diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/kdump/kdump.rst | 8 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | Documentation/dev-tools/checkpatch.rst | 14 | ||||
| -rw-r--r-- | Documentation/process/coding-style.rst | 23 |
4 files changed, 44 insertions, 6 deletions
diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst index 0302a93b1d40..5376890adbeb 100644 --- a/Documentation/admin-guide/kdump/kdump.rst +++ b/Documentation/admin-guide/kdump/kdump.rst @@ -136,10 +136,6 @@ System kernel config options CONFIG_KEXEC_CORE=y - Subsequently, CRASH_CORE is selected by KEXEC_CORE:: - - CONFIG_CRASH_CORE=y - 2) Enable "sysfs file system support" in "Filesystem" -> "Pseudo filesystems." This is usually enabled by default:: @@ -168,6 +164,10 @@ Dump-capture kernel config options (Arch Independent) CONFIG_CRASH_DUMP=y + And this will select VMCORE_INFO and CRASH_RESERVE:: + CONFIG_VMCORE_INFO=y + CONFIG_CRASH_RESERVE=y + 2) Enable "/proc/vmcore support" under "Filesystems" -> "Pseudo filesystems":: CONFIG_PROC_VMCORE=y diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 90f79a285427..ef25e06ec08c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3787,10 +3787,12 @@ Format: [state][,regs][,debounce][,die] nmi_watchdog= [KNL,BUGS=X86] Debugging features for SMP kernels - Format: [panic,][nopanic,][num] + Format: [panic,][nopanic,][rNNN,][num] Valid num: 0 or 1 0 - turn hardlockup detector in nmi_watchdog off 1 - turn hardlockup detector in nmi_watchdog on + rNNN - configure the watchdog with raw perf event 0xNNN + When panic is specified, panic when an NMI watchdog timeout occurs (or 'nopanic' to not panic on an NMI watchdog, if CONFIG_BOOTPARAM_HARDLOCKUP_PANIC is set) @@ -7507,4 +7509,3 @@ memory, and other data can't be written using xmon commands. off xmon is disabled. - diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst index 127968995847..a9fac978a525 100644 --- a/Documentation/dev-tools/checkpatch.rst +++ b/Documentation/dev-tools/checkpatch.rst @@ -906,6 +906,20 @@ Macros, Attributes and Symbols See: https://lore.kernel.org/lkml/1399671106.2912.21.camel@joe-AO725/ + **MACRO_ARG_UNUSED** + If function-like macros do not utilize a parameter, it might result + in a build warning. We advocate for utilizing static inline functions + to replace such macros. + For example, for a macro such as the one below:: + + #define test(a) do { } while (0) + + there would be a warning like below:: + + WARNING: Argument 'a' is not used in function-like macro. + + See: https://www.kernel.org/doc/html/latest/process/coding-style.html#macros-enums-and-rtl + **SINGLE_STATEMENT_DO_WHILE_MACRO** For the multi-statement macros, it is necessary to use the do-while loop to avoid unpredictable code paths. The do-while loop helps to diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst index 9c7cf7347394..7e768c65aa92 100644 --- a/Documentation/process/coding-style.rst +++ b/Documentation/process/coding-style.rst @@ -827,6 +827,29 @@ Macros with multiple statements should be enclosed in a do - while block: do_this(b, c); \ } while (0) +Function-like macros with unused parameters should be replaced by static +inline functions to avoid the issue of unused variables: + +.. code-block:: c + + static inline void fun(struct foo *foo) + { + } + +Due to historical practices, many files still employ the "cast to (void)" +approach to evaluate parameters. However, this method is not advisable. +Inline functions address the issue of "expression with side effects +evaluated more than once", circumvent unused-variable problems, and +are generally better documented than macros for some reason. + +.. code-block:: c + + /* + * Avoid doing this whenever possible and instead opt for static + * inline functions + */ + #define macrofun(foo) do { (void) (foo); } while (0) + Things to avoid when using macros: 1) macros that affect control flow: |