Implement csr_time according to RV32 (sysprog21#114)

Resolve CWE-468.
2011eric · Jul 22, 2023 · 0c81b9f · 0c81b9f
1 parent d35dcf2
commit 0c81b9f
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/src/emulate.c b/src/emulate.c
@@ -96,7 +96,9 @@ static inline void update_time(riscv_t *rv)
     struct timeval tv;
     rv_gettimeofday(&tv);
 
-    rv->csr_time = (uint64_t) tv.tv_sec * 1e6 + (uint32_t) tv.tv_usec;
+    uint64_t t = (uint64_t) tv.tv_sec * 1e6 + (uint32_t) tv.tv_usec;
+    rv->csr_time[0] = t & 0xFFFFFFFF;
+    rv->csr_time[1] = t >> 32;
 }
 
 #if RV32_HAS(Zicsr)
@@ -132,11 +134,11 @@ static uint32_t *csr_get_ptr(riscv_t *rv, uint32_t csr)
     /* TIME/TIMEH - very roughly about 1 ms per tick */
     case CSR_TIME: { /* Timer for RDTIME instruction */
         update_time(rv);
-        return (uint32_t *) (&rv->csr_time) + 0;
+        return &rv->csr_time[0];
     }
     case CSR_TIMEH: { /* Upper 32 bits of time */
         update_time(rv);
-        return (uint32_t *) (&rv->csr_time + 4);
+        return &rv->csr_time[1];
     }
     case CSR_INSTRET: /* Number of Instructions Retired Counter */
         /* Number of Instructions Retired Counter, just use cycle */

diff --git a/src/riscv_private.h b/src/riscv_private.h
@@ -102,7 +102,7 @@ struct riscv_internal {
 
     /* csr registers */
     uint64_t csr_cycle;
-    uint64_t csr_time;
+    uint32_t csr_time[2];
     uint32_t csr_mstatus;
     uint32_t csr_mtvec;
     uint32_t csr_misa;