Re: [PATCH v12 1/5] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdline from KEXEC

From: Chao Fan <fanc.fnst@cn.fujitsu.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>,
	<linux-kernel@vger.kernel.org>, <x86@kernel.org>,
	<tglx@linutronix.de>, <mingo@redhat.com>, <hpa@zytor.com>,
	<keescook@chromium.org>, <bhe@redhat.com>,
	<indou.takao@jp.fujitsu.com>, <caoj.fnst@cn.fujitsu.com>
Subject: Re: [PATCH v12 1/5] x86/boot: Add get_acpi_rsdp() to parse RSDP in cmdline from KEXEC
Date: Wed, 5 Dec 2018 09:40:44 +0800	[thread overview]
Message-ID: <20181205014044.GF30941@localhost.localdomain> (raw)
In-Reply-To: <20181204184220.GC16705@zn.tnic>

On Tue, Dec 04, 2018 at 07:42:20PM +0100, Borislav Petkov wrote:
>On Sat, Dec 01, 2018 at 02:05:39PM +0800, Chao Fan wrote:
>> >I built your whole patchset and got the error.
>> >The error depends on CONFIG_MODVERSIONS.
>> >If CONFIG_MODVERSIONS=y, you will get the build error.
>> 
>> Hi Masa,
>> 
>> Thanks, after that, I got the error.
>> About your solution, it can fix the error. But I am not sure whether
>> it's good.
>
>What does CONFIG_MODVERSIONS=y have to do with this? I don't see the
>connection.
>
>Also, your patch triggers another build error:
>
>ld -m elf_x86_64 -z noreloc-overflow -pie --no-dynamic-linker   -T arch/x86/boot/compressed/vmlinux.lds arch/x86/boot/compressed/head_64.o arch/x86/boot/compressed/misc.o arch/x86/boot/compressed/string.o arch/x86/boot/compressed/cmdline.o arch/x86/boot/compressed/error.o arch/x86/boot/compressed/piggy.o arch/x86/boot/compressed/cpuflags.o arch/x86/boot/compressed/early_serial_console.o arch/x86/boot/compressed/mem_encrypt.o arch/x86/boot/compressed/pgtable_64.o arch/x86/boot/compressed/eboot.o arch/x86/boot/compressed/efi_stub_64.o drivers/firmware/efi/libstub/lib.a arch/x86/boot/compressed/efi_thunk_64.o -o arch/x86/boot/compressed/vmlinux
>ld: arch/x86/boot/compressed/misc.o: in function `_parse_integer_fixup_radix':
>misc.c:(.text+0x3057): undefined reference to `_ctype'
>make[2]: *** [arch/x86/boot/compressed/Makefile:116: arch/x86/boot/compressed/vmlinux] Error 1
>make[1]: *** [arch/x86/boot/Makefile:112: arch/x86/boot/compressed/vmlinux] Error 2
>make: *** [arch/x86/Makefile:289: bzImage] Error 2
>make: *** Waiting for unfinished jobs....
>
>due to misc.o not seeing _ctype.
>
>Looks like this is going to become too hairy and perhaps it would
>be easier and cleaner if you copy all the functions needed into
>arch/x86/boot/cmdline.c and this way get rid of the crazy ifdeffery and
>the subtle build issues.
>
>I mean, we do this already in other places like perf tool is copying
>stuff selectively from kernel proper and since compressed/ is a
>completely separate stage, we probably should do that for the sake of
>keeping our sanity. :)

Thank you, I will do the copying job and consider more about putting
functions to arch/x86/boot/cmdline.c or arch/x86/boot/string.c.
Anyway, this method is simple.

Thanks,
Chao Fan

>
>Thx.
>
>-- 
>Regards/Gruss,
>    Boris.
>
>Good mailing practices for 400: avoid top-posting and trim the reply.
>
>