Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230222033021.983168-1-guoren@kernel.org> <20230222033021.983168-2-guoren@kernel.org>
In-Reply-To: <20230222033021.983168-2-guoren@kernel.org>
From:   Lai Jiangshan <jiangshanlai@gmail.com>
Date:   Thu, 23 Mar 2023 08:43:08 +0800
Message-ID: <CAJhGHyCAZT+NMpSvUaL0fASnD+HMu-zUsT4Emr9h_VFgYHowVQ@mail.gmail.com>
Subject: Re: [PATCH -next V17 1/7] compiler_types.h: Add __noinstr_section()
 for noinstr
To:     guoren@kernel.org
Cc:     arnd@arndb.de, palmer@rivosinc.com, tglx@linutronix.de,
        peterz@infradead.org, luto@kernel.org, conor.dooley@microchip.com,
        heiko@sntech.de, jszhang@kernel.org, lazyparser@gmail.com,
        falcon@tinylab.org, chenhuacai@kernel.org, apatel@ventanamicro.com,
        atishp@atishpatra.org, mark.rutland@arm.com, ben@decadent.org.uk,
        bjorn@kernel.org, palmer@dabbelt.com, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
        Lai Jiangshan <laijs@linux.alibaba.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@rivosinc.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Wed, Feb 22, 2023 at 11:56=E2=80=AFAM <guoren@kernel.org> wrote:
>
> From: Lai Jiangshan <laijs@linux.alibaba.com>
>
> Using __noinstr_section() doesn't automatically disable all
> instrumentations on the section. Inhibition for some
> instrumentations requires extra code. I.E. KPROBES explicitly
> avoids instrumenting on .noinstr.text.
>
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Suggested-by: Peter Zijlstra <peterz@infradead.org>
> Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Bj=C3=B6rn T=C3=B6pel <bjorn@rivosinc.com>
> Tested-by: Jisheng Zhang <jszhang@kernel.org>
> Tested-by: Guo Ren <guoren@kernel.org>
> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>

Hello

The change has been made upstream as a part of the commit
2b5a0e425e6e(objtool/idle: Validate __cpuidle code as noinstr).

https://lore.kernel.org/r/20230112195540.373461409@infradead.org

Thanks
Lai

> ---
>  include/linux/compiler_types.h | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_type=
s.h
> index 7c1afe0f4129..0a2ca5755be7 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -231,12 +231,19 @@ struct ftrace_likely_data {
>  #define __no_sanitize_or_inline __always_inline
>  #endif
>
> -/* Section for code which can't be instrumented at all */
> -#define noinstr                                                         =
       \
> -       noinline notrace __attribute((__section__(".noinstr.text")))    \
> -       __no_kcsan __no_sanitize_address __no_profile __no_sanitize_cover=
age \
> +/*
> + * Using __noinstr_section() doesn't automatically disable all instrumen=
tations
> + * on the section.  Inhibition for some instrumentations requires extra =
code.
> + * I.E. KPROBES explicitly avoids instrumenting on .noinstr.text.
> + */
> +#define __noinstr_section(section)                             \
> +       noinline notrace __section(section) __no_profile        \
> +       __no_kcsan __no_sanitize_address __no_sanitize_coverage \
>         __no_sanitize_memory
>
> +/* Section for code which can't be instrumented at all */
> +#define noinstr __noinstr_section(".noinstr.text")
> +
>  #endif /* __KERNEL__ */
>
>  #endif /* __ASSEMBLY__ */
> --
> 2.36.1
>