- int ptshift = (LEVELS-1)*PTIDXBITS;
- for (reg_t i = 0; i < LEVELS; i++, ptshift -= PTIDXBITS) {
- reg_t idx = (addr >> (PGSHIFT+ptshift)) & ((1<<PTIDXBITS)-1);
+reg_t mmu_t::walk(reg_t addr, access_type type, reg_t mode)
+{
+ vm_info vm = decode_vm_info(proc->max_xlen, mode, proc->get_state()->satp);
+ if (vm.levels == 0)
+ return addr & ((reg_t(2) << (proc->xlen-1))-1); // zero-extend from xlen
+
+ bool s_mode = mode == PRV_S;
+ bool sum = get_field(proc->state.mstatus, MSTATUS_SUM);
+ bool mxr = get_field(proc->state.mstatus, MSTATUS_MXR);
+
+ // verify bits xlen-1:va_bits-1 are all equal
+ int va_bits = PGSHIFT + vm.levels * vm.idxbits;
+ reg_t mask = (reg_t(1) << (proc->xlen - (va_bits-1))) - 1;
+ reg_t masked_msbs = (addr >> (va_bits-1)) & mask;
+ if (masked_msbs != 0 && masked_msbs != mask)
+ vm.levels = 0;
+
+ reg_t base = vm.ptbase;
+ for (int i = vm.levels - 1; i >= 0; i--) {
+ int ptshift = i * vm.idxbits;
+ reg_t idx = (addr >> (PGSHIFT + ptshift)) & ((1 << vm.idxbits) - 1);