diff options
Diffstat (limited to 'Documentation/dev-tools')
| -rw-r--r-- | Documentation/dev-tools/coccinelle.rst | 55 | ||||
| -rw-r--r-- | Documentation/dev-tools/gcov.rst | 4 | ||||
| -rw-r--r-- | Documentation/dev-tools/kasan.rst | 10 | ||||
| -rw-r--r-- | Documentation/dev-tools/kcsan.rst | 3 | ||||
| -rw-r--r-- | Documentation/dev-tools/kgdb.rst | 18 | ||||
| -rw-r--r-- | Documentation/dev-tools/kmemleak.rst | 2 | ||||
| -rw-r--r-- | Documentation/dev-tools/kunit/kunit-tool.rst | 17 | ||||
| -rw-r--r-- | Documentation/dev-tools/kunit/start.rst | 2 | ||||
| -rw-r--r-- | Documentation/dev-tools/sparse.rst | 6 |
9 files changed, 59 insertions, 58 deletions
diff --git a/Documentation/dev-tools/coccinelle.rst b/Documentation/dev-tools/coccinelle.rst index 70274c3f5f5a..74c5e6aeeff5 100644 --- a/Documentation/dev-tools/coccinelle.rst +++ b/Documentation/dev-tools/coccinelle.rst @@ -85,7 +85,7 @@ Four basic modes are defined: ``patch``, ``report``, ``context``, and file:line:column-column: message - ``context`` highlights lines of interest and their context in a - diff-like style.Lines of interest are indicated with ``-``. + diff-like style. Lines of interest are indicated with ``-``. - ``org`` generates a report in the Org mode format of Emacs. @@ -119,7 +119,7 @@ For each semantic patch, a commit message is proposed. It gives a description of the problem being checked by the semantic patch, and includes a reference to Coccinelle. -As any static code analyzer, Coccinelle produces false +As with any static code analyzer, Coccinelle produces false positives. Thus, reports must be carefully checked, and patches reviewed. @@ -135,18 +135,18 @@ the parallelism, set the J= variable. For example, to run across 4 CPUs:: make coccicheck MODE=report J=4 -As of Coccinelle 1.0.2 Coccinelle uses Ocaml parmap for parallelization, +As of Coccinelle 1.0.2 Coccinelle uses Ocaml parmap for parallelization; if support for this is detected you will benefit from parmap parallelization. When parmap is enabled coccicheck will enable dynamic load balancing by using -``--chunksize 1`` argument, this ensures we keep feeding threads with work +``--chunksize 1`` argument. This ensures we keep feeding threads with work one by one, so that we avoid the situation where most work gets done by only a few threads. With dynamic load balancing, if a thread finishes early we keep feeding it more work. When parmap is enabled, if an error occurs in Coccinelle, this error -value is propagated back, the return value of the ``make coccicheck`` -captures this return value. +value is propagated back, and the return value of the ``make coccicheck`` +command captures this return value. Using Coccinelle with a single semantic patch --------------------------------------------- @@ -175,15 +175,22 @@ For example, to check drivers/net/wireless/ one may write:: make coccicheck M=drivers/net/wireless/ To apply Coccinelle on a file basis, instead of a directory basis, the -following command may be used:: +C variable is used by the makefile to select which files to work with. +This variable can be used to run scripts for the entire kernel, a +specific directory, or for a single file. - make C=1 CHECK="scripts/coccicheck" +For example, to check drivers/bluetooth/bfusb.c, the value 1 is +passed to the C variable to check files that make considers +need to be compiled.:: -To check only newly edited code, use the value 2 for the C flag, i.e.:: + make C=1 CHECK=scripts/coccicheck drivers/bluetooth/bfusb.o - make C=2 CHECK="scripts/coccicheck" +The value 2 is passed to the C variable to check files regardless of +whether they need to be compiled or not.:: -In these modes, which works on a file basis, there is no information + make C=2 CHECK=scripts/coccicheck drivers/bluetooth/bfusb.o + +In these modes, which work on a file basis, there is no information about semantic patches displayed, and no commit message proposed. This runs every semantic patch in scripts/coccinelle by default. The @@ -198,12 +205,12 @@ Debugging Coccinelle SmPL patches Using coccicheck is best as it provides in the spatch command line include options matching the options used when we compile the kernel. -You can learn what these options are by using V=1, you could then +You can learn what these options are by using V=1; you could then manually run Coccinelle with debug options added. Alternatively you can debug running Coccinelle against SmPL patches -by asking for stderr to be redirected to stderr, by default stderr -is redirected to /dev/null, if you'd like to capture stderr you +by asking for stderr to be redirected to stderr. By default stderr +is redirected to /dev/null; if you'd like to capture stderr you can specify the ``DEBUG_FILE="file.txt"`` option to coccicheck. For instance:: @@ -211,8 +218,8 @@ instance:: make coccicheck COCCI=scripts/coccinelle/free/kfree.cocci MODE=report DEBUG_FILE=cocci.err cat cocci.err -You can use SPFLAGS to add debugging flags, for instance you may want to -add both --profile --show-trying to SPFLAGS when debugging. For instance +You can use SPFLAGS to add debugging flags; for instance you may want to +add both --profile --show-trying to SPFLAGS when debugging. For example you may want to use:: rm -f err.log @@ -229,7 +236,7 @@ DEBUG_FILE support is only supported when using coccinelle >= 1.0.2. -------------------- Coccinelle supports reading .cocciconfig for default Coccinelle options that -should be used every time spatch is spawned, the order of precedence for +should be used every time spatch is spawned. The order of precedence for variables for .cocciconfig is as follows: - Your current user's home directory is processed first @@ -237,7 +244,7 @@ variables for .cocciconfig is as follows: - The directory provided with the --dir option is processed last, if used Since coccicheck runs through make, it naturally runs from the kernel -proper dir, as such the second rule above would be implied for picking up a +proper dir; as such the second rule above would be implied for picking up a .cocciconfig when using ``make coccicheck``. ``make coccicheck`` also supports using M= targets. If you do not supply @@ -260,13 +267,13 @@ If not using the kernel's coccicheck target, keep the above precedence order logic of .cocciconfig reading. If using the kernel's coccicheck target, override any of the kernel's .coccicheck's settings using SPFLAGS. -We help Coccinelle when used against Linux with a set of sensible defaults +We help Coccinelle when used against Linux with a set of sensible default options for Linux with our own Linux .cocciconfig. This hints to coccinelle -git can be used for ``git grep`` queries over coccigrep. A timeout of 200 +that git can be used for ``git grep`` queries over coccigrep. A timeout of 200 seconds should suffice for now. The options picked up by coccinelle when reading a .cocciconfig do not appear -as arguments to spatch processes running on your system, to confirm what +as arguments to spatch processes running on your system. To confirm what options will be used by Coccinelle run:: spatch --print-options-only @@ -290,7 +297,7 @@ given to it when options are in conflict. :: Coccinelle supports idutils as well but requires coccinelle >= 1.0.6. When no ID file is specified coccinelle assumes your ID database file -is in the file .id-utils.index on the top level of the kernel, coccinelle +is in the file .id-utils.index on the top level of the kernel. Coccinelle carries a script scripts/idutils_index.sh which creates the database with:: mkid -i C --output .id-utils.index @@ -317,7 +324,7 @@ SmPL patch specific options --------------------------- SmPL patches can have their own requirements for options passed -to Coccinelle. SmPL patch specific options can be provided by +to Coccinelle. SmPL patch-specific options can be provided by providing them at the top of the SmPL patch, for instance:: // Options: --no-includes --include-headers @@ -327,7 +334,7 @@ SmPL patch Coccinelle requirements As Coccinelle features get added some more advanced SmPL patches may require newer versions of Coccinelle. If an SmPL patch requires -at least a version of Coccinelle, this can be specified as follows, +a minimum version of Coccinelle, this can be specified as follows, as an example if requiring at least Coccinelle >= 1.0.5:: // Requires: 1.0.5 diff --git a/Documentation/dev-tools/gcov.rst b/Documentation/dev-tools/gcov.rst index 7bd013596217..9e989baae154 100644 --- a/Documentation/dev-tools/gcov.rst +++ b/Documentation/dev-tools/gcov.rst @@ -22,7 +22,7 @@ Possible uses: * minimizing kernel configurations (do I need this option if the associated code is never run?) -.. _gcov: http://gcc.gnu.org/onlinedocs/gcc/Gcov.html +.. _gcov: https://gcc.gnu.org/onlinedocs/gcc/Gcov.html .. _lcov: http://ltp.sourceforge.net/coverage/lcov.php @@ -171,7 +171,7 @@ Note on compilers GCC and LLVM gcov tools are not necessarily compatible. Use gcov_ to work with GCC-generated .gcno and .gcda files, and use llvm-cov_ for Clang. -.. _gcov: http://gcc.gnu.org/onlinedocs/gcc/Gcov.html +.. _gcov: https://gcc.gnu.org/onlinedocs/gcc/Gcov.html .. _llvm-cov: https://llvm.org/docs/CommandGuide/llvm-cov.html Build differences between GCC and Clang gcov are handled by Kconfig. It diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index c652d740735d..38fd5681fade 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -13,11 +13,8 @@ KASAN uses compile-time instrumentation to insert validity checks before every memory access, and therefore requires a compiler version that supports that. Generic KASAN is supported in both GCC and Clang. With GCC it requires version -4.9.2 or later for basic support and version 5.0 or later for detection of -out-of-bounds accesses for stack and global variables and for inline -instrumentation mode (see the Usage section). With Clang it requires version -7.0.0 or later and it doesn't support detection of out-of-bounds accesses for -global variables yet. +8.3.0 or later. With Clang it requires version 7.0.0 or later, but detection of +out-of-bounds accesses for global variables is only supported since Clang 11. Tag-based KASAN is only supported in Clang and requires version 7.0.0 or later. @@ -193,6 +190,9 @@ function calls GCC directly inserts the code to check the shadow memory. This option significantly enlarges kernel but it gives x1.1-x2 performance boost over outline instrumented kernel. +Generic KASAN prints up to 2 call_rcu() call stacks in reports, the last one +and the second to last. + Software tag-based KASAN ~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/Documentation/dev-tools/kcsan.rst b/Documentation/dev-tools/kcsan.rst index b38379f06194..be7a0b0e1f28 100644 --- a/Documentation/dev-tools/kcsan.rst +++ b/Documentation/dev-tools/kcsan.rst @@ -8,7 +8,8 @@ approach to detect races. KCSAN's primary purpose is to detect `data races`_. Usage ----- -KCSAN requires Clang version 11 or later. +KCSAN is supported by both GCC and Clang. With GCC we require version 11 or +later, and with Clang also require version 11 or later. To enable KCSAN configure the kernel with:: diff --git a/Documentation/dev-tools/kgdb.rst b/Documentation/dev-tools/kgdb.rst index 61293f40bc6e..c908ef4d3f04 100644 --- a/Documentation/dev-tools/kgdb.rst +++ b/Documentation/dev-tools/kgdb.rst @@ -316,7 +316,7 @@ driver as a loadable kernel module kgdbwait will not do anything. Kernel parameter: ``kgdbcon`` ----------------------------- -The ``kgdbcon`` feature allows you to see :c:func:`printk` messages inside gdb +The ``kgdbcon`` feature allows you to see printk() messages inside gdb while gdb is connected to the kernel. Kdb does not make use of the kgdbcon feature. @@ -432,7 +432,7 @@ This is a quick example of how to use kdb. ``ps`` Displays only the active processes ``ps A`` Shows all the processes ``summary`` Shows kernel version info and memory usage - ``bt`` Get a backtrace of the current process using :c:func:`dump_stack` + ``bt`` Get a backtrace of the current process using dump_stack() ``dmesg`` View the kernel syslog buffer ``go`` Continue the system =========== ================================================================= @@ -724,7 +724,7 @@ The kernel debugger is organized into a number of components: The arch-specific portion implements: - contains an arch-specific trap catcher which invokes - :c:func:`kgdb_handle_exception` to start kgdb about doing its work + kgdb_handle_exception() to start kgdb about doing its work - translation to and from gdb specific packet format to :c:type:`pt_regs` @@ -769,7 +769,7 @@ The kernel debugger is organized into a number of components: config. Later run ``modprobe kdb_hello`` and the next time you enter the kdb shell, you can run the ``hello`` command. - - The implementation for :c:func:`kdb_printf` which emits messages directly + - The implementation for kdb_printf() which emits messages directly to I/O drivers, bypassing the kernel log. - SW / HW breakpoint management for the kdb shell @@ -872,10 +872,10 @@ The kgdboc driver contains logic to configure communications with an attached keyboard. The keyboard infrastructure is only compiled into the kernel when ``CONFIG_KDB_KEYBOARD=y`` is set in the kernel configuration. -The core polled keyboard driver driver for PS/2 type keyboards is in +The core polled keyboard driver for PS/2 type keyboards is in ``drivers/char/kdb_keyboard.c``. This driver is hooked into the debug core when kgdboc populates the callback in the array called -:c:type:`kdb_poll_funcs[]`. The :c:func:`kdb_get_kbd_char` is the top-level +:c:type:`kdb_poll_funcs[]`. The kdb_get_kbd_char() is the top-level function which polls hardware for single character input. kgdboc and kms @@ -887,10 +887,10 @@ that you have a video driver which has a frame buffer console and atomic kernel mode setting support. Every time the kernel debugger is entered it calls -:c:func:`kgdboc_pre_exp_handler` which in turn calls :c:func:`con_debug_enter` +kgdboc_pre_exp_handler() which in turn calls con_debug_enter() in the virtual console layer. On resuming kernel execution, the kernel -debugger calls :c:func:`kgdboc_post_exp_handler` which in turn calls -:c:func:`con_debug_leave`. +debugger calls kgdboc_post_exp_handler() which in turn calls +con_debug_leave(). Any video driver that wants to be compatible with the kernel debugger and the atomic kms callbacks must implement the ``mode_set_base_atomic``, diff --git a/Documentation/dev-tools/kmemleak.rst b/Documentation/dev-tools/kmemleak.rst index fce262883984..a41a2d238af2 100644 --- a/Documentation/dev-tools/kmemleak.rst +++ b/Documentation/dev-tools/kmemleak.rst @@ -8,8 +8,6 @@ with the difference that the orphan objects are not freed but only reported via /sys/kernel/debug/kmemleak. A similar method is used by the Valgrind tool (``memcheck --leak-check``) to detect the memory leaks in user-space applications. -Kmemleak is supported on x86, arm, arm64, powerpc, sparc, sh, microblaze, mips, -s390, nds32, arc and xtensa. Usage ----- diff --git a/Documentation/dev-tools/kunit/kunit-tool.rst b/Documentation/dev-tools/kunit/kunit-tool.rst index 949af2da81e5..29ae2fee8123 100644 --- a/Documentation/dev-tools/kunit/kunit-tool.rst +++ b/Documentation/dev-tools/kunit/kunit-tool.rst @@ -19,13 +19,13 @@ compiles the kernel as a standalone Linux executable that can be run like any other program directly inside of a host operating system. To be clear, it does not require any virtualization support: it is just a regular program. -What is a kunitconfig? -====================== +What is a .kunitconfig? +======================= It's just a defconfig that kunit_tool looks for in the base directory. kunit_tool uses it to generate a .config as you might expect. In addition, it verifies that the generated .config contains the CONFIG options in the -kunitconfig; the reason it does this is so that it is easy to be sure that a +.kunitconfig; the reason it does this is so that it is easy to be sure that a CONFIG that enables a test actually ends up in the .config. How do I use kunit_tool? @@ -46,16 +46,9 @@ However, you most likely want to use it with the following options: - ``--timeout`` sets a maximum amount of time to allow tests to run. - ``--jobs`` sets the number of threads to use to build the kernel. -If you just want to use the defconfig that ships with the kernel, you can -append the ``--defconfig`` flag as well: - -.. code-block:: bash - - ./tools/testing/kunit/kunit.py run --timeout=30 --jobs=`nproc --all` --defconfig - .. note:: - This command is particularly helpful for getting started because it - just works. No kunitconfig needs to be present. + This command will work even without a .kunitconfig file: if no + .kunitconfig is present, a default one will be used instead. For a list of all the flags supported by kunit_tool, you can run: diff --git a/Documentation/dev-tools/kunit/start.rst b/Documentation/dev-tools/kunit/start.rst index bb112cf70624..d23385e3e159 100644 --- a/Documentation/dev-tools/kunit/start.rst +++ b/Documentation/dev-tools/kunit/start.rst @@ -18,7 +18,7 @@ The wrapper can be run with: .. code-block:: bash - ./tools/testing/kunit/kunit.py run --defconfig + ./tools/testing/kunit/kunit.py run For more information on this wrapper (also called kunit_tool) check out the :doc:`kunit-tool` page. diff --git a/Documentation/dev-tools/sparse.rst b/Documentation/dev-tools/sparse.rst index 6f4870528226..02102be7ff49 100644 --- a/Documentation/dev-tools/sparse.rst +++ b/Documentation/dev-tools/sparse.rst @@ -9,6 +9,8 @@ Sparse is a semantic checker for C programs; it can be used to find a number of potential problems with kernel code. See https://lwn.net/Articles/689907/ for an overview of sparse; this document contains some kernel-specific sparse information. +More information on sparse, mainly about its internals, can be found in +its official pages at https://sparse.docs.kernel.org. Using sparse for typechecking @@ -73,8 +75,8 @@ sparse would otherwise report a context imbalance. Getting sparse -------------- -You can get latest released versions from the Sparse homepage at -https://sparse.wiki.kernel.org/index.php/Main_Page +You can get tarballs of the latest released versions from: +https://www.kernel.org/pub/software/devel/sparse/dist/ Alternatively, you can get snapshots of the latest development version of sparse using git to clone:: |