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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 42A48C48BE8 for ; Sat, 22 Jun 2019 08:51:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F6B3208CA for ; Sat, 22 Jun 2019 08:51:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="iz2Wh5lK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726404AbfFVIvP (ORCPT ); Sat, 22 Jun 2019 04:51:15 -0400 Received: from mail-wm1-f66.google.com ([209.85.128.66]:39987 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726310AbfFVIvP (ORCPT ); Sat, 22 Jun 2019 04:51:15 -0400 Received: by mail-wm1-f66.google.com with SMTP id v19so8655875wmj.5 for ; Sat, 22 Jun 2019 01:51:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=HO4NlEgMlVr7RQNzUTkiZe3whDgA7iGbSEYeXfsjzfo=; b=iz2Wh5lKIKrtIT+GilYCiOborf/BB+0KAnXOBgcowZHsTrFSpVUgXEsP8RADKbgcjA AiNEbMFDsQHqYVnWhYpACbjywEFmgTQHxJbOZh0qTYuoixUa9GwiPPPJ7c9Pohwgpt+k usZtN0O+w4JAQj2x3sfCJefE7RL8k9GJwvaw6Q4C065/h9Z0VFvC/r/CllXb4R5ZPrDV +a49/gi4z3nP3UUHtSONU1xhrt+djS34PKGvVpsc4yihqBsw7ULFsoBJS4VNLegoUAqE kYjdwP3jxhffTl7ROUZHCgTdMj8VgCtkkMDZcwxIueXwu5dCXzu3BIFp6fCTwkKb+fym LquA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=HO4NlEgMlVr7RQNzUTkiZe3whDgA7iGbSEYeXfsjzfo=; b=bdoVWWFoyKEkWJQIEvudR7lh78Eb9YdoB6RV4cItg2jpmNvmj4qBzdl8aX2u/YC7KL h6LzqZX5Wv7ZUwAtcU0mejNDDeq5Wvci8IoRDqZmOgAmK+zapCrn94loJCz7uwyYTYFe qiXmF15QzJhvFeNtGzlB/MrLslG9ZK3QwvTblAozVAk3duln62Vyy+ZmfhjCU/dJC0U9 vNiIwTJZLdkmH26kwu6arFObfjF9jlDjmLeieR9HiPk3T7ZEJHrleZ7/iMXxP1X0qQfM XL7uWExmLrkR2r+NsLMIEBeDrbLXrurElJGIf2bmG17VZY7vD/+c73HAR3YYhNS2xSmK ZNzw== X-Gm-Message-State: APjAAAVhEaLId6vwuX+NHcWjqurbDLUtwSCmhWwGduu4XCFJxoRaokyT 5Hxb3lLDCrO2jDaC0RaGUXUTlX0vCFlVSjhH X-Google-Smtp-Source: APXvYqzFnpgqxmtOy6/8NHQqNbTQ+elWE4WF/mHbUz0J17z0cEJj/TLZyZd5RkNkH5JI9MXqXsFM5A== X-Received: by 2002:a7b:c450:: with SMTP id l16mr7720525wmi.0.1561193472725; Sat, 22 Jun 2019 01:51:12 -0700 (PDT) Received: from sudo.home ([2a01:cb1d:112:6f00:4bd:3f91:4ef8:ae7e]) by smtp.gmail.com with ESMTPSA id v15sm4863589wrt.25.2019.06.22.01.51.11 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 22 Jun 2019 01:51:12 -0700 (PDT) From: Ard Biesheuvel To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, Hans de Goede , Jonathan Richardson , Luo XinanX , "Prakhya, Sai Praneeth" , Qian Cai , Tian Baofeng Subject: [PATCH 1/4] efi/memreserve: deal with memreserve entries in unmapped memory Date: Sat, 22 Jun 2019 10:51:03 +0200 Message-Id: <20190622085106.24859-2-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190622085106.24859-1-ard.biesheuvel@linaro.org> References: <20190622085106.24859-1-ard.biesheuvel@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org 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 --- drivers/firmware/efi/efi.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 16b2137d117c..4b7cf7bc0ded 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -1009,14 +1009,16 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) /* 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 */ @@ -1024,7 +1026,13 @@ int __ref efi_mem_reserve_persistent(phys_addr_t addr, u64 size) 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; -- 2.20.1