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Fri, 29 Apr 2022 13:37:18 -0700 (PDT) Date: Fri, 29 Apr 2022 13:36:36 -0700 In-Reply-To: <20220429203644.2868448-1-samitolvanen@google.com> Message-Id: <20220429203644.2868448-14-samitolvanen@google.com> Mime-Version: 1.0 References: <20220429203644.2868448-1-samitolvanen@google.com> X-Developer-Key: i=samitolvanen@google.com; a=openpgp; fpr=35CCFB63B283D6D3AEB783944CB5F6848BBC56EE X-Developer-Signature: v=1; a=openpgp-sha256; l=1454; h=from:subject; bh=tehRW82jP0RyTtdlRN0VdoftCcUQiAtEwsyBl3tnXQM=; b=owEB7QES/pANAwAKAUy19oSLvFbuAcsmYgBibExXrPGtzBdwEr3WsUJMcTa5SnMpMUdhtG1ELjyr Yo4vk3yJAbMEAAEKAB0WIQQ1zPtjsoPW0663g5RMtfaEi7xW7gUCYmxMVwAKCRBMtfaEi7xW7gG8C/ 4rBi6pp+EX2VhofKNrL5OB4Nbj0tmkbvch9On+rothI5RrjLElKTQ7rJKCbeCMf/fd9MhXmmy30ZDc 0i6d/nQFbMUJNbP3YvHszFfVozL5oetNY0LKa1tEWLrl1PmBWiMM1Y0hzUx695EFNuB9Z/IgzAWJHc VyKoFSgqL/HZvX7mFYcG2EAsOE+icuxIZICSAVt8NfVenhy3oKckN6+QZSZVHFbTE8sAiAE8x4UgZ4 nSjkqIrcznKGhg5HogEmdwZzCaAcGZxDqdA0V1aaU4kyfLHFp9XZzKmiiUwTYYSWwvCY9Tvo+xL+Vu 0CTamYHWDP1HUePZ8CB/mw9CsUeTuhu6zkvuMYcG354jmx7ooV+gAhNyCiEi4fKTuxQ5a1mRQuNNRE 8SsQdB8squmkfEfpsoDlQCt5QaUw4WeUghUIX9vTwT7ISqGIun7rYMiGMRNi2bz7Bl6AT0hPw82Lgr VbBurkClkSn9jw/pGy7ura6cWEncKA6ChV3483s2teTmc= X-Mailer: git-send-email 2.36.0.464.gb9c8b46e94-goog Subject: [RFC PATCH 13/21] cfi: Add the cfi_unchecked macro From: Sami Tolvanen To: linux-kernel@vger.kernel.org Cc: Kees Cook , Josh Poimboeuf , Peter Zijlstra , x86@kernel.org, Catalin Marinas , Will Deacon , Mark Rutland , Nathan Chancellor , Nick Desaulniers , Joao Moreira , Sedat Dilek , Steven Rostedt , linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev, Sami Tolvanen X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220429_133720_466477_50C02E00 X-CRM114-Status: GOOD ( 13.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The cfi_unchecked macro allows CFI checking to be disabled for a specific indirect call expression, by passing the expression as an argument to the macro. For example: static void call(void (*f)(void)) { cfi_unchecked(f()); } Signed-off-by: Sami Tolvanen --- include/linux/compiler-clang.h | 2 ++ include/linux/compiler_types.h | 4 ++++ 2 files changed, 6 insertions(+) diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h index c4ff42859077..0d6a0e7e36dc 100644 --- a/include/linux/compiler-clang.h +++ b/include/linux/compiler-clang.h @@ -94,4 +94,6 @@ #if CONFIG_CFI_CLANG /* Disable CFI checking inside a function. */ #define __nocfi __attribute__((__no_sanitize__("kcfi"))) +/* Disable CFI checking for the indirect call expression. */ +#define cfi_unchecked(expr) __builtin_kcfi_call_unchecked(expr) #endif diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index bdd2526af46a..41f547fe9724 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -263,6 +263,10 @@ struct ftrace_likely_data { # define __nocfi #endif +#ifndef cfi_unchecked +# define cfi_unchecked(expr) expr +#endif + /* * Any place that could be marked with the "alloc_size" attribute is also * a place to be marked with the "malloc" attribute. Do this as part of the