From aa2854437330161176435730c743c5387a95037f Mon Sep 17 00:00:00 2001
From: Daniel Verkamp
Date: Fri, 15 Aug 2008 14:16:16 -0400
Subject: [librm] Add rm stack copying functions

---
 src/arch/i386/include/librm.h          |  3 +++
 src/arch/i386/transitions/librm_mgmt.c | 45 ++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100755 src/arch/i386/transitions/librm_mgmt.c

diff --git a/src/arch/i386/include/librm.h b/src/arch/i386/include/librm.h
index e9827de8..07a85c59 100755
--- a/src/arch/i386/include/librm.h
+++ b/src/arch/i386/include/librm.h
@@ -279,6 +279,9 @@ user_to_phys ( userptr_t buffer, off_t offset ) {
 	return virt_to_phys ( ( void * ) buffer + offset );
 }
 
+extern uint16_t copy_user_to_rm_stack ( userptr_t data, size_t size );
+extern void remove_user_from_rm_stack ( userptr_t data, size_t size );
+
 /* TEXT16_CODE: declare a fragment of code that resides in .text16 */
 #define TEXT16_CODE( asm_code_str )			\
 	".section \".text16\", \"ax\", @progbits\n\t"	\
diff --git a/src/arch/i386/transitions/librm_mgmt.c b/src/arch/i386/transitions/librm_mgmt.c
new file mode 100755
index 00000000..59b2eabc
--- /dev/null
+++ b/src/arch/i386/transitions/librm_mgmt.c
@@ -0,0 +1,45 @@
+/*
+ * librm: a library for interfacing to real-mode code
+ *
+ * Michael Brown <mbrown@fensystems.co.uk>
+ *
+ */
+
+#include <stdint.h>
+#include <librm.h>
+
+/*
+ * This file provides functions for managing librm.
+ *
+ */
+
+/**
+ * Allocate space on the real-mode stack and copy data there from a
+ * user buffer
+ *
+ * @v data			User buffer
+ * @v size			Size of stack data
+ * @ret sp			New value of real-mode stack pointer
+ */
+uint16_t copy_user_to_rm_stack ( userptr_t data, size_t size ) {
+	userptr_t rm_stack;
+	rm_sp -= size;
+	rm_stack = real_to_user ( rm_ss, rm_sp );
+	memcpy_user ( rm_stack, 0, data, 0, size );
+	return rm_sp;
+};
+
+/**
+ * Deallocate space on the real-mode stack, optionally copying back
+ * data to a user buffer.
+ *
+ * @v data			User buffer
+ * @v size			Size of stack data
+ */
+void remove_user_from_rm_stack ( userptr_t data, size_t size ) {
+	if ( data ) {
+		userptr_t rm_stack = real_to_user ( rm_ss, rm_sp );
+		memcpy_user ( rm_stack, 0, data, 0, size );
+	}
+	rm_sp += size;
+};
-- 
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