linux.git/arch/alpha/kernel/perf_event.c, branch v6.0

alpha: fix spelling mistakes

2021-07-26T05:33:04+00:00

Fix some spelling mistakes in comments:
delarations ==> declarations
softare ==> software
suffiently ==> sufficiently
requred ==> required
unaliged ==> unaligned

Signed-off-by: gushengxian 
Signed-off-by: Matt Turner

alpha: Use pr_warn instead of pr_warning

2019-10-18T08:26:32+00:00

As said in commit f2c2cbcc35d4 ("powerpc: Use pr_warn instead of
pr_warning"), removing pr_warning so all logging messages use a
consistent _warn style. Let's do it.

Link: http://lkml.kernel.org/r/20191018031850.48498-1-wangkefeng.wang@huawei.com
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Signed-off-by: Kefeng Wang 
Reviewed-by: Sergey Senozhatsky 
Signed-off-by: Petr Mladek

perf/core, arch/alpha: Strengthen exclusion checks with PERF_PMU_CAP_NO_EXCLUDE

2019-01-21T10:01:21+00:00

As the Alpha PMU doesn't support context exclusion let's advertise
the PERF_PMU_CAP_NO_EXCLUDE capability. This ensures that perf will
prevent us from handling events where any exclusion flags are set.
Let's also remove the now unnecessary check for exclusion flags.

This change means that __hw_perf_event_init will now also
indicate that it doesn't support exclude_host and exclude_guest and
will now implicitly return -EINVAL instead of -EPERM. This is likely
more desirable as -EPERM will result in a kernel.perf_event_paranoid
related warning from the perf userspace utility.

Signed-off-by: Andrew Murray 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Arnaldo Carvalho de Melo 
Cc: Benjamin Herrenschmidt 
Cc: Borislav Petkov 
Cc: Ivan Kokshaysky 
Cc: Linus Torvalds 
Cc: Mark Rutland 
Cc: Matt Turner 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Richard Henderson 
Cc: Russell King 
Cc: Sascha Hauer 
Cc: Shawn Guo 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: linux-arm-kernel@lists.infradead.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: robin.murphy@arm.com
Cc: suzuki.poulose@arm.com
Link: https://lkml.kernel.org/r/1547128414-50693-5-git-send-email-andrew.murray@arm.com
Signed-off-by: Ingo Molnar

perf: Fix sibling iteration

2018-03-16T19:44:12+00:00

Mark noticed that the change to sibling_list changed some iteration
semantics; because previously we used group_list as list entry,
sibling events would always have an empty sibling_list.

But because we now use sibling_list for both list head and list entry,
siblings will report as having siblings.

Fix this with a custom for_each_sibling_event() iterator.

Fixes: 8343aae66167 ("perf/core: Remove perf_event::group_entry")
Reported-by: Mark Rutland 
Suggested-by: Mark Rutland 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Thomas Gleixner 
Cc: vincent.weaver@maine.edu
Cc: alexander.shishkin@linux.intel.com
Cc: torvalds@linux-foundation.org
Cc: alexey.budankov@linux.intel.com
Cc: valery.cherepennikov@intel.com
Cc: eranian@google.com
Cc: acme@redhat.com
Cc: linux-tip-commits@vger.kernel.org
Cc: davidcc@google.com
Cc: kan.liang@intel.com
Cc: Dmitry.Prohorov@intel.com
Cc: jolsa@redhat.com
Link: https://lkml.kernel.org/r/20180315170129.GX4043@hirez.programming.kicks-ass.net

perf/core: Remove perf_event::group_entry

2018-03-12T14:28:49+00:00

Now that all the grouping is done with RB trees, we no longer need
group_entry and can replace the whole thing with sibling_list.

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Mark Rutland 
Cc: Alexander Shishkin 
Cc: Alexey Budankov 
Cc: Arnaldo Carvalho de Melo 
Cc: David Carrillo-Cisneros 
Cc: Dmitri Prokhorov 
Cc: Jiri Olsa 
Cc: Kan Liang 
Cc: Linus Torvalds 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Valery Cherepennikov 
Cc: Vince Weaver 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

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 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

alpha: Replace __get_cpu_var

2014-08-26T17:45:53+00:00

__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x).  This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.

Other use cases are for storing and retrieving data from the current
processors percpu area.  __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.

__get_cpu_var() is defined as :

#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))

__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.

this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.

This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset.  Thereby address calculations are avoided and less registers
are used when code is generated.

At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.

The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e.  using a global
register that may be set to the per cpu base.

Transformations done to __get_cpu_var()

1. Determine the address of the percpu instance of the current processor.

	DEFINE_PER_CPU(int, y);
	int *x = &__get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(&y);

2. Same as #1 but this time an array structure is involved.

	DEFINE_PER_CPU(int, y[20]);
	int *x = __get_cpu_var(y);

    Converts to

	int *x = this_cpu_ptr(y);

3. Retrieve the content of the current processors instance of a per cpu
variable.

	DEFINE_PER_CPU(int, y);
	int x = __get_cpu_var(y)

   Converts to

	int x = __this_cpu_read(y);

4. Retrieve the content of a percpu struct

	DEFINE_PER_CPU(struct mystruct, y);
	struct mystruct x = __get_cpu_var(y);

   Converts to

	memcpy(&x, this_cpu_ptr(&y), sizeof(x));

5. Assignment to a per cpu variable

	DEFINE_PER_CPU(int, y)
	__get_cpu_var(y) = x;

   Converts to

	__this_cpu_write(y, x);

6. Increment/Decrement etc of a per cpu variable

	DEFINE_PER_CPU(int, y);
	__get_cpu_var(y)++

   Converts to

	__this_cpu_inc(y)

CC: Ivan Kokshaysky 
Cc: Matt Turner 
Acked-by: Richard Henderson 
Signed-off-by: Christoph Lameter 
Signed-off-by: Tejun Heo

alpha: perf: fix out-of-bounds array access triggered from raw event

2013-11-17T00:37:10+00:00

Vince's perf fuzzer uncovered the following issue on Alpha:

Unable to handle kernel paging request at virtual address fffffbfe4e46a0e8
CPU 0 perf_fuzzer(1278): Oops 0
pc = []  ra = []  ps = 0007    Not tainted
pc is at alpha_perf_event_set_period+0x60/0xf0
ra is at alpha_pmu_enable+0x1a4/0x1c0
v0 = 0000000000000000  t0 = 00000000000fffff  t1 = fffffc007b3f5800
t2 = fffffbff275faa94  t3 = ffffffffc9b9bd89  t4 = fffffbfe4e46a098
t5 = 0000000000000020  t6 = fffffbfe4e46a0b8  t7 = fffffc007f4c8000
s0 = 0000000000000000  s1 = fffffc0001b0c018  s2 = fffffc0001b0c020
s3 = fffffc007b3f5800  s4 = 0000000000000001  s5 = ffffffffc9b9bd85
s6 = 0000000000000001
a0 = 0000000000000006  a1 = fffffc007b3f5908  a2 = fffffbfe4e46a098
a3 = 00000005000108c0  a4 = 0000000000000000  a5 = 0000000000000000
t8 = 0000000000000001  t9 = 0000000000000001  t10= 0000000027829f6f
t11= 0000000000000020  pv = fffffc000031fb60  at = fffffc0000950900
gp = fffffc0000940900  sp = fffffc007f4cbca8
Disabling lock debugging due to kernel taint
Trace:
[] alpha_pmu_enable+0x1a4/0x1c0
[] perf_pmu_enable+0x48/0x60
[] __perf_install_in_context+0x15c/0x230
[] remote_function+0x80/0xa0
[] __perf_install_in_context+0x0/0x230
[] smp_call_function_single+0x1b4/0x1d0
[] task_function_call+0x60/0x80
[] __perf_install_in_context+0x0/0x230
[] task_function_call+0x34/0x80
[] perf_install_in_context+0x9c/0x150
[] __perf_install_in_context+0x0/0x230
[] SYSC_perf_event_open+0x360/0xac0
[] entSys+0xa4/0xc0

This is due to the raw event encoding being used as an index directly
into the ev67_mapping array, rather than being validated against the
ev67_pmc_event_type enumeration instead. Unlike other architectures,
which allow raw events to propagate into the hardware counters with
little interference, the limited number of events on Alpha and the
strict event <-> counter relationships mean that raw events actually
correspond to the Linux-specific Alpha events, rather than anything
defined by the architecture.

This patch adds a new callback to alpha_pmu_t for validating the raw
event encoding with the Linux event types for the PMU, preventing the
out-of-bounds array access.

Cc: Peter Zijlstra 
Acked-by: Michael Cree 
Acked-by: Matt Turner 
Signed-off-by: Will Deacon

perf: Pass last sampling period to perf_sample_data_init()

2012-05-09T13:23:12+00:00

We always need to pass the last sample period to
perf_sample_data_init(), otherwise the event distribution will be
wrong. Thus, modifiyng the function interface with the required period
as argument. So basically a pattern like this:

        perf_sample_data_init(&data, ~0ULL);
        data.period = event->hw.last_period;

will now be like that:

        perf_sample_data_init(&data, ~0ULL, event->hw.last_period);

Avoids unininitialized data.period and simplifies code.

Signed-off-by: Robert Richter 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1333390758-10893-3-git-send-email-robert.richter@amd.com
Signed-off-by: Ingo Molnar

perf: Disable PERF_SAMPLE_BRANCH_* when not supported

2012-03-05T13:55:42+00:00

PERF_SAMPLE_BRANCH_* is disabled for:

 - SW events (sw counters, tracepoints)
 - HW breakpoints
 - ALL but Intel x86 architecture
 - AMD64 processors

Signed-off-by: Stephane Eranian 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1328826068-11713-10-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar