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Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :)
From: |
Vladimir 'φ-coder/phcoder' Serbinenko |
Subject: |
Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :) |
Date: |
Fri, 04 Apr 2014 08:37:20 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.3.0 |
On 03.04.2014 21:54, Andrey Borzenkov wrote:
> В Thu, 3 Apr 2014 12:26:57 -0700
> Ram Pai <address@hidden> пишет:
>
>>>>>
>>>>>> Well. that is the issue. Various distros have varied support for
>>>>>> cross-compilation (multi-arch support). If the distro does not
>>>>>> have 32bit BE libraries natively installed (out-of-the-box), they
>>>>>> wont be able to generate a 32bit BE grub loader.
>>>>>
>>>>> We speak only about target code that runs at boot time. This code does
>>>>> not use any library.
>>>>
>>>> I am not a compiler/toolchain expert. But dont we need all the necessary
>>>> tools and libraries in /lib/<arch>-<dist>-linux/ directory for cross
>>>> compilation; even to generate static executables?
>>>>
>>>>> It only needs compiler support. GRUB does not
>>>>> support anything besides gcc and recently some clang support was added.
>>>>> Do you have real life example of distribution which does not support
>>>>> -mbig gcc option to produce big-endian *code*?
>>>>
>>>> This is ideally what I want too. But it is not possible
>>>> **out-of-the-box** on any distro for power arch. I am told
>>>> that debian has a new multi-arch support added which makes this
>>>> work out-of-the-box, but it is still in early stages to work
>>>> seemlessly **out-of-the-box**. I may be wrong.
>>>>
>>>
>>> If distribution is capable of building Linux kernel, it should be
>>> capable of compiling 32 bit big-endian code. Linux startup code on
>>> PowerPC is built as 32 bit big-endian:
>>>
>>> BOOTCFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
>>> -fno-strict-aliasing -Os -msoft-float -pipe \
>>> -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \
>>> -isystem $(shell $(CROSS32CC) -print-file-name=include) \
>>> -mbig-endian
>>
>>
>> But that is different though. Yes it is possible to cross compile for
>> any target on any arch. But the key is that the environment needs to be
>> setup to do so.
>>
>> We are talking about generating crosscompiled grub boot loader by an
>> uninitiated/not-so-expert adminstrator. If the distribution makes it
>> easy for that administrator to be able to cross-compile, than life is
>> easy. But that is not generally the case though.
>
> E-h-h ... could you be more specific? You need exactly the same tool
> set to compile 32 bit big-endian grub as to compile Linux kernel. So
> it follows that generally it is impossible to compile Linux kernel on
> distributions for ppc64le. Is it what you mean?
>
>> The administrator has
>> to scramble around to find the right cross-compilation setup installed
>> on her system to achieve the end result.
>>
>
> I try to understand what exactly is required beyond what is needed to
> compile Linux kernel? I do not consider need to install a couple of
> RPMs as high burden.
>
> Here is what grub2 on SUSE needs:
>
> %ifarch x86_64 ppc64
> BuildRequires: gcc-32bit
> BuildRequires: glibc-32bit
> BuildRequires: glibc-devel-32bit
> %else
> BuildRequires: gcc
> BuildRequires: glibc-devel
> %ifarch s390x
> BuildRequires: glibc-static
> %endif
> %endif
>
> See https://build.opensuse.org/package/show/Base:System/grub2
I see you have some outdated patches like btrfs ones, you shouldn't need
them now (didn't really look in them).
As for eliminating libgcc dependency I created branch phcoder/no-libgcc.
For ppc only ucmpdi2 was needed actually.
> for
> details. It simply forces -m32 -big-endian for powerpc. It also includes
> brute-force patche to work around libgcc issue that probably may be
> done differently, but otherwise it is amazingly small change.
>
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- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), (continued)
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Ram Pai, 2014/04/03
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Vladimir 'phcoder' Serbinenko, 2014/04/03
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Andrey Borzenkov, 2014/04/03
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Ram Pai, 2014/04/04
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Andrey Borzenkov, 2014/04/04
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Dinar Valeev, 2014/04/04
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Andrey Borzenkov, 2014/04/04
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Dinar Valeev, 2014/04/04
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Ram Pai, 2014/04/04
- Message not available
- Fwd: Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Vladimir 'phcoder' Serbinenko, 2014/04/04
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :),
Vladimir 'φ-coder/phcoder' Serbinenko <=
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Andrey Borzenkov, 2014/04/04
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Vladimir 'φ-coder/phcoder' Serbinenko, 2014/04/05
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Andrey Borzenkov, 2014/04/05
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Vladimir 'φ-coder/phcoder' Serbinenko, 2014/04/05
- Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Andrey Borzenkov, 2014/04/05
Re: [RFC PATCH 21/23] powerpc64 is not necessarily BigEndian anymore! :), Ram Pai, 2014/04/02