x86: use non-set_fs based maccess routines

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.

[[email protected]: coding style fixes]

Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Christoph Hellwig authored and Linus Torvalds committed 2020-06-09 09:39:16 -07:00
1 parent b58294ead1
commit fa94111d94
1 file changed
+16
+16
View File
@@ -523,5 +523,21 @@ do { \
unsafe_copy_loop(__ucu_dst, __ucu_src, __ucu_len, u8, label); \
} while (0)
#define HAVE_GET_KERNEL_NOFAULT
#define __get_kernel_nofault(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 __put_kernel_nofault(dst, src, type, err_label) \
__put_user_size(*((type *)(src)), (__force type __user *)(dst), \
sizeof(type), err_label)
#endif /* _ASM_X86_UACCESS_H */