From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.3]) (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 325B7299923 for ; Mon, 20 Jul 2026 03:23:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.3 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784517825; cv=none; b=Ijx0PovGU6A9EVWt4gDJ/cjPpZDwH1vTqRzIYa7IyoHpoueD6EjEHf4Qnp+PRR2cBPgY0vCzsro8QGYhKf7Xkbohau80yfUEG7c+7dKx7VrdnLfn4kJIDtWU8Qej5zj9pTv3CqgUGclgAX7WTt+U5nLQ7wgQL2511p8MVTrvDGc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784517825; c=relaxed/simple; bh=4H//D7t0+mrgrXpIFbvvRS0N05zA3G0FWaAANvcXJIQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UKhSlZGrRCUTdJszQbhjp3ajAhKBlAZy4lF+2mS1s17Dx5KrBdAOELFBHfukV82UuphDuMfbyxxFBxhqBfGetOk+7viND4bNPfqi25/JyG0wQFFnwFnR8Aj12BacbYO/fCuxQEiV9Nz18bENxVyuked9gofXWYWdMbKcI2UTzRM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=IIYkWQwC; arc=none smtp.client-ip=117.135.210.3 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="IIYkWQwC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=5U kUr8RuelSHMMnVvP5mpx/Yb4/yO3VgsdZyG7QnLwM=; b=IIYkWQwCO4Ls5jXYrP Tb4+oj96r5TjsaL2NszGZnvrvRbFbUN/oockCbz2LzJn83LXI6t6Q3/lYmdS7h47 uA7OseJCf2ZmtCEsjUKlsj85/G9limsmke6BPxDbkWQAG6rUF4Hlj6DOnO+Lt6XH qrwLnI8zIESwvBRorobmuHZLo= Received: from Ubuntu.. (unknown []) by gzsmtp3 (Coremail) with SMTP id PigvCgBH+wKTlF1qrd2XIg--.2654S4; Mon, 20 Jul 2026 11:23:02 +0800 (CST) From: Xiaofeng Yuan To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Alexandre Ghiti , Nam Cao , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, xiaofengmian@163.com Subject: [PATCH v4 2/2] riscv: patch: skip fixmap mapping when kernel text is already writable Date: Mon, 20 Jul 2026 03:22:57 +0000 Message-ID: <20260720032258.5188-3-xiaofengmian@163.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260720032258.5188-1-xiaofengmian@163.com> References: <20260720032258.5188-1-xiaofengmian@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:PigvCgBH+wKTlF1qrd2XIg--.2654S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7CF1xuw4UGF43Kr17ZFWxtFb_yoW8GFyDpF s7JF1rZFW5JF4Fv39Fkw1kuryYywnxtrsxGFnrXFyavwsIq34rXwn3W3y2qF10gr1j9w47 uFsxArZI9a4UG37anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziebyZUUUUU= X-CM-SenderInfo: p0ld0w5hqjzxldq6il2tof0z/xtbC5RY8P2pdlJaH-wAA39 Currently patch_map() always creates a temporary writable mapping via fixmap for kernel text addresses, even when CONFIG_STRICT_MODULE_RWX is disabled and the kernel text is already mapped with _PAGE_WRITE. This is unnecessary overhead at best, and on minimal configurations it can cause page faults. Skip the fixmap path for kernel text when CONFIG_STRICT_MODULE_RWX is not enabled, since the text pages are already writable in this case. Signed-off-by: Xiaofeng Yuan --- v2: add commit description v3: early return when !CONFIG_STRICT_MODULE_RWX (per Nam Cao's suggestion) diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 16b243376f..caef41d5ef 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -44,15 +44,16 @@ static __always_inline void *patch_map(void *addr, const unsigned int fixmap) uintptr_t uintaddr = (uintptr_t) addr; phys_addr_t phys; + if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) + return addr; + if (core_kernel_text(uintaddr) || is_kernel_exittext(uintaddr)) { phys = __pa_symbol(addr); - } else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) { + } else { struct page *page = vmalloc_to_page(addr); BUG_ON(!page); phys = page_to_phys(page) + offset_in_page(addr); - } else { - return addr; } return (void *)set_fixmap_offset(fixmap, phys); -- 2.43.0