linux-stable.git/include/linux/kernel.h, branch v6.18.33

tracing: move tracing declarations from kernel.h to a dedicated header

2026-05-23T11:06:49+00:00

[ Upstream commit bec261fec6d41318e414c4064f2b67c6db628acd ]

Tracing is a half of the kernel.h in terms of LOCs, although it's a
self-consistent part.  It is intended for quick debugging purposes and
isn't used by the normal tracing utilities.

Move it to a separate header.  If someone needs to just throw a
trace_printk() in their driver, they will not have to pull all the heavy
tracing machinery.

This is a pure move.

Link: https://lkml.kernel.org/r/20260116042510.241009-7-ynorov@nvidia.com
Signed-off-by: Yury Norov 
Acked-by: Steven Rostedt 
Reviewed-by: Andy Shevchenko 
Reviewed-by: Joel Fernandes 
Cc: Aaron Tomlin 
Cc: Andi Shyti 
Cc: Christophe Leroy (CS GROUP) 
Cc: Greg Kroah-Hartman 
Cc: Jani Nikula 
Cc: Petr Pavlu 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Stable-dep-of: 473e470f16f9 ("tracing: move __printf() attribute on __ftrace_vbprintk()")
Signed-off-by: Sasha Levin

tracing: remove size parameter in __trace_puts()

2026-05-23T11:06:49+00:00

[ Upstream commit 86e685ff364394b477cd1c476029480a2a1960c5 ]

The __trace_puts() function takes a string pointer and the size of the
string itself.  All users currently simply pass in the strlen() of the
string it is also passing in.  There's no reason to pass in the size.
Instead have the __trace_puts() function do the strlen() within the
function itself.

This fixes a header recursion issue where using strlen() in the macro
calling __trace_puts() requires adding #include  in order
to use strlen().  Removing the use of strlen() from the header fixes the
recursion issue.

Link: https://lore.kernel.org/all/aUN8Hm377C5A0ILX@yury/
Link: https://lkml.kernel.org/r/20260116042510.241009-6-ynorov@nvidia.com
Signed-off-by: Steven Rostedt (Google) 
Signed-off-by: Yury Norov 
Reviewed-by: Andy Shevchenko 
Reviewed-by: Joel Fernandes 
Cc: Aaron Tomlin 
Cc: Andi Shyti 
Cc: Christophe Leroy (CS GROUP) 
Cc: Greg Kroah-Hartman 
Cc: Jani Nikula 
Cc: Petr Pavlu 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Stable-dep-of: 473e470f16f9 ("tracing: move __printf() attribute on __ftrace_vbprintk()")
Signed-off-by: Sasha Levin

kernel.h: add comments for enum system_states

2025-09-14T00:32:55+00:00

Provide some basic comments about the system_states and what they imply. 
Also convert the comments to kernel-doc format.

Split the enum declaration from the definition of the system_state
variable so that kernel-doc notation works cleanly with it.  This is
picked up by Documentation/driver-api/basics.rst so it does not need
further inclusion in the kernel docbooks.

Link: https://lkml.kernel.org/r/20250907043857.2941203-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap 
Acked-by: Rafael J. Wysocki  # v1
Reviewed-by: Mauro Carvalho Chehab 	[v5]
Cc: "Brown, Len" 
Cc: Greg Kroah-Hartman 
Cc: James Bottomley 
Cc: Jani Nikula 
Cc: Jonathan Corbet 
Cc: Mauro Carvalho Chehab 
Cc: Pavel Machek 
Signed-off-by: Andrew Morton

tracing: Remove redundant config HAVE_FTRACE_MCOUNT_RECORD

2025-07-23T00:15:56+00:00

Ftrace is tightly coupled with architecture specific code because it
requires the use of trampolines written in assembly. This means that when
a new feature or optimization is made, it must be done for all
architectures. To simplify the approach, CONFIG_HAVE_FTRACE_* configs are
added to denote which architecture has the new enhancement so that other
architectures can still function until they too have been updated.

The CONFIG_HAVE_FTRACE_MCOUNT was added to help simplify the
DYNAMIC_FTRACE work, but now every architecture that implements
DYNAMIC_FTRACE also has HAVE_FTRACE_MCOUNT set too, making it redundant
with the HAVE_DYNAMIC_FTRACE.

Remove the HAVE_FTRACE_MCOUNT config and use DYNAMIC_FTRACE directly where
applicable.

Link: https://lore.kernel.org/all/20250703154916.48e3ada7@gandalf.local.home/

Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Cc: Mark Rutland 
Cc: Linus Torvalds 
Link: https://lore.kernel.org/20250704104838.27a18690@gandalf.local.home
Signed-off-by: Steven Rostedt (Google)

kernel.h: move PTR_IF() and u64_to_user_ptr() to util_macros.h

2025-05-12T00:54:06+00:00

While the natural choice of PTR_IF() is kconfig.h, the latter is too broad
to include C code and actually the macro was moved out from there in the
past.  But kernel.h is neither a good choice for that.  Move it to
util_macros.h.  Do the same for u64_to_user_ptr().

While moving, add necessary documentation.

Link: https://lkml.kernel.org/r/20250324105228.775784-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexandru Ardelean 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton

kernel.h: move READ/WRITE definitions to

2025-05-12T00:54:06+00:00

Patch series "kernel.h: Move out a couple of macros and constants".

kernel.h hosts a couple of macros and constants that may be better placed.
Do that.  Also add missing documentation.  No functional changes
intended.


This patch (of 2):

Headers shouldn't be forced to include  just to
gain these simple constants.

Link: https://lkml.kernel.org/r/20250324105228.775784-1-andriy.shevchenko@linux.intel.com
Link: https://lkml.kernel.org/r/20250324105228.775784-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Andy Shevchenko 
Cc: Alexandru Ardelean 
Signed-off-by: Andrew Morton

tracing: Support to dump instance traces by ftrace_dump_on_oops

2024-03-18T14:33:06+00:00

Currently ftrace only dumps the global trace buffer on an OOPs. For
debugging a production usecase, instance trace will be helpful to
check specific problems since global trace buffer may be used for
other purposes.

This patch extend the ftrace_dump_on_oops parameter to dump a specific
or multiple trace instances:

  - ftrace_dump_on_oops=0: as before -- don't dump
  - ftrace_dump_on_oops[=1]: as before -- dump the global trace buffer
  on all CPUs
  - ftrace_dump_on_oops=2 or =orig_cpu: as before -- dump the global
  trace buffer on CPU that triggered the oops
  - ftrace_dump_on_oops=: new behavior -- dump the
  tracing instance matching 
  - ftrace_dump_on_oops[=2/orig_cpu],[=2/orig_cpu],
  [=2/orig_cpu]: new behavior -- dump the global trace
  buffer and multiple instance buffer on all CPUs, or only dump on CPU
  that triggered the oops if =2 or =orig_cpu is given

Also, the sysctl node can handle the input accordingly.

Link: https://lore.kernel.org/linux-trace-kernel/20240223083126.1817731-1-quic_hyiwei@quicinc.com

Cc: Ross Zwisler 
Cc: 
Cc: 
Cc: 
Cc: 
Cc: 
Cc: 
Cc: 
Signed-off-by: Huang Yiwei 
Signed-off-by: Steven Rostedt (Google)

kernel.h: Move lib/cmdline.c prototypes to string.h

2024-02-29T21:38:03+00:00

The lib/cmdline.c is basically a set of some small string parsers
which are wide used in the kernel. Their prototypes belong to the
string.h rather then kernel.h.

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20231003130142.2936503-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Kees Cook

kernel.h: Move upper__bits() and lower__bits() to wordpart.h

2024-02-29T21:38:01+00:00

The wordpart.h header is collecting APIs related to the handling
parts of the word (usually in byte granularity). The upper_*_bits()
and lower_*_bits() are good candidates to be moved to there.

This helps to clean up header dependency hell with regard to kernel.h
as the latter gathers completely unrelated stuff together and slows
down compilation (especially when it's included into other header).

Signed-off-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20240214172752.3605073-1-andriy.shevchenko@linux.intel.com
Reviewed-by: Randy Dunlap 
Signed-off-by: Kees Cook

kernel.h: removed REPEAT_BYTE from kernel.h

2024-02-01T17:47:59+00:00

This patch creates wordpart.h and includes it in asm/word-at-a-time.h
for all architectures. WORD_AT_A_TIME_CONSTANTS depends on kernel.h
because of REPEAT_BYTE. Moving this to another header and including it
where necessary allows us to not include the bloated kernel.h. Making
this implicit dependency on REPEAT_BYTE explicit allows for later
improvements in the lib/string.c inclusion list.

Suggested-by: Al Viro 
Suggested-by: Andy Shevchenko 
Signed-off-by: Tanzir Hasan 
Reviewed-by: Andy Shevchenko 
Link: https://lore.kernel.org/r/20231226-libstringheader-v6-1-80aa08c7652c@google.com
Signed-off-by: Kees Cook