From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE47BC433ED for ; Mon, 19 Apr 2021 12:22:12 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4B9CE6127C for ; Mon, 19 Apr 2021 12:22:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B9CE6127C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4FP5Xx51z2z30F3 for ; Mon, 19 Apr 2021 22:22:09 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=ksngFMTA; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=ellerman.id.au (client-ip=203.11.71.1; helo=ozlabs.org; envelope-from=mpe@ellerman.id.au; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=ksngFMTA; dkim-atps=neutral Received: from ozlabs.org (ozlabs.org [203.11.71.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4FP5XS2H08z2xYl for ; Mon, 19 Apr 2021 22:21:43 +1000 (AEST) Received: by ozlabs.org (Postfix) id 4FP5XQ3k59z9vDx; Mon, 19 Apr 2021 22:21:42 +1000 (AEST) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4FP5XN6hwYz9vDV; Mon, 19 Apr 2021 22:21:40 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ellerman.id.au; s=201909; t=1618834902; bh=ozMqPJ3D5LeS0fKqMMOHm/0k1FsuW3w/Tknt0WqvEtI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=ksngFMTA/LRUOyHWyzFSOcAtgpiEUSkHXYThjpIMzPezZXvwgLZloLLO/3TB+ZJPH DXKOmx0hJVslwYwAnAed32T4N1Nbw0f2gbq5o449s6rDfDX8Qm3wT7Cb3X7mDuQ+0z 4V8K4sfbnwMvvBCPaYkyX5os7S1pPJKLdtqU26C6rGOBHaZXJQBVsHgkmuYhTsVxMy PkGrAGDawlnZTGhzM6ly+tsnXrP95znyVsvdOEqq+w/v6BxgTvNZBGiSCsBq6rReX9 OXJbmMAvn4G7lLw0WnZW8QJCQh+zx4JNKfnS/v3zoWX+rhu6NuGoSSVleXdUfjz5hF 4u8mVPkDQaULA== From: Michael Ellerman To: Hari Bathini , Sourabh Jain Subject: Re: [PATCH v4] powerpc/kexec_file: use current CPU info while setting up FDT In-Reply-To: <3c004e09-7db2-1bb8-352a-0695278eea93@linux.ibm.com> References: <20210419083624.1124390-1-sourabhjain@linux.ibm.com> <3c004e09-7db2-1bb8-352a-0695278eea93@linux.ibm.com> Date: Mon, 19 Apr 2021 22:21:39 +1000 Message-ID: <877dkyea7g.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mahesh@linux.vnet.ibm.com, stable@vger.kernel.org, bauerman@linux.ibm.com, linuxppc-dev@ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hari Bathini writes: > On 19/04/21 2:06 pm, Sourabh Jain wrote: >> kexec_file_load uses initial_boot_params in setting up the device-tree >> for the kernel to be loaded. Though initial_boot_params holds info >> about CPUs at the time of boot, it doesn't account for hot added CPUs. >> >> So, kexec'ing with kexec_file_load syscall would leave the kexec'ed >> kernel with inaccurate CPU info. Also, if kdump kernel is loaded with >> kexec_file_load syscall and the system crashes on a hot added CPU, >> capture kernel hangs failing to identify the boot CPU. >> >> Kernel panic - not syncing: sysrq triggered crash >> CPU: 24 PID: 6065 Comm: echo Kdump: loaded Not tainted 5.12.0-rc5upstream #54 >> Call Trace: >> [c0000000e590fac0] [c0000000007b2400] dump_stack+0xc4/0x114 (unreliable) >> [c0000000e590fb00] [c000000000145290] panic+0x16c/0x41c >> [c0000000e590fba0] [c0000000008892e0] sysrq_handle_crash+0x30/0x40 >> [c0000000e590fc00] [c000000000889cdc] __handle_sysrq+0xcc/0x1f0 >> [c0000000e590fca0] [c00000000088a538] write_sysrq_trigger+0xd8/0x178 >> [c0000000e590fce0] [c0000000005e9b7c] proc_reg_write+0x10c/0x1b0 >> [c0000000e590fd10] [c0000000004f26d0] vfs_write+0xf0/0x330 >> [c0000000e590fd60] [c0000000004f2aec] ksys_write+0x7c/0x140 >> [c0000000e590fdb0] [c000000000031ee0] system_call_exception+0x150/0x290 >> [c0000000e590fe10] [c00000000000ca5c] system_call_common+0xec/0x278 >> --- interrupt: c00 at 0x7fff905b9664 >> NIP: 00007fff905b9664 LR: 00007fff905320c4 CTR: 0000000000000000 >> REGS: c0000000e590fe80 TRAP: 0c00 Not tainted (5.12.0-rc5upstream) >> MSR: 800000000280f033 CR: 28000242 >> XER: 00000000 >> IRQMASK: 0 >> GPR00: 0000000000000004 00007ffff5fedf30 00007fff906a7300 0000000000000001 >> GPR04: 000001002a7355b0 0000000000000002 0000000000000001 00007ffff5fef616 >> GPR08: 0000000000000001 0000000000000000 0000000000000000 0000000000000000 >> GPR12: 0000000000000000 00007fff9073a160 0000000000000000 0000000000000000 >> GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 >> GPR20: 0000000000000000 00007fff906a4ee0 0000000000000002 0000000000000001 >> GPR24: 00007fff906a0898 0000000000000000 0000000000000002 000001002a7355b0 >> GPR28: 0000000000000002 00007fff906a1790 000001002a7355b0 0000000000000002 >> NIP [00007fff905b9664] 0x7fff905b9664 >> LR [00007fff905320c4] 0x7fff905320c4 >> --- interrupt: c00 >> >> To avoid this from happening, extract current CPU info from of_root >> device node and use it for setting up the fdt in kexec_file_load case. >> >> Fixes: 6ecd0163d360 ("powerpc/kexec_file: Add appropriate regions for memory reserve map") >> >> Signed-off-by: Sourabh Jain >> Reviewed-by: Hari Bathini >> Cc: >> --- >> arch/powerpc/kexec/file_load_64.c | 98 +++++++++++++++++++++++++++++++ >> 1 file changed, 98 insertions(+) >> >> --- >> Changelog: >> >> v1 -> v3 >> - https://lists.ozlabs.org/pipermail/linuxppc-dev/2021-April/227756.html >> >> v3 -> v4 >> - Rearranged if-else statement in update_cpus_node function to avoid >> redundant checks for positive cpus_offset. >> --- >> >> diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c >> index 02b9e4d0dc40..195ef303d530 100644 >> --- a/arch/powerpc/kexec/file_load_64.c >> +++ b/arch/powerpc/kexec/file_load_64.c >> @@ -960,6 +960,99 @@ unsigned int kexec_fdt_totalsize_ppc64(struct kimage *image) >> return fdt_size; >> } >> >> +/** >> + * add_node_prop - Read property from device node structure and add >> + * them to fdt. >> + * @fdt: Flattened device tree of the kernel >> + * @node_offset: offset of the node to add a property at >> + * np: device node pointer >> + * >> + * Returns 0 on success, negative errno on error. >> + */ >> +static int add_node_prop(void *fdt, int node_offset, const struct device_node *np) >> +{ >> + int ret = 0; >> + struct property *pp; >> + unsigned long flags; >> + >> + if (!np) >> + return -EINVAL; >> + >> + raw_spin_lock_irqsave(&devtree_lock, flags); >> + for (pp = np->properties; pp; pp = pp->next) { >> + ret = fdt_setprop(fdt, node_offset, pp->name, >> + pp->value, pp->length); >> + if (ret < 0) { >> + pr_err("Unable to add %s property: %s\n", >> + pp->name, fdt_strerror(ret)); >> + goto out; >> + } >> + } >> +out: >> + raw_spin_unlock_irqrestore(&devtree_lock, flags); >> + return ret; >> +} >> + >> +/** >> + * update_cpus_node - Update cpus node of flattened device-tree using of_root >> + * device node. >> + * @fdt: Flattened device tree of the kernel. >> + * >> + * Returns 0 on success, negative errno on error. >> + */ >> +static int update_cpus_node(void *fdt) >> +{ >> + struct device_node *cpus_node, *dn; >> + int cpus_offset, cpus_subnode_off, ret = 0; >> + >> + cpus_offset = fdt_path_offset(fdt, "/cpus"); >> + if (cpus_offset < 0 && cpus_offset != -FDT_ERR_NOTFOUND) { >> + pr_err("Malformed device tree: error reading /cpus node: %s\n", >> + fdt_strerror(cpus_offset)); >> + return cpus_offset; >> + } else { > > >> + if (cpus_offset > 0) { >> + ret = fdt_del_node(fdt, cpus_offset); >> + if (ret < 0) { >> + pr_err("Error deleting /cpus node: %s\n", >> + fdt_strerror(ret)); >> + return -EINVAL; >> + } >> + } >> + >> + /* Add cpus node to fdt */ >> + cpus_offset = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"), >> + "cpus"); >> + if (cpus_offset < 0) { >> + pr_err("Error creating /cpus node: %s\n", >> + fdt_strerror(cpus_offset)); >> + return -EINVAL; >> + } >> + >> + /* Add cpus node properties */ >> + cpus_node = of_find_node_by_path("/cpus"); >> + ret = add_node_prop(fdt, cpus_offset, cpus_node); >> + if (ret < 0) >> + return ret; >> + >> + /* Loop through all subnodes of cpus and add them to fdt */ >> + for_each_node_by_type(dn, "cpu") { >> + cpus_subnode_off = fdt_add_subnode(fdt, >> + cpus_offset, >> + dn->full_name); >> + if (cpus_subnode_off < 0) { >> + pr_err("Unable to add %s subnode: %s\n", >> + dn->full_name, fdt_strerror(cpus_subnode_off)); >> + return cpus_subnode_off; >> + } >> + ret = add_node_prop(fdt, cpus_subnode_off, dn); >> + if (ret < 0) >> + return ret; >> + } > > The above code block doesn't really need an explicit else condition.. Yeah, use the early return to avoid having to indent all the rest of that logic. Please send a v5. cheers