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/linux-master/include/linux/
H A Drcupdate.hdiff 448e9f34 Fri Sep 08 14:36:01 MDT 2023 Frederic Weisbecker <frederic@kernel.org> rcu: Standardize explicit CPU-hotplug calls

rcu_report_dead() and rcutree_migrate_callbacks() have their headers in
rcupdate.h while those are pure rcutree calls, like the other CPU-hotplug
functions.

Also rcu_cpu_starting() and rcu_report_dead() have different naming
conventions while they mirror each other's effects.

Fix the headers and propose a naming that relates both functions and
aligns with the prefix of other rcutree CPU-hotplug functions.

Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
diff 7e3f926b Wed Feb 01 08:09:54 MST 2023 Uladzislau Rezki (Sony) <urezki@gmail.com> rcu/kvfree: Eliminate k[v]free_rcu() single argument macro

The kvfree_rcu() and kfree_rcu() APIs are hazardous in that if you forget
the second argument, it works, but might sleep. This sleeping can be a
correctness bug from atomic contexts, and even in non-atomic contexts it
might introduce unacceptable latencies. This commit therefore removes the
single-argument kvfree_rcu() and kfree_rcu() macros. Code that would have
previously used these single-argument kvfree_rcu() and kfree_rcu() macros
should instead use kvfree_rcu_mightsleep() or kfree_rcu_mightsleep().

[ paulmck: Apply Joel Fernandes feedback. ]

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
diff ae65a521 Thu Mar 02 08:01:00 MST 2023 Vlastimil Babka <vbabka@suse.cz> mm/slab: document kfree() as allowed for kmem_cache_alloc() objects

This will make it easier to free objects in situations when they can
come from either kmalloc() or kmem_cache_alloc(), and also allow
kfree_rcu() for freeing objects from kmem_cache_alloc().

For the SLAB and SLUB allocators this was always possible so with SLOB
gone, we can document it as supported.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
diff 608723c4 Wed Feb 01 08:08:07 MST 2023 Uladzislau Rezki (Sony) <urezki@gmail.com> rcu/kvfree: Add kvfree_rcu_mightsleep() and kfree_rcu_mightsleep()

The kvfree_rcu() and kfree_rcu() APIs are hazardous in that if you forget
the second argument, it works, but might sleep. This sleeping can be a
correctness bug from atomic contexts, and even in non-atomic contexts
it might introduce unacceptable latencies. This commit therefore adds
kvfree_rcu_mightsleep() and kfree_rcu_mightsleep(), which will replace
the single-argument kvfree_rcu() and kfree_rcu(), respectively.

This commit enables a series of commits that switch from single-argument
kvfree_rcu() and kfree_rcu() to their _mightsleep() counterparts. Once
all of these commits land, the single-argument versions will be removed.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff 150154aa Wed Dec 01 02:20:53 MST 2021 Uladzislau Rezki (Sony) <urezki@gmail.com> rcu: Fix description of kvfree_rcu()

The kvfree_rcu() header comment's description of the "ptr" parameter
is unclear, therefore rephrase it to make it clear that it is a pointer
to the memory to eventually be passed to kvfree().

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff 1893afd6 Thu Apr 29 12:18:01 MDT 2021 Paul E. McKenney <paulmck@kernel.org> rcu: Improve comments describing RCU read-side critical sections

There are a number of places that call out the fact that preempt-disable
regions of code now act as RCU read-side critical sections, where
preempt-disable regions of code include irq-disable regions of code,
bh-disable regions of code, hardirq handlers, and NMI handlers. However,
someone relying solely on (for example) the call_rcu() header comment
might well have no idea that preempt-disable regions of code have RCU
semantics.

This commit therefore updates the header comments for
call_rcu(), synchronize_rcu(), rcu_dereference_bh_check(), and
rcu_dereference_sched_check() to call out these new(ish) forms of RCU
readers.

Reported-by: Michel Lespinasse <michel@lespinasse.org>
[ paulmck: Apply Matthew Wilcox and Michel Lespinasse feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff ba9e6cab Tue Mar 09 01:55:58 MST 2021 Thomas Gleixner <tglx@linutronix.de> rcu: Prevent false positive softirq warning on RT

Soft interrupt disabled sections can legitimately be preempted or schedule
out when blocking on a lock on RT enabled kernels so the RCU preempt check
warning has to be disabled for RT kernels.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210309085727.626304079@linutronix.de
diff 8b5bd67c Fri Nov 13 01:54:48 MST 2020 Paul E. McKenney <paulmck@kernel.org> srcu: Provide polling interfaces for Tiny SRCU grace periods

There is a need for a polling interface for SRCU grace
periods, so this commit supplies get_state_synchronize_srcu(),
start_poll_synchronize_srcu(), and poll_state_synchronize_srcu() for this
purpose. The first can be used if future grace periods are inevitable
(perhaps due to a later call_srcu() invocation), the second if future
grace periods might not otherwise happen, and the third to check if a
grace period has elapsed since the corresponding call to either of the
first two.

As with get_state_synchronize_rcu() and cond_synchronize_rcu(),
the return value from either get_state_synchronize_srcu() or
start_poll_synchronize_srcu() must be passed in to a later call to
poll_state_synchronize_srcu().

Link: https://lore.kernel.org/rcu/20201112201547.GF3365678@moria.home.lan/
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
[ paulmck: Add EXPORT_SYMBOL_GPL() per kernel test robot feedback. ]
[ paulmck: Apply feedback from Neeraj Upadhyay. ]
Link: https://lore.kernel.org/lkml/20201117004017.GA7444@paulmck-ThinkPad-P72/
Reviewed-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff 01b1d88b Fri Jul 26 15:19:38 MDT 2019 Thomas Gleixner <tglx@linutronix.de> rcu: Use CONFIG_PREEMPTION

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by
CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same
functionality which today depends on CONFIG_PREEMPT.

Switch the conditionals in RCU to use CONFIG_PREEMPTION.

That's the first step towards RCU on RT. The further tweaks are work in
progress. This neither touches the selftest bits which need a closer look
by Paul.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20190726212124.210156346@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff 4d232dfe Tue Jul 10 01:53:40 MDT 2018 Paul E. McKenney <paulmck@kernel.org> rcu: Remove !PREEMPT code from rcu_note_voluntary_context_switch()

Because RCU-tasks exists only in PREEMPT kernels and because RCU-sched
no longer exists in PREEMPT kernels, it is no longer necessary for the
rcu_note_voluntary_context_switch() macro to do anything for !PREEMPT
kernels. This commit therefore removes !PREEMPT-related code from
this macro, namely, the rcu_all_qs().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
/linux-master/kernel/
H A DMakefilediff 30f3bb09 Tue Nov 15 01:33:48 MST 2022 Zhen Lei <thunder.leizhen@huawei.com> kallsyms: Add self-test facility

Added test cases for basic functions and performance of functions
kallsyms_lookup_name(), kallsyms_on_each_symbol() and
kallsyms_on_each_match_symbol(). It also calculates the compression rate
of the kallsyms compression algorithm for the current symbol set.

The basic functions test begins by testing a set of symbols whose address
values are known. Then, traverse all symbol addresses and find the
corresponding symbol name based on the address. It's impossible to
determine whether these addresses are correct, but we can use the above
three functions along with the addresses to test each other. Due to the
traversal operation of kallsyms_on_each_symbol() is too slow, only 60
symbols can be tested in one second, so let it test on average once
every 128 symbols. The other two functions validate all symbols.

If the basic functions test is passed, print only performance test
results. If the test fails, print error information, but do not perform
subsequent performance tests.

Start self-test automatically after system startup if
CONFIG_KALLSYMS_SELFTEST=y.

Example of output content: (prefix 'kallsyms_selftest:' is omitted
start
---------------------------------------------------------
| nr_symbols | compressed size | original size | ratio(%) |
|---------------------------------------------------------|
| 107543 | 1357912 | 2407433 | 56.40 |
---------------------------------------------------------
kallsyms_lookup_name() looked up 107543 symbols
The time spent on each symbol is (ns): min=630, max=35295, avg=7353
kallsyms_on_each_symbol() traverse all: 11782628 ns
kallsyms_on_each_match_symbol() traverse all: 9261 ns
finish

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
diff 8fd4ddda Sun Mar 13 17:49:36 MDT 2022 Christophe Leroy <christophe.leroy@csgroup.eu> static_call: Don't make __static_call_return0 static

System.map shows that vmlinux contains several instances of
__static_call_return0():

c0004fc0 t __static_call_return0
c0011518 t __static_call_return0
c00d8160 t __static_call_return0

arch_static_call_transform() uses the middle one to check whether we are
setting a call to __static_call_return0 or not:

c0011520 <arch_static_call_transform>:
c0011520: 3d 20 c0 01 lis r9,-16383 <== r9 = 0xc001 << 16
c0011524: 39 29 15 18 addi r9,r9,5400 <== r9 += 0x1518
c0011528: 7c 05 48 00 cmpw r5,r9 <== r9 has value 0xc0011518 here

So if static_call_update() is called with one of the other instances of
__static_call_return0(), arch_static_call_transform() won't recognise it.

In order to work properly, global single instance of __static_call_return0() is required.

Fixes: 3f2a8fc4b15d ("static_call/x86: Add __static_call_return0()")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/30821468a0e7d28251954b578e5051dc09300d04.1647258493.git.christophe.leroy@csgroup.eu
diff b4e9c954 Mon Jun 01 17:42:40 MDT 2020 Al Viro <viro@zeniv.linux.org.uk> introduction of regset ->get() wrappers, switching ELF coredumps to those

Two new helpers: given a process and regset, dump into a buffer.
regset_get() takes a buffer and size, regset_get_alloc() takes size
and allocates a buffer.

Return value in both cases is the amount of data actually dumped in
case of success or -E... on error.

In both cases the size is capped by regset->n * regset->size, so
->get() is called with offset 0 and size no more than what regset
expects.

binfmt_elf.c callers of ->get() are switched to using those; the other
caller (copy_regset_to_user()) will need some preparations to switch.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff ad774086 Mon Dec 31 01:24:09 MST 2018 Masahiro Yamada <yamada.masahiro@socionext.com> kbuild: change filechk to surround the given command with { }

filechk_* rules often consist of multiple 'echo' lines. They must be
surrounded with { } or ( ) to work correctly. Otherwise, only the
string from the last 'echo' would be written into the target.

Let's take care of that in the 'filechk' in scripts/Kbuild.include
to clean up filechk_* rules.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff cf65a0f6 Tue Jun 12 11:01:45 MDT 2018 Christoph Hellwig <hch@lst.de> dma-mapping: move all DMA mapping code to kernel/dma

Currently the code is split over various files with dma- prefixes in the
lib/ and drives/base directories, and the number of files keeps growing.
Move them into a single directory to keep the code together and remove
the file name prefixes. To match the irq infrastructure this directory
is placed under the kernel/ directory.

Signed-off-by: Christoph Hellwig <hch@lst.de>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff d06505b2 Tue Nov 01 16:31:50 MDT 2016 Paul Bolle <pebolle@tiscali.nl> Remove last traces of ikconfig.h

The build system stopped generating ikconfig.h in v2.6.8. Remove an entry
for it in dontdiff. There's also a reference to it in a small comment.
Remove that comment too, as it is of little help in any case.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff f5bffecd Wed Jul 23 00:01:58 MDT 2014 Alexei Starovoitov <ast@kernel.org> net: filter: split filter.c into two files

BPF is used in several kernel components. This split creates logical boundary
between generic eBPF core and the rest

kernel/bpf/core.c: eBPF interpreter

net/core/filter.c: classic->eBPF converter, classic verifiers, socket filters

This patch only moves functions.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff 58edae3a Sat Feb 08 01:01:10 MST 2014 Andi Kleen <ak@linux.intel.com> lto: Disable LTO for sys_ni

The assembler alias code in cond_syscall does not work
when compiled for LTO. Just disable LTO for that file.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391846481-31491-6-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff 58edae3a Sat Feb 08 01:01:10 MST 2014 Andi Kleen <ak@linux.intel.com> lto: Disable LTO for sys_ni

The assembler alias code in cond_syscall does not work
when compiled for LTO. Just disable LTO for that file.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391846481-31491-6-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

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