test

arch/x86_64/archctl.c

@@ -0,0 +1,18 @@
+#include <zinnia/errno.h>
+#include <uapi/archctl.h>
+#include <x86_64/asm.h>
+#include <x86_64/defs.h>
+
+errno_t arch_archctl(uintptr_t op, uintptr_t arg) {
+    switch (op) {
+    case __ARCHCTL_SET_FSBASE:
+        asm_wrmsr(MSR_FS_BASE, arg);
+        return 0;
+    case __ARCHCTL_SET_GSBASE:
+        // Update the inactive GSBASE MSR, not ours.
+        asm_wrmsr(MSR_KERNEL_GS_BASE, arg);
+        return 0;
+    default:
+        return EINVAL;
+    }
+}