Provide arch_kernel_read and arch_kernel_write routines to implement the
maccess routines without messing with set_fs and without stac/clac that
opens up access to user space.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/x86/include/asm/uaccess.h | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index d8f283b9a569c..765e18417b3ba 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -523,5 +523,21 @@ do { \
unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \
} while (0)
+#define HAVE_ARCH_PROBE_KERNEL
+
+#define arch_kernel_read(dst, src, type, err_label) \
+do { \
+ int __kr_err; \
+ \
+ __get_user_size(*((type *)dst), (__force type __user *)src, \
+ sizeof(type), __kr_err); \
+ if (unlikely(__kr_err)) \
+ goto err_label; \
+} while (0)
+
+#define arch_kernel_write(dst, src, type, err_label) \
+ __put_user_size(*((type *)(src)), (__force type __user *)(dst), \
+ sizeof(type), err_label)
+
#endif /* _ASM_X86_UACCESS_H */
--
2.26.2
