From: Chao Fan <fanc.fnst@cn.fujitsu.com>
To: Baoquan He <bhe@redhat.com>
Cc: <dyoung@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
"bp@alien8.de" <bp@alien8.de>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"keescook@chromium.org" <keescook@chromium.org>,
"msys.mizuma@gmail.com" <msys.mizuma@gmail.com>,
"Indoh, Takao" <indou.takao@fujitsu.com>,
"Cao, Jin" <caoj.fnst@cn.fujitsu.com>
Subject: Re: [PATCH v9 5/8] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdlien from kexec
Date: Mon, 22 Oct 2018 15:30:51 +0800 [thread overview]
Message-ID: <20181022073050.GB7641@localhost.localdomain> (raw)
In-Reply-To: <20181022060613.GK1885@192.168.1.4>
On Mon, Oct 22, 2018 at 02:06:13PM +0800, Baoquan He wrote:
>On 10/22/18 at 05:30am, Fan, Chao wrote:
>> >> +static void get_acpi_rsdp(acpi_physical_address *rsdp_addr)
>> >> +{
>> >> +#ifdef CONFIG_KEXEC
>> >> + unsigned long long res;
>> >> + int len = 0;
>> >> + char *val;
>> >> +
>> >> + val = malloc(20);
>> >
>> >Why is the length 20? Defined a macro?
>> >
>>
>> Not a calculation, if it's enough to store the address, that will be OK.
>
>Sorry, I didn't catch. It's 16 in setup_acpi_rsdp() of
>drivers/acpi/osl.c . What does 'that' mean?
The second parameter of kstrtoull(), the 16 you mentioned means
hexadecimal, not the length.
I checked my host and guest, the value are ACPI20=0xbfbfa014, ACPI20=0xdb807000.
The length of memory is 8. Well the max memory address is 16, add
"0x" and '\0' is 19. So I set it as 20.
I am not sure whether 8 is enough for the address, if OK, 11 will
be enough, or 19 is OK.
If my understanding is wrong, please tell me.
Thanks,
Chao Fan
>
>Wondering why not making it 200, it's also enough to store the address.
>
>
next prev parent reply other threads:[~2018-10-22 7:31 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-17 10:20 [PATCH v9 0/8] x86/boot/KASLR: Parse ACPI table and limit kaslr in immovable memory Chao Fan
2018-10-17 10:20 ` [PATCH v9 1/8] x86/boot: Introduce cmdline_find_option_arg()to detect if option=arg in cmdline Chao Fan
2018-10-18 4:01 ` Baoquan He
2018-10-18 6:15 ` Chao Fan
2018-10-17 10:20 ` [PATCH v9 2/8] x86/boot: Copy kstrtoull() to compressed period Chao Fan
2018-10-18 4:03 ` Baoquan He
2018-10-18 5:51 ` Chao Fan
2018-10-18 6:01 ` Baoquan He
2018-10-18 6:08 ` Chao Fan
2018-10-17 10:20 ` [PATCH v9 3/8] x86/boot: Add efi_get_rsdp_addr() to dig out RSDP from EFI table Chao Fan
2018-10-18 4:35 ` Baoquan He
2018-10-18 5:54 ` Chao Fan
2018-10-18 5:56 ` Baoquan He
2018-10-18 6:10 ` Chao Fan
2018-10-17 10:20 ` [PATCH v9 4/8] x86/boot: Add bios_get_rsdp_addr() to search RSDP in memory Chao Fan
2018-10-17 10:20 ` [PATCH v9 5/8] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdlien from kexec Chao Fan
2018-10-21 2:26 ` Baoquan He
2018-10-22 5:30 ` Fan, Chao
2018-10-22 6:06 ` Baoquan He
2018-10-22 7:30 ` Chao Fan [this message]
2018-10-22 7:36 ` Baoquan He
2018-10-17 10:20 ` [PATCH v9 6/8] x86/boot: Dig out SRAT table from RSDP and find immovable memory Chao Fan
2018-10-18 6:12 ` Chao Fan
2018-10-21 2:34 ` Baoquan He
2018-10-22 5:29 ` Fan, Chao
2018-10-22 6:08 ` Baoquan He
2018-10-17 10:20 ` [PATCH v9 7/8] x86/boot/KASLR: Walk srat tables to filter " Chao Fan
2018-10-18 4:23 ` Baoquan He
2018-10-18 5:56 ` Chao Fan
2018-10-17 10:20 ` [PATCH v9 8/8] x86/boot/KASLR: Limit kaslr to choosing the " Chao Fan
2018-10-18 4:21 ` Baoquan He
2018-10-22 10:13 ` Chao Fan
2018-10-22 10:24 ` Baoquan He
2018-10-22 10:49 ` Chao Fan
2018-10-18 3:59 ` [PATCH v9 0/8] x86/boot/KASLR: Parse ACPI table and limit kaslr in " Baoquan He
2018-10-18 5:48 ` Chao Fan
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