linux-toradex.git/kernel/kcsan/encoding.h, branch v6.9-rc4

kcsan: Add missing license and copyright headers

2021-03-08T22:27:43+00:00

Adds missing license and/or copyright headers for KCSAN source files.

Signed-off-by: Marco Elver 
Signed-off-by: Paul E. McKenney

kcsan: Fix encoding masks and regain address bit

2020-11-07T01:19:26+00:00

The watchpoint encoding masks for size and address were off-by-one bit
each, with the size mask using 1 unnecessary bit and the address mask
missing 1 bit. However, due to the way the size is shifted into the
encoded watchpoint, we were effectively wasting and never using the
extra bit.

For example, on x86 with PAGE_SIZE==4K, we have 1 bit for the is-write
bit, 14 bits for the size bits, and then 49 bits left for the address.
Prior to this fix we would end up with this usage:

	[ write<1> | size<14> | wasted<1> | address<48> ]

Fix it by subtracting 1 bit from the GENMASK() end and start ranges of
size and address respectively. The added static_assert()s verify that
the masks are as expected. With the fixed version, we get the expected
usage:

	[ write<1> | size<14> |             address<49> ]

Functionally no change is expected, since that extra address bit is
insignificant for enabled architectures.

Acked-by: Boqun Feng 
Signed-off-by: Marco Elver 
Signed-off-by: Paul E. McKenney

kcsan: Never set up watchpoints on NULL pointers

2020-11-03T01:08:51+00:00

Avoid setting up watchpoints on NULL pointers, as otherwise we would
crash inside the KCSAN runtime (when checking for value changes) instead
of the instrumented code.

Because that may be confusing, skip any address less than PAGE_SIZE.

Reviewed-by: Dmitry Vyukov 
Signed-off-by: Marco Elver 
Signed-off-by: Paul E. McKenney

kernel/: fix repeated words in comments

2020-10-16T18:11:19+00:00

Fix multiple occurrences of duplicated words in kernel/.

Fix one typo/spello on the same line as a duplicate word.  Change one
instance of "the the" to "that the".  Otherwise just drop one of the
repeated words.

Signed-off-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Link: https://lkml.kernel.org/r/98202fa6-8919-ef63-9efe-c0fad5ca7af1@infradead.org
Signed-off-by: Linus Torvalds

kcsan: Prefer __always_inline for fast-path

2020-03-21T08:40:19+00:00

Prefer __always_inline for fast-path functions that are called outside
of user_access_save, to avoid generating UACCESS warnings when
optimizing for size (CC_OPTIMIZE_FOR_SIZE). It will also avoid future
surprises with compiler versions that change the inlining heuristic even
when optimizing for performance.

Reported-by: Randy Dunlap 
Acked-by: Randy Dunlap  # build-tested
Signed-off-by: Marco Elver 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Ingo Molnar 
Link: http://lkml.kernel.org/r/58708908-84a0-0a81-a836-ad97e33dbb62@infradead.org

kcsan: Improve various small stylistic details

2019-11-20T09:47:23+00:00

Tidy up a few bits:

  - Fix typos and grammar, improve wording.

  - Remove spurious newlines that are col80 warning artifacts where the
    resulting line-break is worse than the disease it's curing.

  - Use core kernel coding style to improve readability and reduce
    spurious code pattern variations.

  - Use better vertical alignment for structure definitions and initialization
    sequences.

  - Misc other small details.

No change in functionality intended.

Cc: linux-kernel@vger.kernel.org
Cc: Marco Elver 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Cc: Thomas Gleixner 
Cc: Paul E. McKenney 
Cc: Will Deacon 
Signed-off-by: Ingo Molnar

kcsan: Add Kernel Concurrency Sanitizer infrastructure

2019-11-16T15:23:13+00:00

Kernel Concurrency Sanitizer (KCSAN) is a dynamic data-race detector for
kernel space. KCSAN is a sampling watchpoint-based data-race detector.
See the included Documentation/dev-tools/kcsan.rst for more details.

This patch adds basic infrastructure, but does not yet enable KCSAN for
any architecture.

Signed-off-by: Marco Elver 
Acked-by: Paul E. McKenney 
Signed-off-by: Paul E. McKenney