From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1EE05158DCD for ; Tue, 9 Apr 2024 23:37:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712705833; cv=none; b=aRG+GMVWSZ/5ZpuLTFG6Zm9oXi8KLtYOTXGd/wC6tqd7uVUsuifIw2QNsjbMVlrPPPQSe8HnY1DqFLueS8SkgVmFOAIJJG59Rivk2C5n4Bf+oRMpeFF4I5avpbSY+wd9xmDmQSKGK5IpRz0iQL+J60PTTvtDdtuO6goy+5IRskc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712705833; c=relaxed/simple; bh=5IWHRqqI3seHjc0H8avvGZOeJtWf+yYAE01YKdMRMjI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=i/hVCPJzxP6uheOKu8cU6Og6ODf/VvGGzdLqytiO5DbOG6aZbgJpV+Welr3FGAsxyBrE5lt9LnHVL2OT5DZMkIjlKmrI7teQpG1pEJ5sOOvbi1JDGm5QYYJ5On9S8cSjhQ8uHbaCXPuvVbANLCD/d/sxYUTAKgCfnRNpG9IufOE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=ZJ+RrgOK; arc=none smtp.client-ip=209.85.214.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="ZJ+RrgOK" Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-1e2232e30f4so54535015ad.2 for ; Tue, 09 Apr 2024 16:37:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1712705831; x=1713310631; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=R3GBllj8XS/Lgw7EDpDRRfiZJH4dQ/8JO1yJUn0SBBo=; b=ZJ+RrgOKjpOz9xlBHcWvU73KNORXrOrMjwh4nPUz3JCkOgWGnPN88mBWsC7QFTCz2h JDa2g/M33Sx1YvD0C9qx/TOVi5dSKjxD0QfJKrKazgY/j0LEkJKwggviFDiWxOJK1vjt dQe0ZoRzVidNxlDGSZGCMBHEO3gs9g2yfNgH0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712705831; x=1713310631; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=R3GBllj8XS/Lgw7EDpDRRfiZJH4dQ/8JO1yJUn0SBBo=; b=RZquEatVEfc3Sp4cUV2Vh5GjxVh9WDOr27qYm9qw1LZ8iUVqTtwAv+CZw8jGJ2lhqs zLNdPnUhNMDUdt05B7HK5Z9xHoqUHK31T4RTPXgNHWaZuAMHlNQOoPiXCkid4EewtDJV fivmQWcjqC7Lf56eD8iESMMNf3vRGmO5FSxuCr4cCBwsQGCmA4unHGjmz0cqCtB9+9Az t1lWUH62w3ZjPTDO6DPBbIcTJgvntAKIc/FRAqKOeM1641vlXwo8FLlNkP6s+5QWGsn4 BaW49LbQoE8GqJaELMlCy24IWw55sHMWE1slsG5fhUBE3bG/q4w6Qycwv1drQI/GiiNE qmEA== X-Forwarded-Encrypted: i=1; AJvYcCV0dmHLPnnT+NeNvbF455i0xG8JhPZWSyRpvb+v5c2Tujzz8EHUGm2BTPMZl4OH5gNdcNC0YJMMOO0E3EqiIG7z8iHh5WoB5TV8XU5j X-Gm-Message-State: AOJu0YwCjyuygKz3bRVtpL0YWJfUstWC4WZWxmDnyNZ+uvCArsstceTD A5Mku6Ajiyw0MfLCDidlhgJCP6yDDwckgQypq3QjU2bwsDko1cEcVZw3DzvQtA== X-Google-Smtp-Source: AGHT+IFGdPZEzpneRh+zF6NNUt7U7MwmMmltzsSaPxDXzFgDYjGM/3hI5oS+TZohMG0Jhx7lVLFtgw== X-Received: by 2002:a17:902:9303:b0:1e0:a3dd:82df with SMTP id bc3-20020a170902930300b001e0a3dd82dfmr1075461plb.38.1712705831382; Tue, 09 Apr 2024 16:37:11 -0700 (PDT) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id kn12-20020a170903078c00b001e0c91d448fsm9479230plb.112.2024.04.09.16.37.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Apr 2024 16:37:10 -0700 (PDT) Date: Tue, 9 Apr 2024 16:37:10 -0700 From: Kees Cook To: "Luck, Tony" Cc: Steven Rostedt , "linux-kernel@vger.kernel.org" , "linux-trace-kernel@vger.kernel.org" , Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Lorenzo Stoakes , "linux-mm@kvack.org" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "x86@kernel.org" , "H. Peter Anvin" , Peter Zijlstra , "Guilherme G. Piccoli" , "linux-hardening@vger.kernel.org" , Guenter Roeck , Ross Zwisler , "wklin@google.com" , Vineeth Remanan Pillai , Joel Fernandes , Suleiman Souhlal , Linus Torvalds , Catalin Marinas , Will Deacon Subject: Re: [POC][RFC][PATCH 0/2] pstore/mm/x86: Add wildcard memmap to map pstore consistently Message-ID: <202404091628.BEC1FAC8@keescook> References: <20240409210254.660888920@goodmis.org> <20240409172358.34ea19f0@gandalf.local.home> <202404091519.B7B2221@keescook> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Apr 09, 2024 at 10:25:33PM +0000, Luck, Tony wrote: > >> I forgot to mention that this makes it trivial for any machine that doesn't > >> clear memory on soft-reboot, to enable console ramoops (to have access to > >> the last boot dmesg without needing serial). > >> > >> I tested this on a couple of my test boxes and on QEMU, and it works rather > >> well. > > > > I've long wanted a "stable for this machine and kernel" memory region > > like this for pstore. It would make testing much easier. > > Which systems does this work on? I'd assume that servers (and anything > else with ECC memory) would nuke contents while resetting ECC to clean > state. Do ECC servers wipe their RAM by default? I know that if you build with CONFIG_RESET_ATTACK_MITIGATION=y on an EFI system that supports the MemoryOverwriteRequestControl EFI variable you'll get a RAM wipe... -- Kees Cook