Binary code patching on i386

This commit ports the infrastructure to do binary code patching from amd64.
The existing code patching for SMAP is converted to the new infrastruture.

ok kettenis@
"should go in" deraadt@

1 files changed, 52 insertions, 0 deletions

diff --git a/sys/arch/i386/include/codepatch.h b/sys/arch/i386/include/codepatch.h
new file mode 100644
index 00000000000..cf9ad7abaca
--- /dev/null
+++ b/sys/arch/i386/include/codepatch.h
@@ -0,0 +1,52 @@
+/*      $OpenBSD: codepatch.h,v 1.1 2015/04/19 06:27:17 sf Exp $    */
+/*
+ * Copyright (c) 2014-2015 Stefan Fritsch <sf@sfritsch.de>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef _MACHINE_CODEPATCH_H_
+#define _MACHINE_CODEPATCH_H_
+
+#include <machine/param.h>
+
+#ifndef _LOCORE
+
+void *codepatch_maprw(vaddr_t *nva, vaddr_t dest);
+void codepatch_unmaprw(vaddr_t nva);
+void codepatch_fill_nop(void *caddr, uint16_t len);
+void codepatch_nop(uint16_t tag);
+void codepatch_replace(uint16_t tag, void *code, size_t len);
+void codepatch_call(uint16_t tag, void *func);
+
+#endif /* !_LOCORE */
+
+/*
+ * Mark the start of some code snippet to be patched.
+ */
+#define	CODEPATCH_START	998:
+/*
+ * Mark the end of some code to be patched, and assign the given tag.
+ */
+#define	CODEPATCH_END(tag)			 \
+	999:					 \
+	.section .codepatch, "a"		;\
+	.int (998b - KERNBASE)			;\
+	.short (999b - 998b)			;\
+	.short tag				;\
+	.previous
+
+#define CPTAG_STAC		1
+#define CPTAG_CLAC		2
+
+#endif /* _MACHINE_CODEPATCH_H_ */