From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-100.freemail.mail.aliyun.com (out30-100.freemail.mail.aliyun.com [115.124.30.100]) (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 B92EE33D505; Tue, 1 Sep 2026 13:11:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.100 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788268306; cv=none; b=URFTz62PaoW0DJPkHWVIGcMw94f1HSVpahML2UUxSjI+pmeh3f+veFq2driY8ujsvSTBR3VLHmFO3vSb4ilFh6JwKv73ZeoCZ5eRw2qq1ExbVvnbCXaWZrIxmsuIIuKAMOg/dDWrUCLJiamcdH07Q7WG8iP/cnKtgpWXZj2VaaU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788268306; c=relaxed/simple; bh=+Xn2xSVt6Y4AR6W37ZftozKIkqPqngS2wWhVGJC6Ces=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=aY6+3wpzBqkRxSyBB1mZIZSG5FBLhMJWRJRcv/V909vkTmztPQ64tjKLQ5bR5lSHo77xS+qHNxhX1fJGOK/oxGu7Gy9mIIfp1WrL7ecJFd6uSRRJA3c4keEbYOXYsSbSbsX9xTkTq9oU02rZBF3eWgXEIwhQs9RRRT9Gpltsts8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=CYLLPrOX; arc=none smtp.client-ip=115.124.30.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="CYLLPrOX" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1788268298; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=ATJH11bxVHIskQuz+vJepFf7SUqYuoorOP97hyHmC+g=; b=CYLLPrOXEmpGrCPe1+wFisykuMsRd3FgbiyqStxUxxYsUbAIWqkiyenOxxeiFYpjacChZD+lSA7s3iAcboZU8v5JxFRc0iBThChn5eCRK8I9LqhzE7A+RUV7bD4p+ofewS/aqUv37is4tnw8QC2JN/NN2nwc1zXE9GAFpJD3aEE= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R551e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037033178;MF=cp0613@linux.alibaba.com;NM=1;PH=DS;RN=21;SR=0;TI=SMTPD_---0XA8SKn1_1788268294; Received: from DESKTOP-S9E58SO.localdomain(mailfrom:cp0613@linux.alibaba.com fp:SMTPD_---0XA8SKn1_1788268294 cluster:ay36) by smtp.aliyun-inc.com; Tue, 01 Sep 2026 21:11:37 +0800 From: Chen Pei To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, memxor@gmail.com, bjorn@kernel.org, puranjay@kernel.org Cc: ihor.solodrai@linux.dev, eddyz87@gmail.com, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, jolsa@kernel.org, emil@etsalapatis.com, pulehui@huawei.com, pjw@kernel.org, palmer@dabbelt.com, guoren@kernel.org, bpf@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH bpf] bpf, riscv: Make arena support depend on ZACAS Date: Tue, 1 Sep 2026 21:11:32 +0800 Message-ID: <20260901131132.16241-1-cp0613@linux.alibaba.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The arena range tree allocates its nodes with kmalloc_nolock() since commit f8c67d8550ee ("bpf: Use kmalloc_nolock() in range tree"). kmalloc_nolock() requires slab caches with cmpxchg128 support (__CMPXCHG_DOUBLE); on riscv cmpxchg128 is provided by the ZACAS extension. On systems without ZACAS every arena map creation fails with a misleading -ENOMEM. Report the missing support instead: make bpf_jit_supports_arena() return system_has_cmpxchg128(), so arena map creation fails with -EOPNOTSUPP on systems without ZACAS. This matches how arena BPF_CMPXCHG instructions are already gated on ZACAS in bpf_jit_supports_insn(). Fixes: f8c67d8550ee ("bpf: Use kmalloc_nolock() in range tree") Cc: stable@vger.kernel.org Signed-off-by: Chen Pei --- This issue was reported by sashiko-bot: https://sashiko.dev/#/patchset/20260901120013.16104-1-cp0613@linux.alibaba.com?part=1 Question for reviewers: should the arena selftests gate on ZACAS, e.g. probing it via riscv_hwprobe() (RISCV_ISA_EXT_ZACAS) and SKIPping cleanly on systems without the extension? arch/riscv/net/bpf_jit_comp64.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 74efe4b138d2..0061c1d4ed98 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -2128,7 +2128,11 @@ bool bpf_jit_supports_ptr_xchg(void) bool bpf_jit_supports_arena(void) { - return true; + /* + * The arena range tree uses kmalloc_nolock(), which needs + * cmpxchg128, provided by ZACAS on riscv. + */ + return system_has_cmpxchg128(); } bool bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena) -- 2.50.1