Access memory through the scope of current privilege level (#386)

* add opcode for csrrsi and csrrci

* enable MMU while reading/writing memory using progbuf

* fix style issues

* keep old behavior for progbufsize<4, perform r/w/csr only when necessary

* do not pass progbufsize, only write mstatus if changed

* add config option to enable virtualization feature

* throw error if virt enabled but unavaliable, outsource modify_privilege

* support virtualization for read_memory_progbuf_one

src/target/riscv/program.c

@@ -109,6 +109,18 @@ int riscv_program_lbr(struct riscv_program *p, enum gdb_regno d, enum gdb_regno
 	return riscv_program_insert(p, lb(d, b, offset));
 }
 
+int riscv_program_csrrsi(struct riscv_program *p, enum gdb_regno d, unsigned int z, enum gdb_regno csr)
+{
+	assert(csr >= GDB_REGNO_CSR0 && csr <= GDB_REGNO_CSR4095);
+	return riscv_program_insert(p, csrrsi(d, z, csr - GDB_REGNO_CSR0));
+}
+
+int riscv_program_csrrci(struct riscv_program *p, enum gdb_regno d, unsigned int z, enum gdb_regno csr)
+{
+	assert(csr >= GDB_REGNO_CSR0 && csr <= GDB_REGNO_CSR4095);
+	return riscv_program_insert(p, csrrci(d, z, csr - GDB_REGNO_CSR0));
+}
+
 int riscv_program_csrr(struct riscv_program *p, enum gdb_regno d, enum gdb_regno csr)
 {
 	assert(csr >= GDB_REGNO_CSR0 && csr <= GDB_REGNO_CSR4095);