Merged mcb30-realmode-redesign back to HEAD

src/arch/i386/transitions/librm_mgmt.c

@@ -0,0 +1,87 @@
+/*
+ * librm: a library for interfacing to real-mode code
+ *
+ * Michael Brown <mbrown@fensystems.co.uk>
+ *
+ */
+
+#ifdef KEEP_IT_REAL
+/* Build a null object under -DKEEP_IT_REAL */
+#else
+
+#include "stdint.h"
+#include "stddef.h"
+#include "string.h"
+#include "librm.h"
+
+/*
+ * This file provides functions for managing librm.
+ *
+ */
+
+/* Current location of librm in base memory */
+char *installed_librm = librm;
+
+/*
+ * Install librm to base memory
+ *
+ */
+void install_librm ( void *addr ) {
+	memcpy ( addr, librm, librm_size );
+	installed_librm = addr;
+}
+
+/*
+ * Increment lock count of librm
+ *
+ */
+void lock_librm ( void ) {
+	inst_librm_ref_count++;
+}
+
+/*
+ * Decrement lock count of librm
+ *
+ */
+void unlock_librm ( void ) {
+#ifdef DEBUG_LIBRM
+	if ( inst_librm_ref_count == 0 ) {
+		printf ( "librm: ref count gone negative\n" );
+		lockup();
+	}
+#endif
+	inst_librm_ref_count--;
+}
+
+/*
+ * Allocate space on the real-mode stack and copy data there.
+ *
+ */
+uint16_t copy_to_rm_stack ( void *data, size_t size ) {
+#ifdef DEBUG_LIBRM
+	if ( inst_rm_stack.offset <= size ) {
+		printf ( "librm: out of space in RM stack\n" );
+		lockup();
+	}
+#endif
+	inst_rm_stack.offset -= size;
+	copy_to_real ( inst_rm_stack.segment, inst_rm_stack.offset,
+		       data, size );
+	return inst_rm_stack.offset;
+};
+
+/*
+ * Deallocate space on the real-mode stack, optionally copying back
+ * data.
+ *
+ */
+void remove_from_rm_stack ( void *data, size_t size ) {
+	if ( data ) {
+		copy_from_real ( data,
+				 inst_rm_stack.segment, inst_rm_stack.offset,
+				 size );
+	}
+	inst_rm_stack.offset += size;
+};
+
+#endif /* KEEP_IT_REAL */