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:   Fri, 29 Mar 2019 16:29:29 +0800
From:   Chao Fan <fanc.fnst@cn.fujitsu.com>
To:     Junichi Nomura <j-nomura@ce.jp.nec.com>
CC:     Borislav Petkov <bp@alien8.de>, "bhe@redhat.com" <bhe@redhat.com>,
        Dave Young <dyoung@redhat.com>,
        "kasong@redhat.com" <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>
Subject: Re: [PATCH] x86/boot: Use efi_setup_data for searching RSDP on
 kexec-ed kernel
Message-ID: <20190329082929.GH4234@localhost.localdomain>
References: <20190325122302.GC13160@dhcp-128-65.nay.redhat.com>
 <20190325123229.GL12016@zn.tnic>
 <20190325231000.GA9184@jeru.linux.bs1.fc.nec.co.jp>
 <20190326135714.GG1867@zn.tnic>
 <20190327014852.GA3659@MiWiFi-R3L-srv>
 <73322ba9-e436-68db-7863-afd31607d969@ce.jp.nec.com>
 <20190328064343.GA1877@MiWiFi-R3L-srv>
 <20190328074337.GA9470@jeru.linux.bs1.fc.nec.co.jp>
 <20190328155256.GP22720@zn.tnic>
 <20190329072037.GA5840@jeru.linux.bs1.fc.nec.co.jp>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20190329072037.GA5840@jeru.linux.bs1.fc.nec.co.jp>
User-Agent: Mutt/1.11.3 (2019-02-01)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, Mar 29, 2019 at 07:20:38AM +0000, Junichi Nomura wrote:
>Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in
>boot_params") broke kexec boot on EFI systems.  efi_get_rsdp_addr()
>in the early parsing code tries to search RSDP from EFI table but
>that will crash because the table address is virtual when the kernel
>was booted by kexec.
[...]
>-			guid  = tbl->guid;
>-			table = tbl->table;
>-		}
>-
>-		if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
>-			rsdp_addr = table;
>-		else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
>-			return table;
>-	}
>+	return __efi_get_rsdp_addr(config_tables, nr_tables, efi_64);
>+#else
>+	return 0;
> #endif
>-	return rsdp_addr;

I remeber the rsdp_addr is defined before #ifdef CONFIG_EFI
If so, you don't need
#else
	return 0;

BY the way, what's your patch based on? I like add patch on my local
branch and then review code, but failed.
I try to use 'patch -p1 <' your patch to the latest tip master branch,
but failed.

Thanks,
Chao Fan

> }
> 
> static u8 compute_checksum(u8 *buffer, u32 length)
>@@ -221,6 +284,9 @@ acpi_physical_address get_rsdp_addr(void)
> 		pa = boot_params->acpi_rsdp_addr;
> 
> 	if (!pa)
>+		pa = kexec_get_rsdp_addr();
>+
>+	if (!pa)
> 		pa = efi_get_rsdp_addr();
> 
> 	if (!pa)
>
>