From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: "linux-kbuild@vger.kernel.org" <linux-kbuild@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nicolas Schier <nicolas@fjasle.eu>,
Peter Zijlstra <peterz@infradead.org>,
"linux-modules@vger.kernel.org" <linux-modules@vger.kernel.org>,
"llvm@lists.linux.dev" <llvm@lists.linux.dev>,
Ard Biesheuvel <ardb@kernel.org>,
Sami Tolvanen <samitolvanen@google.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: Build/boot problem with 7b4537199a4a (Re: [PATCH v6 02/10] kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS)
Date: Sat, 20 Aug 2022 17:51:38 +0000 [thread overview]
Message-ID: <0da799d5-aa19-b116-89ce-0ca37780624a@csgroup.eu> (raw)
In-Reply-To: <CAK7LNAQnYQH4BhYkw2G3KMDYRY3mzU9Yd1NudCABG8qpDVRtrQ@mail.gmail.com>
Le 20/08/2022 à 19:01, Masahiro Yamada a écrit :
> On Sat, Aug 20, 2022 at 11:15 PM Christophe Leroy
> <christophe.leroy@csgroup.eu> wrote:
>>
>>
>>
>> Le 20/08/2022 à 14:51, Masahiro Yamada a écrit :
>>> On Sat, Aug 20, 2022 at 7:02 PM Christophe Leroy
>>> <christophe.leroy@csgroup.eu> wrote:
>>>>
>>>> Hi,
>>>>
>>>> Le 13/05/2022 à 13:39, Masahiro Yamada a écrit :
>>>>> include/{linux,asm-generic}/export.h defines a weak symbol, __crc_*
>>>>> as a placeholder.
>>>>>
>>>>> Genksyms writes the version CRCs into the linker script, which will be
>>>>> used for filling the __crc_* symbols. The linker script format depends
>>>>> on CONFIG_MODULE_REL_CRCS. If it is enabled, __crc_* holds the offset
>>>>> to the reference of CRC.
>>>>>
>>>>> It is time to get rid of this complexity.
>>>>>
>>>>> Now that modpost parses text files (.*.cmd) to collect all the CRCs,
>>>>> it can generate C code that will be linked to the vmlinux or modules.
>>>>>
>>>>> Generate a new C file, .vmlinux.export.c, which contains the CRCs of
>>>>> symbols exported by vmlinux. It is compiled and linked to vmlinux in
>>>>> scripts/link-vmlinux.sh.
>>>>>
>>>>> Put the CRCs of symbols exported by modules into the existing *.mod.c
>>>>> files. No additional build step is needed for modules. As before,
>>>>> *.mod.c are compiled and linked to *.ko in scripts/Makefile.modfinal.
>>>>>
>>>>> No linker magic is used here. The new C implementation works in the
>>>>> same way, whether CONFIG_RELOCATABLE is enabled or not.
>>>>> CONFIG_MODULE_REL_CRCS is no longer needed.
>>>>>
>>>>> Previously, Kbuild invoked additional $(LD) to update the CRCs in
>>>>> objects, but this step is unneeded too.
>>>>>
>>>>> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
>>>>> Tested-by: Nathan Chancellor <nathan@kernel.org>
>>>>> Tested-by: Nicolas Schier <nicolas@fjasle.eu>
>>>>> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
>>>>
>>>> Problem with v6.0-rc1
>>>> Problem with v5.19
>>>> No problem with v5.18
>>>>
>>>> Bisected to 7b4537199a4a ("kbuild: link symbol CRCs at final link,
>>>> removing CONFIG_MODULE_REL_CRCS")
>>>>
>>>> The above patch leads to the following problem building
>>>> mpc85xx_defconfig + CONFIG_RELOCATABLE
>>>
>>>
>>>
>>> Is this because the relocation implementation on ppc is incomplete?
>>> (and is it the reason why relock_check.sh exists?)
>>>
>>> arch/powerpc/kernel/reloc_32.S does not support R_PPC_UADDR32
>>>
>>>
>>
>> Might be the reason.
>>
>> Is it expected that your patch adds an unsupported relocation ?
>>
>> Why was that relocation type unneeded before ?
>>
>> Thanks
>> Christophe
>
>
> I posted a patch (although I believe my commit is innocent).
>
> https://lore.kernel.org/lkml/20220820165129.1147589-1-masahiroy@kernel.org/T/#u
>
> The relocs_check.sh warnings are gone.
> Please do a boot test.
> Thanks.
>
Yes it works, many Thanks.
The fixes tag should probably be c857c43b34ec ("powerpc: Don't use a
function descriptor for system call table")
Christophe
next prev parent reply other threads:[~2022-08-20 17:51 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-13 11:39 [PATCH v6 00/10] kbuild: yet another series of cleanups (modpost, LTO, MODULE_REL_CRCS, export.h) Masahiro Yamada
2022-05-13 11:39 ` [PATCH v6 01/10] modpost: extract symbol versions from *.cmd files Masahiro Yamada
2022-05-28 22:47 ` Guenter Roeck
2022-05-29 4:27 ` Masahiro Yamada
2022-05-13 11:39 ` [PATCH v6 02/10] kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS Masahiro Yamada
2022-08-20 10:02 ` Build/boot problem with 7b4537199a4a (Re: [PATCH v6 02/10] kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS) Christophe Leroy
2022-08-20 12:05 ` Sedat Dilek
2022-08-20 14:10 ` Christophe Leroy
2022-08-20 12:51 ` Masahiro Yamada
2022-08-20 14:15 ` Christophe Leroy
2022-08-20 17:01 ` Masahiro Yamada
2022-08-20 17:51 ` Christophe Leroy [this message]
2022-05-13 11:39 ` [PATCH v6 03/10] kbuild: stop merging *.symversions Masahiro Yamada
2022-05-13 11:39 ` [PATCH v6 04/10] genksyms: adjust the output format to modpost Masahiro Yamada
2022-05-13 11:39 ` [PATCH v6 05/10] kbuild: do not create *.prelink.o for Clang LTO or IBT Masahiro Yamada
2022-05-13 11:39 ` [PATCH v6 06/10] kbuild: check static EXPORT_SYMBOL* by script instead of modpost Masahiro Yamada
2022-05-25 8:31 ` Guenter Roeck
2022-05-25 10:51 ` Masahiro Yamada
2022-06-07 14:22 ` Jon Hunter
2022-06-07 14:25 ` Nathan Chancellor
2022-06-07 14:34 ` Jon Hunter
2022-05-13 11:39 ` [PATCH v6 07/10] kbuild: make built-in.a rule robust against too long argument error Masahiro Yamada
2022-05-13 11:39 ` [PATCH v6 08/10] kbuild: make *.mod " Masahiro Yamada
2022-05-13 11:39 ` [PATCH v6 09/10] kbuild: add cmd_and_savecmd macro Masahiro Yamada
2022-05-13 11:39 ` [PATCH v6 10/10] kbuild: rebuild multi-object modules when objtool is updated Masahiro Yamada
2022-05-13 12:20 ` [PATCH v6 00/10] kbuild: yet another series of cleanups (modpost, LTO, MODULE_REL_CRCS, export.h) Masahiro Yamada
[not found] ` <CA+icZUUWww3fXvjQcefgFuq=tPO6+FYDbHE2E5PmL-BSJg4+cw@mail.gmail.com>
2022-05-22 6:49 ` Masahiro Yamada
2022-05-22 9:45 ` Sedat Dilek
2022-05-22 14:15 ` Sedat Dilek
2022-05-22 16:09 ` Masahiro Yamada
2022-05-22 16:18 ` Sedat Dilek
2022-05-22 22:34 ` Sedat Dilek
[not found] ` <2c496d24174e63b27ec047f383df6700@matoro.tk>
2022-08-06 7:23 ` Sedat Dilek
2022-08-06 13:12 ` matoro
2022-08-08 5:54 ` Masahiro Yamada
2022-08-08 13:26 ` matoro
2022-08-08 17:36 ` Masahiro Yamada
2022-08-08 18:42 ` matoro
2022-08-09 15:20 ` Masahiro Yamada
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