From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B50D2FF148; Tue, 17 Feb 2026 10:27:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771324033; cv=none; b=ruif2kGDiB6Lb5H2IJQffLj1t5TP4BaB70xXj00NfyeeP/aj7nzqY/QkU5QS+JL73kFtLgMDTxdDgKz7bwrmh3AP140TP5dV1fOKebncJ4WUAHJXhovzgfRLTFEAPlzzxDy2arddBK/TLcRvDL/1HgNNKnRKvveuDC0q29fNUdI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771324033; c=relaxed/simple; bh=A1RZeYH6sHmVQh3ml2jbUXSijJJc+yhNtIXFCMMdagk=; h=MIME-Version:Date:From:To:Cc:Message-Id:In-Reply-To:References: Subject:Content-Type; b=OQVGhYf03/FjDX84f3NIi4HHrwQd8rdS8tkh7asO7U92efQgFFxoZJLOv3OC19WjYe/J7gJkI5F1UQ7hVC05jECYtm2ifZNf/NDjjlU3dqIerB0IKnJkpgxx22T2oQJZ8xPFDZBOExE8+RM/UMWkWmrhfhiivEbDB+hXPttE4Vk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kGTZyWK9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kGTZyWK9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6CD4BC19423; Tue, 17 Feb 2026 10:27:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771324032; bh=A1RZeYH6sHmVQh3ml2jbUXSijJJc+yhNtIXFCMMdagk=; h=Date:From:To:Cc:In-Reply-To:References:Subject:From; b=kGTZyWK9NxTBeFN83u6JR8u46jSt/HGQRh8X8Wc1W8Jdg2KABSt1+TzNn0aI5SpMH YC6g6hC4pTUUh4iO7d0BWe6EU/6CD9gDrn/2cZbLXf9GD8C96WlkSZtyB9+Uj5lXDQ 2zI4nabQR1mYSnd7wNFL0P29KPd/+tTv3k0IpPbcvlXYLz5+LNdJqzEH9/7LllfE/q kWDNnGBAbxkLC2Svs2CTIjvKWjL/GKEKvbflW65uivF0+22E7p8h4n1OTcpYvmWsRo ngviNI4I7oTvLeOJgPXIgmRnGFEnlxjIuHmfvVHc8OKXfsOKwXF1AZ89Ey+5j0aEsg JgIHauhOptjdw== Received: from phl-compute-01.internal (phl-compute-01.internal [10.202.2.41]) by mailfauth.phl.internal (Postfix) with ESMTP id 574D6F40069; Tue, 17 Feb 2026 05:27:11 -0500 (EST) Received: from phl-imap-02 ([10.202.2.81]) by phl-compute-01.internal (MEProxy); Tue, 17 Feb 2026 05:27:11 -0500 X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefgedrtddtgddvudelhedvucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceu rghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujf gurhepofggfffhvfevkfgjfhfutgfgsehtjeertdertddtnecuhfhrohhmpedftehrugcu uehivghshhgvuhhvvghlfdcuoegrrhgusgeskhgvrhhnvghlrdhorhhgqeenucggtffrrg htthgvrhhnpedvueehiedtvedtleekuddutefgffdtleetfeetveejveejieehfefhjeei jeefudenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpe grrhguodhmvghsmhhtphgruhhthhhpvghrshhonhgrlhhithihqdduieejtdehtddtjeel qdeffedvudeigeduhedqrghruggspeepkhgvrhhnvghlrdhorhhgseifohhrkhhofhgrrh gurdgtohhmpdhnsggprhgtphhtthhopeehpdhmohguvgepshhmthhpohhuthdprhgtphht thhopeigkeeisehkvghrnhgvlhdrohhrghdprhgtphhtthhopehkvgigvggtsehlihhsth hsrdhinhhfrhgruggvrggurdhorhhgpdhrtghpthhtohepugihohhunhhgsehrvgguhhgr thdrtghomhdprhgtphhtthhopehlihhnuhigqdgvfhhisehvghgvrhdrkhgvrhhnvghlrd horhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghl rdhorhhg X-ME-Proxy: Feedback-ID: ice86485a:Fastmail Received: by mailuser.phl.internal (Postfix, from userid 501) id 1D43C700065; Tue, 17 Feb 2026 05:27:11 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ThreadId: AR4vd3DIDa3F Date: Tue, 17 Feb 2026 11:26:50 +0100 From: "Ard Biesheuvel" To: "Dave Young" Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, x86@kernel.org Message-Id: <665dc599-8488-4761-b3c3-07b994cb82b8@app.fastmail.com> In-Reply-To: References: <824bf9d5-93d3-4791-a064-3852014a1264@app.fastmail.com> <61f0c9ad-a435-4856-8ebe-d5a81f72330e@app.fastmail.com> Subject: Re: [PATCH] efi/x86-stub: store acpi_rsdp_addr in bootparams Content-Type: text/plain Content-Transfer-Encoding: 7bit On Tue, 17 Feb 2026, at 11:01, Dave Young wrote: > On Tue, 17 Feb 2026 at 17:20, Ard Biesheuvel wrote: >> >> >> On Tue, 17 Feb 2026, at 09:19, Dave Young wrote: >> > Hi Ard, >> > >> > On Tue, 17 Feb 2026 at 16:10, Ard Biesheuvel wrote: >> >> >> >> Hi Dave, >> >> >> >> On Tue, 17 Feb 2026, at 09:04, Dave Young wrote: >> >> > Kernel panic occurs during a kexec reboot when EFI runtime services >> >> > are not enabled in the first kernel. The issue is that the second >> >> > kernel cannot find the ACPI RSDP address during boot. >> >> > >> >> > In legacy boot, the acpi_rsdp_addr is set in early x86 boot code. >> >> > However, kernel decompression has moved to the EFI stub for EFI boot. >> >> > Therefore, the x86 EFI stub must also be updated to store the >> >> > acpi_rsdp_addr in the boot parameters to ensure the kexec kernel >> >> > can find it. >> >> > >> >> > (Note: If the pre-kexec kernel was itself a kexec boot, the later kexec >> >> > reboot will still utilize the legacy decompressor path, so the original >> >> > code remains functional though some cleanups can be done later.) >> >> > >> >> > Signed-off-by: Dave Young >> >> > --- >> >> > drivers/firmware/efi/libstub/x86-stub.c | 18 ++++++++++++++++++ >> >> > 1 file changed, 18 insertions(+) >> >> > >> >> >> >> If this issue is kexec-specific, can we move this to where the kexec code prepares the boot_params struct for the next kernel? >> >> >> > >> > The kexec use case is it depends on the pre-kexec kernel saving it >> > during boot for noefi case. I do not have a better idea to do it in >> > kexec code for the time being. >> >> How about something like this? > > Thanks! It works for me, however the legacy kexec_load syscall still > failed with a panic I did not dig into the root cause yet, I supposed > it will find the rsdp from /sys/firmware/efi/systab file, maybe some > userspace code bug. > > Anyway I'm fine with this fix, would you like to send a formal patch > since you proposed it? Otherwise I will resend with the changes. > Excellent. I'll queue it with a link to this thread.