The patch titled
Subject: maccess: clarify kerneldoc comments
has been removed from the -mm tree. Its filename was
maccess-clarify-kerneldoc-comments.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: maccess: clarify kerneldoc comments
Add proper kerneldoc comments for probe_kernel_read_strict and
probe_kernel_read strncpy_from_unsafe_strict and explain the different
versus the non-strict version.
Link: http://lkml.kernel.org/r/20200521152301.2587579-5-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/maccess.c | 60 +++++++++++++++++++++++++++++++++++--------------
1 file changed, 43 insertions(+), 17 deletions(-)
--- a/mm/maccess.c~maccess-clarify-kerneldoc-comments
+++ a/mm/maccess.c
@@ -31,29 +31,36 @@ probe_write_common(void __user *dst, con
}
/**
- * 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")));
_
Patches currently in -mm which might be from hch@xxxxxx are
amdgpu-a-null-mm-does-not-mean-a-thread-is-a-kthread.patch
kernel-move-use_mm-unuse_mm-to-kthreadc.patch
kernel-move-use_mm-unuse_mm-to-kthreadc-v2.patch
kernel-better-document-the-use_mm-unuse_mm-api-contract.patch
kernel-better-document-the-use_mm-unuse_mm-api-contract-v2.patch
kernel-set-user_ds-in-kthread_use_mm.patch
