Date: Tue, 1 Mar 2011 09:56:30 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Jan Beulich <JBeulich@novell.com>, Jeff Dike <jdike@addtoit.com>
Cc: heukelum@fastmail.fm, tglx@linutronix.de, mingo@redhat.com,
        linux-kernel@vger.kernel.org, hpa@zytor.com
Subject: Re: [tip:x86/asm] x86-64: Add CFI annotations to lib/rwsem_64.S
Message-ID: <20110301085630.GA16050@elte.hu>
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* Jan Beulich <JBeulich@novell.com> wrote:

> >>> On 28.02.11 at 19:26, Ingo Molnar <mingo@elte.hu> wrote:
> 
> > * tip-bot for Jan Beulich <JBeulich@novell.com> wrote:
> > 
> >> Commit-ID:  39f2205e1abd1b6fffdaf45e1f1c3049a5f8999c
> >> Gitweb:     
> > http://git.kernel.org/tip/39f2205e1abd1b6fffdaf45e1f1c3049a5f8999c 
> >> Author:     Jan Beulich <JBeulich@novell.com>
> >> AuthorDate: Mon, 28 Feb 2011 15:31:59 +0000
> >> Committer:  Ingo Molnar <mingo@elte.hu>
> >> CommitDate: Mon, 28 Feb 2011 18:06:21 +0100
> >> 
> >> x86-64: Add CFI annotations to lib/rwsem_64.S
> >> 
> >> These weren't part of the initial commit of this code.
> >> 
> >> Signed-off-by: Jan Beulich <jbeulich@novell.com>
> >> Cc: Alexander van Heukelum <heukelum@fastmail.fm>
> >> LKML-Reference: <4D6BCDFF02000078000341B0@vpn.id2.novell.com>
> >> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> >> ---
> >>  arch/x86/lib/rwsem_64.S |   56 ++++++++++++++++++++++++++++------------------
> >>  1 files changed, 34 insertions(+), 22 deletions(-)
> > 
> > this change breaks the UML build:
> > 
> >  tip/arch/um/sys-x86_64/../../x86/lib/rwsem_64.S:46: Error: no such 
> > instruction: `pushq_cfi %rdi'
> 
> Any reason why arch/um/Kconfig.x86 has X86_32 but not
> X86_64? That's resulting in asm/dwarf2.h producing the 32-bit
> (pushl_cfi & Co) macros instead of the 64-bit ones. And I
> wonder what other inconsistencies this may cause...

No idea - UML seems stale. I've Cc:-ed Jeff Dike just in case.

> If this is on purpose (i.e. simply adding X86_64 as a new config
> option there isn't the right solution), what would be the preferred
> way of fixing this in asm/dwarf2.h:
> - #ifndef CONFIG_X86_32,
> - #ifdef CONFIG_64BIT,
> - yet something else?

You could try it out - UML isnt that hard to build: "make ARCH=um" and then run the 
resulting binary. It will produce bootup messages then fails when mounting root. 
That's enough of a build & functionality test.

Thanks,

	Ingo
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