Enable vector unit if present (continuation of 77a5df5694)

machine/encoding.h

@@ -33,6 +33,7 @@
 #define SSTATUS_UPIE        0x00000010
 #define SSTATUS_SPIE        0x00000020
 #define SSTATUS_SPP         0x00000100
+#define SSTATUS_VS          0x01800000
 #define SSTATUS_FS          0x00006000
 #define SSTATUS_XS          0x00018000
 #define SSTATUS_SUM         0x00040000

machine/minit.c

@@ -23,13 +23,17 @@ void* kernel_end;
 
 static void mstatus_init()
 {
+  uintptr_t mstatus = 0;
+
   // Enable FPU
   if (supports_extension('F'))
-    write_csr(mstatus, MSTATUS_FS);
+    mstatus |= MSTATUS_FS;
 
   // Enable vector extension
   if (supports_extension('V'))
-    write_csr(mstatus, MSTATUS_VS);
+    mstatus |= MSTATUS_VS;
+
+  write_csr(mstatus, mstatus);
 
   // Enable user/supervisor use of perf counters
   if (supports_extension('S'))

pk/pk.c

@@ -187,7 +187,7 @@ void boot_loader(uintptr_t dtb)
   write_csr(stvec, &trap_entry);
   write_csr(sscratch, 0);
   write_csr(sie, 0);
-  set_csr(sstatus, SSTATUS_SUM | SSTATUS_FS);
+  set_csr(sstatus, SSTATUS_SUM | SSTATUS_FS | SSTATUS_VS);
 
   file_init();
   enter_supervisor_mode(rest_of_boot_loader, pk_vm_init(), 0);