[v3 6/7] powerpc: add machine check safe copy_to_user

[Santosh Sivaraj]

Use  memcpy_mcsafe() implementation to define copy_to_user_mcsafe()

Signed-off-by: Santosh Sivaraj <sant...@fossix.org>
---
 arch/powerpc/Kconfig               |  1 +
 arch/powerpc/include/asm/uaccess.h | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 8c1c636308c8..a173b392c272 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -134,6 +134,7 @@ config PPC
        select ARCH_HAS_STRICT_KERNEL_RWX       if ((PPC_BOOK3S_64 || PPC32) && 
!RELOCATABLE && !HIBERNATION)
        select ARCH_HAS_TICK_BROADCAST          if GENERIC_CLOCKEVENTS_BROADCAST
        select ARCH_HAS_UACCESS_FLUSHCACHE      if PPC64
+       select ARCH_HAS_UACCESS_MCSAFE          if PPC64
        select ARCH_HAS_UBSAN_SANITIZE_ALL
        select ARCH_HAS_ZONE_DEVICE             if PPC_BOOK3S_64
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/powerpc/include/asm/uaccess.h 
b/arch/powerpc/include/asm/uaccess.h
index 76f34346b642..f8fcaab4c5bc 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -386,6 +386,18 @@ static inline unsigned long raw_copy_to_user(void __user 
*to,
        return ret;
 }
 
+static __always_inline unsigned long __must_check
+copy_to_user_mcsafe(void __user *to, const void *from, unsigned long n)
+{
+       if (likely(check_copy_size(from, n, true))) {
+               allow_write_to_user(to, n);
+               n = memcpy_mcsafe(to, from, n);
+               prevent_write_to_user(to, n);
+       }
+
+       return n;
+}
+
 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 
 static inline unsigned long clear_user(void __user *addr, unsigned long size)
-- 
2.20.1