From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, joao@overdrivepizza.com, hjl.tools@gmail.com,
jpoimboe@redhat.com, andrew.cooper3@citrix.com,
linux-kernel@vger.kernel.org, ndesaulniers@google.com,
keescook@chromium.org, samitolvanen@google.com,
mark.rutland@arm.com, alyssa.milburn@intel.com, mbenes@suse.cz,
mhiramat@kernel.org, alexei.starovoitov@gmail.com
Subject: Re: [PATCH v2 14/39] x86/ibt,ftrace: Make function-graph play nice
Date: Thu, 24 Feb 2022 10:42:30 -0500 [thread overview]
Message-ID: <20220224104230.4a9a3125@gandalf.local.home> (raw)
In-Reply-To: <YhemGUoGmrzxuc+C@hirez.programming.kicks-ass.net>
On Thu, 24 Feb 2022 16:36:57 +0100
Peter Zijlstra <peterz@infradead.org> wrote:
> On Thu, Feb 24, 2022 at 03:51:52PM +0100, Peter Zijlstra wrote:
> > @@ -316,10 +317,12 @@ SYM_FUNC_START(return_to_handler)
> >
> > call ftrace_return_to_handler
> >
> > - movq %rax, %rdi
> > + movq %rax, 16(%rsp)
> > movq 8(%rsp), %rdx
> > movq (%rsp), %rax
> > - addq $24, %rsp
> > - JMP_NOSPEC rdi
> > +
> > + addq $16, %rsp
> > + UNWIND_HINT_FUNC
> > + RET
> > SYM_FUNC_END(return_to_handler)
> > #endif
>
> While talking about this with Mark, an alternative solution is something
> like this, that would keep the RSB balanced and only mess up the current
> return.
>
> No idea it if makes an appreciatable difference on current hardware,
> therefore I went with the simpler option above.
>
> @@ -307,7 +315,7 @@ EXPORT_SYMBOL(__fentry__)
>
> #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> SYM_FUNC_START(return_to_handler)
> - subq $24, %rsp
> + subq $16, %rsp
>
> /* Save the return values */
> movq %rax, (%rsp)
> @@ -319,7 +327,13 @@ SYM_FUNC_START(return_to_handler)
> movq %rax, %rdi
> movq 8(%rsp), %rdx
> movq (%rsp), %rax
> - addq $24, %rsp
> - JMP_NOSPEC rdi
> +
> + addq $16, %rsp
> + ANNOTATE_INTRA_FUNCTION_CALL
> + call .Ldo_rop
> +.Ldo_rop:
What's the overhead of an added call (for every function call that is being
traced)?
-- Steve
> + mov %rdi, (%rsp)
> + UNWIND_HINT_FUNC
> + RET
> SYM_FUNC_END(return_to_handler)
> #endif
>
next prev parent reply other threads:[~2022-02-24 15:42 UTC|newest]
Thread overview: 183+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-24 14:51 [PATCH v2 00/39] x86: Kernel IBT Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 01/39] kbuild: Fix clang build Peter Zijlstra
2022-02-25 0:11 ` Kees Cook
2022-03-01 21:16 ` Nick Desaulniers
2022-03-02 0:47 ` Kees Cook
2022-03-02 0:53 ` Fangrui Song
2022-03-02 16:37 ` Nathan Chancellor
2022-03-02 18:40 ` Kees Cook
2022-03-02 19:18 ` Nick Desaulniers
2022-03-02 21:15 ` Nathan Chancellor
2022-03-02 22:07 ` Nick Desaulniers
2022-03-02 23:00 ` Kees Cook
2022-03-02 23:10 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 02/39] static_call: Avoid building empty .static_call_sites Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 03/39] x86/module: Fix the paravirt vs alternative order Peter Zijlstra
2022-03-01 14:37 ` Miroslav Benes
2022-02-24 14:51 ` [PATCH v2 04/39] objtool: Add --dry-run Peter Zijlstra
2022-02-25 0:27 ` Kees Cook
2022-03-01 14:37 ` Miroslav Benes
2022-02-24 14:51 ` [PATCH v2 05/39] x86: Base IBT bits Peter Zijlstra
2022-02-25 0:35 ` Kees Cook
2022-02-25 0:46 ` Nathan Chancellor
2022-02-25 22:08 ` Nathan Chancellor
2022-02-26 0:29 ` Joao Moreira
2022-02-26 4:58 ` Kees Cook
2022-02-26 4:59 ` Fāng-ruì Sòng
2022-02-26 5:04 ` Kees Cook
2022-02-25 13:41 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 06/39] x86/ibt: Add ANNOTATE_NOENDBR Peter Zijlstra
2022-02-25 0:36 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 07/39] x86/entry: Sprinkle ENDBR dust Peter Zijlstra
2022-02-24 22:37 ` Josh Poimboeuf
2022-02-25 0:42 ` Kees Cook
2022-02-25 9:22 ` Andrew Cooper
2022-02-24 14:51 ` [PATCH v2 08/39] x86/linkage: Add ENDBR to SYM_FUNC_START*() Peter Zijlstra
2022-02-25 0:45 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 09/39] x86/ibt,paravirt: Sprinkle ENDBR Peter Zijlstra
2022-02-25 0:47 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 10/39] x86/ibt,crypto: Add ENDBR for the jump-table entries Peter Zijlstra
2022-02-24 22:41 ` Josh Poimboeuf
2022-02-25 0:50 ` Kees Cook
2022-02-25 10:22 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 11/39] x86/ibt,kvm: Add ENDBR to fastops Peter Zijlstra
2022-02-25 0:54 ` Kees Cook
2022-02-25 10:24 ` Peter Zijlstra
2022-02-25 13:09 ` David Laight
2022-02-24 14:51 ` [PATCH v2 12/39] x86/ibt,ftrace: Search for __fentry__ location Peter Zijlstra
2022-02-24 15:55 ` Masami Hiramatsu
2022-02-24 15:58 ` Steven Rostedt
2022-02-24 15:59 ` Steven Rostedt
2022-02-24 16:01 ` Steven Rostedt
2022-02-24 22:46 ` Josh Poimboeuf
2022-02-24 22:51 ` Steven Rostedt
2022-02-25 1:34 ` Masami Hiramatsu
2022-02-25 2:19 ` Steven Rostedt
2022-02-25 10:20 ` Masami Hiramatsu
2022-02-25 13:36 ` Steven Rostedt
2022-03-01 18:57 ` Naveen N. Rao
2022-03-01 19:20 ` Steven Rostedt
2022-03-02 13:20 ` Peter Zijlstra
2022-03-02 16:01 ` Steven Rostedt
2022-03-02 19:47 ` Steven Rostedt
2022-03-02 20:48 ` Steven Rostedt
2022-03-02 20:51 ` Peter Zijlstra
2022-03-03 9:45 ` Naveen N. Rao
2022-03-03 13:04 ` Peter Zijlstra
2022-03-03 14:34 ` Steven Rostedt
2022-03-03 15:59 ` Peter Zijlstra
2022-03-06 3:48 ` Masami Hiramatsu
2022-03-09 11:47 ` Naveen N. Rao
2022-03-03 14:39 ` Naveen N. Rao
2022-02-25 0:55 ` Kees Cook
2022-03-02 16:25 ` Naveen N. Rao
2022-02-24 14:51 ` [PATCH v2 13/39] x86/livepatch: Validate " Peter Zijlstra
2022-02-24 23:02 ` Josh Poimboeuf
2022-02-24 14:51 ` [PATCH v2 14/39] x86/ibt,ftrace: Make function-graph play nice Peter Zijlstra
2022-02-24 15:36 ` Peter Zijlstra
2022-02-24 15:42 ` Steven Rostedt [this message]
2022-02-24 23:09 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 15/39] x86/ibt,kprobes: Fix more +0 assumptions Peter Zijlstra
2022-02-25 0:58 ` Kees Cook
2022-02-25 1:32 ` Masami Hiramatsu
2022-02-25 10:46 ` Peter Zijlstra
2022-02-25 13:42 ` Masami Hiramatsu
2022-02-25 15:41 ` Peter Zijlstra
2022-02-26 2:10 ` Masami Hiramatsu
2022-02-26 11:48 ` Peter Zijlstra
2022-02-25 14:14 ` Steven Rostedt
2022-02-26 7:09 ` Masami Hiramatsu
2022-02-28 6:07 ` Masami Hiramatsu
2022-02-28 23:25 ` Peter Zijlstra
2022-03-01 2:49 ` Masami Hiramatsu
2022-03-01 8:28 ` Peter Zijlstra
2022-03-01 17:19 ` Naveen N. Rao
2022-03-01 19:12 ` Peter Zijlstra
2022-03-01 20:05 ` Peter Zijlstra
2022-03-02 15:59 ` Naveen N. Rao
2022-03-02 16:38 ` Peter Zijlstra
2022-03-02 16:17 ` Naveen N. Rao
2022-03-02 19:32 ` Peter Zijlstra
2022-03-02 19:39 ` Peter Zijlstra
2022-03-03 12:11 ` Naveen N. Rao
2022-03-03 1:54 ` Masami Hiramatsu
2022-03-02 0:11 ` Masami Hiramatsu
2022-03-02 10:25 ` Peter Zijlstra
2022-03-01 17:03 ` Naveen N. Rao
2022-02-24 14:51 ` [PATCH v2 16/39] x86/bpf: Add ENDBR instructions to prologue and trampoline Peter Zijlstra
2022-02-24 23:37 ` Josh Poimboeuf
2022-02-25 0:59 ` Kees Cook
2022-02-25 11:20 ` Peter Zijlstra
2022-02-25 12:24 ` Peter Zijlstra
2022-02-25 22:46 ` Josh Poimboeuf
2022-02-24 14:51 ` [PATCH v2 17/39] x86/ibt,ftrace: Add ENDBR to samples/ftrace Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 18/39] x86/ibt: Add IBT feature, MSR and #CP handling Peter Zijlstra
2022-02-24 23:55 ` Josh Poimboeuf
2022-02-25 10:51 ` Peter Zijlstra
2022-02-25 11:10 ` Peter Zijlstra
2022-02-25 23:51 ` Josh Poimboeuf
2022-02-26 11:55 ` Peter Zijlstra
2022-02-25 1:09 ` Kees Cook
2022-02-25 19:59 ` Edgecombe, Rick P
2022-03-01 15:14 ` Peter Zijlstra
2022-03-01 21:02 ` Peter Zijlstra
2022-03-01 23:13 ` Josh Poimboeuf
2022-03-02 1:59 ` Edgecombe, Rick P
2022-03-02 13:49 ` Peter Zijlstra
2022-03-02 18:38 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 19/39] x86: Disable IBT around firmware Peter Zijlstra
2022-02-25 1:10 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 20/39] x86/bugs: Disable Retpoline when IBT Peter Zijlstra
2022-02-25 1:11 ` Kees Cook
2022-02-25 2:22 ` Josh Poimboeuf
2022-02-25 10:55 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 21/39] x86/ibt: Annotate text references Peter Zijlstra
2022-02-25 0:47 ` Josh Poimboeuf
2022-02-25 12:57 ` Peter Zijlstra
2022-02-25 13:04 ` Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 22/39] x86/ibt,ftrace: Annotate ftrace code patching Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 23/39] x86/ibt,sev: Annotations Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 24/39] x86/text-patching: Make text_gen_insn() IBT aware Peter Zijlstra
2022-02-25 0:49 ` Josh Poimboeuf
2022-02-24 14:52 ` [PATCH v2 25/39] x86/ibt,paravirt: Use text_gen_insn() for paravirt_patch() Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 26/39] x86/entry: Cleanup PARAVIRT Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 27/39] x86/entry,xen: Early rewrite of restore_regs_and_return_to_kernel() Peter Zijlstra
2022-02-24 17:51 ` Andrew Cooper
2022-02-24 14:52 ` [PATCH v2 28/39] x86/ibt,xen: Sprinkle the ENDBR Peter Zijlstra
2022-02-25 0:54 ` Josh Poimboeuf
2022-02-25 13:16 ` Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 29/39] objtool: Rename --duplicate to --lto Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 30/39] Kbuild: Allow whole module objtool runs Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 31/39] objtool: Read the NOENDBR annotation Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 32/39] x86/ibt: Dont generate ENDBR in .discard.text Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 33/39] objtool: Add IBT/ENDBR decoding Peter Zijlstra
2022-03-03 10:53 ` Miroslav Benes
2022-03-03 11:06 ` Andrew Cooper
2022-03-03 12:33 ` Miroslav Benes
2022-03-03 14:13 ` Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 34/39] objtool: Validate IBT assumptions Peter Zijlstra
2022-02-27 3:13 ` Josh Poimboeuf
2022-02-27 17:00 ` Peter Zijlstra
2022-02-27 22:20 ` Josh Poimboeuf
2022-02-28 9:47 ` Peter Zijlstra
2022-02-28 18:36 ` Josh Poimboeuf
2022-02-28 20:10 ` Peter Zijlstra
2022-02-28 9:26 ` Peter Zijlstra
2022-02-28 18:39 ` Josh Poimboeuf
2022-02-24 14:52 ` [PATCH v2 35/39] objtool: IBT fix direct JMP/CALL Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 36/39] objtool: Find unused ENDBR instructions Peter Zijlstra
2022-02-27 3:46 ` Josh Poimboeuf
2022-02-28 12:41 ` Peter Zijlstra
2022-02-28 17:36 ` Josh Poimboeuf
2022-02-24 14:52 ` [PATCH v2 37/39] x86/ibt: Finish --ibt-fix-direct on module loading Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 38/39] x86/ibt: Ensure module init/exit points have references Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 39/39] x86/alternative: Use .ibt_endbr_sites to seal indirect calls Peter Zijlstra
2022-02-24 20:26 ` [PATCH v2 00/39] x86: Kernel IBT Josh Poimboeuf
2022-02-25 15:28 ` Peter Zijlstra
2022-02-25 15:43 ` Peter Zijlstra
2022-02-25 17:26 ` Josh Poimboeuf
2022-02-25 17:32 ` Steven Rostedt
2022-02-25 19:53 ` Peter Zijlstra
2022-02-25 20:15 ` Josh Poimboeuf
2022-03-01 23:10 ` Josh Poimboeuf
2022-03-02 10:20 ` Peter Zijlstra
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