Received-SPF: pass (google.com: domain of linux-kernel+bounces-688-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Message-Id: <20231215092707.669401084@infradead.org>
User-Agent: quilt/0.65
Date: Fri, 15 Dec 2023 10:12:21 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: paul.walmsley@sifive.com,
 palmer@dabbelt.com,
 aou@eecs.berkeley.edu,
 tglx@linutronix.de,
 mingo@redhat.com,
 bp@alien8.de,
 dave.hansen@linux.intel.com,
 x86@kernel.org,
 hpa@zytor.com,
 davem@davemloft.net,
 dsahern@kernel.org,
 daniel@iogearbox.net,
 andrii@kernel.org,
 martin.lau@linux.dev,
 song@kernel.org,
 yonghong.song@linux.dev,
 john.fastabend@gmail.com,
 kpsingh@kernel.org,
 sdf@google.com,
 haoluo@google.com,
 jolsa@kernel.org,
 Arnd Bergmann <arnd@arndb.de>,
 samitolvanen@google.com,
 keescook@chromium.org,
 nathan@kernel.org,
 ndesaulniers@google.com,
 linux-riscv@lists.infradead.org,
 linux-kernel@vger.kernel.org,
 netdev@vger.kernel.org,
 bpf@vger.kernel.org,
 linux-arch@vger.kernel.org,
 llvm@lists.linux.dev,
 jpoimboe@kernel.org,
 joao@overdrivepizza.com,
 mark.rutland@arm.com,
 peterz@infradead.org
Subject: [PATCH v3 5/7] cfi: Add CFI_NOSEAL()
References: <20231215091216.135791411@infradead.org>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8

Add a CFI_NOSEAL() helper to mark functions that need to retain their
CFI information, despite not otherwise leaking their address.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/include/asm/cfi.h |    5 +++++
 include/linux/cfi.h        |    4 ++++
 2 files changed, 9 insertions(+)

--- a/arch/x86/include/asm/cfi.h
+++ b/arch/x86/include/asm/cfi.h
@@ -8,6 +8,7 @@
  * Copyright (C) 2022 Google LLC
  */
 #include <linux/bug.h>
+#include <asm/ibt.h>
 
 /*
  * An overview of the various calling conventions...
@@ -138,4 +139,8 @@ static inline u32 cfi_get_func_hash(void
 }
 #endif /* CONFIG_CFI_CLANG */
 
+#if HAS_KERNEL_IBT == 1
+#define CFI_NOSEAL(x)	asm(IBT_NOSEAL(__stringify(x)))
+#endif
+
 #endif /* _ASM_X86_CFI_H */
--- a/include/linux/cfi.h
+++ b/include/linux/cfi.h
@@ -46,4 +46,8 @@ static inline void module_cfi_finalize(c
 #endif /* CONFIG_ARCH_USES_CFI_TRAPS */
 #endif /* CONFIG_MODULES */
 
+#ifndef CFI_NOSEAL
+#define CFI_NOSEAL(x)
+#endif
+
 #endif /* _LINUX_CFI_H */