1 files changed, 37 insertions, 0 deletions
diff --git a/task/umode_vma.c b/task/umode_vma.c
new file mode 100644
index 0000000..880e047
--- /dev/null
+++ b/task/umode_vma.c
@@ -0,0 +1,37 @@
+#include "umode_vma.h"
+#include "arch/processor.h"
+#include "api/errno.h"
+#include "print.h"
+
+__attribute__((naked))
+int
+_umode_vma_fail(void)
+{
+    __asm__ volatile(" \
+    movq %%rbp, %%rsp; \
+    popq %%rbp; \
+    mov $1, %%eax; \
+    retq":::);
+}
+
+int
+user_vma_read(void *dest, const void *src, size_t w)
+{
+    if((uintptr_t)src > USERLAND_MEMORY_LIMIT) return -EACCESS;
+
+    _exrtab_push((void*)_umode_vma_fail);
+    for(size_t i = 0; i < w; i++) ((char*)dest)[i] = ((const char*)src)[i];
+    _exrtab_pop();
+    return 0;
+}
+
+int
+user_vma_write(void *dest, const void *src, size_t w)
+{
+    if((uintptr_t)dest > USERLAND_MEMORY_LIMIT) return -EACCESS;
+    
+    _exrtab_push((void*)_umode_vma_fail);
+    for(size_t i = 0; i < w; i++) ((char*)dest)[i] = ((const char*)src)[i];
+    _exrtab_pop();
+    return 0;
+}