Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 11 Apr 2019 11:21:28 +0200
User-Agent: K-9 Mail for Android
In-Reply-To: <2946b5e3-90bf-d617-16a4-d2225b490b5d@ce.jp.nec.com>
References: <20190408231011.GA5402@jeru.linux.bs1.fc.nec.co.jp> <20190410171431.GE26580@zn.tnic> <7cbc096d-0548-18b1-a335-8ba114f234a7@ce.jp.nec.com> <20190411080927.GA30080@zn.tnic> <e4de0520-ade8-2834-dadf-7af68701356b@ce.jp.nec.com> <20190411083738.GC30080@zn.tnic> <2946b5e3-90bf-d617-16a4-d2225b490b5d@ce.jp.nec.com>
MIME-Version: 1.0
Content-Type: text/plain;
 charset=utf-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [PATCH v4] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel
To:     Junichi Nomura <j-nomura@ce.jp.nec.com>
CC:     Dave Young <dyoung@redhat.com>,
        Chao Fan <fanc.fnst@cn.fujitsu.com>,
        Baoquan He <bhe@redhat.com>, Kairui Song <kasong@redhat.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "kexec@lists.infradead.org" <kexec@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
From:   Boris Petkov <bp@alien8.de>
Message-ID: <DFC5B552-9B44-422B-8EAE-A32C24BB7A88@alien8.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On April 11, 2019 11:13:03 AM GMT+02:00, Junichi Nomura <j-nomura@ce=2Ejp=
=2Enec=2Ecom> wrote:
>On 4/11/19 5:37 PM, Borislav Petkov wrote:
>> On Thu, Apr 11, 2019 at 08:16:45AM +0000, Junichi Nomura wrote:
>>> kexec_get_rsdp_addr() might fail on kexec-booted kernel, e=2Eg=2E if t=
he
>>> setup_data was invalid=2E In such a case, falling back to
>efi_get_rsdp_addr()
>>> will hit the problem of accessing invalid table pointer again=2E
>>=20
>> Then you need to do this:
>>=20
>> 	if (kexeced kernel) {
>> 		addr =3D kexec_get_rsdp_addr();
>> 		if (!addr) {
>> 			/* cannot get address */
>> 			return -1;
>> 		}
>>=20
>> 		return addr;
>> 	}
>>=20
>> and the calling function get_rsdp_addr() must check the return value
>and
>> if it is not 0, return immediately=2E
>
>Do you mean making get_rsdp_addr() like this?

Does that look like what I've typed above?

--=20
Sent from a small device: formatting sux and brevity is inevitable=2E