patch-2.4.8 linux/arch/cris/lib/csumcpfruser.S

• Lines: 65
• Date: Thu Jul 26 15:10:06 2001
• Orig file: v2.4.7/linux/arch/cris/lib/csumcpfruser.S
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.7/linux/arch/cris/lib/csumcpfruser.S linux/arch/cris/lib/csumcpfruser.S
@@ -0,0 +1,64 @@
+/*
+ * Add-on to transform csum_partial_copy_nocheck in checksumcopy.S into
+ * csum_partial_copy_from_user by adding exception records.
+ *
+ * Copyright (C) 2001 Axis Communications AB.
+ *
+ * Author: Hans-Peter Nilsson.
+ */
+
+#include <asm/errno.h>
+
+/* Same function body, but a different name.  If we just added exception
+   records to _csum_partial_copy_nocheck and made it generic, we wouldn't
+   know a user fault from a kernel fault and we would have overhead in
+   each kernel caller for the error-pointer argument.
+
+   unsigned int csum_partial_copy_from_user
+     (const char *src, char *dst, int len, unsigned int sum, int *errptr);
+
+   Note that the errptr argument is only set if we encounter an error.
+   It is conveniently located on the stack, so the normal function body
+   does not have to handle it.  */
+
+#define _csum_partial_copy_nocheck _csum_partial_copy_from_user
+
+/* There are local labels numbered 1, 2 and 3 present to mark the
+   different from-user accesses.  */
+#include "checksumcopy.S"
+
+	.section .fixup,"ax"
+
+;; Here from the movem loop; restore stack.
+4:
+	movem	[sp+],r8
+;; r12 is already decremented.  Add back chunk_size-2.
+	addq	40-2,r12
+
+;; Here from the word loop; r12 is off by 2; add it back.
+5:
+	addq	2,r12
+
+;; Here from a failing single byte.
+6:
+
+;; Signal in *errptr that we had a failing access.
+	moveq	-EFAULT,r9
+	move.d	r9,[[sp]]
+
+;; Clear the rest of the destination area using memset.  Preserve the
+;; checksum for the readable bytes.
+	push	srp
+	push	r13
+	move.d	r11,r10
+	clear.d	r11
+	jsr	_memset
+	pop	r10
+	jump	[sp+]
+
+	.previous
+	.section __ex_table,"a"
+	.dword 1b,4b
+	.dword 2b,5b
+	.dword 3b,6b
+	.previous