linux-kernel - Re: [PATCH 17/19] perf tools: Build syscall table .c header from kernel's syscall

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Date:	Thu, 7 Apr 2016 18:50:08 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	David Ahern <dsahern@...il.com>
Cc:	Ingo Molnar <mingo@...nel.org>, linux-kernel@...r.kernel.org,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Wang Nan <wangnan0@...wei.com>
Subject: Re: [PATCH 17/19] perf tools: Build syscall table .c header from
 kernel's syscall_64.tbl

Em Thu, Apr 07, 2016 at 03:39:21PM -0600, David Ahern escreveu:
> On 4/7/16 2:58 PM, Arnaldo Carvalho de Melo wrote:
> >We used libaudit to map ids to syscall names and vice-versa, but that
> >imposes a delay in supporting new syscalls, having to wait for libaudit
> >to get those new syscalls on its tables.
 
> and for the distribution to get the new libaudit.

yeap
 
> >To remove that delay, for x86_64 initially, grab a copy of
> >arch/x86/entry/syscalls/syscall_64.tbl and use it to generate those
> >tables.
> 
> Now that's a benefit for perf in the kernel tree. What happens for out of
> tree perf builds? Are the requisite files included in the tarball?
> (apparently no, since the manifest file is not updated or perhaps I missed
> it)

Well, we're removing references to files outside tools/, so what was
done in this case was to copy the files:

[acme@...et linux]$ ls -la tools/perf/arch/x86/entry/syscalls/
total 28
drwxrwxr-x. 2 acme acme  4096 Apr  7 16:59 .
drwxrwxr-x. 3 acme acme  4096 Apr  7 16:59 ..
-rw-rw-r--. 1 acme acme 12972 Apr  7 16:59 syscall_64.tbl
-rwxrwxr-x. 1 acme acme   596 Apr  7 16:59 syscalltbl.sh
[acme@...et linux]$ 

Then we have logic for when the kernel one gets out of sync, to be
warned about, see:

tools/perf/arch/x86/Makefile

E.g.:

[acme@...et linux]$ git diff
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 2e5b565adacc..e8af21d804f8 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -333,6 +333,7 @@
 324    common  membarrier              sys_membarrier
 325    common  mlock2                  sys_mlock2
 326    common  copy_file_range         sys_copy_file_range
+327    common  leftpad                 sys_leftpad
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
[acme@...et linux]$
[acme@...et linux]$ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf ; m
make: Entering directory '/home/acme/git/linux/tools/perf'

[acme@...et linux]$ make -C tools/perf build-test
make: Entering directory '/home/acme/git/linux/tools/perf'
- tarpkg: ./tests/perf-targz-src-pkg .

  BUILD:   Doing 'make -j4' parallel build

Auto-detecting system features:
...                         dwarf: [ on  ]
<SNIP>

  GEN      /tmp/build/perf/common-cmds.h
Warning: x86_64's syscall_64.tbl differs from kernel
  CC       /tmp/build/perf/fixdep.o
  LD       /tmp/build/perf/fixdep-in.o

---------------------------------------

Looking at it now it needs some more polish, i.e. it should have a GEN ...
line, but that can be done on top of this patchkit :-)

For completeness:

[acme@...et linux]$ diff -u tools/perf/arch/x86/entry/syscalls/syscall_64.tbl arch/x86/entry/syscalls/syscall_64.tbl
--- tools/perf/arch/x86/entry/syscalls/syscall_64.tbl	2016-04-07 16:59:44.938061779 -0300
+++ arch/x86/entry/syscalls/syscall_64.tbl	2016-04-07 18:43:51.543992781 -0300
@@ -333,6 +333,7 @@
 324	common	membarrier		sys_membarrier
 325	common	mlock2			sys_mlock2
 326	common	copy_file_range		sys_copy_file_range
+327	common	leftpad			sys_leftpad
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
[acme@...et linux]$

And 'make -C tools/perf build-test' does the tarball creation and out-of-tree
build as its first step, to make sure it continues working, so all that is
needed is there :-)

[acme@...et linux]$ make -C tools/perf build-test
make: Entering directory '/home/acme/git/linux/tools/perf'
- tarpkg: ./tests/perf-targz-src-pkg .
- /home/acme/git/linux/tools/perf/BUILD_TEST_FEATURE_DUMP: cd . && make FEATURE_DUMP_COPY=/home/acme/git/linux/tools/perf/BUILD_TEST_FEATURE_DUMP  feature-dump
cd . && make FEATURE_DUMP_COPY=/home/acme/git/linux/tools/perf/BUILD_TEST_FEATURE_DUMP feature-dump
              make_minimal_O: cd . && make NO_LIBPERL=1 NO_LIBPYTHON=1 NO_NEWT=1 NO_GTK2=1 NO_DEMANGLE=1 NO_LIBELF=1 NO_LIBUNWIND=1 NO_BACKTRACE=1 NO_LIBNUMA=1 NO_LIBAUDIT=1 NO_LIBBIONIC=1 NO_LIBDW_DWARF_UNWIND=1 NO_AUXTRACE=1 NO_LIBBPF=1 NO_LIBCRYPTO=1 FEATURES_DUMP=/home/acme/git/linux/tools/perf/BUILD_TEST_FEATURE_DUMP -j4 O=/tmp/tmp.6KCw8TRjm7 DESTDIR=/tmp/tmp.6yw98RESmd
<SNIP>

Best regards,

- Arnaldo