1 files changed, 92 insertions, 0 deletions
diff --git a/arch/tile/lib/memcpy_user_64.c b/arch/tile/lib/memcpy_user_64.c
new file mode 100644
index 00000000..37440caa
--- /dev/null
+++ b/arch/tile/lib/memcpy_user_64.c
@@ -0,0 +1,92 @@
+/*
+ * Copyright 2011 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * Do memcpy(), but trap and return "n" when a load or store faults.
+ *
+ * Note: this idiom only works when memcpy() compiles to a leaf function.
+ * Here leaf function not only means it does not have calls, but also
+ * requires no stack operations (sp, stack frame pointer) and no
+ * use of callee-saved registers, else "jrp lr" will be incorrect since
+ * unwinding stack frame is bypassed. Since memcpy() is not complex so
+ * these conditions are satisfied here, but we need to be careful when
+ * modifying this file. This is not a clean solution but is the best
+ * one so far.
+ *
+ * Also note that we are capturing "n" from the containing scope here.
+ */
+
+#define _ST(p, inst, v)						\
+	({							\
+		asm("1: " #inst " %0, %1;"			\
+		    ".pushsection .coldtext.memcpy,\"ax\";"	\
+		    "2: { move r0, %2; jrp lr };"		\
+		    ".section __ex_table,\"a\";"		\
+		    ".quad 1b, 2b;"				\
+		    ".popsection"				\
+		    : "=m" (*(p)) : "r" (v), "r" (n));		\
+	})
+
+#define _LD(p, inst)						\
+	({							\
+		unsigned long __v;				\
+		asm("1: " #inst " %0, %1;"			\
+		    ".pushsection .coldtext.memcpy,\"ax\";"	\
+		    "2: { move r0, %2; jrp lr };"		\
+		    ".section __ex_table,\"a\";"		\
+		    ".quad 1b, 2b;"				\
+		    ".popsection"				\
+		    : "=r" (__v) : "m" (*(p)), "r" (n));	\
+		__v;						\
+	})
+
+#define USERCOPY_FUNC __copy_to_user_inatomic
+#define ST1(p, v) _ST((p), st1, (v))
+#define ST2(p, v) _ST((p), st2, (v))
+#define ST4(p, v) _ST((p), st4, (v))
+#define ST8(p, v) _ST((p), st, (v))
+#define LD1 LD
+#define LD2 LD
+#define LD4 LD
+#define LD8 LD
+#include "memcpy_64.c"
+
+#define USERCOPY_FUNC __copy_from_user_inatomic
+#define ST1 ST
+#define ST2 ST
+#define ST4 ST
+#define ST8 ST
+#define LD1(p) _LD((p), ld1u)
+#define LD2(p) _LD((p), ld2u)
+#define LD4(p) _LD((p), ld4u)
+#define LD8(p) _LD((p), ld)
+#include "memcpy_64.c"
+
+#define USERCOPY_FUNC __copy_in_user_inatomic
+#define ST1(p, v) _ST((p), st1, (v))
+#define ST2(p, v) _ST((p), st2, (v))
+#define ST4(p, v) _ST((p), st4, (v))
+#define ST8(p, v) _ST((p), st, (v))
+#define LD1(p) _LD((p), ld1u)
+#define LD2(p) _LD((p), ld2u)
+#define LD4(p) _LD((p), ld4u)
+#define LD8(p) _LD((p), ld)
+#include "memcpy_64.c"
+
+unsigned long __copy_from_user_zeroing(void *to, const void __user *from,
+				       unsigned long n)
+{
+	unsigned long rc = __copy_from_user_inatomic(to, from, n);
+	if (unlikely(rc))
+		memset(to + n - rc, 0, rc);
+	return rc;
+}