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>
2017-11-01 21:07:57 +07:00
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/* SPDX-License-Identifier: GPL-2.0 */
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2007-05-08 14:34:53 +07:00
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#ifndef _ARCH_POWERPC_LOCAL_H
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#define _ARCH_POWERPC_LOCAL_H
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powerpc/64s: Implement local_t using irq soft masking
local_t is used for atomic modifications for per-CPU data, versus
re-entrant modifications via interrupts.
local_t read-modify-write atomic operations are currently implemented
with hardware atomics (larx/stcx), which are quite slow. This patch
implements them by masking all types of interrupts that may do local_t
operations ("standard" and perf interrupts).
Rusty's benchmark (https://lkml.org/lkml/2008/12/16/450) gives the
following timings for the local_t test, in nanoseconds per iteration:
larx/stcx irq+pmu disable
_inc 38 10
_add 38 10
_read 4 4
_add_return 38 10
There are still some interrupt types (system reset, machine check, and
watchdog), which can not safely use local_t operations, because they
are not masked.
An alternative approach was proposed, using a CR bit to mark a critical
section, which is tested in the interrupt return path, and would then
branch to a fixup handler (similar to exception fixups), which re-starts
the operation. The problem with this was the complexity of the fixup
handler and the latency of the slow path.
https://lists.ozlabs.org/pipermail/linuxppc-dev/2014-November/123024.html
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-12-20 10:55:57 +07:00
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#ifdef CONFIG_PPC_BOOK3S_64
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#include <linux/percpu.h>
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#include <linux/atomic.h>
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#include <linux/irqflags.h>
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#include <asm/hw_irq.h>
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typedef struct
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{
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long v;
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} local_t;
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#define LOCAL_INIT(i) { (i) }
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static __inline__ long local_read(local_t *l)
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{
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return READ_ONCE(l->v);
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}
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static __inline__ void local_set(local_t *l, long i)
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{
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WRITE_ONCE(l->v, i);
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}
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#define LOCAL_OP(op, c_op) \
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static __inline__ void local_##op(long i, local_t *l) \
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{ \
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unsigned long flags; \
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\
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powerpc_local_irq_pmu_save(flags); \
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l->v c_op i; \
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powerpc_local_irq_pmu_restore(flags); \
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}
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#define LOCAL_OP_RETURN(op, c_op) \
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static __inline__ long local_##op##_return(long a, local_t *l) \
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{ \
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long t; \
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unsigned long flags; \
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\
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powerpc_local_irq_pmu_save(flags); \
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t = (l->v c_op a); \
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powerpc_local_irq_pmu_restore(flags); \
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\
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return t; \
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}
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#define LOCAL_OPS(op, c_op) \
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LOCAL_OP(op, c_op) \
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LOCAL_OP_RETURN(op, c_op)
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LOCAL_OPS(add, +=)
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LOCAL_OPS(sub, -=)
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#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)
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#define local_inc_return(l) local_add_return(1LL, l)
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#define local_inc(l) local_inc_return(l)
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/*
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* local_inc_and_test - increment and test
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* @l: pointer of type local_t
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*
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* Atomically increments @l by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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#define local_inc_and_test(l) (local_inc_return(l) == 0)
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#define local_dec_return(l) local_sub_return(1LL, l)
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#define local_dec(l) local_dec_return(l)
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#define local_sub_and_test(a, l) (local_sub_return((a), (l)) == 0)
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#define local_dec_and_test(l) (local_dec_return((l)) == 0)
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static __inline__ long local_cmpxchg(local_t *l, long o, long n)
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{
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long t;
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unsigned long flags;
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powerpc_local_irq_pmu_save(flags);
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t = l->v;
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if (t == o)
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l->v = n;
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powerpc_local_irq_pmu_restore(flags);
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return t;
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}
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static __inline__ long local_xchg(local_t *l, long n)
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{
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long t;
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unsigned long flags;
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powerpc_local_irq_pmu_save(flags);
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t = l->v;
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l->v = n;
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powerpc_local_irq_pmu_restore(flags);
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return t;
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}
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/**
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* local_add_unless - add unless the number is a given value
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* @l: pointer of type local_t
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* @a: the amount to add to v...
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* @u: ...unless v is equal to u.
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*
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* Atomically adds @a to @l, so long as it was not @u.
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* Returns non-zero if @l was not @u, and zero otherwise.
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*/
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static __inline__ int local_add_unless(local_t *l, long a, long u)
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{
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unsigned long flags;
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int ret = 0;
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powerpc_local_irq_pmu_save(flags);
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if (l->v != u) {
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l->v += a;
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ret = 1;
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}
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powerpc_local_irq_pmu_restore(flags);
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return ret;
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}
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#define local_inc_not_zero(l) local_add_unless((l), 1, 0)
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/* Use these for per-cpu local_t variables: on some archs they are
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* much more efficient than these naive implementations. Note they take
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* a variable, not an address.
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*/
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#define __local_inc(l) ((l)->v++)
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#define __local_dec(l) ((l)->v++)
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#define __local_add(i,l) ((l)->v+=(i))
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#define __local_sub(i,l) ((l)->v-=(i))
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#else /* CONFIG_PPC64 */
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2017-12-20 10:55:56 +07:00
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#include <asm-generic/local.h>
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2007-05-08 14:34:53 +07:00
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powerpc/64s: Implement local_t using irq soft masking
local_t is used for atomic modifications for per-CPU data, versus
re-entrant modifications via interrupts.
local_t read-modify-write atomic operations are currently implemented
with hardware atomics (larx/stcx), which are quite slow. This patch
implements them by masking all types of interrupts that may do local_t
operations ("standard" and perf interrupts).
Rusty's benchmark (https://lkml.org/lkml/2008/12/16/450) gives the
following timings for the local_t test, in nanoseconds per iteration:
larx/stcx irq+pmu disable
_inc 38 10
_add 38 10
_read 4 4
_add_return 38 10
There are still some interrupt types (system reset, machine check, and
watchdog), which can not safely use local_t operations, because they
are not masked.
An alternative approach was proposed, using a CR bit to mark a critical
section, which is tested in the interrupt return path, and would then
branch to a fixup handler (similar to exception fixups), which re-starts
the operation. The problem with this was the complexity of the fixup
handler and the latency of the slow path.
https://lists.ozlabs.org/pipermail/linuxppc-dev/2014-November/123024.html
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-12-20 10:55:57 +07:00
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#endif /* CONFIG_PPC64 */
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2007-05-08 14:34:53 +07:00
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#endif /* _ARCH_POWERPC_LOCAL_H */
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