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From:   Brian Gerst <brgerst@gmail.com>
Date:   Tue, 5 May 2020 16:39:01 -0400
Message-ID: <CAMzpN2i9bZhxagk1dNhHpZmYyHjNiPQU_yRmwY9y85LemkNFNw@mail.gmail.com>
Subject: Re: [patch V4 part 1 19/36] x86/entry: Exclude low level entry code
 from sanitizing
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        Frederic Weisbecker <frederic@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Joel Fernandes <joel@joelfernandes.org>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Juergen Gross <jgross@suse.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Will Deacon <will@kernel.org>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>
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On Tue, May 5, 2020 at 10:13 AM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> The sanitizers are not really applicable to the fragile low level entry
> code. code. Entry code needs to carefully setup a normal 'runtime'
> environment.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>  arch/x86/entry/Makefile |    8 ++++++++
>  1 file changed, 8 insertions(+)
>
> --- a/arch/x86/entry/Makefile
> +++ b/arch/x86/entry/Makefile
> @@ -3,6 +3,14 @@
>  # Makefile for the x86 low level entry code
>  #
>
> +KASAN_SANITIZE := n
> +UBSAN_SANITIZE := n
> +KCOV_INSTRUMENT := n
> +
> +CFLAGS_REMOVE_common.o = $(CC_FLAGS_FTRACE) -fstack-protector -fstack-protector-strong
> +CFLAGS_REMOVE_syscall_32.o = $(CC_FLAGS_FTRACE) -fstack-protector -fstack-protector-strong
> +CFLAGS_REMOVE_syscall_64.o = $(CC_FLAGS_FTRACE) -fstack-protector -fstack-protector-strong

Is this necessary for syscall_*.o?  They just contain the syscall
tables (ie. data).

--
Brian Gerst