maccess: clarify kerneldoc comments (4f6de12b) · Commits · 戴 / test

mm/maccess.c

+43 −17

Original line number	Diff line number	Diff line
		@@ -31,29 +31,36 @@ probe_write_common(void __user dst, const void src, size_t size)
		}

		/**
		* probe_kernel_read(): safely attempt to read from a kernel-space location
		* probe_kernel_read(): safely attempt to read from any location
		* @dst: pointer to the buffer that shall take the data
		* @src: address to read from
		* @size: size of the data chunk
		*
		* Safely read from address @src to the buffer at @dst. If a kernel fault
		* happens, handle that and return -EFAULT.
		* Same as probe_kernel_read_strict() except that for architectures with
		* not fully separated user and kernel address spaces this function also works
		* for user address tanges.
		*
		* DO NOT USE THIS FUNCTION - it is broken on architectures with entirely
		* separate kernel and user address spaces, and also a bad idea otherwise.
		*/
		long __weak probe_kernel_read(void dst, const void src, size_t size)
		__attribute__((alias("__probe_kernel_read")));

		/**
		* probe_kernel_read_strict(): safely attempt to read from kernel-space
		* @dst: pointer to the buffer that shall take the data
		* @src: address to read from
		* @size: size of the data chunk
		*
		* Safely read from kernel address @src to the buffer at @dst. If a kernel
		* fault happens, handle that and return -EFAULT.
		*
		* We ensure that the copy_from_user is executed in atomic context so that
		* do_page_fault() doesn't attempt to take mmap_lock. This makes
		* probe_kernel_read() suitable for use within regions where the caller
		* already holds mmap_lock, or other locks which nest inside mmap_lock.
		*
		* probe_kernel_read_strict() is the same as probe_kernel_read() except for
		* the case where architectures have non-overlapping user and kernel address
		* ranges: probe_kernel_read_strict() will additionally return -EFAULT for
		* probing memory on a user address range where probe_user_read() is supposed
		* to be used instead.
		*/

		long __weak probe_kernel_read(void dst, const void src, size_t size)
		__attribute__((alias("__probe_kernel_read")));

		long __weak probe_kernel_read_strict(void dst, const void src, size_t size)
		__attribute__((alias("__probe_kernel_read")));

		@@ -154,15 +161,34 @@ EXPORT_SYMBOL_GPL(probe_user_write);
		* If @count is smaller than the length of the string, copies @count-1 bytes,
		* sets the last byte of @dst buffer to NUL and returns @count.
		*
		* strncpy_from_unsafe_strict() is the same as strncpy_from_unsafe() except
		* for the case where architectures have non-overlapping user and kernel address
		* ranges: strncpy_from_unsafe_strict() will additionally return -EFAULT for
		* probing memory on a user address range where strncpy_from_unsafe_user() is
		* supposed to be used instead.
		* Same as strncpy_from_unsafe_strict() except that for architectures with
		* not fully separated user and kernel address spaces this function also works
		* for user address tanges.
		*
		* DO NOT USE THIS FUNCTION - it is broken on architectures with entirely
		* separate kernel and user address spaces, and also a bad idea otherwise.
		*/
		long __weak strncpy_from_unsafe(char dst, const void unsafe_addr, long count)
		__attribute__((alias("__strncpy_from_unsafe")));

		/**
		* strncpy_from_unsafe_strict: - Copy a NUL terminated string from unsafe
		* address.
		* @dst: Destination address, in kernel space. This buffer must be at
		* least @count bytes long.
		* @unsafe_addr: Unsafe address.
		* @count: Maximum number of bytes to copy, including the trailing NUL.
		*
		* Copies a NUL-terminated string from unsafe address to kernel buffer.
		*
		* On success, returns the length of the string INCLUDING the trailing NUL.
		*
		* If access fails, returns -EFAULT (some data may have been copied
		* and the trailing NUL added).
		*
		* If @count is smaller than the length of the string, copies @count-1 bytes,
		* sets the last byte of @dst buffer to NUL and returns @count.
		*/
		long __weak strncpy_from_unsafe_strict(char dst, const void unsafe_addr,
		long count)
		__attribute__((alias("__strncpy_from_unsafe")));

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