powerpc: add machine check safe copy_to_user

Use  memcpy_mcsafe() implementation to define copy_to_user_mcsafe()

Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820081352.8641-8-santosh@fossix.org

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9bc8ac5..78f5203 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -137,6 +137,7 @@ 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
+       select ARCH_HAS_UACCESS_MCSAFE          if PPC64
        select ARCH_HAS_UBSAN_SANITIZE_ALL
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select ARCH_KEEP_MEMBLOCK

diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 8b03eb4..15002b5 100644 (file)
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -387,6 +387,20 @@ 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))) {
+               if (access_ok(to, n)) {
+                       allow_write_to_user(to, n);
+                       n = memcpy_mcsafe((void *)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)