MTC packets provide finer grain timestamp information than TSC packets.
MTC packets record time using the hardware crystal clock (CTC) which is
related to TSC packets using a TMA packet.
This patch just adds decoder support.
Support for a default value and validation of values is provided by a
later patch. Also documentation is updated in a separate patch.
For details refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-21-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Record additional information in the AUXTRACE_INFO event in preparation
for decoding MTC and CYC packets. Pass the information to the decoder.
The AUXTRACE_INFO record can be extended by using the size to indicate
the presence of new members.
The additional information includes PMU config bit positions and the TSC
to CTC (hardware crystal clock) ratio needed to decode MTC packets.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-20-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
New features have been added to Intel PT which include a number of new
packet definitions.
This patch adds packet definitions for new packets: TMA, MTC, CYC, VMCS,
TRACESTOP and MNT. Also another bit in PIP is defined.
This patch only adds support for the definitions. Later patches add
support for decoding TMA, MTC, CYC and TRACESTOP which is where those
packets are explained.
VMCS and the newly defined bit in PIP are used with virtualization which
is not supported yet. MNT is a maintenance packet which the decoder
should ignore.
For details, refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-19-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The PSB packet is a synchronization packet that provides a starting
point for decoding or recovery from errors.
This patch adds support for a new Intel PT feature that allows the
frequency of PSB packets to be specified.
Support for this feature is indicated by
/sys/bus/event_source/devices/intel_pt/caps/psb_cyc which contains "1"
if the feature is supported and "0" otherwise.
The PSB period can be specified as a PMU config term e.g. perf record -e
intel_pt/psb_period=2/u sleep 1
The default value is 3 or the nearest lower value that is supported. 0
is always supported.
Valid values are given by:
/sys/bus/event_source/devices/intel_pt/caps/psb_periods
which contains a hexadecimal value, the bits of which represent valid
values e.g. bit 2 set means value 2 is valid.
The value is converted to the approximate number of trace bytes between
PSB packets as:
2 ^ (value + 11)
e.g. value 3 means 16KiB bytes between PSBs
If an invalid value is entered, the error message will give a list of
valid values e.g.
$ perf record -e intel_pt/psb_period=15/u uname
Invalid psb_period for intel_pt. Valid values are: 0-5
tools/perf/Documentation/intel-pt.txt is updated in a later patch as
there are a number of new features being added.
For more information about PSB periods refer to the Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace from June 2015 or
later.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-18-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
So that we can erase the progress bar after we're done with it, avoiding
things like:
-------------------------------------------------------------------
┌─Error:──────────────────────────────────────────────────────┐
│Can't annotate unmapped_area_topdown: │
│ │
│No vmlinux file with build id a826726b5ddacfab1f0bade868f1a79│
│was found in the path. │
│ │
│Note that annotation using /proc/kcore requires CAP_SYS_RAWIO│
┌Processin│ │──┐
│ │Please use: │ │
└─────────│ │──┘
│ perf buildid-cache -vu vmlinux │
│ │
│or: │
│ │
│ --vmlinux vmlinux │
│ │
│ │
│Press any key... │
└─────────────────────────────────────────────────────────────┘
Can't annotate unmapped_area_topdown:
-------------------------------------------------------------------
I.e. that finished progress bar behind the error window. It is not a
problem when we end up redrawing the whole screen, but its ugly when
we present such error windows, provide a TUI method so that code like
the above may avoid this situation, as will be done with the annotation
code in the next cset.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-qvktnojzwwe37pweging058t@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The 'annotate' tool does some filtering in the entries in a DSO but
forgot to reset the cache done in dso__find_symbol(), cauxing a SEGV:
[root@zoo ~]# perf annotate netlink_poll
perf: Segmentation fault
-------- backtrace --------
perf[0x526ceb]
/lib64/libc.so.6(+0x34960)[0x7faedfbe0960]
perf(rb_erase+0x223)[0x499d63]
perf[0x4213e9]
perf[0x4bc123]
perf[0x4bc621]
perf[0x4bf26b]
perf[0x4bc855]
perf(perf_session__process_events+0x340)[0x4bddc0]
perf(cmd_annotate+0x6bb)[0x421b5b]
perf[0x479063]
perf(main+0x60a)[0x42098a]
/lib64/libc.so.6(__libc_start_main+0xf0)[0x7faedfbcbfe0]
perf[0x420aa9]
[0x0]
[root@zoo ~]#
Fix it by reseting the find cache when removing symbols.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Fixes: b685ac22b4 ("perf symbols: Add front end cache for DSO symbol lookup")
Link: http://lkml.kernel.org/n/tip-b2y9x46y0t8yem1ive41zqyp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
A problem can occur in a statically linked perf when vmlinux can be found:
# perf probe --add sys_epoll_pwait
probe-definition(0): sys_epoll_pwait
symbol:sys_epoll_pwait file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
Looking at the vmlinux_path (7 entries long)
Using /lib/modules/4.2.0-rc1+/build/vmlinux for symbols
Open Debuginfo file: /lib/modules/4.2.0-rc1+/build/vmlinux
Try to find probe point from debuginfo.
Symbol sys_epoll_pwait address found : ffffffff8122bd40
Matched function: SyS_epoll_pwait
Failed to get call frame on 0xffffffff8122bd40
An error occurred in debuginfo analysis (-2).
Error: Failed to add events. Reason: No such file or directory (Code: -2)
The reason is caused by libdw that, if libdw is statically linked, it
can't load libebl_{arch}.so reliable.
In this case it is still possible to get the address from
/proc/kalksyms. However, perf tries that only when libdw returns
-EBADF.
This patch gives it another chance to utilize symbol table, even if
libdw returns an error code other than -EBADF.
After applying this patch:
# perf probe -nv --add sys_epoll_pwait
probe-definition(0): sys_epoll_pwait
symbol:sys_epoll_pwait file:(null) line:0 offset:0 return:0 lazy:(null)
0 arguments
Looking at the vmlinux_path (7 entries long)
Using /lib/modules/4.2.0-rc1+/build/vmlinux for symbols
Open Debuginfo file: /lib/modules/4.2.0-rc1+/build/vmlinux
Try to find probe point from debuginfo.
Symbol sys_epoll_pwait address found : ffffffff8122bd40
Matched function: SyS_epoll_pwait
Failed to get call frame on 0xffffffff8122bd40
An error occurred in debuginfo analysis (-2).
Trying to use symbols.
Opening /sys/kernel/debug/tracing/kprobe_events write=1
Added new event:
Writing event: p:probe/sys_epoll_pwait _text+2276672
probe:sys_epoll_pwait (on sys_epoll_pwait)
You can now use it in all perf tools, such as:
perf record -e probe:sys_epoll_pwait -aR sleep 1
Although libdw returns an error (Failed to get call frame), perf tries
symbol table and finally gets correct address.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1440151770-129878-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add a script to produce a call-graph from data exported to a postgresql
database and derived from a processor trace event like intel_pt or intel_bts.
Refer to comments in the scripts call-graph-from-postgresql.py and
export-to-postgresql.py for more details on how to set up the environment,
install the required packages, etc.
Committer note:
From the scripts, for convenience while reading 'git log':
An example of using this script with Intel PT:
$ perf record -e intel_pt//u ls
$ perf script -s ~/libexec/perf-core/scripts/python/export-to-postgresql.py pt_example branches calls
2015-05-29 12:49:23.464364 Creating database...
2015-05-29 12:49:26.281717 Writing to intermediate files...
2015-05-29 12:49:27.190383 Copying to database...
2015-05-29 12:49:28.140451 Removing intermediate files...
2015-05-29 12:49:28.147451 Adding primary keys
2015-05-29 12:49:28.655683 Adding foreign keys
2015-05-29 12:49:29.365350 Done
$ python tools/perf/scripts/python/call-graph-from-postgresql.py pt_example
# The result is a GUI window with a tree representing a context-sensitive
# call-graph. Expanding a couple of levels of the tree and adjusting column
# widths to suit will display something like:
Call Graph: pt_example
Call Path |Object |Count|Time(ns)|Time(%)|Branch Count|Branch Count(%)
v- ls
v- 2638:2638
v- _start ld-2.19.so 1 10074071 100.0 211135 100.0
|- unknown unknown 1 13198 0.1 1 0.0
>- _dl_start ld-2.19.so 1 1400980 13.9 19637 9.3
>- _d_linit_internal ld-2.19.so 1 448152 4.4 11094 5.3
v-__libc_start_main@plt ls 1 8211741 81.5 180397 85.4
>- _dl_fixup ld-2.19.so 1 7607 0.1 108 0.1
>- __cxa_atexit libc-2.19.so 1 11737 0.1 10 0.0
>- __libc_csu_init ls 1 10354 0.1 10 0.0
|- _setjmp libc-2.19.so 1 0 0.0 4 0.0
v- main ls 1 8182043 99.6 180254 99.9
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-11-git-send-email-adrian.hunter@intel.com
[ Added 'python-pyside qt-postgresql' to the yum cmdline installing required packages ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Running the following perf-stat command on an arm64 system produces the
following result...
[root@aarch64 ~]# perf stat -e kmem:mm_page_alloc -a sleep 1
Warning: [kmem:mm_page_alloc] function sizeof not defined
Warning: Error: expected type 4 but read 0
Segmentation fault
[root@aarch64 ~]#
The second warning was a result of the first warning not stopping
processing after it detected the issue.
That is, code that found the issue reported the first problem, but
because it did not exit out of the functions smoothly, it caused the
other warning to appear and not only that, it later caused the SIGSEGV.
Signed-off-by: Dean Nelson <dnelson@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20150820151632.13927.13791.email-sent-by-dnelson@teal
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Events that don't sample the timestamp have a timestamp value of -1.
Intel PT processing wasn't taking that into account.
This is particularly noticeable with Intel BTS because timestamps are
not requested by default.
Then, if the conversion of -1 to TSC results in a small number, the
processing is unaffected.
However if the conversion results in a big number, then the data is
processed prematurely before relevant sideband data like mmap events,
which in turn results in samples with unknown dsos.
Commiter note:
Since BTS wasn't upstream, I split the patch to fold the BTS part with
the patch introducing it, to avoid having this bug in the commit
history. PT was already upstream, so this patch contains that part.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1440060692-5585-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The "/proc/kcore requires CAP_SYS_RAWIO" message comes up all the time
for 'perf script' if vmlinux is not found and the user isn't root, even
when the kernel is not being traced and even though the message is only
really relevant for annotation.
Change it to pr_debug and instead put a note in the message displayed if
annotation is not possible.
Also, the file being accessed might not be /proc/kcore. Tools can be
directed to a different location using the --kallsyms option in which
case kcore is expected to be in the same directory. Adjust the message
so it is not misleading in that case.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Li Zhang <zhlcindy@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1440065260-8802-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Patch "perf script: Don't assume evsel position of tracking events"
changed 'perf script' to use 'perf_evlist__id2evsel()'. That results
in a segfault if there is more than 1 event and there are
synthesized mmap events e.g.
$ perf record -e cycles,instructions -p$$ sleep 1
$ perf script --show-mmap-events
Segmentation fault (core dumped)
That happens because these synthesized events have an 'id' of zero
which does not match any 'evsel'.
Currently, these synthesized events use the sample type of the first
evsel.
Change 'perf_evlist__id2evsel()' to reflect that which also makes
it consistent with 'perf_evlist__event2evsel()'.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: 06b234ec26 ("perf script: Don't assume evsel position of tracking events")
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1440059205-1765-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
- Fix buildid processing done at the end of a 'perf record' session, a
problem that happened in workloads involving lots of small short-lived
processes. That code was not asking the perf_session layer to order
the events.
Make the code more robust to handle some of the problems with such
out-of-order events and fix 'perf record' to ask for ordered events
on systems where we have perf_event_attr.sample_id_all. (Adrian Hunter)
- Show backtrace when handling a SIGSEGV in 'perf top --stdio' (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It was just freezing instead of informing about the SEGV, fix it and
also print a backtrace, just like in the TUI mode and in 'perf trace'.
Tested by provoking a NULL deref when pressing 'z':
0.31% libc-2.20.so [.] malloc_consolidate
0.31% ld-2.20.so [.] _dl_relocate_object
0.28% cc1 [.] ht_lookup
0.28% cc1 [.] ira_init_register_move_cost
perf: Segmentation fault
Obtained 7 stack frames.
perf(dump_stack+0x32) [0x4d69f2]
perf(sighandler_dump_stack+0x29) [0x4d6a89]
/lib64/libc.so.6(+0x34960) [0x7f5064333960]
perf() [0x438790]
/lib64/libpthread.so.0(+0x752a) [0x7f50663dd52a]
/lib64/libc.so.6(clone+0x6d) [0x7f50643ff22d]
#
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-pewrpzqd29rgmhu2wkk7fhww@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When processing a fork event, the tools lookup the parent thread by its
tid. In a couple of cases, it is possible for that thread to have the
wrong pid.
That can happen if the data is being processed out of order, or if the
(fork) event that would have removed the erroneous thread was lost.
Assume the latter case, print a dump message, remove the erroneous
thread, create a new one with the correct pid, and keep going.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1439994561-27436-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We currently register a platform device for e820 type-12 memory and
register a nvdimm bus beneath it. Registering the platform device
triggers the device-core machinery to probe for a driver, but that
search currently comes up empty. Building the nvdimm-bus registration
into the e820_pmem platform device registration in this way forces
libnvdimm to be built-in. Instead, convert the built-in portion of
CONFIG_X86_PMEM_LEGACY to simply register a platform device and move the
rest of the logic to the driver for e820_pmem, for the following
reasons:
1/ Letting e820_pmem support be a module allows building and testing
libnvdimm.ko changes without rebooting
2/ All the normal policy around modules can be applied to e820_pmem
(unbind to disable and/or blacklisting the module from loading by
default)
3/ Moving the driver to a generic location and converting it to scan
"iomem_resource" rather than "e820.map" means any other architecture can
take advantage of this simple nvdimm resource discovery mechanism by
registering a resource named "Persistent Memory (legacy)"
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Test PACKET_FANOUT_EBPF by inserting a program into the the kernel
with bpf(), then attaching it to the fanout group. Observe the same
payload-based distribution as in the PACKET_FANOUT_CBPF test.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Test PACKET_FANOUT_CBPF by inserting a cBPF program that selects a
socket by payload. Requires modifying the test program to send
packets with multiple payloads.
Also fix a bug in testing the return value of mmap()
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add support for Intel Processor Trace.
Intel PT support fits within the new auxtrace infrastructure. Recording
is supporting by identifying the Intel PT PMU, parsing options and
setting up events.
Decoding is supported by queuing up trace data by cpu or thread and then
decoding synchronously delivering synthesized event samples into the
session processing for tools to consume.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-7-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add support for decoding an Intel Processor Trace.
Intel PT trace data must be 'decoded' which involves walking the object
code and matching the trace data packets.
The decoder requests a buffer of binary data via a get_trace()
call-back, which it decodes using instruction information which it gets
via another call-back walk_insn().
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-6-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add support for decoding instructions for Intel Processor Trace. The
kernel x86 instruction decoder is copied for this.
This essentially provides intel_pt_get_insn() which takes a binary
buffer, uses the kernel's x86 instruction decoder to get details of the
instruction and then categorizes it for consumption by an Intel PT
decoder.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1439450095-30122-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix the following 32-bit compilation errors:
util/annotate.c: In function ‘addr_map_symbol__account_cycles’:
util/annotate.c:643:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘u64’ [-Werror=format=]
pr_debug2("BB with bad start: addr %lx start %lx sym %lx saddr %lx\n",
^
util/annotate.c:643:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 5 has type ‘u64’ [-Werror=format=]
util/annotate.c:643:3: error: format ‘%lx’ expects argument of type ‘long unsigned int’, but argument 6 has type ‘u64’ [-Werror=format=]
These were introduced by the patch:
"perf report: Add infrastructure for a cycles histogram"
Also change the 'saddr' variable from 'unsigned long' to 'u64'
noting that theoretically we could be processing data captured
on a 64-bit machine but processing it on a 32-bit machine.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: d4957633bf ("perf report: Add infrastructure for a cycles histogram")
Link: http://lkml.kernel.org/r/1439536294-18241-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We forgot to install the tempfile, so when the selftests are installed
and then run the subpage_prot_file test fails.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently if generic_buffer is invoked without first enabling any
channels in scan_elements/*_en, it will fail unable to enable the
buffer because bytes_per_datum inside the kernel will be zero if
no channels are available.
It is implied that the user of the program should enable channels
manually or with a script before executing generic_buffer.
Be more helpful by stopping execution if no enabled channels can
be found, and print a helptext that will tell you what is wrong
and what needs to be done.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This makes the event monitor bail out with a helpful error
message if a device does not support events, as a related
fix to iio core now makes it return -ENODEV properly.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Kill arch_memremap_pmem() and just let the architecture specify the
flags to be passed to memremap(). Default to writethrough by default.
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
