Skip to content

L
linux
Switch branch/tag
  1. 03 Nov, 2021 2 commits
  3. 04 Oct, 2021 2 commits
    • Andrea Arcangeli's avatar
      x86: deduplicate the spectre_v2_user documentation · d9bbdbf3
      Andrea Arcangeli authored 
      This would need updating to make prctl be the new default, but it's
simpler to delete it and refer to the dup.
Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201105001406.13005-2-aarcange@redhat.com
      d9bbdbf3
    • Andrea Arcangeli's avatar
      x86: change default to spec_store_bypass_disable=prctl spectre_v2_user=prctl · 2f46993d
      Andrea Arcangeli authored 
      Switch the kernel default of SSBD and STIBP to the ones with
CONFIG_SECCOMP=n (i.e. spec_store_bypass_disable=prctl
spectre_v2_user=prctl) even if CONFIG_SECCOMP=y.

Several motivations listed below:

- If SMT is enabled the seccomp jail can still attack the rest of the
  system even with spectre_v2_user=seccomp by using MDS-HT (except on
  XEON PHI where MDS can be tamed with SMT left enabled, but that's a
  special case). Setting STIBP become a very expensive window dressing
  after MDS-HT was discovered.

- The seccomp jail cannot attack the kernel with spectre-v2-HT
  regardless (even if STIBP is not set), but with MDS-HT the seccomp
  jail can attack the kernel too.

- With spec_store_bypass_disable=prctl the seccomp jail can attack the
  other userland (guest or host mode) using spectre-v2-HT, but the
  userland attack is already mitigated by both ASLR and pid namespaces
  for host userland and through virt isolation with libkrun or
  kata. (if something if somebody is worried about spectre-v2-HT it's
  best to mount proc with hidepid=2,gid=proc on workstations where not
  all apps may run under container runtimes, rather than slowing down
  all seccomp jails, but the best is to add pid namespaces to the
  seccomp jail). As opposed MDS-HT is not mitigated and the seccomp
  jail can still attack all other host and guest userland if SMT is
  enabled even with spec_store_bypass_disable=seccomp.

- If full security is required then MDS-HT must also be mitigated with
  nosmt and then spectre_v2_user=prctl and spectre_v2_user=seccomp
  would become identical.

- Setting spectre_v2_user=seccomp is overall lower priority than to
  setting javascript.options.wasm false in about:config to protect
  against remote wasm MDS-HT, instead of worrying about Spectre-v2-HT
  and STIBP which again is already statistically well mitigated by
  other means in userland and it's fully mitigated in kernel with
  retpolines (unlike the wasm assist call with MDS-HT).

- SSBD is needed to prevent reading the JIT memory and the primary
  user being the OpenJDK. However the primary user of SSBD wouldn't be
  covered by spec_store_bypass_disable=seccomp because it doesn't use
  seccomp and the primary user also explicitly declined to set
  PR_SET_SPECULATION_CTRL+PR_SPEC_STORE_BYPASS despite it easily
  could. In fact it would need to set it only when the sandboxing
  mechanism is enabled for javaws applets, but it still declined it by
  declaring security within the same user address space as an
  untenable objective for their JIT, even in the sandboxing case where
  performance would be a lesser concern (for the record: I kind of
  disagree in not setting PR_SPEC_STORE_BYPASS in the sandbox case and
  I prefer to run javaws through a wrapper that sets
  PR_SPEC_STORE_BYPASS if I need). In turn it can be inferred that
  even if the primary user of SSBD would use seccomp, they would
  invoke it with SECCOMP_FILTER_FLAG_SPEC_ALLOW by now.

- runc/crun already set SECCOMP_FILTER_FLAG_SPEC_ALLOW by default, k8s
  and podman have a default json seccomp allowlist that cannot be
  slowed down, so for the #1 seccomp user this change is already a
  noop.

- systemd/sshd or other apps that use seccomp, if they really need
  STIBP or SSBD, they need to explicitly set the
  PR_SET_SPECULATION_CTRL by now. The stibp/ssbd seccomp blind
  catch-all approach was done probably initially with a wishful
  thinking objective to pretend to have a peace of mind that it could
  magically fix it all. That was wishful thinking before MDS-HT was
  discovered, but after MDS-HT has been discovered it become just
  window dressing.

- For qemu "-sandbox" seccomp jail it wouldn't make sense to set STIBP
  or SSBD. SSBD doesn't help with KVM because there's no JIT (if it's
  needed with TCG it should be an opt-in with
  PR_SET_SPECULATION_CTRL+PR_SPEC_STORE_BYPASS and it shouldn't
  slowdown KVM for nothing). For qemu+KVM STIBP would be even more
  window dressing than it is for all other apps, because in the
  qemu+KVM case there's not only the MDS attack to worry about with
  SMT enabled. Even after disabling SMT, there's still a theoretical
  spectre-v2 attack possible within the same thread context from guest
  mode to host ring3 that the host kernel retpoline mitigation has no
  theoretical chance to mitigate. On some kernels a
  ibrs-always/ibrs-retpoline opt-in model is provided that will
  enabled IBRS in the qemu host ring3 userland which fixes this
  theoretical concern. Only after enabling IBRS in the host userland
  it would then make sense to proceed and worry about STIBP and an
  attack on the other host userland, but then again SMT would need to
  be disabled for full security anyway, so that would render STIBP
  again a noop.

- last but not the least: the lack of "spec_store_bypass_disable=prctl
  spectre_v2_user=prctl" means the moment a guest boots and
  sshd/systemd runs, the guest kernel will write to SPEC_CTRL MSR
  which will make the guest vmexit forever slower, forcing KVM to
  issue a very slow rdmsr instruction at every vmexit. So the end
  result is that SPEC_CTRL MSR is only available in GCE. Most other
  public cloud providers don't expose SPEC_CTRL, which means that not
  only STIBP/SSBD isn't available, but IBPB isn't available either
  (which would cause no overhead to the guest or the hypervisor
  because it's write only and requires no reading during vmexit). So
  the current default already net loss in security (missing IBPB)
  which means most public cloud providers cannot achieve a fully
  secure guest with nosmt (and nosmt is enough to fully mitigate
  MDS-HT). It also means GCE and is unfairly penalized in performance
  because it provides the option to enable full security in the guest
  as an opt-in (i.e. nosmt and IBPB). So this change will allow all
  cloud providers to expose SPEC_CTRL without incurring into any
  hypervisor slowdown and at the same time it will remove the unfair
  penalization of GCE performance for doing the right thing and it'll
  allow to get full security with nosmt with IBPB being available (and
  STIBP becoming meaningless).

Example to put things in prospective: the STIBP enabled in seccomp has
never been about protecting apps using seccomp like sshd from an
attack from a malicious userland, but to the contrary it has always
been about protecting the system from an attack from sshd, after a
successful remote network exploit against sshd. In fact initially it
wasn't obvious STIBP would work both ways (STIBP was about preventing
the task that runs with STIBP to be attacked with spectre-v2-HT, but
accidentally in the STIBP case it also prevents the attack in the
other direction). In the hypothetical case that sshd has been remotely
exploited the last concern should be STIBP being set, because it'll be
still possible to obtain info even from the kernel by using MDS if
nosmt wasn't set (and if it was set, STIBP is a noop in the first
place). As opposed kernel cannot leak anything with spectre-v2 HT
because of retpolines and the userland is mitigated by ASLR already
and ideally PID namespaces too. If something it'd be worth checking if
sshd run the seccomp thread under pid namespaces too if available in
the running kernel. SSBD also would be a noop for sshd, since sshd
uses no JIT. If sshd prefers to keep doing the STIBP window dressing
exercise, it still can even after this change of defaults by opting-in
with PR_SPEC_INDIRECT_BRANCH.

Ultimately setting SSBD and STIBP by default for all seccomp jails is
a bad sweet spot and bad default with more cons than pros that end up
reducing security in the public cloud (by giving an huge incentive to
not expose SPEC_CTRL which would be needed to get full security with
IBPB after setting nosmt in the guest) and by excessively hurting
performance to more secure apps using seccomp that end up having to
opt out with SECCOMP_FILTER_FLAG_SPEC_ALLOW.

The following is the verified result of the new default with SMT
enabled:

(gdb) print spectre_v2_user_stibp
$1 = SPECTRE_V2_USER_PRCTL
(gdb) print spectre_v2_user_ibpb
$2 = SPECTRE_V2_USER_PRCTL
(gdb) print ssb_mode
$3 = SPEC_STORE_BYPASS_PRCTL
Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201104235054.5678-1-aarcange@redhat.comAcked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/lkml/AAA2EF2C-293D-4D5B-BFA6-FF655105CD84@redhat.comAcked-by: default avatarWaiman Long <longman@redhat.com>
Link: https://lore.kernel.org/lkml/c0722838-06f7-da6b-138f-e0f26362f16a@redhat.com
      2f46993d
  5. 20 Sep, 2021 2 commits
    • Linus Torvalds's avatar
      Linux 5.15-rc2 · e4e737bb
      Linus Torvalds authored
      e4e737bb
    • Linus Torvalds's avatar
      pci_iounmap'2: Electric Boogaloo: try to make sense of it all · 316e8d79
      Linus Torvalds authored 
      Nathan Chancellor reports that the recent change to pci_iounmap in
commit 9caea000 ("parisc: Declare pci_iounmap() parisc version only
when CONFIG_PCI enabled") causes build errors on arm64.

It took me about two hours to convince myself that I think I know what
the logic of that mess of #ifdef's in the <asm-generic/io.h> header file
really aim to do, and rewrite it to be easier to follow.

Famous last words.

Anyway, the code has now been lifted from that grotty header file into
lib/pci_iomap.c, and has fairly extensive comments about what the logic
is.  It also avoids indirecting through another confusing (and badly
named) helper function that has other preprocessor config conditionals.

Let's see what odd architecture did something else strange in this area
to break things.  But my arm64 cross build is clean.

Fixes: 9caea000 ("parisc: Declare pci_iounmap() parisc version only when CONFIG_PCI enabled")
Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ulrich Teichert <krypton@ulrich-teichert.org>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      316e8d79
  7. 19 Sep, 2021 18 commits
  9. 18 Sep, 2021 12 commits
    • Linus Torvalds's avatar
      alpha: move __udiv_qrnnd library function to arch/alpha/lib/ · d4d016ca
      Linus Torvalds authored 
      We already had the implementation for __udiv_qrnnd (unsigned divide for
multi-precision arithmetic) as part of the alpha math emulation code.

But you can disable the math emulation code - even if you shouldn't -
and then the MPI code that actually wants this functionality (and is
needed by various crypto functions) will fail to build.

So move the extended-precision divide code to be a regular library
function, just like all the regular division code is.  That way ie is
available regardless of math-emulation.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d4d016ca
    • Linus Torvalds's avatar
      alpha: mark 'Jensen' platform as no longer broken · ab41f75e
      Linus Torvalds authored 
      Ok, it almost certainly is still broken on actual hardware, but the
immediate reason for it having been marked BROKEN was a build error that
is fixed by just making sure the low-level IO header file is included
sufficiently early that the __EXTERN_INLINE hackery takes effect.

This was marked broken back in 2017 by commit 1883c9f4 ("alpha: mark
jensen as broken"), but Ulrich Teichert made me look at it as part of my
cross-build work to make sure -Werror actually does the right thing.

There are lots of alpha configurations that do not build cleanly, but
now it's no longer because Jensen wouldn't be buildable.  That said,
because the Jensen platform doesn't force PCI to be enabled (Jensen only
had EISA), it ends up being somewhat interesting as a source of odd
configs.
Reported-by: default avatarUlrich Teichert <krypton@ulrich-teichert.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ab41f75e
    • Andrii Nakryiko's avatar
      perf bpf: Ignore deprecation warning when using libbpf's btf__get_from_id() · 219d720e
      Andrii Nakryiko authored 
      Perf code re-implements libbpf's btf__load_from_kernel_by_id() API as
a weak function, presumably to dynamically link against old version of
libbpf shared library. Unfortunately this causes compilation warning
when perf is compiled against libbpf v0.6+.

For now, just ignore deprecation warning, but there might be a better
solution, depending on perf's needs.
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: kernel-team@fb.com
LPU-Reference: 20210914170004.4185659-1-andrii@kernel.org
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      219d720e
    • Ian Rogers's avatar
      libperf evsel: Make use of FD robust. · aba5daeb
      Ian Rogers authored 
      FD uses xyarray__entry that may return NULL if an index is out of
bounds. If NULL is returned then a segv happens as FD unconditionally
dereferences the pointer. This was happening in a case of with perf
iostat as shown below. The fix is to make FD an "int*" rather than an
int and handle the NULL case as either invalid input or a closed fd.

  $ sudo gdb --args perf stat --iostat  list
  ...
  Breakpoint 1, perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
  50      {
  (gdb) bt
   #0  perf_evsel__alloc_fd (evsel=0x5555560951a0, ncpus=1, nthreads=1) at evsel.c:50
   #1  0x000055555585c188 in evsel__open_cpu (evsel=0x5555560951a0, cpus=0x555556093410,
      threads=0x555556086fb0, start_cpu=0, end_cpu=1) at util/evsel.c:1792
   #2  0x000055555585cfb2 in evsel__open (evsel=0x5555560951a0, cpus=0x0, threads=0x555556086fb0)
      at util/evsel.c:2045
   #3  0x000055555585d0db in evsel__open_per_thread (evsel=0x5555560951a0, threads=0x555556086fb0)
      at util/evsel.c:2065
   #4  0x00005555558ece64 in create_perf_stat_counter (evsel=0x5555560951a0,
      config=0x555555c34700 <stat_config>, target=0x555555c2f1c0 <target>, cpu=0) at util/stat.c:590
   #5  0x000055555578e927 in __run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
      at builtin-stat.c:833
   #6  0x000055555578f3c6 in run_perf_stat (argc=1, argv=0x7fffffffe4a0, run_idx=0)
      at builtin-stat.c:1048
   #7  0x0000555555792ee5 in cmd_stat (argc=1, argv=0x7fffffffe4a0) at builtin-stat.c:2534
   #8  0x0000555555835ed3 in run_builtin (p=0x555555c3f540 <commands+288>, argc=3,
      argv=0x7fffffffe4a0) at perf.c:313
   #9  0x0000555555836154 in handle_internal_command (argc=3, argv=0x7fffffffe4a0) at perf.c:365
   #10 0x000055555583629f in run_argv (argcp=0x7fffffffe2ec, argv=0x7fffffffe2e0) at perf.c:409
   #11 0x0000555555836692 in main (argc=3, argv=0x7fffffffe4a0) at perf.c:539
  ...
  (gdb) c
  Continuing.
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (uncore_iio_0/event=0x83,umask=0x04,ch_mask=0xF,fc_mask=0x07/).
  /bin/dmesg | grep -i perf may provide additional information.

  Program received signal SIGSEGV, Segmentation fault.
  0x00005555559b03ea in perf_evsel__close_fd_cpu (evsel=0x5555560951a0, cpu=1) at evsel.c:166
  166                     if (FD(evsel, cpu, thread) >= 0)

v3. fixes a bug in perf_evsel__run_ioctl where the sense of a branch was
    backward.
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Acked-by: default avatarJiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210918054440.2350466-1-irogers@google.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      aba5daeb
    • Michael Petlan's avatar
      perf machine: Initialize srcline string member in add_location struct · 57f0ff05
      Michael Petlan authored 
      It's later supposed to be either a correct address or NULL. Without the
initialization, it may contain an undefined value which results in the
following segmentation fault:

  # perf top --sort comm -g --ignore-callees=do_idle

terminates with:

  #0  0x00007ffff56b7685 in __strlen_avx2 () from /lib64/libc.so.6
  #1  0x00007ffff55e3802 in strdup () from /lib64/libc.so.6
  #2  0x00005555558cb139 in hist_entry__init (callchain_size=<optimized out>, sample_self=true, template=0x7fffde7fb110, he=0x7fffd801c250) at util/hist.c:489
  #3  hist_entry__new (template=template@entry=0x7fffde7fb110, sample_self=sample_self@entry=true) at util/hist.c:564
  #4  0x00005555558cb4ba in hists__findnew_entry (hists=hists@entry=0x5555561d9e38, entry=entry@entry=0x7fffde7fb110, al=al@entry=0x7fffde7fb420,
      sample_self=sample_self@entry=true) at util/hist.c:657
  #5  0x00005555558cba1b in __hists__add_entry (hists=hists@entry=0x5555561d9e38, al=0x7fffde7fb420, sym_parent=<optimized out>, bi=bi@entry=0x0, mi=mi@entry=0x0,
      sample=sample@entry=0x7fffde7fb4b0, sample_self=true, ops=0x0, block_info=0x0) at util/hist.c:288
  #6  0x00005555558cbb70 in hists__add_entry (sample_self=true, sample=0x7fffde7fb4b0, mi=0x0, bi=0x0, sym_parent=<optimized out>, al=<optimized out>, hists=0x5555561d9e38)
      at util/hist.c:1056
  #7  iter_add_single_cumulative_entry (iter=0x7fffde7fb460, al=<optimized out>) at util/hist.c:1056
  #8  0x00005555558cc8a4 in hist_entry_iter__add (iter=iter@entry=0x7fffde7fb460, al=al@entry=0x7fffde7fb420, max_stack_depth=<optimized out>, arg=arg@entry=0x7fffffff7db0)
      at util/hist.c:1231
  #9  0x00005555557cdc9a in perf_event__process_sample (machine=<optimized out>, sample=0x7fffde7fb4b0, evsel=<optimized out>, event=<optimized out>, tool=0x7fffffff7db0)
      at builtin-top.c:842
  #10 deliver_event (qe=<optimized out>, qevent=<optimized out>) at builtin-top.c:1202
  #11 0x00005555558a9318 in do_flush (show_progress=false, oe=0x7fffffff80e0) at util/ordered-events.c:244
  #12 __ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP, timestamp=timestamp@entry=0) at util/ordered-events.c:323
  #13 0x00005555558a9789 in __ordered_events__flush (timestamp=<optimized out>, how=<optimized out>, oe=<optimized out>) at util/ordered-events.c:339
  #14 ordered_events__flush (how=OE_FLUSH__TOP, oe=0x7fffffff80e0) at util/ordered-events.c:341
  #15 ordered_events__flush (oe=oe@entry=0x7fffffff80e0, how=how@entry=OE_FLUSH__TOP) at util/ordered-events.c:339
  #16 0x00005555557cd631 in process_thread (arg=0x7fffffff7db0) at builtin-top.c:1114
  #17 0x00007ffff7bb817a in start_thread () from /lib64/libpthread.so.0
  #18 0x00007ffff5656dc3 in clone () from /lib64/libc.so.6

If you look at the frame #2, the code is:

488	 if (he->srcline) {
489          he->srcline = strdup(he->srcline);
490          if (he->srcline == NULL)
491              goto err_rawdata;
492	 }

If he->srcline is not NULL (it is not NULL if it is uninitialized rubbish),
it gets strdupped and strdupping a rubbish random string causes the problem.

Also, if you look at the commit 1fb7d06a, it adds the srcline property
into the struct, but not initializing it everywhere needed.

Committer notes:

Now I see, when using --ignore-callees=do_idle we end up here at line
2189 in add_callchain_ip():

2181         if (al.sym != NULL) {
2182                 if (perf_hpp_list.parent && !*parent &&
2183                     symbol__match_regex(al.sym, &parent_regex))
2184                         *parent = al.sym;
2185                 else if (have_ignore_callees && root_al &&
2186                   symbol__match_regex(al.sym, &ignore_callees_regex)) {
2187                         /* Treat this symbol as the root,
2188                            forgetting its callees. */
2189                         *root_al = al;
2190                         callchain_cursor_reset(cursor);
2191                 }
2192         }

And the al that doesn't have the ->srcline field initialized will be
copied to the root_al, so then, back to:

1211 int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
1212                          int max_stack_depth, void *arg)
1213 {
1214         int err, err2;
1215         struct map *alm = NULL;
1216
1217         if (al)
1218                 alm = map__get(al->map);
1219
1220         err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent,
1221                                         iter->evsel, al, max_stack_depth);
1222         if (err) {
1223                 map__put(alm);
1224                 return err;
1225         }
1226
1227         err = iter->ops->prepare_entry(iter, al);
1228         if (err)
1229                 goto out;
1230
1231         err = iter->ops->add_single_entry(iter, al);
1232         if (err)
1233                 goto out;
1234

That al at line 1221 is what hist_entry_iter__add() (called from
sample__resolve_callchain()) saw as 'root_al', and then:

        iter->ops->add_single_entry(iter, al);

will go on with al->srcline with a bogus value, I'll add the above
sequence to the cset and apply, thanks!
Signed-off-by: default avatarMichael Petlan <mpetlan@redhat.com>
CC: Milian Wolff <milian.wolff@kdab.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: 1fb7d06a ("perf report Use srcline from callchain for hist entries")
Link: https //lore.kernel.org/r/20210719145332.29747-1-mpetlan@redhat.com
Reported-by: default avatarJuri Lelli <jlelli@redhat.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      57f0ff05
    • Adrian Hunter's avatar
      perf script: Fix ip display when type != attr->type · ff6f41fb
      Adrian Hunter authored 
      set_print_ip_opts() was not being called when type != attr->type
because there is not a one-to-one relationship between output types
and attr->type. That resulted in ip not printing.

The attr_type() function is removed, and the match of attr->type to
output type is corrected.

Example on ADL using taskset to select an atom cpu:

 # perf record -e cpu_atom/cpu-cycles/ taskset 0x1000 uname
 Linux
 [ perf record: Woken up 1 times to write data ]
 [ perf record: Captured and wrote 0.003 MB perf.data (7 samples) ]

 Before:

  # perf script | head
         taskset   428 [-01] 10394.179041:          1 cpu_atom/cpu-cycles/:
         taskset   428 [-01] 10394.179043:          1 cpu_atom/cpu-cycles/:
         taskset   428 [-01] 10394.179044:         11 cpu_atom/cpu-cycles/:
         taskset   428 [-01] 10394.179045:        407 cpu_atom/cpu-cycles/:
         taskset   428 [-01] 10394.179046:      16789 cpu_atom/cpu-cycles/:
         taskset   428 [-01] 10394.179052:     676300 cpu_atom/cpu-cycles/:
           uname   428 [-01] 10394.179278:    4079859 cpu_atom/cpu-cycles/:

 After:

  # perf script | head
         taskset   428 10394.179041:          1 cpu_atom/cpu-cycles/:  ffffffff95a0bb97 __intel_pmu_enable_all.constprop.48+0x47 ([kernel.kallsyms])
         taskset   428 10394.179043:          1 cpu_atom/cpu-cycles/:  ffffffff95a0bb97 __intel_pmu_enable_all.constprop.48+0x47 ([kernel.kallsyms])
         taskset   428 10394.179044:         11 cpu_atom/cpu-cycles/:  ffffffff95a0bb97 __intel_pmu_enable_all.constprop.48+0x47 ([kernel.kallsyms])
         taskset   428 10394.179045:        407 cpu_atom/cpu-cycles/:  ffffffff95a0bb97 __intel_pmu_enable_all.constprop.48+0x47 ([kernel.kallsyms])
         taskset   428 10394.179046:      16789 cpu_atom/cpu-cycles/:  ffffffff95a0bb97 __intel_pmu_enable_all.constprop.48+0x47 ([kernel.kallsyms])
         taskset   428 10394.179052:     676300 cpu_atom/cpu-cycles/:      7f829ef73800 cfree+0x0 (/lib/libc-2.32.so)
           uname   428 10394.179278:    4079859 cpu_atom/cpu-cycles/:  ffffffff95bae912 vma_interval_tree_remove+0x1f2 ([kernel.kallsyms])
Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: default avatarKan Liang <kan.liang@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20210911133053.15682-1-adrian.hunter@intel.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      ff6f41fb
    • Ravi Bangoria's avatar
      perf annotate: Fix fused instr logic for assembly functions · 7efbcc8c
      Ravi Bangoria authored 
      Some x86 microarchitectures fuse a subset of cmp/test/ALU instructions
with branch instructions, and thus perf annotate highlight such valid
pairs as fused.

When annotated with source, perf uses struct disasm_line to contain
either source or instruction line from objdump output. Usually, a C
statement generates multiple instructions which include such
cmp/test/ALU + branch instruction pairs. But in case of assembly
function, each individual assembly source line generate one
instruction.

The 'perf annotate' instruction fusion logic assumes the previous
disasm_line as the previous instruction line, which is wrong because,
for assembly function, previous disasm_line contains source line.  And
thus perf fails to highlight valid fused instruction pairs for assembly
functions.

Fix it by searching backward until we find an instruction line and
consider that disasm_line as fused with current branch instruction.

Before:
         │    cmpq    %rcx, RIP+8(%rsp)
    0.00 │      cmp    %rcx,0x88(%rsp)
         │    je      .Lerror_bad_iret      <--- Source line
    0.14 │   ┌──je     b4                   <--- Instruction line
         │   │movl    %ecx, %eax

After:
         │    cmpq    %rcx, RIP+8(%rsp)
    0.00 │   ┌──cmp    %rcx,0x88(%rsp)
         │   │je      .Lerror_bad_iret
    0.14 │   ├──je     b4
         │   │movl    %ecx, %eax
Reviewed-by: default avatarJin Yao <yao.jin@linux.intel.com>
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@amd.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kim Phillips <kim.phillips@amd.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https //lore.kernel.org/r/20210911043854.8373-1-ravi.bangoria@amd.com
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      7efbcc8c
    • Linus Torvalds's avatar
      Merge tag 's390-5.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux · 93ff9f13
      Linus Torvalds authored 
      Pull s390 fixes from Vasily Gorbik:

 - Fix potential out-of-range access during secure boot facility
   detection.

 - Fully validate the VMA before calling follow_pte() in pci code.

 - Remove arch specific WARN_DYNAMIC_STACK config option.

 - Fix zcrypto kernel doc comments.

 - Update defconfigs.

* tag 's390-5.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390: remove WARN_DYNAMIC_STACK
  s390/ap: fix kernel doc comments
  s390: update defconfigs
  s390/sclp: fix Secure-IPL facility detection
  s390/pci_mmio: fully validate the VMA before calling follow_pte()
      93ff9f13
    • Linus Torvalds's avatar
      Merge tag 'devicetree-fixes-for-5.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux · d1a88690
      Linus Torvalds authored 
      Pull devicetree fixes from Rob Herring:

 - Revert fw_devlink tracking 'phy-handle' links. This broke at least a
   few platforms. A better solution is being worked on.

 - Add Samsung UFS binding which fell thru the cracks

 - Doc reference fixes from Mauro

 - Fix for restricted DMA error handling

* tag 'devicetree-fixes-for-5.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  dt-bindings: arm: Fix Toradex compatible typo
  of: restricted dma: Fix condition for rmem init
  dt-bindings: arm: mediatek: mmsys: update mediatek,mmsys.yaml reference
  dt-bindings: net: dsa: sja1105: update nxp,sja1105.yaml reference
  dt-bindings: ufs: Add bindings for Samsung ufs host
  Revert "of: property: fw_devlink: Add support for "phy-handle" property"
      d1a88690
    • Linus Torvalds's avatar
      tgafb: clarify dependencies · cd395d52
      Linus Torvalds authored 
      The TGA boards were based on the DECchip 21030 PCI graphics accelerator
used mainly for alpha, and existed in a TURBOchannel (TC) version for
the DECstation (MIPS) workstations.

However, the config option for the TGA code is a bit confused, and says

	depends on FB && (ALPHA || TC)

because people didn't really want to enable the option for random PCI
environments, so the "ALPHA" stands in for that case (while the TC case
is then the MIPS DECstation case).

So that config dependency is kind of a mixture of architecture and bus
choices.  But it's incorrect, in that there were non-PCI-based alpha
hardware, and then the driver just causes warnings:

  drivers/video/fbdev/tgafb.c:1532:13: error: ‘tgafb_unregister’ defined but not used [-Werror=unused-function]
   1532 | static void tgafb_unregister(struct device *dev)
        |             ^~~~~~~~~~~~~~~~
  drivers/video/fbdev/tgafb.c:1387:12: error: ‘tgafb_register’ defined but not used [-Werror=unused-function]
   1387 | static int tgafb_register(struct device *dev)
        |            ^~~~~~~~~~~~~~

so let's make the config option dependencies a bit more explict:

	depends on FB
	depends on PCI || TC
	depends on ALPHA || TC

where that first "FB" is the software configuration dependency, the
second "PCI || TC" is the hardware bus dependency, while that final
"ALPHA || TC" dependency is the "don't bother asking except for these
situations.

We could make that third case have "COMPILE_TEST" as an option, and mark
the register/unregister functions as __maybe_unused, but I'm not sure
it's really worth it.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cd395d52
    • Linus Torvalds's avatar
      alpha: make 'Jensen' IO functions build again · cc9d3aaa
      Linus Torvalds authored 
      The Jensen IO functions are overly copmplicated because some of the IO
addresses refer to special 'local IO' ports, and they get accessed
differently.

That then makes gcc not actually inline them, and since they were marked
"extern inline" when included through the regular <asm/io.h> path, and
then only marked "inline" when included from sys_jensen.c, you never
necessarily got a body for the IO functions at all.

The intent of the sys_jensen.c code is to actually get the non-inlined
copy generated, so remove the 'inline' from the magic macro that is
supposed to sort this all out.

Also, do not mix 'extern inline' functions (that may or may not be
inlined and will not generate a function body if they are not) with
'static inline' (that _will_ generate a function body when not inlined).
Because gcc will complain about this situation:

   error: ‘jensen_bus_outb’ is static but used in inline function ‘jensen_outb’ which is not static

because gcc basically doesn't know whether to generate a body for that
static inline function or not for that call site.

So make all of these use that __EXTERN_INLINE marker.  Gcc will
generally not inline these things on use, and then generate the function
body out-of-line in sys_jensen.c.

This makes the core IO functions build for the alpha Jensen config.

Not that the rest then builds, because it turns out Jensen also doesn't
enable PCI, which then makes other drievrs very unhappy, but that's a
separate issue.
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cc9d3aaa
    • Linus Torvalds's avatar
      spi: Fix tegra20 build with CONFIG_PM=n · efafec27
      Linus Torvalds authored 
      Without CONFIG_PM enabled, the SET_RUNTIME_PM_OPS() macro ends up being
empty, and the only use of tegra_slink_runtime_{resume,suspend} goes
away, resulting in

  drivers/spi/spi-tegra20-slink.c:1200:12: error: ‘tegra_slink_runtime_resume’ defined but not used [-Werror=unused-function]
   1200 | static int tegra_slink_runtime_resume(struct device *dev)
        |            ^~~~~~~~~~~~~~~~~~~~~~~~~~
  drivers/spi/spi-tegra20-slink.c:1188:12: error: ‘tegra_slink_runtime_suspend’ defined but not used [-Werror=unused-function]
   1188 | static int tegra_slink_runtime_suspend(struct device *dev)
        |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~

mark the functions __maybe_unused to make the build happy.

This hits the alpha allmodconfig build (and others).
Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      efafec27
  11. 17 Sep, 2021 4 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7