From:   guoren@kernel.org
To:     arnd@arndb.de, guoren@kernel.org, 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
Cc:     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?q?Bj=C3=B6rn=20T=C3=B6pel?= <bjorn@rivosinc.com>
Subject: [PATCH -next V17 1/7] compiler_types.h: Add __noinstr_section() for noinstr
Date:   Tue, 21 Feb 2023 22:30:15 -0500
Message-Id: <20230222033021.983168-2-guoren@kernel.org>
In-Reply-To: <20230222033021.983168-1-guoren@kernel.org>
References: <20230222033021.983168-1-guoren@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

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: Björn Töpel <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>
---
 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_types.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_coverage \
+/*
+ * 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.
+ */
+#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