From: Linus Torvalds <torvalds@linux-foundation.org>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: David Laight <David.Laight@aculab.com>,
Thomas Gleixner <tglx@linutronix.de>,
Joao Moreira <joao@overdrivepizza.com>,
Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
"the arch/x86 maintainers" <x86@kernel.org>,
Tim Chen <tim.c.chen@linux.intel.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
"Cooper, Andrew" <andrew.cooper3@citrix.com>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Johannes Wikner <kwikner@ethz.ch>,
Alyssa Milburn <alyssa.milburn@linux.intel.com>,
Jann Horn <jannh@google.com>, "H.J. Lu" <hjl.tools@gmail.com>,
"Moreira, Joao" <joao.moreira@intel.com>,
"Nuzman, Joseph" <joseph.nuzman@intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
"Gross, Jurgen" <jgross@suse.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Peter Collingbourne <pcc@google.com>
Subject: Re: [patch 00/38] x86/retbleed: Call depth tracking mitigation
Date: Tue, 19 Jul 2022 10:27:00 -0700 [thread overview]
Message-ID: <CAHk-=wghqo3OtyR54FkBjkuELubPE3RzRNYU1z90BYtfuaoxzA@mail.gmail.com> (raw)
In-Reply-To: <YtbolH9YegJWUmHT@google.com>
On Tue, Jul 19, 2022 at 10:23 AM Sami Tolvanen <samitolvanen@google.com> wrote:
>
> The preamble hash is encoded into an instruction just to avoid special
> casing objtool, which would otherwise get confused about the random
> bytes. On arm64, we just emit a bare constant before the function.
Ahh.
I think objtool would want to understand about kCFI anyway, so I think
in the long run that hack isn't a goog idea.
But I get why you'd do it as a "do this as just a compiler thing and
hide it from objtool" as a development strategy.
Linus
next prev parent reply other threads:[~2022-07-19 17:35 UTC|newest]
Thread overview: 142+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-16 23:17 [patch 00/38] x86/retbleed: Call depth tracking mitigation Thomas Gleixner
2022-07-16 23:17 ` [patch 01/38] x86/paravirt: Ensure proper alignment Thomas Gleixner
2022-07-16 23:17 ` [patch 02/38] x86/cpu: Use native_wrmsrl() in load_percpu_segment() Thomas Gleixner
2022-07-17 0:22 ` Andrew Cooper
2022-07-17 15:20 ` Linus Torvalds
2022-07-17 19:08 ` Thomas Gleixner
2022-07-17 20:08 ` Thomas Gleixner
2022-07-17 20:13 ` Thomas Gleixner
2022-07-17 21:54 ` Thomas Gleixner
2022-07-18 5:11 ` Juergen Gross
2022-07-18 6:54 ` Thomas Gleixner
2022-07-18 8:55 ` Thomas Gleixner
2022-07-18 9:31 ` Peter Zijlstra
2022-07-18 10:33 ` Thomas Gleixner
2022-07-18 11:42 ` Thomas Gleixner
2022-07-18 17:52 ` [patch 0/3] x86/cpu: Sanitize switch_to_new_gdt() Thomas Gleixner
2022-07-18 17:52 ` [patch 1/3] x86/cpu: Remove segment load from switch_to_new_gdt() Thomas Gleixner
2022-07-18 18:43 ` Linus Torvalds
2022-07-18 18:55 ` Thomas Gleixner
2022-07-18 17:52 ` [patch 2/3] x86/cpu: Get rid of redundant switch_to_new_gdt() invocations Thomas Gleixner
2022-07-18 17:52 ` [patch 3/3] x86/cpu: Re-enable stackprotector Thomas Gleixner
2022-07-16 23:17 ` [patch 03/38] x86/modules: Set VM_FLUSH_RESET_PERMS in module_alloc() Thomas Gleixner
2022-07-16 23:17 ` [patch 04/38] x86/vdso: Ensure all kernel code is seen by objtool Thomas Gleixner
2022-07-16 23:17 ` [patch 05/38] btree: Initialize early when builtin Thomas Gleixner
2022-07-16 23:17 ` [patch 06/38] objtool: Allow GS relative relocs Thomas Gleixner
2022-07-16 23:17 ` [patch 07/38] objtool: Track init section Thomas Gleixner
2022-07-16 23:17 ` [patch 08/38] objtool: Add .call_sites section Thomas Gleixner
2022-07-16 23:17 ` [patch 09/38] objtool: Add .sym_sites section Thomas Gleixner
2022-07-16 23:17 ` [patch 10/38] objtool: Add --hacks=skylake Thomas Gleixner
2022-07-16 23:17 ` [patch 11/38] objtool: Allow STT_NOTYPE -> STT_FUNC+0 tail-calls Thomas Gleixner
2022-07-16 23:17 ` [patch 12/38] x86/entry: Make sync_regs() invocation a tail call Thomas Gleixner
2022-07-16 23:17 ` [patch 13/38] x86/modules: Make module_alloc() generally available Thomas Gleixner
2022-07-16 23:17 ` [patch 14/38] x86/Kconfig: Add CONFIG_CALL_THUNKS Thomas Gleixner
2022-07-16 23:17 ` [patch 15/38] x86/retbleed: Add X86_FEATURE_CALL_DEPTH Thomas Gleixner
2022-07-16 23:17 ` [patch 16/38] modules: Make struct module_layout unconditionally available Thomas Gleixner
2022-07-16 23:17 ` [patch 17/38] module: Add arch_data to module_layout Thomas Gleixner
2022-07-16 23:17 ` [patch 18/38] mm/vmalloc: Provide huge page mappings Thomas Gleixner
2022-07-16 23:17 ` [patch 19/38] x86/module: Provide __module_alloc() Thomas Gleixner
2022-07-16 23:17 ` [patch 20/38] x86/alternatives: Provide text_poke_[copy|set]_locked() Thomas Gleixner
2022-07-16 23:17 ` [patch 21/38] x86/entry: Make some entry symbols global Thomas Gleixner
2022-07-16 23:17 ` [patch 22/38] x86/paravirt: Make struct paravirt_call_site unconditionally available Thomas Gleixner
2022-07-16 23:17 ` [patch 23/38] x86/callthunks: Add call patching for call depth tracking Thomas Gleixner
2022-07-16 23:17 ` [patch 24/38] module: Add layout for callthunks tracking Thomas Gleixner
2022-07-16 23:17 ` [patch 25/38] x86/modules: Add call thunk patching Thomas Gleixner
2022-07-16 23:17 ` [patch 26/38] x86/returnthunk: Allow different return thunks Thomas Gleixner
2022-07-16 23:17 ` [patch 27/38] x86/asm: Provide ALTERNATIVE_3 Thomas Gleixner
2022-07-16 23:17 ` [patch 28/38] x86/retbleed: Add SKL return thunk Thomas Gleixner
2022-07-16 23:17 ` [patch 29/38] x86/retpoline: Add SKL retthunk retpolines Thomas Gleixner
2022-07-16 23:17 ` [patch 30/38] x86/retbleed: Add SKL call thunk Thomas Gleixner
2022-07-16 23:18 ` [patch 31/38] x86/calldepth: Add ret/call counting for debug Thomas Gleixner
2022-07-16 23:18 ` [patch 32/38] static_call: Add call depth tracking support Thomas Gleixner
2022-07-16 23:18 ` [patch 33/38] kallsyms: Take callthunks into account Thomas Gleixner
2022-07-16 23:18 ` [patch 34/38] x86/orc: Make it callthunk aware Thomas Gleixner
2022-07-16 23:18 ` [patch 35/38] kprobes: Add callthunk blacklisting Thomas Gleixner
2022-07-16 23:18 ` [patch 36/38] x86/ftrace: Make it call depth tracking aware Thomas Gleixner
2022-07-18 21:01 ` Steven Rostedt
2022-07-19 8:46 ` Peter Zijlstra
2022-07-19 13:06 ` Steven Rostedt
2022-07-16 23:18 ` [patch 37/38] x86/bpf: Emit call depth accounting if required Thomas Gleixner
2022-07-19 5:30 ` Alexei Starovoitov
2022-07-19 8:34 ` Peter Zijlstra
2022-07-16 23:18 ` [patch 38/38] x86/retbleed: Add call depth tracking mitigation Thomas Gleixner
2022-07-17 9:45 ` [patch 00/38] x86/retbleed: Call " David Laight
2022-07-17 15:07 ` Thomas Gleixner
2022-07-17 17:56 ` David Laight
2022-07-17 19:15 ` Thomas Gleixner
2022-07-18 19:29 ` Thomas Gleixner
2022-07-18 19:30 ` Thomas Gleixner
2022-07-18 19:51 ` Linus Torvalds
2022-07-18 20:44 ` Thomas Gleixner
2022-07-18 21:01 ` Linus Torvalds
2022-07-18 21:43 ` Peter Zijlstra
2022-07-18 22:34 ` Linus Torvalds
2022-07-18 23:52 ` Peter Zijlstra
2022-07-18 21:18 ` Peter Zijlstra
2022-07-18 22:22 ` Thomas Gleixner
2022-07-18 22:47 ` Joao Moreira
2022-07-18 22:55 ` Sami Tolvanen
2022-07-18 23:08 ` Joao Moreira
2022-07-18 23:19 ` Thomas Gleixner
2022-07-18 23:42 ` Linus Torvalds
2022-07-18 23:52 ` Linus Torvalds
2022-07-18 23:57 ` Peter Zijlstra
2022-07-19 0:03 ` Linus Torvalds
2022-07-19 0:11 ` Linus Torvalds
2022-07-19 0:23 ` Peter Zijlstra
2022-07-19 1:02 ` Linus Torvalds
2022-07-19 17:19 ` Sami Tolvanen
2022-07-20 21:13 ` Peter Zijlstra
2022-07-21 8:21 ` David Laight
2022-07-21 10:56 ` David Laight
2022-07-21 15:54 ` Peter Zijlstra
2022-07-21 17:55 ` Peter Zijlstra
2022-07-21 18:06 ` Linus Torvalds
2022-07-21 18:27 ` Peter Zijlstra
2022-07-21 18:32 ` Linus Torvalds
2022-07-21 20:22 ` Joao Moreira
2022-07-22 0:16 ` Sami Tolvanen
2022-07-22 10:23 ` Peter Zijlstra
2022-07-22 15:38 ` Sami Tolvanen
2022-07-21 22:01 ` David Laight
2022-07-22 11:03 ` Peter Zijlstra
2022-07-22 13:27 ` David Laight
2022-07-23 9:50 ` Thomas Gleixner
2022-07-19 0:01 ` Linus Torvalds
2022-07-19 0:19 ` Joao Moreira
2022-07-19 17:21 ` Sami Tolvanen
2022-07-19 17:58 ` Joao Moreira
2022-07-19 8:26 ` David Laight
2022-07-19 16:27 ` Linus Torvalds
2022-07-19 17:23 ` Sami Tolvanen
2022-07-19 17:27 ` Linus Torvalds [this message]
2022-07-19 18:06 ` Sami Tolvanen
2022-07-19 20:10 ` Peter Zijlstra
2022-07-18 22:48 ` Sami Tolvanen
2022-07-18 22:59 ` Thomas Gleixner
2022-07-18 23:10 ` Sami Tolvanen
2022-07-18 23:39 ` Linus Torvalds
2022-07-18 23:51 ` Peter Zijlstra
2022-07-20 9:00 ` Thomas Gleixner
2022-07-20 16:55 ` Sami Tolvanen
2022-07-20 19:42 ` Sami Tolvanen
2022-07-22 20:11 ` Tim Chen
2022-07-22 22:18 ` Linus Torvalds
2022-07-18 19:55 ` Thomas Gleixner
2022-07-19 10:24 ` Virt " Andrew Cooper
2022-07-19 14:13 ` Thomas Gleixner
2022-07-19 16:23 ` Andrew Cooper
2022-07-19 21:17 ` Thomas Gleixner
2022-07-19 14:45 ` Michael Kelley (LINUX)
2022-07-19 20:16 ` Peter Zijlstra
2022-07-20 16:57 ` [patch 00/38] x86/retbleed: " Steven Rostedt
2022-07-20 17:09 ` Linus Torvalds
2022-07-20 17:24 ` Peter Zijlstra
2022-07-20 17:50 ` Steven Rostedt
2022-07-20 18:07 ` Linus Torvalds
2022-07-20 18:31 ` Steven Rostedt
2022-07-20 18:43 ` Linus Torvalds
2022-07-20 19:11 ` Steven Rostedt
2022-07-20 19:36 ` Kees Cook
2022-07-20 19:43 ` Steven Rostedt
2022-07-20 21:36 ` Peter Zijlstra
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