From patchwork Tue Apr 21 09:04:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tiezhu Yang X-Patchwork-Id: 11500885 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 10DAD913 for ; Tue, 21 Apr 2020 09:04:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 02B3420CC7 for ; Tue, 21 Apr 2020 09:04:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728055AbgDUJEv (ORCPT ); Tue, 21 Apr 2020 05:04:51 -0400 Received: from mail.loongson.cn ([114.242.206.163]:34794 "EHLO loongson.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726052AbgDUJEv (ORCPT ); Tue, 21 Apr 2020 05:04:51 -0400 Received: from linux.localdomain (unknown [113.200.148.30]) by mail.loongson.cn (Coremail) with SMTP id AQAAf9DxT2knt55emXsqAA--.36S5; Tue, 21 Apr 2020 17:04:44 +0800 (CST) From: Tiezhu Yang To: Thomas Bogendoerfer Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, Xuefeng Li , Juxin Gao Subject: [PATCH 3/3] MIPS: Reduce possibility of kernel panic under CONFIG_SWIOTLB Date: Tue, 21 Apr 2020 17:04:29 +0800 Message-Id: <1587459869-12183-4-git-send-email-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1587459869-12183-1-git-send-email-yangtiezhu@loongson.cn> References: <1587459869-12183-1-git-send-email-yangtiezhu@loongson.cn> X-CM-TRANSID: AQAAf9DxT2knt55emXsqAA--.36S5 X-Coremail-Antispam: 1UD129KBjvJXoWxXw43uFW3Cr13Aw18Ar4UCFg_yoW5GF1kpr y7C3WYqr4vqrn7A3yfC348ZF1akwn5Cry7W3yavr4ruw1DXrs8Ar4vgF43XF1xtrW0qF4a qa4FvFW09Fs7AaUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBS14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2048vs2IY020E87I2jVAFwI0_JrWl82xGYIkIc2 x26xkF7I0E14v26r4j6ryUM28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8wA2z4x0 Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_Gr1UM2 8EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS 0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2 IY67AKxVWUGVWUXwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0 Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY02Avz4vE14v_GFWl42xK82 IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC2 0s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAKI48JMI IF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF 0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVW8JVWxJwCI42IY6I8E87 Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUUHq2DUUUU X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org In the current code, if CONFIG_SWIOTLB is set, when failed to get IO TLB memory from the low pages by plat_swiotlb_setup(), it may lead to the boot process failed with kernel panic. (1) On the Loongson and SiByte platform arch/mips/loongson64/dma.c arch/mips/sibyte/common/dma.c void __init plat_swiotlb_setup(void) { swiotlb_init(1); } kernel/dma/swiotlb.c void __init swiotlb_init(int verbose) { ... vstart = memblock_alloc_low(PAGE_ALIGN(bytes), PAGE_SIZE); if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose)) return; ... pr_warn("Cannot allocate buffer"); no_iotlb_memory = true; } phys_addr_t swiotlb_tbl_map_single() { ... if (no_iotlb_memory) panic("Can not allocate SWIOTLB buffer earlier ..."); ... } (2) On the Cavium OCTEON platform arch/mips/cavium-octeon/dma-octeon.c void __init plat_swiotlb_setup(void) { ... octeon_swiotlb = memblock_alloc_low(swiotlbsize, PAGE_SIZE); if (!octeon_swiotlb) panic("%s: Failed to allocate %zu bytes align=%lx\n", __func__, swiotlbsize, PAGE_SIZE); ... } Because IO_TLB_DEFAULT_SIZE is 64M, if the rest size of low memory is less than 64M when call plat_swiotlb_setup(), we can easily reproduce the panic case. In order to reduce the possibility of kernel panic when failed to get IO TLB memory under CONFIG_SWIOTLB, it is better to allocate low memory as small as possible before plat_swiotlb_setup(), so make sparse_init() using top-down allocation. Reported-by: Juxin Gao Co-developed-by: Juxin Gao Signed-off-by: Juxin Gao Signed-off-by: Tiezhu Yang --- arch/mips/kernel/setup.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index 5481a0c..8db533c 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -700,7 +700,17 @@ static void __init arch_mem_init(char **cmdline_p) memblock_reserve(crashk_res.start, resource_size(&crashk_res)); #endif device_tree_init(); + + /* + * In order to reduce the possibility of kernel panic when failed to + * get IO TLB memory under CONFIG_SWIOTLB, it is better to allocate + * low memory as small as possible before plat_swiotlb_setup(), so + * make sparse_init() using top-down allocation. + */ + memblock_set_bottom_up(false); sparse_init(); + memblock_set_bottom_up(true); + plat_swiotlb_setup(); dma_contiguous_reserve(PFN_PHYS(max_low_pfn));