diff mbox

[v2,5/7] btrace, gdbserver: remove the to_supports_btrace target method

Message ID 1516976072-19282-6-git-send-email-markus.t.metzger@intel.com
State New
Headers show

Commit Message

Metzger, Markus T Jan. 26, 2018, 2:14 p.m. UTC
Remove the to_supports_btrace target method and instead rely on detecting errors
when trying to enable recording.  This will also provide a suitable error
message explaining why recording is not possible.

2018-01-26  Markus Metzger  <markus.t.metzger@intel.com>

gdb/
	* btrace.c (btrace_enable): Remove target_supports_btrace call.
	* nat/linux-btrace.c (perf_event_pt_event_type): Move.
	(kernel_supports_bts, kernel_supports_pt, linux_supports_bts)
	(linux_supports_pt, linux_supports_btrace): Remove.
	(linux_enable_bts): Call cpu_supports_bts.
	* nat/linux-btrace.h (linux_supports_btrace): Remove.
	* remote.c (remote_supports_btrace): Remove.
	(init_remote_ops): Remove remote_supports_btrace.
	* target-delegates.c: Regenerated.
	* target.c (target_supports_btrace): Remove.
	* target.h (target_ops) <to_supports_btrace>: Remove
	(target_supports_btrace): Remove.
	* x86-linux-nat.c (x86_linux_create_target): Remove
	linux_supports_btrace.

gdbserver/
	* linux-low.c (linux_target_ops): Remove linux_supports_btrace.
	* nto-low.c (nto_target_ops): Remove NULL for supports_btrace.
	* spu-low.c (spu_target_ops): Likewise.
	* win32-low.c (win32_target_ops): Likewise.
	* server.c (supported_btrace_packets): Report packets unconditionally.
	* target.h (target_ops) <supports_btrace>: Remove.
	(target_supports_btrace): Remove.
---
 gdb/btrace.c              |   3 -
 gdb/gdbserver/linux-low.c |   2 -
 gdb/gdbserver/nto-low.c   |   1 -
 gdb/gdbserver/server.c    |  25 +----
 gdb/gdbserver/spu-low.c   |   1 -
 gdb/gdbserver/target.h    |   7 --
 gdb/gdbserver/win32-low.c |   1 -
 gdb/nat/linux-btrace.c    | 273 ++++------------------------------------------
 gdb/nat/linux-btrace.h    |   3 -
 gdb/remote.c              |  32 ------
 gdb/target-delegates.c    |  33 ------
 gdb/target.c              |   8 --
 gdb/target.h              |   7 --
 gdb/x86-linux-nat.c       |   1 -
 14 files changed, 24 insertions(+), 373 deletions(-)

Comments

Maciej W. Rozycki Feb. 24, 2018, 4:31 p.m. UTC | #1
On Fri, 26 Jan 2018, Markus Metzger wrote:

> Remove the to_supports_btrace target method and instead rely on detecting errors
> when trying to enable recording.  This will also provide a suitable error
> message explaining why recording is not possible.

 Hmm, v3 of this change (apparently never posted), that is specifically 
commit de6242d30757 ("btrace, gdbserver: remove the to_supports_btrace 
target method"), has broken remote `mips-linux' target debugging 
completely, that is an attempt to make a remote connection fails in the 
initial handshake, e.g.:

Process .../gdb/testsuite/outputs/gdb.base/advance/advance created; pid = 25519
Listening on port 2346
target remote 1.2.3.4:2346
Remote debugging using 1.2.3.4:2346
Reading symbols from .../lib/ld.so.1...done.
0x77fc8de0 in __start () from .../lib/ld.so.1
Protocol error: qXfer:btrace-conf (read-btrace-conf) conflicting enabled responses.
(gdb) continue
The program is not being run.
(gdb) FAIL: gdb.base/advance.exp: can't run to main

See the attached RSP packet exchange log for details.  Please investigate.

  Maciej
Remote debugging using 1.2.3.4:2346
Sending packet: $qSupported:multiprocess+;swbreak+;hwbreak+;qRelocInsn+;fork-events+;vfork-events+;exec-events+;vContSupported+;QThreadEvents+;no-resumed+;xmlRegisters=i386#6a...Ack
Packet received: PacketSize=3fff;QPassSignals+;QProgramSignals+;QStartupWithShell+;QEnvironmentHexEncoded+;QEnvironmentReset+;QEnvironmentUnset+;QSetWorkingDir+;qXfer:libraries-svr4:read+;augmented-libraries-svr4-read+;qXfer:auxv:read+;qXfer:spu:read+;qXfer:spu:write+;qXfer:siginfo:read+;qXfer:siginfo:write+;qXfer:features:read+;QStartNoAckMode+;qXfer:osdata:read+;multiprocess+;fork-events+;vfork-events+;exec-events+;QNonStop+;QDisableRandomization+;qXfer:threads:read+;BreakpointCommands+;QAgent+;Qbtrace:bts+;Qbtrace-conf:b
Packet qSupported (supported-packets) is supported
Sending packet: $vMustReplyEmpty#3a...Ack
Packet received: 
Sending packet: $QStartNoAckMode#b0...Ack
Packet received: OK
Sending packet: $QProgramSignals:0;1;3;4;6;7;8;9;a;b;c;d;e;f;10;11;12;13;14;15;16;17;18;19;1a;1b;1c;1d;1e;1f;20;21;22;23;24;25;26;27;28;29;2a;2b;2c;2d;2e;2f;30;31;32;33;34;35;36;37;38;39;3a;3b;3c;3d;3e;3f;40;41;42;43;44;45;46;47;48;49;4a;4b;4c;4d;4e;4f;50;51;52;53;54;55;56;57;58;59;5a;5b;5c;5d;5e;5f;60;61;62;63;64;65;66;67;68;69;6a;6b;6c;6d;6e;6f;70;71;72;73;74;75;76;77;78;79;7a;7b;7c;7d;7e;7f;80;81;82;83;84;85;86;87;88;89;8a;8b;8c;8d;8e;8f;90;91;92;93;94;95;96;97;#75...Packet received: OK
Sending packet: $Hgp0.0#ad...Packet received: OK
Sending packet: $qXfer:features:read:target.xml:0,fff#7d...Packet received: l<?xml version="1.0"?>\n<!-- Copyright (C) 2012-2018 Free Software Foundation, Inc.\n\n     Copying and distribution of this file, with or without modification,\n     are permitted in any medium without royalty provided the copyright\n     notice and this notice are preserved.  -->\n\n<!DOCTYPE target SYSTEM "gdb-target.dtd">\n<target>\n  <architecture>mips</architecture>\n  <osabi>GNU/Linux</osabi>\n  <xi:include href="mips-cpu.xml"/>\n  <xi:include href="mips-cp0.xml"/>\n  <xi:include href="mips-fpu.xml"/>\n  <xi:inclu[14 bytes omitted]
Sending packet: $qXfer:features:read:mips-cpu.xml:0,fff#24...Packet received: l<?xml version="1.0"?>\n<!-- Copyright (C) 2007-2018 Free Software Foundation, Inc.\n\n     Copying and distribution of this file, with or without modification,\n     are permitted in any medium without royalty provided the copyright\n     notice and this notice are preserved.  -->\n\n<!DOCTYPE feature SYSTEM "gdb-target.dtd">\n<feature name="org.gnu.gdb.mips.cpu">\n  <reg name="r0" bitsize="32" regnum="0"/>\n  <reg name="r1" bitsize="32"/>\n  <reg name="r2" bitsize="32"/>\n  <reg name="r3" bitsize="32"/>\n  <reg name="[13 bytes omitted]
Sending packet: $qXfer:features:read:mips-cp0.xml:0,fff#df...Packet received: l<?xml version="1.0"?>\n<!-- Copyright (C) 2007-2018 Free Software Foundation, Inc.\n\n     Copying and distribution of this file, with or without modification,\n     are permitted in any medium without royalty provided the copyright\n     notice and this notice are preserved.  -->\n\n<!DOCTYPE feature SYSTEM "gdb-target.dtd">\n<feature name="org.gnu.gdb.mips.cp0">\n  <reg name="status" bitsize="32" regnum="32"/>\n  <reg name="badvaddr" bitsize="32" regnum="35"/>\n  <reg name="cause" bitsize="32" regnum="36"/>\n</featu[12 bytes omitted]
Sending packet: $qXfer:features:read:mips-fpu.xml:0,fff#27...Packet received: l<?xml version="1.0"?>\n<!-- Copyright (C) 2007-2018 Free Software Foundation, Inc.\n\n     Copying and distribution of this file, with or without modification,\n     are permitted in any medium without royalty provided the copyright\n     notice and this notice are preserved.  -->\n\n<!DOCTYPE feature SYSTEM "gdb-target.dtd">\n<feature name="org.gnu.gdb.mips.fpu">\n  <reg name="f0" bitsize="32" type="ieee_single" regnum="38"/>\n  <reg name="f1" bitsize="32" type="ieee_single"/>\n  <reg name="f2" bitsize="32" type="ie[11 bytes omitted]
Sending packet: $qXfer:features:read:mips-dsp.xml:0,fff#23...Packet received: l<?xml version="1.0"?>\n<!-- Copyright (C) 2012-2018 Free Software Foundation, Inc.\n\n     Copying and distribution of this file, with or without modification,\n     are permitted in any medium without royalty provided the copyright\n     notice and this notice are preserved.  -->\n\n<!DOCTYPE feature SYSTEM "gdb-target.dtd">\n<feature name="org.gnu.gdb.mips.dsp">\n  <reg name="hi1" bitsize="32" regnum="72"/>\n  <reg name="lo1" bitsize="32" regnum="73"/>\n  <reg name="hi2" bitsize="32" regnum="74"/>\n  <reg name="lo2"[12 bytes omitted]
Sending packet: $QNonStop:0#8c...Packet received: OK
Sending packet: $qTStatus#49...Packet received: 
Packet qTStatus (trace-status) is NOT supported
Sending packet: $?#3f...Packet received: T051d:d0baff7f;25:e08dfc77;thread:p6a61.6a61;core:0;
Sending packet: $qXfer:threads:read::0,fff#03...Packet received: l<threads>\n<thread id="p6a61.6a61" core="0" name="advance"/>\n</threads>\n
Sending packet: $qAttached:6a61#c7...Packet received: 0
Packet qAttached (query-attached) is supported
Sending packet: $Hc-1#09...Packet received: E01
Sending packet: $qOffsets#4b...Packet received: 
Sending packet: $qXfer:libraries-svr4:read::0,fff#91...Packet received: l<library-list-svr4 version="1.0"/>
Sending packet: $qXfer:auxv:read::0,1000#6b...Packet received: l!\000\000\000\000@ÿw\020\000\000\000\000\000\000\000\006\000\000\000\000@\000\000\021\000\000\000d\000\000\000\003\000\000\0004\000@\000\004\000\000\000 \000\000\000\005\000\000\000\t\000\000\000\a\000\000\000\000\200üw\b\000\000\000\000\000\000\000\t\000\000\000À\005@\000\013\000\000\000cy\000\000\f\000\000\000cy\000\000\r\000\000\000\204\003\000\000\016\000\000\000\204\003\000\000\027\000\000\000\000\000\000\000\031\000\000\000Ó»ÿ\177\037\000\000\000\221¿ÿ\177\017\000\000\000ã»ÿ\177\000\000\000\000\000\000\000\000[10 bytes omitted]
Sending packet: $vFile:setfs:0#bf...Packet received: F0
Packet vFile:setfs (hostio-setfs) is supported
Sending packet: $vFile:open:2f70726f632f32373233332f7461736b2f32373233332f6d617073,0,1c0#db...Packet received: F3
Packet vFile:open (hostio-open) is supported
readahead cache miss 251
Sending packet: $vFile:pread:3,3fff,0#96...Packet received: F33c;00400000-00404000 r-xp 00000000 00:1d 357628039  .../gdb/testsuite/outputs/gdb.base/advance/advance\n00410000-00414000 rwxp 00000000 00:1d 357628039  .../gdb/testsuite/outputs/gdb.base/advance/advance\n77fc8000-77fec000 r-xp 00000000 00:1d 3529929641  .../lib/ld-2.27.9000.so\n77ff0000-77ff4000 r--p 00000000 00:00 0   [3 bytes omitted]
Packet vFile:pread (hostio-pread) is supported
readahead cache miss 252
Sending packet: $vFile:pread:3,3fff,33c#2f...Packet received: F0;
Sending packet: $vFile:close:3#b3...Packet received: F0
Packet vFile:close (hostio-close) is supported
Sending packet: $qXfer:libraries-svr4:read::0,fff#91...Packet received: l<library-list-svr4 version="1.0"/>
Reading symbols from .../lib/ld.so.1...done.
Sending packet: $qSymbol::#5b...Packet received: qSymbol:6e70746c5f76657273696f6e
Packet qSymbol (symbol-lookup) is supported
Sending packet: $qSymbol::6e70746c5f76657273696f6e#4d...Packet received: OK
Sending packet: $m77fd9d40,4#06...Packet received: 0800e003
Sending packet: $m77ff4000,34#fe...Packet received: 7f454c4601010100000000000000000003000800010000009002000034000000c40b00000510007034002000070028000f000e00
Sending packet: $m77ff4034,e0#33...Packet received: 0300007018010000180100001801000018000000180000000400000008000000000000703001000030010000300100001800000018000000040000000400000001000000000000000000000000000000980a0000980a0000050000000000010002000000d0090000d0090000d0090000c0000000c00000000400000004000000040000004802000048020000480200003c0000003c000000040000000400000050e57464000000000000000000000000000000000000000000000000040000000000000000000000000000000000000000000000000000000000000004000000
Sending packet: $m77ff4000,1fff#fa...Packet received: 7f454c4601010100000000000000000003000800010000009002000034000000c40b00000510007034002000070028000f000e000300007018010000180100001801000018000000180000000400000008000000000000703001000030010000300100001800000018000000040000000400000001000000000000000000000000000000980a0000980a0000050000000000010002000000d0090000d0090000d0090000c0000000c00000000400000004000000040000004802000048020000480200003c0000003c000000040000000400000050e5746400000000000000000000000000000000000000000000000004000000000000000000000000000000
Sending packet: $m77ff5fff,1fff#9d...Packet received: 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Sending packet: $m77ff7ffe,2#6d...Packet received: 0000
Sending packet: $qSymbol::#5b...Packet received: qSymbol:6e70746c5f76657273696f6e
Sending packet: $qSymbol::6e70746c5f76657273696f6e#4d...Packet received: OK
Sending packet: $qXfer:threads:read::0,fff#03...Packet received: l<threads>\n<thread id="p6a61.6a61" core="0" name="advance"/>\n</threads>\n
Sending packet: $m77fc8de0,4#35...Packet received: 25c8e003
Sending packet: $m77fc8ddc,4#67...Packet received: 00000000
Sending packet: $m77fc8de0,4#35...Packet received: 25c8e003
Sending packet: $m77fc8ddc,4#67...Packet received: 00000000
Sending packet: $m77fc8de0,4#35...Packet received: 25c8e003
0x77fc8de0 in __start ()
   from .../lib/ld.so.1
Sending packet: $qSymbol::#5b...Packet received: qSymbol:6e70746c5f76657273696f6e
Sending packet: $qSymbol::6e70746c5f76657273696f6e#4d...Packet received: OK
Sending packet: $qXfer:btrace-conf:read::0,fff#5c...Packet received: 
Protocol error: qXfer:btrace-conf (read-btrace-conf) conflicting enabled responses.
Yao Qi Feb. 28, 2018, noon UTC | #2
"Maciej W. Rozycki" <macro@mips.com> writes:

>  Hmm, v3 of this change (apparently never posted), that is specifically 
> commit de6242d30757 ("btrace, gdbserver: remove the to_supports_btrace 
> target method"), has broken remote `mips-linux' target debugging 
> completely, that is an attempt to make a remote connection fails in the 
> initial handshake, e.g.:
>
> Process .../gdb/testsuite/outputs/gdb.base/advance/advance created; pid = 25519
> Listening on port 2346
> target remote 1.2.3.4:2346
> Remote debugging using 1.2.3.4:2346
> Reading symbols from .../lib/ld.so.1...done.
> 0x77fc8de0 in __start () from .../lib/ld.so.1
> Protocol error: qXfer:btrace-conf (read-btrace-conf) conflicting enabled responses.
> (gdb) continue
> The program is not being run.
> (gdb) FAIL: gdb.base/advance.exp: can't run to main

For the record, since non-x86 gdbserver is broken, it takes much longer
to run gdb tests on non-x86 gdbserver buildbot builders,
On Ubuntu-AArch64-native-gdbserver-m64, the time is changed from 17 mins
to 5 hrs 50 mins; 
https://gdb-build.sergiodj.net/builders/Ubuntu-AArch64-native-gdbserver-m64/builds/4141
On CentOS-ppc64be-native-gdbserver-m64, the time is changed from 48 mins
to 6 hrs 34 mins;
https://gdb-build.sergiodj.net/builders/CentOS-ppc64be-native-gdbserver-m64/builds/155

CentOS-ppc64le-native-gdbserver-m64, Fedora-ppc64le-native-gdbserver-m64 and
Debian-s390x-native-gdbserver-m64 are affected as well.

By the time Markus's fix is pushed in, these builders can run tests for
only 4 commits every day, and there are already 184 commits pushed after
commit de6242d30757.  It takes at least 46 days to build and test every
commit.  If we take "try" jobs submitted in the last several days into
account, it takes more time to clear the queue.

Sergio, in short, non-x86 gdbserver is broken, it takes several hours to
run gdb tests with gdbserver builders.  As a result, many builds are
pending there, and it still also takes much time to clean them up.
After Markus commit his fix, can we do something to let non-x86
gdbserver builders to skip these pending builds, and "jump" to Markus's fix?
Or can we temporarily disable non-x86 builders, restart them after the
fix is committed, and make sure builders pick the most recent commit
rather than resuming from the pending builds.
Sergio Durigan Junior Feb. 28, 2018, 4:27 p.m. UTC | #3
On Wednesday, February 28 2018, Yao Qi wrote:

> "Maciej W. Rozycki" <macro@mips.com> writes:
>
>>  Hmm, v3 of this change (apparently never posted), that is specifically 
>> commit de6242d30757 ("btrace, gdbserver: remove the to_supports_btrace 
>> target method"), has broken remote `mips-linux' target debugging 
>> completely, that is an attempt to make a remote connection fails in the 
>> initial handshake, e.g.:
>>
>> Process .../gdb/testsuite/outputs/gdb.base/advance/advance created; pid = 25519
>> Listening on port 2346
>> target remote 1.2.3.4:2346
>> Remote debugging using 1.2.3.4:2346
>> Reading symbols from .../lib/ld.so.1...done.
>> 0x77fc8de0 in __start () from .../lib/ld.so.1
>> Protocol error: qXfer:btrace-conf (read-btrace-conf) conflicting enabled responses.
>> (gdb) continue
>> The program is not being run.
>> (gdb) FAIL: gdb.base/advance.exp: can't run to main
>
> For the record, since non-x86 gdbserver is broken, it takes much longer
> to run gdb tests on non-x86 gdbserver buildbot builders,
> On Ubuntu-AArch64-native-gdbserver-m64, the time is changed from 17 mins
> to 5 hrs 50 mins; 
> https://gdb-build.sergiodj.net/builders/Ubuntu-AArch64-native-gdbserver-m64/builds/4141
> On CentOS-ppc64be-native-gdbserver-m64, the time is changed from 48 mins
> to 6 hrs 34 mins;
> https://gdb-build.sergiodj.net/builders/CentOS-ppc64be-native-gdbserver-m64/builds/155
>
> CentOS-ppc64le-native-gdbserver-m64, Fedora-ppc64le-native-gdbserver-m64 and
> Debian-s390x-native-gdbserver-m64 are affected as well.

Ah, that explains the failures I am seeing.

> By the time Markus's fix is pushed in, these builders can run tests for
> only 4 commits every day, and there are already 184 commits pushed after
> commit de6242d30757.  It takes at least 46 days to build and test every
> commit.  If we take "try" jobs submitted in the last several days into
> account, it takes more time to clear the queue.
>
> Sergio, in short, non-x86 gdbserver is broken, it takes several hours to
> run gdb tests with gdbserver builders.  As a result, many builds are
> pending there, and it still also takes much time to clean them up.
> After Markus commit his fix, can we do something to let non-x86
> gdbserver builders to skip these pending builds, and "jump" to Markus's fix?
> Or can we temporarily disable non-x86 builders, restart them after the
> fix is committed, and make sure builders pick the most recent commit
> rather than resuming from the pending builds.

What I can do is manually cancel all the build until Markus's commit.
I've done that before for other builders, so it is possible.

I'll keep an eye and do that when the commit is pushed.  Thanks for
keeping me in the loop, Yao.
Metzger, Markus T March 1, 2018, 11:33 a.m. UTC | #4
Hello Sergio,

> What I can do is manually cancel all the build until Markus's commit.
> I've done that before for other builders, so it is possible.

I pushed the fix.

I'm sorry about the breakage this caused and the lost test coverage for
the commits for which we will have to cancel testing.

Thanks for helping with buildbot, Sergio.

Regards,
Markus.


> -----Original Message-----
> From: Sergio Durigan Junior [mailto:sergiodj@redhat.com]
> Sent: 28 February 2018 17:27
> To: Yao Qi <qiyaoltc@gmail.com>
> Cc: Maciej W. Rozycki <macro@mips.com>; Metzger, Markus T
> <markus.t.metzger@intel.com>; gdb-patches@sourceware.org
> Subject: Re: [PATCH v2 5/7] btrace, gdbserver: remove the to_supports_btrace
> target method
> 
> On Wednesday, February 28 2018, Yao Qi wrote:
> 
> > "Maciej W. Rozycki" <macro@mips.com> writes:
> >
> >>  Hmm, v3 of this change (apparently never posted), that is
> >> specifically commit de6242d30757 ("btrace, gdbserver: remove the
> >> to_supports_btrace target method"), has broken remote `mips-linux'
> >> target debugging completely, that is an attempt to make a remote
> >> connection fails in the initial handshake, e.g.:
> >>
> >> Process .../gdb/testsuite/outputs/gdb.base/advance/advance created;
> >> pid = 25519 Listening on port 2346 target remote 1.2.3.4:2346 Remote
> >> debugging using 1.2.3.4:2346 Reading symbols from
> >> .../lib/ld.so.1...done.
> >> 0x77fc8de0 in __start () from .../lib/ld.so.1 Protocol error:
> >> qXfer:btrace-conf (read-btrace-conf) conflicting enabled responses.
> >> (gdb) continue
> >> The program is not being run.
> >> (gdb) FAIL: gdb.base/advance.exp: can't run to main
> >
> > For the record, since non-x86 gdbserver is broken, it takes much
> > longer to run gdb tests on non-x86 gdbserver buildbot builders, On
> > Ubuntu-AArch64-native-gdbserver-m64, the time is changed from 17 mins
> > to 5 hrs 50 mins;
> > https://gdb-build.sergiodj.net/builders/Ubuntu-AArch64-native-gdbserve
> > r-m64/builds/4141 On CentOS-ppc64be-native-gdbserver-m64, the time is
> > changed from 48 mins to 6 hrs 34 mins;
> > https://gdb-build.sergiodj.net/builders/CentOS-ppc64be-native-gdbserve
> > r-m64/builds/155
> >
> > CentOS-ppc64le-native-gdbserver-m64,
> > Fedora-ppc64le-native-gdbserver-m64 and
> > Debian-s390x-native-gdbserver-m64 are affected as well.
> 
> Ah, that explains the failures I am seeing.
> 
> > By the time Markus's fix is pushed in, these builders can run tests
> > for only 4 commits every day, and there are already 184 commits pushed
> > after commit de6242d30757.  It takes at least 46 days to build and
> > test every commit.  If we take "try" jobs submitted in the last
> > several days into account, it takes more time to clear the queue.
> >
> > Sergio, in short, non-x86 gdbserver is broken, it takes several hours
> > to run gdb tests with gdbserver builders.  As a result, many builds
> > are pending there, and it still also takes much time to clean them up.
> > After Markus commit his fix, can we do something to let non-x86
> > gdbserver builders to skip these pending builds, and "jump" to Markus's fix?
> > Or can we temporarily disable non-x86 builders, restart them after the
> > fix is committed, and make sure builders pick the most recent commit
> > rather than resuming from the pending builds.
> 
> What I can do is manually cancel all the build until Markus's commit.
> I've done that before for other builders, so it is possible.
> 
> I'll keep an eye and do that when the commit is pushed.  Thanks for keeping me
> in the loop, Yao.
> 
> --
> Sergio
> GPG key ID: 237A 54B1 0287 28BF 00EF  31F4 D0EB 7628 65FC 5E36 Please send
> encrypted e-mail if possible http://sergiodj.net/
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Maciej W. Rozycki March 1, 2018, 6:47 p.m. UTC | #5
Hi Markus,

> > What I can do is manually cancel all the build until Markus's commit.
> > I've done that before for other builders, so it is possible.
> 
> I pushed the fix.

 For the record, my test board has been restored to normal operation and I 
have now finished regression-testing with the `mips-mti-linux-gnu' remote 
target and its three ABIs, with no problems observed compared to results 
as at commit de6242d30757^.

 Thank you for getting the fix completed so quickly.

  Maciej
Sergio Durigan Junior March 1, 2018, 7:27 p.m. UTC | #6
On Thursday, March 01 2018, Markus T. Metzger wrote:

> Hello Sergio,
>
>> What I can do is manually cancel all the build until Markus's commit.
>> I've done that before for other builders, so it is possible.
>
> I pushed the fix.
>
> I'm sorry about the breakage this caused and the lost test coverage for
> the commits for which we will have to cancel testing.
>
> Thanks for helping with buildbot, Sergio.

Hey Markus,

Thanks for letting me know.  I'm cancelling the pending builds on a few
builders that were affected by this issue.  Let's keep an eye and see if
there's anything else I should do :-).

Cheers,
Yao Qi March 5, 2018, 12:13 p.m. UTC | #7
Sergio Durigan Junior <sergiodj@redhat.com> writes:

> I'm cancelling the pending builds on a few
> builders that were affected by this issue.  Let's keep an eye and see if
> there's anything else I should do :-).

Hi Sergio,
Did you cancel pending builds?  There are still many pending builds on
some non-x86 gdbserver builders.
Sergio Durigan Junior March 5, 2018, 4:13 p.m. UTC | #8
On Monday, March 05 2018, Yao Qi wrote:

> Sergio Durigan Junior <sergiodj@redhat.com> writes:
>
>> I'm cancelling the pending builds on a few
>> builders that were affected by this issue.  Let's keep an eye and see if
>> there's anything else I should do :-).
>
> Hi Sergio,
> Did you cancel pending builds?  There are still many pending builds on
> some non-x86 gdbserver builders.

Hi Yao,

I didn't cancel the pending builds of the ppc{be,le} builders, because I
remember seeing them even before this regression.  I will do that now.

Thanks,
Yao Qi March 6, 2018, 9:02 a.m. UTC | #9
On Mon, Mar 5, 2018 at 4:13 PM, Sergio Durigan Junior
<sergiodj@redhat.com> wrote:
>
> I didn't cancel the pending builds of the ppc{be,le} builders, because I
> remember seeing them even before this regression.  I will do that now.
>

Can you also cancel the pending builds on Ubuntu-AArch64-native-gdbserver-m64?
Sergio Durigan Junior March 6, 2018, 4:32 p.m. UTC | #10
On Tuesday, March 06 2018, Yao Qi wrote:

> On Mon, Mar 5, 2018 at 4:13 PM, Sergio Durigan Junior
> <sergiodj@redhat.com> wrote:
>>
>> I didn't cancel the pending builds of the ppc{be,le} builders, because I
>> remember seeing them even before this regression.  I will do that now.
>>
>
> Can you also cancel the pending builds on Ubuntu-AArch64-native-gdbserver-m64?

Done.  I'm monitoring Ubuntu-AArch64-m64 to see if it will be able to
catch up, otherwise I'll cancel its pending builds as well.

Thanks,
diff mbox

Patch

diff --git a/gdb/btrace.c b/gdb/btrace.c
index ffcf53a..2b031a4 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -1582,9 +1582,6 @@  btrace_enable (struct thread_info *tp, const struct btrace_config *conf)
     error (_("GDB does not support Intel Processor Trace."));
 #endif /* !defined (HAVE_LIBIPT) */
 
-  if (!target_supports_btrace (conf->format))
-    error (_("Target does not support branch tracing."));
-
   DEBUG ("enable thread %s (%s)", print_thread_id (tp),
 	 target_pid_to_str (tp->ptid));
 
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 38142bb..c1ba961 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -7531,7 +7531,6 @@  static struct target_ops linux_target_ops = {
   linux_qxfer_libraries_svr4,
   linux_supports_agent,
 #ifdef HAVE_LINUX_BTRACE
-  linux_supports_btrace,
   linux_enable_btrace,
   linux_low_disable_btrace,
   linux_low_read_btrace,
@@ -7541,7 +7540,6 @@  static struct target_ops linux_target_ops = {
   NULL,
   NULL,
   NULL,
-  NULL,
 #endif
   linux_supports_range_stepping,
   linux_proc_pid_to_exec_file,
diff --git a/gdb/gdbserver/nto-low.c b/gdb/gdbserver/nto-low.c
index a570ca9..b68b811 100644
--- a/gdb/gdbserver/nto-low.c
+++ b/gdb/gdbserver/nto-low.c
@@ -991,7 +991,6 @@  static struct target_ops nto_target_ops = {
   NULL, /* get_min_fast_tracepoint_insn_len */
   NULL, /* qxfer_libraries_svr4 */
   NULL, /* support_agent */
-  NULL, /* support_btrace */
   NULL, /* enable_btrace */
   NULL, /* disable_btrace */
   NULL, /* read_btrace */
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 5ce6281..cb02b58 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -2104,27 +2104,10 @@  crc32 (CORE_ADDR base, int len, unsigned int crc)
 static void
 supported_btrace_packets (char *buf)
 {
-  int btrace_supported = 0;
-
-  if (target_supports_btrace (BTRACE_FORMAT_BTS))
-    {
-      strcat (buf, ";Qbtrace:bts+");
-      strcat (buf, ";Qbtrace-conf:bts:size+");
-
-      btrace_supported = 1;
-    }
-
-  if (target_supports_btrace (BTRACE_FORMAT_PT))
-    {
-      strcat (buf, ";Qbtrace:pt+");
-      strcat (buf, ";Qbtrace-conf:pt:size+");
-
-      btrace_supported = 1;
-    }
-
-  if (!btrace_supported)
-    return;
-
+  strcat (buf, ";Qbtrace:bts+");
+  strcat (buf, ";Qbtrace-conf:bts:size+");
+  strcat (buf, ";Qbtrace:pt+");
+  strcat (buf, ";Qbtrace-conf:pt:size+");
   strcat (buf, ";Qbtrace:off+");
   strcat (buf, ";qXfer:btrace:read+");
   strcat (buf, ";qXfer:btrace-conf:read+");
diff --git a/gdb/gdbserver/spu-low.c b/gdb/gdbserver/spu-low.c
index fd1f8d6..5b880d2 100644
--- a/gdb/gdbserver/spu-low.c
+++ b/gdb/gdbserver/spu-low.c
@@ -717,7 +717,6 @@  static struct target_ops spu_target_ops = {
   NULL, /* get_min_fast_tracepoint_insn_len */
   NULL, /* qxfer_libraries_svr4 */
   NULL, /* support_agent */
-  NULL, /* support_btrace */
   NULL, /* enable_btrace */
   NULL, /* disable_btrace */
   NULL, /* read_btrace */
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index 295e64d..dcefe1a 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -391,9 +391,6 @@  struct target_ops
   /* Return true if target supports debugging agent.  */
   int (*supports_agent) (void);
 
-  /* Check whether the target supports branch tracing.  */
-  int (*supports_btrace) (struct target_ops *, enum btrace_format);
-
   /* Enable branch tracing for PTID based on CONF and allocate a branch trace
      target information struct for reading and for disabling branch trace.  */
   struct btrace_target_info *(*enable_btrace)
@@ -623,10 +620,6 @@  int kill_inferior (int);
   (the_target->supports_agent ? \
    (*the_target->supports_agent) () : 0)
 
-#define target_supports_btrace(format)			\
-  (the_target->supports_btrace				\
-   ? (*the_target->supports_btrace) (the_target, format) : 0)
-
 #define target_enable_btrace(ptid, conf) \
   (*the_target->enable_btrace) (ptid, conf)
 
diff --git a/gdb/gdbserver/win32-low.c b/gdb/gdbserver/win32-low.c
index b1d9b51..9f0c4e4 100644
--- a/gdb/gdbserver/win32-low.c
+++ b/gdb/gdbserver/win32-low.c
@@ -1842,7 +1842,6 @@  static struct target_ops win32_target_ops = {
   NULL, /* get_min_fast_tracepoint_insn_len */
   NULL, /* qxfer_libraries_svr4 */
   NULL, /* support_agent */
-  NULL, /* support_btrace */
   NULL, /* enable_btrace */
   NULL, /* disable_btrace */
   NULL, /* read_btrace */
diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index 2b37e41..23ad778 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -175,23 +175,6 @@  perf_event_read_all (struct perf_event_buffer *pev, gdb_byte **data,
   pev->last_head = data_head;
 }
 
-/* Determine the event type.
-   Returns zero on success and fills in TYPE; returns -1 otherwise.  */
-
-static int
-perf_event_pt_event_type (int *type)
-{
-  gdb_file_up file
-    =  gdb_fopen_cloexec ("/sys/bus/event_source/devices/intel_pt/type", "r");
-  if (file == nullptr)
-    return -1;
-
-  int found = fscanf (file.get (), "%d", type);
-  if (found == 1)
-    return 0;
-  return -1;
-}
-
 /* Try to determine the start address of the Linux kernel.  */
 
 static uint64_t
@@ -376,176 +359,6 @@  perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin,
   return btrace;
 }
 
-/* Check whether the kernel supports BTS.  */
-
-static int
-kernel_supports_bts (void)
-{
-  struct perf_event_attr attr;
-  pid_t child, pid;
-  int status, file;
-
-  errno = 0;
-  child = fork ();
-  switch (child)
-    {
-    case -1:
-      warning (_("test bts: cannot fork: %s."), safe_strerror (errno));
-      return 0;
-
-    case 0:
-      status = ptrace (PTRACE_TRACEME, 0, NULL, NULL);
-      if (status != 0)
-	{
-	  warning (_("test bts: cannot PTRACE_TRACEME: %s."),
-		   safe_strerror (errno));
-	  _exit (1);
-	}
-
-      status = raise (SIGTRAP);
-      if (status != 0)
-	{
-	  warning (_("test bts: cannot raise SIGTRAP: %s."),
-		   safe_strerror (errno));
-	  _exit (1);
-	}
-
-      _exit (1);
-
-    default:
-      pid = waitpid (child, &status, 0);
-      if (pid != child)
-	{
-	  warning (_("test bts: bad pid %ld, error: %s."),
-		   (long) pid, safe_strerror (errno));
-	  return 0;
-	}
-
-      if (!WIFSTOPPED (status))
-	{
-	  warning (_("test bts: expected stop. status: %d."),
-		   status);
-	  return 0;
-	}
-
-      memset (&attr, 0, sizeof (attr));
-
-      attr.type = PERF_TYPE_HARDWARE;
-      attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
-      attr.sample_period = 1;
-      attr.sample_type = PERF_SAMPLE_IP | PERF_SAMPLE_ADDR;
-      attr.exclude_kernel = 1;
-      attr.exclude_hv = 1;
-      attr.exclude_idle = 1;
-
-      file = syscall (SYS_perf_event_open, &attr, child, -1, -1, 0);
-      if (file >= 0)
-	close (file);
-
-      kill (child, SIGKILL);
-      ptrace (PTRACE_KILL, child, NULL, NULL);
-
-      pid = waitpid (child, &status, 0);
-      if (pid != child)
-	{
-	  warning (_("test bts: bad pid %ld, error: %s."),
-		   (long) pid, safe_strerror (errno));
-	  if (!WIFSIGNALED (status))
-	    warning (_("test bts: expected killed. status: %d."),
-		     status);
-	}
-
-      return (file >= 0);
-    }
-}
-
-/* Check whether the kernel supports Intel Processor Trace.  */
-
-static int
-kernel_supports_pt (void)
-{
-  struct perf_event_attr attr;
-  pid_t child, pid;
-  int status, file, type;
-
-  errno = 0;
-  child = fork ();
-  switch (child)
-    {
-    case -1:
-      warning (_("test pt: cannot fork: %s."), safe_strerror (errno));
-      return 0;
-
-    case 0:
-      status = ptrace (PTRACE_TRACEME, 0, NULL, NULL);
-      if (status != 0)
-	{
-	  warning (_("test pt: cannot PTRACE_TRACEME: %s."),
-		   safe_strerror (errno));
-	  _exit (1);
-	}
-
-      status = raise (SIGTRAP);
-      if (status != 0)
-	{
-	  warning (_("test pt: cannot raise SIGTRAP: %s."),
-		   safe_strerror (errno));
-	  _exit (1);
-	}
-
-      _exit (1);
-
-    default:
-      pid = waitpid (child, &status, 0);
-      if (pid != child)
-	{
-	  warning (_("test pt: bad pid %ld, error: %s."),
-		   (long) pid, safe_strerror (errno));
-	  return 0;
-	}
-
-      if (!WIFSTOPPED (status))
-	{
-	  warning (_("test pt: expected stop. status: %d."),
-		   status);
-	  return 0;
-	}
-
-      status = perf_event_pt_event_type (&type);
-      if (status != 0)
-	file = -1;
-      else
-	{
-	  memset (&attr, 0, sizeof (attr));
-
-	  attr.size = sizeof (attr);
-	  attr.type = type;
-	  attr.exclude_kernel = 1;
-	  attr.exclude_hv = 1;
-	  attr.exclude_idle = 1;
-
-	  file = syscall (SYS_perf_event_open, &attr, child, -1, -1, 0);
-	  if (file >= 0)
-	    close (file);
-	}
-
-      kill (child, SIGKILL);
-      ptrace (PTRACE_KILL, child, NULL, NULL);
-
-      pid = waitpid (child, &status, 0);
-      if (pid != child)
-	{
-	  warning (_("test pt: bad pid %ld, error: %s."),
-		   (long) pid, safe_strerror (errno));
-	  if (!WIFSIGNALED (status))
-	    warning (_("test pt: expected killed. status: %d."),
-		     status);
-	}
-
-      return (file >= 0);
-    }
-}
-
 /* Check whether an Intel cpu supports BTS.  */
 
 static int
@@ -596,64 +409,6 @@  cpu_supports_bts (void)
     }
 }
 
-/* Check whether the linux target supports BTS.  */
-
-static int
-linux_supports_bts (void)
-{
-  static int cached;
-
-  if (cached == 0)
-    {
-      if (!kernel_supports_bts ())
-	cached = -1;
-      else if (!cpu_supports_bts ())
-	cached = -1;
-      else
-	cached = 1;
-    }
-
-  return cached > 0;
-}
-
-/* Check whether the linux target supports Intel Processor Trace.  */
-
-static int
-linux_supports_pt (void)
-{
-  static int cached;
-
-  if (cached == 0)
-    {
-      if (!kernel_supports_pt ())
-	cached = -1;
-      else
-	cached = 1;
-    }
-
-  return cached > 0;
-}
-
-/* See linux-btrace.h.  */
-
-int
-linux_supports_btrace (struct target_ops *ops, enum btrace_format format)
-{
-  switch (format)
-    {
-    case BTRACE_FORMAT_NONE:
-      return 0;
-
-    case BTRACE_FORMAT_BTS:
-      return linux_supports_bts ();
-
-    case BTRACE_FORMAT_PT:
-      return linux_supports_pt ();
-    }
-
-  internal_error (__FILE__, __LINE__, _("Unknown branch trace format"));
-}
-
 /* Enable branch tracing in BTS format.  */
 
 static struct btrace_target_info *
@@ -664,6 +419,9 @@  linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
   __u64 data_offset;
   int pid, pg;
 
+  if (!cpu_supports_bts ())
+    error (_("GDB does not support BTS for the target cpu."));
+
   gdb::unique_xmalloc_ptr<btrace_target_info> tinfo
     (XCNEW (btrace_target_info));
   tinfo->ptid = ptid;
@@ -770,6 +528,23 @@  linux_enable_bts (ptid_t ptid, const struct btrace_config_bts *conf)
 
 #if defined (PERF_ATTR_SIZE_VER5)
 
+/* Determine the event type.
+   Returns zero on success and fills in TYPE; returns -1 otherwise.  */
+
+static int
+perf_event_pt_event_type (int *type)
+{
+  gdb_file_up file =
+    gdb_fopen_cloexec ("/sys/bus/event_source/devices/intel_pt/type", "r");
+  if (file.get () == nullptr)
+    return -1;
+
+  int found = fscanf (file.get (), "%d", type);
+  if (found == 1)
+    return 0;
+  return -1;
+}
+
 /* Enable branch tracing in Intel Processor Trace format.  */
 
 static struct btrace_target_info *
@@ -1146,14 +921,6 @@  linux_btrace_conf (const struct btrace_target_info *tinfo)
 
 /* See linux-btrace.h.  */
 
-int
-linux_supports_btrace (struct target_ops *ops, enum btrace_format format)
-{
-  return 0;
-}
-
-/* See linux-btrace.h.  */
-
 struct btrace_target_info *
 linux_enable_btrace (ptid_t ptid, const struct btrace_config *conf)
 {
diff --git a/gdb/nat/linux-btrace.h b/gdb/nat/linux-btrace.h
index 31a8d9e..1180301 100644
--- a/gdb/nat/linux-btrace.h
+++ b/gdb/nat/linux-btrace.h
@@ -103,9 +103,6 @@  struct btrace_target_info
 #endif /* HAVE_LINUX_PERF_EVENT_H */
 };
 
-/* See to_supports_btrace in target.h.  */
-extern int linux_supports_btrace (struct target_ops *, enum btrace_format);
-
 /* See to_enable_btrace in target.h.  */
 extern struct btrace_target_info *
   linux_enable_btrace (ptid_t ptid, const struct btrace_config *conf);
diff --git a/gdb/remote.c b/gdb/remote.c
index 5ac84df..b12b690 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -13096,37 +13096,6 @@  remote_btrace_reset (void)
   memset (&rs->btrace_config, 0, sizeof (rs->btrace_config));
 }
 
-/* Check whether the target supports branch tracing.  */
-
-static int
-remote_supports_btrace (struct target_ops *self, enum btrace_format format)
-{
-  if (packet_support (PACKET_Qbtrace_off) != PACKET_ENABLE)
-    return 0;
-  if (packet_support (PACKET_qXfer_btrace) != PACKET_ENABLE)
-    return 0;
-
-  switch (format)
-    {
-      case BTRACE_FORMAT_NONE:
-	return 0;
-
-      case BTRACE_FORMAT_BTS:
-	return (packet_support (PACKET_Qbtrace_bts) == PACKET_ENABLE);
-
-      case BTRACE_FORMAT_PT:
-	/* The trace is decoded on the host.  Even if our target supports it,
-	   we still need to have libipt to decode the trace.  */
-#if defined (HAVE_LIBIPT)
-	return (packet_support (PACKET_Qbtrace_pt) == PACKET_ENABLE);
-#else /* !defined (HAVE_LIBIPT)  */
-	return 0;
-#endif /* !defined (HAVE_LIBIPT)  */
-    }
-
-  internal_error (__FILE__, __LINE__, _("Unknown branch trace format"));
-}
-
 /* Synchronize the configuration with the target.  */
 
 static void
@@ -13650,7 +13619,6 @@  Specify the serial device it is connected to\n\
   remote_ops.to_traceframe_info = remote_traceframe_info;
   remote_ops.to_use_agent = remote_use_agent;
   remote_ops.to_can_use_agent = remote_can_use_agent;
-  remote_ops.to_supports_btrace = remote_supports_btrace;
   remote_ops.to_enable_btrace = remote_enable_btrace;
   remote_ops.to_disable_btrace = remote_disable_btrace;
   remote_ops.to_teardown_btrace = remote_teardown_btrace;
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
index bc84791..3d90c06 100644
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -3438,35 +3438,6 @@  debug_can_use_agent (struct target_ops *self)
   return result;
 }
 
-static int
-delegate_supports_btrace (struct target_ops *self, enum btrace_format arg1)
-{
-  self = self->beneath;
-  return self->to_supports_btrace (self, arg1);
-}
-
-static int
-tdefault_supports_btrace (struct target_ops *self, enum btrace_format arg1)
-{
-  return 0;
-}
-
-static int
-debug_supports_btrace (struct target_ops *self, enum btrace_format arg1)
-{
-  int result;
-  fprintf_unfiltered (gdb_stdlog, "-> %s->to_supports_btrace (...)\n", debug_target.to_shortname);
-  result = debug_target.to_supports_btrace (&debug_target, arg1);
-  fprintf_unfiltered (gdb_stdlog, "<- %s->to_supports_btrace (", debug_target.to_shortname);
-  target_debug_print_struct_target_ops_p (&debug_target);
-  fputs_unfiltered (", ", gdb_stdlog);
-  target_debug_print_enum_btrace_format (arg1);
-  fputs_unfiltered (") = ", gdb_stdlog);
-  target_debug_print_int (result);
-  fputs_unfiltered ("\n", gdb_stdlog);
-  return result;
-}
-
 static struct btrace_target_info *
 delegate_enable_btrace (struct target_ops *self, ptid_t arg1, const struct btrace_config *arg2)
 {
@@ -4436,8 +4407,6 @@  install_delegators (struct target_ops *ops)
     ops->to_use_agent = delegate_use_agent;
   if (ops->to_can_use_agent == NULL)
     ops->to_can_use_agent = delegate_can_use_agent;
-  if (ops->to_supports_btrace == NULL)
-    ops->to_supports_btrace = delegate_supports_btrace;
   if (ops->to_enable_btrace == NULL)
     ops->to_enable_btrace = delegate_enable_btrace;
   if (ops->to_disable_btrace == NULL)
@@ -4624,7 +4593,6 @@  install_dummy_methods (struct target_ops *ops)
   ops->to_traceframe_info = tdefault_traceframe_info;
   ops->to_use_agent = tdefault_use_agent;
   ops->to_can_use_agent = tdefault_can_use_agent;
-  ops->to_supports_btrace = tdefault_supports_btrace;
   ops->to_enable_btrace = tdefault_enable_btrace;
   ops->to_disable_btrace = tdefault_disable_btrace;
   ops->to_teardown_btrace = tdefault_teardown_btrace;
@@ -4784,7 +4752,6 @@  init_debug_target (struct target_ops *ops)
   ops->to_traceframe_info = debug_traceframe_info;
   ops->to_use_agent = debug_use_agent;
   ops->to_can_use_agent = debug_can_use_agent;
-  ops->to_supports_btrace = debug_supports_btrace;
   ops->to_enable_btrace = debug_enable_btrace;
   ops->to_disable_btrace = debug_disable_btrace;
   ops->to_teardown_btrace = debug_teardown_btrace;
diff --git a/gdb/target.c b/gdb/target.c
index ce630f4..70d6842 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -3556,14 +3556,6 @@  target_ranged_break_num_registers (void)
 
 /* See target.h.  */
 
-int
-target_supports_btrace (enum btrace_format format)
-{
-  return current_target.to_supports_btrace (&current_target, format);
-}
-
-/* See target.h.  */
-
 struct btrace_target_info *
 target_enable_btrace (ptid_t ptid, const struct btrace_config *conf)
 {
diff --git a/gdb/target.h b/gdb/target.h
index 52361ba..1520e33 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -1108,10 +1108,6 @@  struct target_ops
     int (*to_can_use_agent) (struct target_ops *)
       TARGET_DEFAULT_RETURN (0);
 
-    /* Check whether the target supports branch tracing.  */
-    int (*to_supports_btrace) (struct target_ops *, enum btrace_format)
-      TARGET_DEFAULT_RETURN (0);
-
     /* Enable branch tracing for PTID using CONF configuration.
        Return a branch trace target information struct for reading and for
        disabling branch trace.  */
@@ -2424,9 +2420,6 @@  extern void update_target_permissions (void);
 
 /* Imported from machine dependent code.  */
 
-/* See to_supports_btrace in struct target_ops.  */
-extern int target_supports_btrace (enum btrace_format);
-
 /* See to_enable_btrace in struct target_ops.  */
 extern struct btrace_target_info *
   target_enable_btrace (ptid_t ptid, const struct btrace_config *);
diff --git a/gdb/x86-linux-nat.c b/gdb/x86-linux-nat.c
index 75f68de..a3bdaff 100644
--- a/gdb/x86-linux-nat.c
+++ b/gdb/x86-linux-nat.c
@@ -340,7 +340,6 @@  x86_linux_create_target (void)
   t->to_read_description = x86_linux_read_description;
 
   /* Add btrace methods.  */
-  t->to_supports_btrace = linux_supports_btrace;
   t->to_enable_btrace = x86_linux_enable_btrace;
   t->to_disable_btrace = x86_linux_disable_btrace;
   t->to_teardown_btrace = x86_linux_teardown_btrace;