[PATCH v10 1/6] uaccess: add generic fallback version of copy_mc_to_user()

[Tong Tiangen]

x86/powerpc has it's implementation of copy_mc_to_user(), we add generic
fallback in include/linux/uaccess.h prepare for other architechures to
enable CONFIG_ARCH_HAS_COPY_MC.

Signed-off-by: Tong Tiangen <tongtiangen@xxxxxxxxxx>
Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
---
 arch/powerpc/include/asm/uaccess.h | 1 +
 arch/x86/include/asm/uaccess.h     | 1 +
 include/linux/uaccess.h            | 9 +++++++++
 3 files changed, 11 insertions(+)

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index f1f9890f50d3..4bfd1e6f0702 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -381,6 +381,7 @@ copy_mc_to_user(void __user *to, const void *from, unsigned long n)
 
 	return n;
 }
+#define copy_mc_to_user copy_mc_to_user
 #endif
 
 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 5c367c1290c3..fd56282ee9a8 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -497,6 +497,7 @@ copy_mc_to_kernel(void *to, const void *from, unsigned len);
 
 unsigned long __must_check
 copy_mc_to_user(void __user *to, const void *from, unsigned len);
+#define copy_mc_to_user copy_mc_to_user
 #endif
 
 /*
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 3064314f4832..550287c92990 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -205,6 +205,15 @@ copy_mc_to_kernel(void *dst, const void *src, size_t cnt)
 }
 #endif
 
+#ifndef copy_mc_to_user
+static inline unsigned long __must_check
+copy_mc_to_user(void *dst, const void *src, size_t cnt)
+{
+	check_object_size(src, cnt, true);
+	return raw_copy_to_user(dst, src, cnt);
+}
+#endif
+
 static __always_inline void pagefault_disabled_inc(void)
 {
 	current->pagefault_disabled++;
-- 
2.25.1