[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Tue, 29 Oct 2019 10:45:22 -0700
From: Sami Tolvanen <samitolvanen@...gle.com>
To: Mark Rutland <mark.rutland@....com>, Nick Desaulniers <ndesaulniers@...gle.com>
Cc: Will Deacon <will@...nel.org>, Catalin Marinas <catalin.marinas@....com>,
Steven Rostedt <rostedt@...dmis.org>, Masami Hiramatsu <mhiramat@...nel.org>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>, Dave Martin <Dave.Martin@....com>,
Kees Cook <keescook@...omium.org>, Laura Abbott <labbott@...hat.com>, Jann Horn <jannh@...gle.com>,
Miguel Ojeda <miguel.ojeda.sandonis@...il.com>,
Masahiro Yamada <yamada.masahiro@...ionext.com>,
clang-built-linux <clang-built-linux@...glegroups.com>,
Kernel Hardening <kernel-hardening@...ts.openwall.com>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 09/17] arm64: disable function graph tracing with SCS
On Fri, Oct 25, 2019 at 4:03 AM Mark Rutland <mark.rutland@....com> wrote:
> I'm guessing it's difficult to always figure out the SCS slot for an
> instrumented callsite unless we pass this explicitly from the ftrace
> entry code, so we'd probably have to change some common infrastructure
> for that.
>
> We have a similar issue with pointer authentication, and we're solving
> that with -fpatchable-function-entry, which allows us to hook the
> callsite before it does anything with the return address. IIUC we could
> use the same mechanism here (and avoid introducing a third).
>
> Are there plans to implement -fpatchable-function-entry on the clang
> side?
I'm not sure if there are plans at the moment, but if this feature is
needed for PAC, adding it to clang shouldn't be a problem. Nick, did
you have any thoughts on this?
Sami
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
