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From: Sami Tolvanen <samitolvanen@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>,
	x86@kernel.org, Kees Cook <keescook@chromium.org>,
	Joao Moreira <joao@overdrivepizza.com>,
	linux-kernel@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH] x86/ibt: Implement FineIBT
Date: Mon, 24 Oct 2022 10:15:59 -0700	[thread overview]
Message-ID: <CABCJKuc8eu0t08E0e1si-Sm2m0QqB1mrzofZy9cJ3G-tHBUZRg@mail.gmail.com> (raw)
In-Reply-To: <Y1QGUXSc43rInacJ@hirez.programming.kicks-ass.net>

On Sat, Oct 22, 2022 at 8:03 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Fri, Oct 21, 2022 at 04:08:59PM -0700, Josh Poimboeuf wrote:
> > On Tue, Oct 18, 2022 at 03:35:50PM +0200, Peter Zijlstra wrote:
> > > +#ifdef CONFIG_FINEIBT
> > > +/*
> > > + * kCFI                                            FineIBT
> > > + *
> > > + * __cfi_\func:                                    __cfi_\func:
> > > + * movl   $0x12345678,%eax                      endbr64                    // 4
> > > + * nop                                          subl   $0x12345678,%r10d   // 7
> > > + * nop                                          jz     1f                  // 2
> > > + * nop                                          ud2                        // 2
> > > + * nop                                     1:   nop                        // 1
> > > + * nop
> > > + * nop
> > > + * nop
> > > + * nop
> > > + * nop
> > > + * nop
> > > + * nop
> >
> > All the "CFI" naming everywhere is very unfortunate.  We already have
> > "call frame information" in both the toolchain and objtool.
> >
> > The feature is called "kCFI" anyway, can Clang call the symbols
> > '__kcfi_*'?
>
> I think the compiler patch is already merged in clang, not sure that's
> still an option, Sami?

Yes, the compiler patch is already in, but if the cfi/kcfi confusion
is a big concern, it's still possible to rename the symbol before
Clang 16 is released. However, I thought we picked the __cfi prefix
earlier to make things less confusing with FineIBT? Joao, are you
still planning on adding FineIBT to Clang as well?

Sami

  reply	other threads:[~2022-10-24 18:55 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-18 13:35 [PATCH] x86/ibt: Implement FineIBT Peter Zijlstra
2022-10-18 14:43 ` David Laight
2022-10-18 15:58   ` Joao Moreira
2022-10-18 17:20     ` Kees Cook
2022-10-18 20:09       ` Joao Moreira
2022-10-19  5:33         ` Kees Cook
2022-10-18 21:27     ` David Laight
2022-10-18 14:47 ` Peter Zijlstra
2022-10-18 18:09 ` Kees Cook
2022-10-18 19:56   ` Peter Zijlstra
2022-10-18 23:31     ` Josh Poimboeuf
2022-10-19  5:22       ` Kees Cook
2022-10-19 11:38       ` Peter Zijlstra
2022-10-19  5:14     ` Kees Cook
2022-10-18 19:59   ` Peter Zijlstra
2022-10-18 21:09     ` Peter Zijlstra
2022-10-19  5:05     ` Kees Cook
2022-10-19 12:03       ` Peter Zijlstra
2022-10-19 15:22         ` Sami Tolvanen
2022-10-20 11:04           ` Peter Zijlstra
2022-10-18 19:59   ` Joao Moreira
2022-10-19  5:32     ` Kees Cook
2022-10-19 19:35       ` Joao Moreira
2022-10-18 20:05   ` Peter Zijlstra
2022-10-19  5:00     ` Kees Cook
2022-10-18 20:09   ` Peter Zijlstra
2022-10-18 20:17     ` Joao Moreira
2022-10-18 20:30       ` Peter Zijlstra
2022-10-19  4:48         ` Joao Moreira
2022-10-19  5:19           ` Kees Cook
2022-10-31 19:13             ` Joao Moreira
2022-11-01 21:39               ` Kees Cook
2022-11-01 21:50                 ` Joao Moreira
2022-10-19  5:18         ` Kees Cook
2022-10-19  5:16     ` Kees Cook
2022-10-20 11:05   ` Peter Zijlstra
2022-10-18 23:38 ` Josh Poimboeuf
2022-10-19  7:29   ` Peter Zijlstra
2022-10-21 23:08 ` Josh Poimboeuf
2022-10-22 15:03   ` Peter Zijlstra
2022-10-24 17:15     ` Sami Tolvanen [this message]
2022-10-24 18:38       ` Joao Moreira

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