Using asm goto in __WARN_FLAGS() and WARN_ON() allows more
flexibility to GCC.
For that add an entry to the exception table so that
program_check_exception() knowns where to resume execution
after a WARNING.
Here are two exemples. The first one is done on PPC32 (which
benefits from the previous patch), the second is on PPC64.
unsigned long test(struct pt_regs *regs)
{
int ret;
WARN_ON(regs->msr & MSR_PR);
return regs->gpr[3];
}
unsigned long test9w(unsigned long a, unsigned long b)
{
if (WARN_ON(!b))
return 0;
return a / b;
}
Before the patch:
000003a8 <test>:
3a8: 81 23 00 84 lwz r9,132(r3)
3ac: 71 29 40 00 andi. r9,r9,16384
3b0: 40 82 00 0c bne 3bc <test+0x14>
3b4: 80 63 00 0c lwz r3,12(r3)
3b8: 4e 80 00 20 blr
3bc: 0f e0 00 00 twui r0,0
3c0: 80 63 00 0c lwz r3,12(r3)
3c4: 4e 80 00 20 blr
0000000000000bf0 <.test9w>:
bf0: 7c 89 00 74 cntlzd r9,r4
bf4: 79 29 d1 82 rldicl r9,r9,58,6
bf8: 0b 09 00 00 tdnei r9,0
bfc: 2c 24 00 00 cmpdi r4,0
c00: 41 82 00 0c beq c0c <.test9w+0x1c>
c04: 7c 63 23 92 divdu r3,r3,r4
c08: 4e 80 00 20 blr
c0c: 38 60 00 00 li r3,0
c10: 4e 80 00 20 blr
After the patch:
000003a8 <test>:
3a8: 81 23 00 84 lwz r9,132(r3)
3ac: 71 29 40 00 andi. r9,r9,16384
3b0: 40 82 00 0c bne 3bc <test+0x14>
3b4: 80 63 00 0c lwz r3,12(r3)
3b8: 4e 80 00 20 blr
3bc: 0f e0 00 00 twui r0,0
0000000000000c50 <.test9w>:
c50: 7c 89 00 74 cntlzd r9,r4
c54: 79 29 d1 82 rldicl r9,r9,58,6
c58: 0b 09 00 00 tdnei r9,0
c5c: 7c 63 23 92 divdu r3,r3,r4
c60: 4e 80 00 20 blr
c70: 38 60 00 00 li r3,0
c74: 4e 80 00 20 blr
In the first exemple, we see GCC doesn't need to duplicate what
happens after the trap.
In the second exemple, we see that GCC doesn't need to emit a test
and a branch in the likely path in addition to the trap.
We've got some WARN_ON() in .softirqentry.text section so it needs
to be added in the OTHER_TEXT_SECTIONS in modpost.c
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/389962b1b702e3c78d169e59bcfac56282889173.1618331882.git.christophe.leroy@csgroup.eu
Pull perf tools fixes from Arnaldo Carvalho de Melo:
- Skip invalid hybrid PMU on hybrid systems when the atom (little) CPUs
are offlined.
- Fix 'perf test' problems related to the recently added hybrid
(BIG/little) code.
- Split ARM's coresight (hw tracing) decode by aux records to avoid
fatal decoding errors.
- Fix add event failure in 'perf probe' when running 32-bit perf in a
64-bit kernel.
- Fix 'perf sched record' failure when CONFIG_SCHEDSTATS is not set.
- Fix memory and refcount leaks detected by ASAn when running 'perf
test', should be clean of warnings now.
- Remove broken definition of __LITTLE_ENDIAN from tools'
linux/kconfig.h, which was breaking the build in some systems.
- Cast PTHREAD_STACK_MIN to int as it may turn into 'long
sysconf(__SC_THREAD_STACK_MIN_VALUE), breaking the build in some
systems.
- Fix libperf build error with LIBPFM4=1.
- Sync UAPI files changed by the memfd_secret new syscall.
* tag 'perf-tools-fixes-for-v5.14-2021-07-18' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (35 commits)
perf sched: Fix record failure when CONFIG_SCHEDSTATS is not set
perf probe: Fix add event failure when running 32-bit perf in a 64-bit kernel
perf data: Close all files in close_dir()
perf probe-file: Delete namelist in del_events() on the error path
perf test bpf: Free obj_buf
perf trace: Free strings in trace__parse_events_option()
perf trace: Free syscall tp fields in evsel->priv
perf trace: Free syscall->arg_fmt
perf trace: Free malloc'd trace fields on exit
perf lzma: Close lzma stream on exit
perf script: Fix memory 'threads' and 'cpus' leaks on exit
perf script: Release zstd data
perf session: Cleanup trace_event
perf inject: Close inject.output on exit
perf report: Free generated help strings for sort option
perf env: Fix memory leak of cpu_pmu_caps
perf test maps__merge_in: Fix memory leak of maps
perf dso: Fix memory leak in dso__new_map()
perf test event_update: Fix memory leak of unit
perf test event_update: Fix memory leak of evlist
...
The tracepoints trace_sched_stat_{wait, sleep, iowait} are not exposed to user
if CONFIG_SCHEDSTATS is not set, "perf sched record" records the three events.
As a result, the command fails.
Before:
#perf sched record sleep 1
event syntax error: 'sched:sched_stat_wait'
\___ unknown tracepoint
Error: File /sys/kernel/tracing/events/sched/sched_stat_wait not found.
Hint: Perhaps this kernel misses some CONFIG_ setting to enable this feature?.
Run 'perf list' for a list of valid events
Usage: perf record [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]
-e, --event <event> event selector. use 'perf list' to list available events
Solution:
Check whether schedstat tracepoints are exposed. If no, these events are not recorded.
After:
# perf sched record sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.163 MB perf.data (1091 samples) ]
# perf sched report
run measurement overhead: 4736 nsecs
sleep measurement overhead: 9059979 nsecs
the run test took 999854 nsecs
the sleep test took 8945271 nsecs
nr_run_events: 716
nr_sleep_events: 785
nr_wakeup_events: 0
...
------------------------------------------------------------
Fixes: 2a09b5de23 ("sched/fair: do not expose some tracepoints to user if CONFIG_SCHEDSTATS is not set")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Yafang Shao <laoar.shao@gmail.com>
Link: http://lore.kernel.org/lkml/20210713112358.194693-1-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The "address" member of "struct probe_trace_point" uses long data type.
If kernel is 64-bit and perf program is 32-bit, size of "address"
variable is 32 bits.
As a result, upper 32 bits of address read from kernel are truncated, an
error occurs during address comparison in kprobe_warn_out_range().
Before:
# perf probe -a schedule
schedule is out of .text, skip it.
Error: Failed to add events.
Solution:
Change data type of "address" variable to u64 and change corresponding
address printing and value assignment.
After:
# perf.new.new probe -a schedule
Added new event:
probe:schedule (on schedule)
You can now use it in all perf tools, such as:
perf record -e probe:schedule -aR sleep 1
# perf probe -l
probe:schedule (on schedule@kernel/sched/core.c)
# perf record -e probe:schedule -aR sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.156 MB perf.data (1366 samples) ]
# perf report --stdio
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 1K of event 'probe:schedule'
# Event count (approx.): 1366
#
# Overhead Command Shared Object Symbol
# ........ ............... ................. ............
#
6.22% migration/0 [kernel.kallsyms] [k] schedule
6.22% migration/1 [kernel.kallsyms] [k] schedule
6.22% migration/2 [kernel.kallsyms] [k] schedule
6.22% migration/3 [kernel.kallsyms] [k] schedule
6.15% migration/10 [kernel.kallsyms] [k] schedule
6.15% migration/11 [kernel.kallsyms] [k] schedule
6.15% migration/12 [kernel.kallsyms] [k] schedule
6.15% migration/13 [kernel.kallsyms] [k] schedule
6.15% migration/14 [kernel.kallsyms] [k] schedule
6.15% migration/15 [kernel.kallsyms] [k] schedule
6.15% migration/4 [kernel.kallsyms] [k] schedule
6.15% migration/5 [kernel.kallsyms] [k] schedule
6.15% migration/6 [kernel.kallsyms] [k] schedule
6.15% migration/7 [kernel.kallsyms] [k] schedule
6.15% migration/8 [kernel.kallsyms] [k] schedule
6.15% migration/9 [kernel.kallsyms] [k] schedule
0.22% rcu_sched [kernel.kallsyms] [k] schedule
...
#
# (Cannot load tips.txt file, please install perf!)
#
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jianlin Lv <jianlin.lv@arm.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lore.kernel.org/lkml/20210715063723.11926-1-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull kunit fixes from Shuah Khan:
"Fixes to kunit tool and documentation:
- fix asserts on older python versions
- fixes to misleading error messages when TAP header format is
incorrect or when file is missing
- documentation fix: drop obsolete information about uml_abort
coverage
- remove unnecessary annotations"
* tag 'linux-kselftest-kunit-fixes-5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
kunit: tool: Assert the version requirement
kunit: tool: remove unnecessary "annotations" import
Documentation: kunit: drop obsolete note about uml_abort for coverage
kunit: tool: Fix error messages for cases of no tests and wrong TAP header
Pull kselftest fix from Shuah Khan:
"A fix to memory-hotplug hot-remove test to stop spamming logs with
dump_page() entries and slowing the system down to a crawl"
* tag 'linux-kselftest-fixes-5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests: memory-hotplug: avoid spamming logs with dump_page(), ratio limit hot-remove error test
ASan reports several memory leaks running:
# perf test "88: Check open filename arg using perf trace + vfs_getname"
The first of these leaks is related to struct trace fields never being
deallocated.
This patch adds the function trace__exit, which is called at the end of
cmd_trace, replacing the existing deallocation, which is now moved
inside the new function.
This function deallocates:
- ev_qualifier
- ev_qualifier_ids.entries
- syscalls.table
- sctbl
- perfconfig_events
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/de5945ed5c0cb882cbfa3268567d0bff460ff016.1626343282.git.rickyman7@gmail.com
[ Removed needless initialization to zero, missing named initializers are zeroed by the compiler ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
ASan reports several memory leaks while running:
# perf test "82: Use vfs_getname probe to get syscall args filenames"
Two of these are caused by some refcounts not being decreased on
perf-script exit, namely script.threads and script.cpus.
This patch adds the missing __put calls in a new perf_script__exit
function, which is called at the end of cmd_script.
This patch concludes the fixes of all remaining memory leaks in perf
test "82: Use vfs_getname probe to get syscall args filenames".
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Fixes: cfc8874a48 ("perf script: Process cpu/threads maps")
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/5ee73b19791c6fa9d24c4d57f4ac1a23609400d7.1626343282.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
