From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-178.mta1.migadu.com (out-178.mta1.migadu.com [95.215.58.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1BCC137F01C for ; Mon, 27 Jul 2026 14:29:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785162595; cv=none; b=HSQ3F09+RfPPO9vql2UmVHqMbf3l63sCp0UupEaRfv9zJ2sj1YUc8hlL5vwyyjZXRBDmQPGvrMnqqJ/Xd0WxL6qyhflE3LsxjooMKaozx92UcOdaU5v1wswp1gJ2BCGOkXnMNbZLAmclH8U+2rUwLZVoW6jGXibv2aTAqV4JmAQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785162595; c=relaxed/simple; bh=xgUC/3Fkqjw/e5LtHgVt3noPBmTgTj7kOpfQkp1kQRs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YZW3QqlOheNkdIInlzFQwT4y/BtwsnzToZurvdf1DNq2wEvZZa+Mkrv9sCUL//dJMvThhhE+v5VUZnb6ORjp6XAlKudQp4/3NqvZxFvfs/qAz48OpxVXjsKMOc+7N4+q0VcpJ9BaNeaBgw4PU8eHh4XU5LhN9jOCfsMNmpRca+E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ZyLvmu/M; arc=none smtp.client-ip=95.215.58.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ZyLvmu/M" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1785162589; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TelY/e6rhqBnbaI//+7mxab5yF5lSU4GighDsL8mjtU=; b=ZyLvmu/MHYpDNbUorLcBJbddnw77+HeD/DLH4+630pkX74zlnxiewseIkfb1Qk4Jrr5wk1 p/eTme8zssK5AaRtUalWpSb6uaj87dcJkyHuzHz+PqgI2S2cA7G0GafjxFncbd3VXndOc0 h047oJQZ2gXZPMmOr+7CsnF2v8yKmCE= From: Leon Hwang To: Catalin Marinas , Will Deacon , Steven Rostedt , Masami Hiramatsu , Mark Rutland , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Shuah Khan , Leon Hwang Cc: bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH 1/2] arm64: ftrace: enable single ftrace_ops for direct calls Date: Mon, 27 Jul 2026 22:28:43 +0800 Message-ID: <20260727142844.21212-2-leon.hwang@linux.dev> In-Reply-To: <20260727142844.21212-1-leon.hwang@linux.dev> References: <20260727142844.21212-1-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT The BPF tracing multi link updates several direct-call sites through one ftrace_ops. Its implementation is therefore gated by HAVE_SINGLE_FTRACE_DIRECT_OPS in addition to DYNAMIC_FTRACE_WITH_DIRECT_CALLS. Select HAVE_SINGLE_FTRACE_DIRECT_OPS whenever arm64 enables dynamic ftrace direct calls. This enables BPF tracing multi links on arm64. Also generalize the unreachable-trampoline comment because the single-ops path does not use ops->direct_call. Assisted-by: Codex:gpt-5.6-sol Signed-off-by: Leon Hwang --- arch/arm64/Kconfig | 2 ++ arch/arm64/kernel/ftrace.c | 3 +-- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 0de419ed780f..c98dca76859b 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -188,6 +188,8 @@ config ARM64 CLANG_SUPPORTS_DYNAMIC_FTRACE_WITH_ARGS) select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \ if DYNAMIC_FTRACE_WITH_ARGS + select HAVE_SINGLE_FTRACE_DIRECT_OPS \ + if DYNAMIC_FTRACE_WITH_DIRECT_CALLS select HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS \ if (DYNAMIC_FTRACE_WITH_ARGS && !CFI && \ (CC_IS_CLANG || !CC_OPTIMIZE_FOR_SIZE)) diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index e1a3c0b3a051..56ba72a87dfa 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -301,8 +301,7 @@ static bool ftrace_find_callable_addr(struct dyn_ftrace *rec, /* * If a custom trampoline is unreachable, rely on the ftrace_caller - * trampoline which knows how to indirectly reach that trampoline - * through ops->direct_call. + * trampoline which knows how to indirectly reach that trampoline. */ if (*addr != FTRACE_ADDR && !reachable_by_bl(*addr, pc)) *addr = FTRACE_ADDR; -- 2.55.0