From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.2]) (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 6602941C30F for ; Wed, 1 Jul 2026 10:29:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.2 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782901753; cv=none; b=OWP2WNBgXMf4A6tOGaMNuOC7gsnt6IQL48CU57Aias7oWiyU+OE9BS5K1m/qmOlSuHfkqem7LxYsrFW5PYMHw70IzFIGfMPj+1q0ylM0a9bhrt2gM4MxtBLektT+q6FtGJXveE5QzsLgXCDSH+xPX0QpnTwu0OxF2zBkQAvag7g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782901753; c=relaxed/simple; bh=j6N0vGzfCT0xjve3DhVETtRgyjWpm1x6M/5H8nbVfTI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P2OhSbuCF+MZHmFT8bit6uJJvNcrqQ+TFIy/spubehHu5FtaxyFh2B85XSIuFUrAttqsj/Qz0+DsaHAdz0du8FmL2Ij0+aZKgdBSGY1D5JtilOEEF+xrIGEjZAqLYhQ3GDpUVnDiSVjCohHktnnVrIllZUZ9/wP0d9Z3mEtiYPg= 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=iScViVvb; arc=none smtp.client-ip=117.135.210.2 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="iScViVvb" 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=X4 GFd4uUZOW7we5fSeAFc/8KabX3AK2wJQHTRrZKz/Y=; b=iScViVvbNYeWoAcHpW 2hOK5d+1Go8MIqNB8hgDgRgeuqFyAztJMBtMUObarVWxGdAjTBXAay8wUlUINF7Y 2dGpE/JPzJlbJd3hsFWa0w/+RFROLEIA0OWHiartkTVRixjsD+7x6B4LbP1HtqIN A9ZwqkByPx9rzVCdPfa6LG7Hk= Received: from Ubuntu.. (unknown []) by gzga-smtp-mtada-g0-2 (Coremail) with SMTP id _____wD3V0jH60Rq_FlzGw--.4936S4; Wed, 01 Jul 2026 18:28:25 +0800 (CST) From: Xiaofeng Yuan To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Alexandre Ghiti , Mark Brown , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, xiaofengmian@163.com Subject: [PATCH 2/2] riscv: patch: skip fixmap mapping when kernel text is already writable Date: Wed, 1 Jul 2026 10:28:22 +0000 Message-ID: <20260701102822.95459-3-xiaofengmian@163.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260701102822.95459-1-xiaofengmian@163.com> References: <20260701102822.95459-1-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:_____wD3V0jH60Rq_FlzGw--.4936S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7CF17CrW7WryxXw17Gr48WFg_yoW8JFyrpa n7Gr1rZFW5JF4Yy39Fkw1DuryjywnYqry3GFsrZFyS9rs8Zry5G34kW342vF10gr1j9w43 ZFZxtrsI9a4UJ37anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0ziebyZUUUUU= X-CM-SenderInfo: p0ld0w5hqjzxldq6il2tof0z/xtbDAgrY22pE68r8CAAA3w Currently patch_map() always creates a temporary writable mapping via fixmap for kernel text addresses, even when CONFIG_STRICT_KERNEL_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_KERNEL_RWX is not enabled, since the text pages are already writable in this case. Signed-off-by: Xiaofeng Yuan --- arch/riscv/kernel/patch.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c index 16b243376..b6e8e1e83 100644 --- a/arch/riscv/kernel/patch.c +++ b/arch/riscv/kernel/patch.c @@ -44,7 +44,8 @@ static __always_inline void *patch_map(void *addr, const unsigned int fixmap) uintptr_t uintaddr = (uintptr_t) addr; phys_addr_t phys; - if (core_kernel_text(uintaddr) || is_kernel_exittext(uintaddr)) { + if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) && + (core_kernel_text(uintaddr) || is_kernel_exittext(uintaddr))) { phys = __pa_symbol(addr); } else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) { struct page *page = vmalloc_to_page(addr); -- 2.43.0