During the work of KVM's dirty page logging optimization, we encountered
the need of copy_in_user() for 32-bit ppc and x86: these will be used for
manipulating dirty bitmaps in user space.
So we implement copy_in_user() for 32-bit with __copy_tofrom_user().
Signed-off-by: Takuya Yoshikawa <yoshikawa.tak...@oss.ntt.co.jp>
Signed-off-by: Fernando Luis Vazquez Cao <ferna...@oss.ntt.co.jp>
CC: Alexander Graf <ag...@suse.de>
CC: Benjamin Herrenschmidt <b...@kernel.crashing.org>
CC: Paul Mackerras <pau...@samba.org>
---
arch/powerpc/include/asm/uaccess.h | 17 +++++++++++++++++
1 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/uaccess.h
b/arch/powerpc/include/asm/uaccess.h
index bd0fb84..3a01ce8 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -359,6 +359,23 @@ static inline unsigned long copy_to_user(void __user *to,
return n;
}
+static inline unsigned long copy_in_user(void __user *to,
+ const void __user *from, unsigned long n)
+{
+ unsigned long over;
+
+ if (likely(access_ok(VERIFY_READ, from, n) &&
+ access_ok(VERIFY_WRITE, to, n)))
+ return __copy_tofrom_user(to, from, n);
+ if (((unsigned long)from < TASK_SIZE) ||
+ ((unsigned long)to < TASK_SIZE)) {
+ over = max((unsigned long)from, (unsigned long)to)
+ + n - TASK_SIZE;
+ return __copy_tofrom_user(to, from, n - over) + over;
+ }
+ return n;
+}
+
#else /* __powerpc64__ */
#define __copy_in_user(to, from, size) \
--
1.7.0.4
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