From: Ingo Molnar <mingo@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: linux-tip-commits@vger.kernel.org,
Andrea Righi <andrea.righi@canonical.com>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org
Subject: Re: [tip: x86/entry] x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y
Date: Thu, 21 Jan 2021 08:49:28 +0100 [thread overview]
Message-ID: <20210121074928.GA1346795@gmail.com> (raw)
In-Reply-To: <161121327995.414.14890124942899525500.tip-bot2@tip-bot2>
* tip-bot2 for Andrea Righi <tip-bot2@linutronix.de> wrote:
> The following commit has been merged into the x86/entry branch of tip:
>
> Commit-ID: e6d92b6680371ae1aeeb6c5eb2387fdc5d9a2c89
> Gitweb: https://git.kernel.org/tip/e6d92b6680371ae1aeeb6c5eb2387fdc5d9a2c89
> Author: Andrea Righi <andrea.righi@canonical.com>
> AuthorDate: Thu, 14 Jan 2021 12:48:35 +01:00
> Committer: Ingo Molnar <mingo@kernel.org>
> CommitterDate: Thu, 21 Jan 2021 08:11:52 +01:00
>
> x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y
>
> With CONFIG_PREEMPTION disabled, arch/x86/entry/thunk_64.o is just an
> empty object file.
>
> With the newer binutils (tested with 2.35.90.20210113-1ubuntu1) the GNU
> assembler doesn't generate a symbol table for empty object files and
> objtool fails with the following error when a valid symbol table cannot
> be found:
>
> arch/x86/entry/thunk_64.o: warning: objtool: missing symbol table
>
> To prevent this from happening, build thunk_$(BITS).o only if
> CONFIG_PREEMPTION is enabled.
>
> BugLink: https://bugs.launchpad.net/bugs/1911359
>
> Fixes: 320100a5ffe5 ("x86/entry: Remove the TRACE_IRQS cruft")
> Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
> Signed-off-by: Ingo Molnar <mingo@kernel.org>
> Cc: Borislav Petkov <bp@alien8.de>
> Link: https://lore.kernel.org/r/YAAvk0UQelq0Ae7+@xps-13-7390
Hm, this fails to build on UML defconfig:
/home/mingo/gcc/cross/lib/gcc/x86_64-linux/9.3.1/../../../../x86_64-linux/bin/ld: arch/x86/um/../entry/thunk_64.o: in function `preempt_schedule_thunk':
/home/mingo/tip.cross/arch/x86/um/../entry/thunk_64.S:34: undefined reference to `preempt_schedule'
/home/mingo/gcc/cross/lib/gcc/x86_64-linux/9.3.1/../../../../x86_64-linux/bin/ld: arch/x86/um/../entry/thunk_64.o: in function `preempt_schedule_notrace_thunk':
/home/mingo/tip.cross/arch/x86/um/../entry/thunk_64.S:35: undefined reference to `preempt_schedule_notrace'
Thanks,
Ingo
next prev parent reply other threads:[~2021-01-21 20:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-14 11:48 [PATCH] x86/entry: build thunk_$(BITS) only if CONFIG_PREEMPTION=y Andrea Righi
2021-01-21 7:14 ` [tip: x86/entry] x86/entry: Build " tip-bot2 for Andrea Righi
2021-01-21 7:49 ` Ingo Molnar [this message]
2021-01-21 8:51 ` Andrea Righi
2021-01-21 10:15 ` Andrea Righi
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