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[209.132.180.67]) by mx.google.com with ESMTP id e9si12153219pgc.321.2019.07.02.01.03.28; Tue, 02 Jul 2019 01:03:29 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=byqQbkww; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727420AbfGBIDY (ORCPT + 30 others); Tue, 2 Jul 2019 04:03:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:48338 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727399AbfGBIDW (ORCPT ); Tue, 2 Jul 2019 04:03:22 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B823C21841; Tue, 2 Jul 2019 08:03:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562054601; bh=FWX6yoUmqpeNc3UXbOoiOv73WGfgMq7r2DRCslZmUHM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=byqQbkwwIW/3aHxCXxjoOwLbGJXfJLjIz3/cvVLLYBsCHsAN86/XsDldBiPQ4KEjG 8TYZ9AHrJZlsUPb5gM+ffGy3g0G9ot08TZ7O9HZFk6GeuKQByro8y4ipxS3t3tZAdY Q73i9R2H2zrWMbEflzTgt/Kv8VDey8Ej51ZqJitQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jonathan Richardson , Ard Biesheuvel Subject: [PATCH 5.1 25/55] efi/memreserve: deal with memreserve entries in unmapped memory Date: Tue, 2 Jul 2019 10:01:33 +0200 Message-Id: <20190702080125.373828717@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190702080124.103022729@linuxfoundation.org> References: <20190702080124.103022729@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ard Biesheuvel commit 18df7577adae6c6c778bf774b3aebcacbc1fb439 upstream. Ensure that the EFI memreserve entries can be accessed, even if they are located in memory that the kernel (e.g., a crashkernel) omits from the linear map. Fixes: 80424b02d42b ("efi: Reduce the amount of memblock reservations ...") Cc: # 5.0+ Reported-by: Jonathan Richardson Reviewed-by: Jonathan Richardson Tested-by: Jonathan Richardson Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/efi/efi.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -1007,14 +1007,16 @@ int __ref efi_mem_reserve_persistent(phy /* first try to find a slot in an existing linked list entry */ for (prsv = efi_memreserve_root->next; prsv; prsv = rsv->next) { - rsv = __va(prsv); + rsv = memremap(prsv, sizeof(*rsv), MEMREMAP_WB); index = atomic_fetch_add_unless(&rsv->count, 1, rsv->size); if (index < rsv->size) { rsv->entry[index].base = addr; rsv->entry[index].size = size; + memunmap(rsv); return 0; } + memunmap(rsv); } /* no slot found - allocate a new linked list entry */ @@ -1022,7 +1024,13 @@ int __ref efi_mem_reserve_persistent(phy if (!rsv) return -ENOMEM; - rsv->size = EFI_MEMRESERVE_COUNT(PAGE_SIZE); + /* + * The memremap() call above assumes that a linux_efi_memreserve entry + * never crosses a page boundary, so let's ensure that this remains true + * even when kexec'ing a 4k pages kernel from a >4k pages kernel, by + * using SZ_4K explicitly in the size calculation below. + */ + rsv->size = EFI_MEMRESERVE_COUNT(SZ_4K); atomic_set(&rsv->count, 1); rsv->entry[0].base = addr; rsv->entry[0].size = size;