From: Thomas Gleixner <tglx@linutronix.de>
To: Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>,
x86@kernel.org, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/17] x86, lto: Mark all top level asm statements as .text
Date: Tue, 26 Mar 2019 23:25:45 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1903262321390.1789@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190326213803.GN18020@tassilo.jf.intel.com>
Andi.
On Tue, 26 Mar 2019, Andi Kleen wrote:
> On Tue, Mar 26, 2019 at 06:03:59PM +0100, Thomas Gleixner wrote:
> > On Thu, 21 Mar 2019, Andi Kleen wrote:
> >
> > > With gcc 8 toplevel assembler statements that do not mark themselves
> > > as .text may end up in other sections.
> >
> > Which is clearly a change in behaviour. Is that intended or just yet
> > another feature of GCC?
>
> I'm not sure it's a new behavior, but I've seen it first
> with gcc 8.
Ok.
> > Your subject says: 'x86, lto:'
> >
> > So is this a LTO related problem or is the section randomization
> > independent of LTO?
>
> The basic behavior is independent of LTO, but I've only seen
> failures with LTO. But I believe in theory it could lead
> to failures even without LTO.
Well, we better should know the real reason for this wreckage. I mean, the
default section for text is suprisingly .text. I don't see a reason why
this would be any different for an assembly function implemented in a C
file.
So the question is whether GCC does something silly in general which gets
'repaired' silentely by the linker or whether it's just an LTO issue.
If it's the former, then we must backport those fixes.
Could you please verify with the GCC people as you seem to have a
reproducer of some sort.
Thanks,
tglx
next prev parent reply other threads:[~2019-03-26 22:25 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 21:59 Fixes and cleanup from LTO tree Andi Kleen
2019-03-21 21:59 ` [PATCH 01/17] kbuild: Disable -Waddress-of-packed-member for gcc 9 Andi Kleen
2019-03-22 13:58 ` Arnd Bergmann
2019-03-22 16:31 ` Andi Kleen
2019-03-22 16:39 ` Peter Zijlstra
2019-03-22 16:57 ` Arnd Bergmann
2019-03-22 16:58 ` Andi Kleen
2019-03-25 16:27 ` David Laight
2019-04-01 1:04 ` Masahiro Yamada
2019-03-21 21:59 ` [PATCH 02/17] x86, lto: Mark all top level asm statements as .text Andi Kleen
2019-03-26 17:03 ` Thomas Gleixner
2019-03-26 21:38 ` Andi Kleen
2019-03-26 22:25 ` Thomas Gleixner [this message]
2019-03-27 0:55 ` Andi Kleen
2019-03-27 1:08 ` Andi Kleen
2019-03-27 14:20 ` Thomas Gleixner
2019-03-27 14:39 ` Ingo Molnar
2019-03-27 14:59 ` Andi Kleen
2019-03-27 15:08 ` Thomas Gleixner
2019-03-27 15:45 ` Andi Kleen
2019-03-27 19:08 ` Thomas Gleixner
2019-03-27 20:40 ` Andi Kleen
2019-03-27 21:55 ` Thomas Gleixner
2019-03-27 22:29 ` Andi Kleen
2019-03-27 22:50 ` Thomas Gleixner
2019-04-02 8:54 ` Thomas Gleixner
2019-03-21 21:59 ` [PATCH 03/17] x86: Don't inline __const_udelay Andi Kleen
2019-03-21 21:59 ` [PATCH 04/17] init: Add __noreorder and mark initcalls __noreorder Andi Kleen
2019-03-21 21:59 ` [PATCH 05/17] Use C version for SYSCALL_ALIAS Andi Kleen
2019-03-21 21:59 ` [PATCH 06/17] locking/core: Mark spinlocks noinline when inline spinlocks are disabled Andi Kleen
2019-03-21 21:59 ` [PATCH 07/17] amdkfd: Fix extern declaration Andi Kleen
2019-03-21 22:00 ` [PATCH 08/17] x86/speculation: Fix __initconst in bugs.c Andi Kleen
2019-03-26 17:24 ` Thomas Gleixner
2019-03-21 22:00 ` [PATCH 09/17] x86/kvm: Make steal_time visible Andi Kleen
2019-03-21 22:00 ` [PATCH 10/17] delta: Fix buffer overrun in delta_ipc_open Andi Kleen
2019-04-01 13:37 ` Hugues FRUCHET
2019-04-01 16:54 ` Andi Kleen
2019-04-02 9:56 ` Hugues FRUCHET
2019-03-21 22:00 ` [PATCH 11/17] x86/kprobes: Make trampoline_handler global and visible Andi Kleen
2019-03-23 9:45 ` Masami Hiramatsu
2019-03-23 14:35 ` Andi Kleen
2019-03-25 1:53 ` Masami Hiramatsu
2019-03-21 22:00 ` [PATCH 12/17] afs: Avoid section confusion in CM_NAME Andi Kleen
2019-03-21 22:00 ` [PATCH 13/17] ASoC: AMD: Fix incorrect extern Andi Kleen
2019-03-21 22:00 ` [PATCH 14/17] crypto: Don't mark AES tables const and cacheline_aligned Andi Kleen
2019-03-26 8:42 ` Rasmus Villemoes
2019-03-26 18:30 ` Andi Kleen
2019-03-21 22:00 ` [PATCH 15/17] x86/hyperv: Make hv_vcpu_is_preempted visible Andi Kleen
2019-03-26 8:15 ` Yi Sun
2019-03-21 22:00 ` [PATCH 16/17] x86/xen: Mark xen_vcpu_stolen as __visible Andi Kleen
2019-03-21 22:00 ` [PATCH 17/17] dm: Fix const confusion in dm Andi Kleen
2019-03-22 8:34 ` [PATCH 12/17] afs: Avoid section confusion in CM_NAME David Howells
2019-03-26 17:00 ` Fixes and cleanup from LTO tree Thomas Gleixner
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