Add Smcsrind/Sscsrind support

This adds the following CSRs:

miselect (0x350), mireg (0x351), mireg2/3 (0x352, 0x353),
mireg4-6 (0x355 - 0x357), siselect (0x150), sireg (0x151),
sireg2/3 (0x152, 0x153), sireg4-6 (0x155 - 0x157), vsiselect (0x250),
vsireg (0x251), mireg2/3 (0x252, 0x253), vsireg4-6 (0x255 - 0x257).

Presently, attempts to read / write from ireg? registers will fail, and
future extensions will provide proxy CSR mappings for the respective
?ireg CSRs.

1 files changed, 62 insertions, 0 deletions

diff --git a/riscv/csrs.cc b/riscv/csrs.cc
index 7ea07d1..4d1e546 100644
--- a/riscv/csrs.cc
+++ b/riscv/csrs.cc
@@ -1574,3 +1574,65 @@ void jvt_csr_t::verify_permissions(insn_t insn, bool write) const {
     }
   }
 }
+
+virtualized_indirect_csr_t::virtualized_indirect_csr_t(processor_t* const proc, csr_t_p orig, csr_t_p virt):
+  virtualized_csr_t(proc, orig, virt) {
+}
+
+void virtualized_indirect_csr_t::verify_permissions(insn_t insn, bool write) const {
+  virtualized_csr_t::verify_permissions(insn, write);
+  if (state->v)
+    virt_csr->verify_permissions(insn, write);
+  else
+    orig_csr->verify_permissions(insn, write);
+}
+
+sscsrind_reg_csr_t::sscsrind_reg_csr_t(processor_t* const proc, const reg_t addr, csr_t_p iselect) :
+  csr_t(proc, addr),
+  iselect(iselect) {
+}
+
+void sscsrind_reg_csr_t::verify_permissions(insn_t insn, bool write) const {
+  // Don't call base verify_permission for VS registers remapped to S-mode
+  if (insn.csr() == address)
+    csr_t::verify_permissions(insn, write);
+
+  csr_t_p proxy_csr = get_reg();
+  if (proxy_csr == nullptr) {
+    if (!state->v) {
+      throw trap_illegal_instruction(insn.bits());
+    } else {
+      throw trap_virtual_instruction(insn.bits());
+    }
+  }
+  proxy_csr->verify_permissions(insn, write);
+}
+
+
+reg_t sscsrind_reg_csr_t::read() const noexcept {
+  csr_t_p target_csr = get_reg();
+  if (target_csr != nullptr) {
+    return target_csr->read();
+  }
+  return 0;
+}
+
+bool sscsrind_reg_csr_t::unlogged_write(const reg_t val) noexcept {
+  csr_t_p proxy_csr = get_reg();
+  if (proxy_csr != nullptr) {
+    proxy_csr->write(val);
+  }
+  return false;
+}
+
+// Returns the actual CSR that maps to value in *siselect or nullptr if no mapping exists
+csr_t_p sscsrind_reg_csr_t::get_reg() const noexcept {
+  auto proxy = ireg_proxy;
+  auto isel = iselect->read();
+  auto it = proxy.find(isel);
+  return it != proxy.end() ? it->second : nullptr;
+}
+
+void sscsrind_reg_csr_t::add_ireg_proxy(const reg_t iselect_value, csr_t_p csr) {
+  ireg_proxy[iselect_value] = csr;
+}