From ed1b52e6643f025d747027dec22ef036f0bd20a0 Mon Sep 17 00:00:00 2001
From: Paul Mundt <lethal@linux-sh.org>
Date: Fri, 11 Jan 2008 13:18:16 +0900
Subject: [PATCH] --- yaml --- r: 75385 b: refs/heads/master c:
 d7587b1445c0087cfcaa03ceae79b52eef4e9e4b h: refs/heads/master i:   75383:
 0e9c5a37f7dcac396d14f8fac64219511ff43e3a v: v3

---
 [refs]                         |  2 +-
 trunk/include/asm-sh/uaccess.h | 42 ++++++++++++----------------------
 2 files changed, 16 insertions(+), 28 deletions(-)

diff --git a/[refs] b/[refs]
index b47af9383259..978e049eb3ba 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 844b43adba74d97f15e56b103c97bfcccaa01aa6
+refs/heads/master: d7587b1445c0087cfcaa03ceae79b52eef4e9e4b
diff --git a/trunk/include/asm-sh/uaccess.h b/trunk/include/asm-sh/uaccess.h
index f18a1a5c95c0..77c391fa93d6 100644
--- a/trunk/include/asm-sh/uaccess.h
+++ b/trunk/include/asm-sh/uaccess.h
@@ -73,38 +73,26 @@ static inline int __access_ok(unsigned long addr, unsigned long size)
 /*
  * __access_ok: Check if address with size is OK or not.
  *
- * We do three checks:
- * (1) is it user space?
- * (2) addr + size --> carry?
- * (3) addr + size >= 0x80000000  (PAGE_OFFSET)
+ * Uhhuh, this needs 33-bit arithmetic. We have a carry..
  *
- * (1) (2) (3) | RESULT
- *  0   0   0  |  ok
- *  0   0   1  |  ok
- *  0   1   0  |  bad
- *  0   1   1  |  bad
- *  1   0   0  |  ok
- *  1   0   1  |  bad
- *  1   1   0  |  bad
- *  1   1   1  |  bad
+ * sum := addr + size;  carry? --> flag = true;
+ * if (sum >= addr_limit) flag = true;
  */
 static inline int __access_ok(unsigned long addr, unsigned long size)
 {
-	unsigned long flag, tmp;
-
-	__asm__("stc	r7_bank, %0\n\t"
-		"mov.l	@(8,%0), %0\n\t"
-		"clrt\n\t"
-		"addc	%2, %1\n\t"
-		"and	%1, %0\n\t"
-		"rotcl	%0\n\t"
-		"rotcl	%0\n\t"
-		"and	#3, %0"
-		: "=&z" (flag), "=r" (tmp)
-		: "r" (addr), "1" (size)
-		: "t");
-
+	unsigned long flag, sum;
+
+	__asm__("clrt\n\t"
+		"addc	%3, %1\n\t"
+		"movt	%0\n\t"
+		"cmp/hi	%4, %1\n\t"
+		"rotcl	%0"
+		:"=&r" (flag), "=r" (sum)
+		:"1" (addr), "r" (size),
+		 "r" (current_thread_info()->addr_limit.seg)
+		:"t");
 	return flag == 0;
+
 }
 #endif /* CONFIG_MMU */