[v5 6/6] powerpc: add machine check safe copy_to_user

From: Santosh Sivaraj
Date: Tue Jul 09 2019 - 08:16:17 EST


Use memcpy_mcsafe() implementation to define copy_to_user_mcsafe()

Signed-off-by: Santosh Sivaraj <santosh@xxxxxxxxxx>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/uaccess.h | 14 ++++++++++++++
2 files changed, 15 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..8899864a5552 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -386,6 +386,20 @@ 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)
--
2.20.1