From patchwork Tue Jan 7 00:40:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 206651 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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=ham 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 D1068C32771 for ; Tue, 7 Jan 2020 00:56:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A62162073D for ; Tue, 7 Jan 2020 00:56:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727427AbgAGA4q (ORCPT ); Mon, 6 Jan 2020 19:56:46 -0500 Received: from mga03.intel.com ([134.134.136.65]:26789 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727233AbgAGA4q (ORCPT ); Mon, 6 Jan 2020 19:56:46 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Jan 2020 16:56:45 -0800 X-IronPort-AV: E=Sophos;i="5.69,404,1571727600"; d="scan'208";a="222404183" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Jan 2020 16:56:45 -0800 Subject: [PATCH v4 4/4] efi: Fix handling of multiple efi_fake_mem= entries From: Dan Williams To: mingo@redhat.com Cc: Dave Young , Taku Izumi , Michael Weiser , Ard Biesheuvel , Thomas Gleixner , Ingo Molnar , linux-efi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org Date: Mon, 06 Jan 2020 16:40:43 -0800 Message-ID: <157835764298.1456824.224151767362114611.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <157835762222.1456824.290100196815539830.stgit@dwillia2-desk3.amr.corp.intel.com> References: <157835762222.1456824.290100196815539830.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-3-g996c MIME-Version: 1.0 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Dave noticed that when specifying multiple efi_fake_mem= entries only the last entry was successfully being reflected in the efi memory map. This is due to the fact that the efi_memmap_insert() is being called multiple times, but on successive invocations the insertion should be applied to the last new memmap rather than the original map at efi_fake_memmap() entry. Rework efi_fake_memmap() to install the new memory map after each efi_fake_mem= entry is parsed. This also fixes an issue in efi_fake_memmap() that caused it to litter emtpy entries into the end of the efi memory map. An empty entry causes efi_memmap_insert() to attempt more memmap splits / copies than efi_memmap_split_count() accounted for when sizing the new map. When that happens efi_memmap_insert() may overrun its allocation, and if you are lucky will spill over to an unmapped page leading to crash signature like the following rather than silent corruption: BUG: unable to handle page fault for address: ffffffffff281000 [..] RIP: 0010:efi_memmap_insert+0x11d/0x191 [..] Call Trace: ? bgrt_init+0xbe/0xbe ? efi_arch_mem_reserve+0x1cb/0x228 ? acpi_parse_bgrt+0xa/0xd ? acpi_table_parse+0x86/0xb8 ? acpi_boot_init+0x494/0x4e3 ? acpi_parse_x2apic+0x87/0x87 ? setup_acpi_sci+0xa2/0xa2 ? setup_arch+0x8db/0x9e1 ? start_kernel+0x6a/0x547 ? secondary_startup_64+0xb6/0xc0 Commit af1648984828 "x86/efi: Update e820 with reserved EFI boot services data to fix kexec breakage" is listed in Fixes: since it introduces more occurrences where efi_memmap_insert() is invoked after an efi_fake_mem= configuration has been parsed. Previously the side effects of vestigial empty entries were benign, but with commit af1648984828 that follow-on efi_memmap_insert() invocation triggers efi_memmap_insert() overruns. Fixes: 0f96a99dab36 ("efi: Add 'efi_fake_mem' boot option") Fixes: af1648984828 ("x86/efi: Update e820 with reserved EFI boot services...") Link: https://lore.kernel.org/r/20191231014630.GA24942@dhcp-128-65.nay.redhat.com Reported-by: Dave Young Cc: Taku Izumi Cc: Michael Weiser Cc: Ard Biesheuvel Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Dan Williams --- drivers/firmware/efi/fake_mem.c | 31 ++++++++++++++++--------------- drivers/firmware/efi/memmap.c | 2 +- include/linux/efi.h | 2 ++ 3 files changed, 19 insertions(+), 16 deletions(-) diff --git a/drivers/firmware/efi/fake_mem.c b/drivers/firmware/efi/fake_mem.c index a8d20568d532..6e0f34a38171 100644 --- a/drivers/firmware/efi/fake_mem.c +++ b/drivers/firmware/efi/fake_mem.c @@ -34,25 +34,16 @@ static int __init cmp_fake_mem(const void *x1, const void *x2) return 0; } -void __init efi_fake_memmap(void) +static void __init efi_fake_range(struct efi_mem_range *efi_range) { struct efi_memory_map_data data = { 0 }; int new_nr_map = efi.memmap.nr_map; efi_memory_desc_t *md; void *new_memmap; - int i; - - if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem) - return; /* count up the number of EFI memory descriptor */ - for (i = 0; i < nr_fake_mem; i++) { - for_each_efi_memory_desc(md) { - struct range *r = &efi_fake_mems[i].range; - - new_nr_map += efi_memmap_split_count(md, r); - } - } + for_each_efi_memory_desc(md) + new_nr_map += efi_memmap_split_count(md, &efi_range->range); /* allocate memory for new EFI memmap */ if (efi_memmap_alloc(new_nr_map, &data) != 0) @@ -61,17 +52,27 @@ void __init efi_fake_memmap(void) /* create new EFI memmap */ new_memmap = early_memremap(data.phys_map, data.size); if (!new_memmap) { - memblock_free(data.phys_map, data.size); + __efi_memmap_free(data.phys_map, data.size, data.flags); return; } - for (i = 0; i < nr_fake_mem; i++) - efi_memmap_insert(&efi.memmap, new_memmap, &efi_fake_mems[i]); + efi_memmap_insert(&efi.memmap, new_memmap, efi_range); /* swap into new EFI memmap */ early_memunmap(new_memmap, data.size); efi_memmap_install(&data); +} + +void __init efi_fake_memmap(void) +{ + int i; + + if (!efi_enabled(EFI_MEMMAP) || !nr_fake_mem) + return; + + for (i = 0; i < nr_fake_mem; i++) + efi_fake_range(&efi_fake_mems[i]); /* print new EFI memmap */ efi_print_memmap(); diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c index bffa320d2f9a..1b6a4aa78a09 100644 --- a/drivers/firmware/efi/memmap.c +++ b/drivers/firmware/efi/memmap.c @@ -29,7 +29,7 @@ static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size) return PFN_PHYS(page_to_pfn(p)); } -static void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags) +void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags) { if (flags & EFI_MEMMAP_MEMBLOCK) { if (slab_is_available()) diff --git a/include/linux/efi.h b/include/linux/efi.h index 416eac01b1a1..539e81c942dc 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1062,6 +1062,8 @@ extern void __iomem *efi_lookup_mapped_addr(u64 phys_addr); extern int __init efi_memmap_alloc(unsigned int num_entries, struct efi_memory_map_data *data); +extern void __efi_memmap_free(u64 phys, unsigned long size, + unsigned long flags); extern int __init efi_memmap_init_early(struct efi_memory_map_data *data); extern int __init efi_memmap_init_late(phys_addr_t addr, unsigned long size); extern void __init efi_memmap_unmap(void);