From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754693AbdDLP1a (ORCPT ); Wed, 12 Apr 2017 11:27:30 -0400 Received: from mail-wm0-f42.google.com ([74.125.82.42]:38897 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754592AbdDLP1X (ORCPT ); Wed, 12 Apr 2017 11:27:23 -0400 From: Matt Fleming To: Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" Cc: Omar Sandoval , Ard Biesheuvel , linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, Matt Fleming , Dave Young , Peter Jones , stable@vger.kernel.org Subject: [PATCH] x86/efi: Don't try to reserve runtime regions Date: Wed, 12 Apr 2017 16:27:19 +0100 Message-Id: <20170412152719.9779-2-matt@codeblueprint.co.uk> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20170412152719.9779-1-matt@codeblueprint.co.uk> References: <20170412152719.9779-1-matt@codeblueprint.co.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Omar Sandoval Reserving a runtime region results in splitting the efi memory descriptors for the runtime region. This results in runtime region descriptors with bogus memory mappings, leading to interesting crashes like the following during a kexec: [ 0.001000] general protection fault: 0000 [#1] SMP [ 0.001000] Modules linked in: [ 0.001000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc1 #53 [ 0.001000] Hardware name: Wiwynn Leopard-Orv2/Leopard-DDR BW, BIOS LBM05 09/30/2016 [ 0.001000] task: ffffffff81e0e4c0 task.stack: ffffffff81e00000 [ 0.001000] RIP: 0010:virt_efi_set_variable+0x85/0x1a0 [ 0.001000] RSP: 0000:ffffffff81e03e18 EFLAGS: 00010202 [ 0.001000] RAX: afafafafafafafaf RBX: ffffffff81e3a4e0 RCX: 0000000000000007 [ 0.001000] RDX: ffffffff81e03e70 RSI: ffffffff81e3a4e0 RDI: ffff88407f8c2de0 [ 0.001000] RBP: ffffffff81e03e60 R08: 0000000000000000 R09: 0000000000000000 [ 0.001000] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff81e03e70 [ 0.001000] R13: 0000000000000007 R14: 0000000000000000 R15: 0000000000000000 [ 0.001000] FS: 0000000000000000(0000) GS:ffff881fff600000(0000) knlGS:0000000000000000 [ 0.001000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.001000] CR2: ffff88407f30f000 CR3: 0000001fff102000 CR4: 00000000000406b0 [ 0.001000] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 0.001000] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 0.001000] Call Trace: [ 0.001000] efi_delete_dummy_variable+0x7a/0x80 [ 0.001000] efi_enter_virtual_mode+0x3e2/0x494 [ 0.001000] start_kernel+0x392/0x418 [ 0.001000] ? set_init_arg+0x55/0x55 [ 0.001000] x86_64_start_reservations+0x2a/0x2c [ 0.001000] x86_64_start_kernel+0xea/0xed [ 0.001000] start_cpu+0x14/0x14 [ 0.001000] Code: 42 25 8d ff 80 3d 43 77 95 00 00 75 68 9c 8f 04 24 48 8b 05 3e 7d 7e 00 48 89 de 4d 89 f9 4d 89 f0 44 89 e9 4c 89 e2 48 8b 40 58 <48> 8b 78 58 31 c0 e8 90 e4 92 ff 48 8b 3c 24 48 c7 c6 2b 0a ca [ 0.001000] RIP: virt_efi_set_variable+0x85/0x1a0 RSP: ffffffff81e03e18 [ 0.001000] ---[ end trace 0bd213e540e9b19f ]--- [ 0.001000] Kernel panic - not syncing: Fatal exception [ 0.001000] ---[ end Kernel panic - not syncing: Fatal exception Runtime regions will not be freed and do not need to be reserved, so skip the memmap modification in this case. Fixes: 8e80632fb23f ("efi/esrt: Use efi_mem_reserve() and avoid a kmalloc()") Signed-off-by: Omar Sandoval Cc: Ard Biesheuvel Cc: Dave Young Cc: Ingo Molnar Cc: Peter Jones Cc: # v4.9+ Signed-off-by: Matt Fleming --- arch/x86/platform/efi/quirks.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index 30031d5293c4..cdfe8c628959 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -201,6 +201,10 @@ void __init efi_arch_mem_reserve(phys_addr_t addr, u64 size) return; } + /* No need to reserve regions that will never be freed. */ + if (md.attribute & EFI_MEMORY_RUNTIME) + return; + size += addr % EFI_PAGE_SIZE; size = round_up(size, EFI_PAGE_SIZE); addr = round_down(addr, EFI_PAGE_SIZE); -- 2.10.0