiss_sc_size = sizeof(struct __riscv_ctx_hdr) +