From 146db387c3a261d4a2e3a096f148570230ecab70 Mon Sep 17 00:00:00 2001
From: Tong Tiangen <tongtiangen@huawei.com>
Date: Wed, 17 Aug 2022 22:55:31 +0800
Subject: [PATCH] uaccess: add generic fallback version of copy_mc_to_user()

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5GB28
CVE: NA

-------------------------------

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@huawei.com>
---
 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 6b808bcdecd5..809e05ab4a14 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -388,6 +388,7 @@ 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
 
 #ifdef __powerpc64__
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index bb1430283c72..ba1439fc3b9a 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -447,6 +447,7 @@ copy_mc_to_kernel(void *to, const void *from, unsigned len);
 
 unsigned long __must_check
 copy_mc_to_user(void *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 c7c6e8b8344d..8e9f25c57230 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -224,6 +224,15 @@ 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++;
-- 
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