From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7AFD8612E for ; Tue, 30 Aug 2022 23:32:17 +0000 (UTC) Received: by mail-yb1-f202.google.com with SMTP id n18-20020a25d612000000b0069661a1dc48so887049ybg.20 for ; Tue, 30 Aug 2022 16:32:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc:subject:date; bh=QaAhiBNrHu6GYkLFA3B7rG1GS8UtnkRvQfTpKHPiaFU=; b=Uzu0hS7fYpQn9SuqY6pJYAs0mwU+Cbcm7VfqttztC5Y7vvGMMQbw4wbd/rsgMajhX8 hCYkTHXcE5WgpL526ftRFAS1iaJreodEJpABN25rLzozJPt3fTcwLmVcYcs0vcC1nhlH yp59OC26/dM0xfLKycIeelmnMx/ctiemiWAngqrglcx45erw27Nl2sLJAj1c3kLUftM8 0iSFHBjA1GYjEC6cZmd4UeYpgAKFk2VTxcYmGZKFX6zgfodGL620Sb3emlMY85C3OcAo bE5fs06VNU0/03FLltVrwNWpMmfeDGopu8w2Crj1CckQW60JmF6IEikz1fcox97zq9e0 FlXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date; bh=QaAhiBNrHu6GYkLFA3B7rG1GS8UtnkRvQfTpKHPiaFU=; b=A0REpLl7zKR9Gvf1XtT/UNyYGTet43WACzOIZW06AZcyCIeL6pPpKP3SXoQgXd0Iht hTncQ/uKAoZkBB7loL/3V7t/yxSV+fxUOGFWxmviniOAbHNaoAow23BDk86/ilQxPiMQ QOAsO5KR9H6omsA1/w0caF7WnEHSsakFLAEuc2g7bC27FqrCWwPHTNdA12RH3sHEu4wr DxAO5KofdQCyB/KpnUgSUbq5k/oIhnTkM5/Q/R/s71hadnEMppzR7/ddCzIGQVjLpY9I xine4wjd8xWhBzZpfe1baL4W4mAhYuOVccOfdcvCc3DhpvJ+s+HYIcLy92ksV9NQ9Xlh yMuw== X-Gm-Message-State: ACgBeo2lMPI4ARTc87rTvYbxvfAaPLKYpHIFfsE0XH3ITlHF188WV/fC YG9BSaK714QL9YeENiFD3JbE8AvWGHdRFfKLfqQ= X-Google-Smtp-Source: AA6agR4FDK+ca8ExoQOJuxzStWcPg0UmoHQzTdwmwi9npQMvWgOYplZw4nRfd6yLznTzYg9mNTUtUOCVf41ZKmBVqKc= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:54d9:7143:6a7d:91d]) (user=samitolvanen job=sendgmr) by 2002:a0d:d850:0:b0:340:d2c0:b022 with SMTP id a77-20020a0dd850000000b00340d2c0b022mr13497429ywe.469.1661902336610; Tue, 30 Aug 2022 16:32:16 -0700 (PDT) Date: Tue, 30 Aug 2022 16:31:24 -0700 In-Reply-To: <20220830233129.30610-1-samitolvanen@google.com> Message-Id: <20220830233129.30610-17-samitolvanen@google.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20220830233129.30610-1-samitolvanen@google.com> X-Developer-Key: i=samitolvanen@google.com; a=openpgp; fpr=35CCFB63B283D6D3AEB783944CB5F6848BBC56EE X-Developer-Signature: v=1; a=openpgp-sha256; l=1745; i=samitolvanen@google.com; h=from:subject; bh=jQm92I9xQfCJPH6jkHCDpzvvJGb/s+FwIZvLF3ZcxmA=; b=owEB7QES/pANAwAKAUy19oSLvFbuAcsmYgBjDp3OLXWXp4dv7z7QEAEH5wDVXEoy6vQwE4MAgTih TKcGqJ2JAbMEAAEKAB0WIQQ1zPtjsoPW0663g5RMtfaEi7xW7gUCYw6dzgAKCRBMtfaEi7xW7uhuC/ 4mLD2OTFFRM6dzC+U3G8nSByx2EP7YNHOfYlhOKl0Gv/CfgBF/GmPU6h3gd2FYTdIVAmx+Jt5i7jod yHHS4gZDl8y9ik+cOIJfaq9PCplP1qzBI5UZveW67TQSOg6aWHjQltgyelJnFQOdFAyzVFhcjo1ZT4 RasjgLDZdDZaCQZXWXBTkwjmqg7yGU6nx6FTkZor6xheRDX2kEOcxc/tAIWc/F3tCwLKZO3b2OacxU kLhRFXfTjDHGI8CEMPaaAiF2HgUeJEAfx8o4vhL4zMeTDaKFmRQlmf7F9COJc6E7kag2I6rBVTMLaT FWl2SlSRnYF0zOFsCumLTWzpoCgAijPhDKp/uWc4Bl+x2WAveRz8IYR1rkvZSXXc/Y0/ys9658hItd QLTUDCSGboZ0fd2TFzIbCfImlNrGKDomVDfTKP6XcarqWEI1dc/zyJKjcz0KqduDH2E4Ieu9sxhkpl Xw4LrtrfDpSWz1SEU4GR+7wRiD1adQkP+R3N0lIVY4BnU= X-Mailer: git-send-email 2.37.2.672.g94769d06f0-goog Subject: [PATCH v4 16/21] objtool: Disable CFI warnings 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 Content-Type: text/plain; charset="UTF-8" The __cfi_ preambles contain a mov instruction that embeds the KCFI type identifier in the following format: ; type preamble __cfi_function: mov , %eax function: ... While the preamble symbols are STT_FUNC and contain valid instructions, they are never executed and always fall through. Skip the warning for them. .kcfi_traps sections point to CFI traps in text sections. Also skip the warning about them referencing !ENDBR instructions. Signed-off-by: Sami Tolvanen Acked-by: Josh Poimboeuf --- tools/objtool/check.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index e55fdf952a3a..48e18737a2d1 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3316,6 +3316,10 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, next_insn = next_insn_to_validate(file, insn); if (func && insn->func && func != insn->func->pfunc) { + /* Ignore KCFI type preambles, which always fall through */ + if (!strncmp(func->name, "__cfi_", 6)) + return 0; + WARN("%s() falls through to next function %s()", func->name, insn->func->name); return 1; @@ -4113,7 +4117,8 @@ static int validate_ibt(struct objtool_file *file) !strcmp(sec->name, "__bug_table") || !strcmp(sec->name, "__ex_table") || !strcmp(sec->name, "__jump_table") || - !strcmp(sec->name, "__mcount_loc")) + !strcmp(sec->name, "__mcount_loc") || + !strcmp(sec->name, ".kcfi_traps")) continue; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The __cfi_ preambles contain a mov instruction that embeds the KCFI type identifier in the following format: ; type preamble __cfi_function: mov , %eax function: ... While the preamble symbols are STT_FUNC and contain valid instructions, they are never executed and always fall through. Skip the warning for them. .kcfi_traps sections point to CFI traps in text sections. Also skip the warning about them referencing !ENDBR instructions. Signed-off-by: Sami Tolvanen Acked-by: Josh Poimboeuf --- tools/objtool/check.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index e55fdf952a3a..48e18737a2d1 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3316,6 +3316,10 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, next_insn = next_insn_to_validate(file, insn); if (func && insn->func && func != insn->func->pfunc) { + /* Ignore KCFI type preambles, which always fall through */ + if (!strncmp(func->name, "__cfi_", 6)) + return 0; + WARN("%s() falls through to next function %s()", func->name, insn->func->name); return 1; @@ -4113,7 +4117,8 @@ static int validate_ibt(struct objtool_file *file) !strcmp(sec->name, "__bug_table") || !strcmp(sec->name, "__ex_table") || !strcmp(sec->name, "__jump_table") || - !strcmp(sec->name, "__mcount_loc")) + !strcmp(sec->name, "__mcount_loc") || + !strcmp(sec->name, ".kcfi_traps")) continue; list_for_each_entry(reloc, &sec->reloc->reloc_list, list) -- 2.37.2.672.g94769d06f0-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel