From: Dmitry Osipenko <digetx@gmail.com>
To: Ard Biesheuvel <ardb@kernel.org>, Kees Cook <keescook@chromium.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Russell King <linux@armlinux.org.uk>,
clang-built-linux <clang-built-linux@googlegroups.com>,
Ingo Molnar <mingo@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v1] ARM: vfp: Use long jump to fix THUMB2 kernel compilation error
Date: Thu, 22 Oct 2020 18:57:03 +0300 [thread overview]
Message-ID: <1d2e2b5d-3035-238c-d2ca-14c0c209a6a1@gmail.com> (raw)
In-Reply-To: <CAMj1kXHXN56xmuwVG3P93Jjwd+NxXTYHtfibPWg5TUADucOdWg@mail.gmail.com>
22.10.2020 10:06, Ard Biesheuvel пишет:
> On Thu, 22 Oct 2020 at 05:30, Kees Cook <keescook@chromium.org> wrote:
>>
>> On Thu, Oct 22, 2020 at 03:00:06AM +0300, Dmitry Osipenko wrote:
>>> 22.10.2020 02:40, Kees Cook пишет:
>>>> On Thu, Oct 22, 2020 at 01:57:37AM +0300, Dmitry Osipenko wrote:
>>>>> The vfp_kmode_exception() function now is unreachable using relative
>>>>> branching in THUMB2 kernel configuration, resulting in a "relocation
>>>>> truncated to fit: R_ARM_THM_JUMP19 against symbol `vfp_kmode_exception'"
>>>>> linker error. Let's use long jump in order to fix the issue.
>>>>
>>>> Eek. Is this with gcc or clang?
>>>
>>> GCC 9.3.0
>>>
>>>>> Fixes: eff8728fe698 ("vmlinux.lds.h: Add PGO and AutoFDO input sections")
>>>>
>>>> Are you sure it wasn't 512dd2eebe55 ("arm/build: Add missing sections") ?
>>>> That commit may have implicitly moved the location of .vfp11_veneer,
>>>> though I thought I had chosen the correct position.
>>>
>>> I re-checked that the fixes tag is correct.
>>>
>>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>>>>> ---
>>>>> arch/arm/vfp/vfphw.S | 3 ++-
>>>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/arch/arm/vfp/vfphw.S b/arch/arm/vfp/vfphw.S
>>>>> index 4fcff9f59947..6e2b29f0c48d 100644
>>>>> --- a/arch/arm/vfp/vfphw.S
>>>>> +++ b/arch/arm/vfp/vfphw.S
>>>>> @@ -82,7 +82,8 @@ ENTRY(vfp_support_entry)
>>>>> ldr r3, [sp, #S_PSR] @ Neither lazy restore nor FP exceptions
>>>>> and r3, r3, #MODE_MASK @ are supported in kernel mode
>>>>> teq r3, #USR_MODE
>>>>> - bne vfp_kmode_exception @ Returns through lr
>>>>> + ldr r1, =vfp_kmode_exception
>>>>> + bxne r1 @ Returns through lr
>>>>>
>>>>> VFPFMRX r1, FPEXC @ Is the VFP enabled?
>>>>> DBGSTR1 "fpexc %08x", r1
>>>>
>>>> This seems like a workaround though? I suspect the vfp11_veneer needs
>>>> moving?
>>>>
>>>
>>> I don't know where it needs to be moved. Please feel free to make a
>>> patch if you have a better idea, I'll be glad to test it.
>>
>> I might have just been distracted by the common "vfp" prefix. It's
>> possible that the text section shuffling just ended up being very large,
>> so probably this patch is right then!
>>
>
> I already sent a fix for this issue:
>
> https://www.armlinux.org.uk/developer/patches/viewpatch.php?id=9018/1
>
The offending commit contains stable tag, so I assume that fixes tag is
mandatory. Yours patch misses the fixes tag.
next prev parent reply other threads:[~2020-10-22 15:57 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 22:57 [PATCH v1] ARM: vfp: Use long jump to fix THUMB2 kernel compilation error Dmitry Osipenko
2020-10-21 23:40 ` Kees Cook
2020-10-22 0:00 ` Dmitry Osipenko
2020-10-22 3:28 ` Kees Cook
2020-10-22 7:06 ` Ard Biesheuvel
2020-10-22 15:57 ` Dmitry Osipenko [this message]
2020-10-22 16:06 ` Ard Biesheuvel
2020-10-22 16:11 ` Russell King - ARM Linux admin
2020-10-22 16:20 ` Ard Biesheuvel
2020-10-22 16:23 ` Russell King - ARM Linux admin
2020-10-22 16:33 ` Ard Biesheuvel
2020-10-22 17:48 ` Russell King - ARM Linux admin
2020-10-22 17:59 ` Ard Biesheuvel
2020-10-26 8:58 ` Ard Biesheuvel
2020-10-29 9:56 ` Ard Biesheuvel
2020-11-03 7:24 ` Ard Biesheuvel
2020-11-03 8:43 ` Dmitry Osipenko
2020-11-09 7:25 ` Ard Biesheuvel
2020-11-10 7:44 ` Dmitry Osipenko
2020-11-10 7:45 ` Ard Biesheuvel
2020-10-22 16:34 ` Dmitry Osipenko
2020-10-22 17:38 ` Russell King - ARM Linux admin
2020-10-22 17:47 ` Ard Biesheuvel
2020-10-22 17:50 ` Russell King - ARM Linux admin
2020-10-22 17:51 ` Ard Biesheuvel
2020-10-22 19:05 ` Dmitry Osipenko
2020-10-22 14:57 ` Russell King - ARM Linux admin
2020-10-22 15:56 ` Dmitry Osipenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1d2e2b5d-3035-238c-d2ca-14c0c209a6a1@gmail.com \
--to=digetx@gmail.com \
--cc=ardb@kernel.org \
--cc=clang-built-linux@googlegroups.com \
--cc=keescook@chromium.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=mingo@kernel.org \
--cc=ndesaulniers@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).