Commit fa94111d authored Jun 08, 2020 by Christoph Hellwig Committed by Linus Torvalds Jun 09, 2020

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.

[akpm@linux-foundation.org: coding style fixes]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-20-hch@lst.de


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b58294ea

arch/x86/include/asm/uaccess.h

+16 −0

Original line number	Diff line number	Diff line
		@@ -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 */