1 files changed, 79 insertions, 0 deletions
diff --git a/machine/unprivileged_memory.h b/machine/unprivileged_memory.h
new file mode 100644
index 0000000..d03cc5e
--- /dev/null
+++ b/machine/unprivileged_memory.h
@@ -0,0 +1,79 @@
+#ifndef _RISCV_MISALIGNED_H
+#define _RISCV_MISALIGNED_H
+
+#include "encoding.h"
+#include <stdint.h>
+
+#define DECLARE_UNPRIVILEGED_LOAD_FUNCTION(type, insn)              \
+  static inline type load_##type(const type* addr, uintptr_t mepc)  \
+  {                                                                 \
+    register uintptr_t __mepc asm ("a2") = mepc;                    \
+    register uintptr_t __mstatus asm ("a3");                        \
+    type val;                                                       \
+    asm ("csrrs %0, mstatus, %3\n"                                  \
+         #insn " %1, %2\n"                                          \
+         "csrw mstatus, %0"                                         \
+         : "+&r" (__mstatus), "=&r" (val)                           \
+         : "m" (*addr), "r" (MSTATUS_MPRV), "r" (__mepc));          \
+    return val;                                                     \
+  }
+
+#define DECLARE_UNPRIVILEGED_STORE_FUNCTION(type, insn)                 \
+  static inline void store_##type(type* addr, type val, uintptr_t mepc) \
+  {                                                                     \
+    register uintptr_t __mepc asm ("a2") = mepc;                        \
+    register uintptr_t __mstatus asm ("a3");                            \
+    asm volatile ("csrrs %0, mstatus, %3\n"                             \
+                  #insn " %1, %2\n"                                     \
+                  "csrw mstatus, %0"                                    \
+                  : "+&r" (__mstatus)                                   \
+                  : "r" (val), "m" (*addr), "r" (MSTATUS_MPRV),         \
+                    "r" (__mepc));                                      \
+  }
+
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(uint8_t, lbu)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(uint16_t, lhu)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(int8_t, lb)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(int16_t, lh)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(int32_t, lw)
+DECLARE_UNPRIVILEGED_STORE_FUNCTION(uint8_t, sb)
+DECLARE_UNPRIVILEGED_STORE_FUNCTION(uint16_t, sh)
+DECLARE_UNPRIVILEGED_STORE_FUNCTION(uint32_t, sw)
+#ifdef __riscv64
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(uint32_t, lwu)
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(uint64_t, ld)
+DECLARE_UNPRIVILEGED_STORE_FUNCTION(uint64_t, sd)
+#else
+DECLARE_UNPRIVILEGED_LOAD_FUNCTION(uint32_t, lw)
+#endif
+
+static uint32_t __attribute__((always_inline)) get_insn(uintptr_t mepc, uintptr_t* mstatus)
+{
+  register uintptr_t __mepc asm ("a2") = mepc;
+  register uintptr_t __mstatus asm ("a3");
+  uint32_t val;
+#ifndef __riscv_compressed
+  asm ("csrrs %[mstatus], mstatus, %[mprv]\n"
+       "lw %[insn], (%[addr])\n"
+       "csrw mstatus, %[mstatus]"
+       : [mstatus] "+&r" (__mstatus), [insn] "=&r" (val)
+       : [mprv] "r" (MSTATUS_MPRV), [addr] "r" (__mepc));
+#else
+  uintptr_t rvc_mask = 3, tmp;
+  asm ("csrrs %[mstatus], mstatus, %[mprv]\n"
+       "lhu %[insn], (%[addr])\n"
+       "and %[tmp], %[insn], %[rvc_mask]\n"
+       "bne %[tmp], %[rvc_mask], 1f\n"
+       "lh %[tmp], 2(%[addr])\n"
+       "sll %[tmp], %[tmp], 16\n"
+       "add %[insn], %[insn], %[tmp]\n"
+       "1: csrw mstatus, %[mstatus]"
+       : [mstatus] "+&r" (__mstatus), [insn] "=&r" (val), [tmp] "=&r" (tmp)
+       : [mprv] "r" (MSTATUS_MPRV), [addr] "r" (__mepc),
+         [rvc_mask] "r" (rvc_mask));
+#endif
+  *mstatus = __mstatus;
+  return val;
+}
+
+#endif