linux-stable.git/tools/perf/util/thread-stack.c, branch linux-6.4.y

x86/retpoline,kprobes: Skip optprobe check for indirect jumps with retpolines and IBT

2023-08-23T15:32:41+00:00

commit 833fd800bf56b74d39d71d3f5936dffb3e0409c6 upstream.

The kprobes optimization check can_optimize() calls
insn_is_indirect_jump() to detect indirect jump instructions in
a target function. If any is found, creating an optprobe is disallowed
in the function because the jump could be from a jump table and could
potentially land in the middle of the target optprobe.

With retpolines, insn_is_indirect_jump() additionally looks for calls to
indirect thunks which the compiler potentially used to replace original
jumps. This extra check is however unnecessary because jump tables are
disabled when the kernel is built with retpolines. The same is currently
the case with IBT.

Based on this observation, remove the logic to look for calls to
indirect thunks and skip the check for indirect jumps altogether if the
kernel is built with retpolines or IBT. Remove subsequently the symbols
__indirect_thunk_start and __indirect_thunk_end which are no longer
needed.

Dropping this logic indirectly fixes a problem where the range
[__indirect_thunk_start, __indirect_thunk_end] wrongly included also the
return thunk. It caused that machines which used the return thunk as
a mitigation and didn't have it patched by any alternative ended up not
being able to use optprobes in any regular function.

Fixes: 0b53c374b9ef ("x86/retpoline: Use -mfunction-return")
Suggested-by: Peter Zijlstra (Intel) 
Suggested-by: Masami Hiramatsu (Google) 
Signed-off-by: Petr Pavlu 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov (AMD) 
Acked-by: Masami Hiramatsu (Google) 
Link: https://lore.kernel.org/r/20230711091952.27944-3-petr.pavlu@suse.com
Signed-off-by: Greg Kroah-Hartman

perf maps: Add functions to access maps

2023-04-04T18:45:38+00:00

Introduce functions to access struct maps. These functions reduce the
number of places reference counting is necessary. While tidying APIs do
some small const-ification, in particlar to unwind_libunwind_ops.

Committer notes:

Fixed up tools/perf/util/unwind-libunwind.c:

-               return ops->get_entries(cb, arg, thread, data, max_stack);
+               return ops->get_entries(cb, arg, thread, data, max_stack, best_effort);

Signed-off-by: Ian Rogers 
Cc: Adrian Hunter 
Cc: Alexander Shishkin 
Cc: Alexey Bayduraev 
Cc: Andi Kleen 
Cc: Andrew Morton 
Cc: Andy Shevchenko 
Cc: Darren Hart 
Cc: Davidlohr Bueso 
Cc: Dmitriy Vyukov 
Cc: Eric Dumazet 
Cc: German Gomez 
Cc: Hao Luo 
Cc: Ingo Molnar 
Cc: James Clark 
Cc: Jiri Olsa 
Cc: John Garry 
Cc: Kajol Jain 
Cc: Kan Liang 
Cc: Leo Yan 
Cc: Madhavan Srinivasan 
Cc: Mark Rutland 
Cc: Masami Hiramatsu 
Cc: Miaoqian Lin 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Riccardo Mancini 
Cc: Shunsuke Nakamura 
Cc: Song Liu 
Cc: Stephane Eranian 
Cc: Stephen Brennan 
Cc: Steven Rostedt (VMware) 
Cc: Thomas Gleixner 
Cc: Thomas Richter 
Cc: Yury Norov 
Link: https://lore.kernel.org/r/20230320212248.1175731-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Add thread_stack__br_sample_late()

2020-05-05T19:35:29+00:00

Add a thread stack function to create a branch stack for hardware events
where the sample records get created some time after the event occurred.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lore.kernel.org/lkml/20200429150751.12570-7-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Add branch stack support

2020-05-05T19:35:29+00:00

Intel PT already has support for creating branch stacks for each context
(per-cpu or per-thread). In the more common per-cpu case, the branch stack
is not separated for different threads, instead being cleared in between
each sample.

That approach will not work very well for adding branch stacks to
regular events. The branch stacks really need to be accumulated
separately for each thread.

As a start to accomplishing that, this patch adds support for putting
branch stack support into the thread-stack. The advantages are:

1. the branches are accumulated separately for each thread
2. the branch stack is cleared only in between continuous traces

This helps pave the way for adding branch stacks to regular events, not
just synthesized events as at present.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lore.kernel.org/lkml/20200429150751.12570-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Add thread_stack__sample_late()

2020-04-16T15:19:15+00:00

Add a thread stack function to create a call chain for hardware events
where the sample records get created some time after the event occurred.

Signed-off-by: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Link: http://lore.kernel.org/lkml/20200401101613.6201-10-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Rename thread->mg to thread->maps

2019-11-26T14:07:46+00:00

One more step on the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter 
Cc: Andi Kleen 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-69vcr8pubpym90skxhmbwhiw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf debug: Remove needless include directives from debug.h

2019-08-31T22:10:19+00:00

All we need there is a forward declaration for 'union perf_event', so
remove it from there and add missing header directives in places using
things from this indirect include.

Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-7ftk0ztstqub1tirjj8o8xbl@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

tools lib: Adopt zalloc()/zfree() from tools/perf

2019-07-09T13:13:26+00:00

Eroding a bit more the tools/perf/util/util.h hodpodge header.

Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-natazosyn9rwjka25tvcnyi0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add missing headers, mostly stdlib.h

2019-07-09T13:13:22+00:00

Part of the erosion of util/util.h, that will lose its include stdlib.h,
we need to add it to places where it is needed but was getting it
indirectly.

Cc: Adrian Hunter 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Link: https://lkml.kernel.org/n/tip-1imnqezw99ahc07fjeb51qby@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf thread-stack: Eliminate code duplicating thread_stack__pop_ks()

2019-06-25T11:47:10+00:00

Use new function thread_stack__pop_ks() in place of equivalent code.

Signed-off-by: Adrian Hunter 
Cc: Jiri Olsa 
Link: http://lkml.kernel.org/r/20190619064429.14940-3-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo