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From: "Michal Suchánek" <msuchanek@suse.de>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org,
	Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
	David Hildenbrand <david@redhat.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Paul Mackerras <paulus@samba.org>,
	Breno Leitao <leitao@debian.org>,
	Michael Neuling <mikey@neuling.org>,
	Diana Craciun <diana.craciun@nxp.com>,
	Firoz Khan <firoz.khan@linaro.org>,
	Hari Bathini <hbathini@linux.ibm.com>,
	Joel Stanley <joel@jms.id.au>, Arnd Bergmann <arnd@arndb.de>,
	Nicholas Piggin <npiggin@gmail.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Thomas Gleixner <tglx@linutronix.de>,
	Allison Randal <allison@lohutok.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Andrew Donnellan <andrew.donnellan@au1.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v7 5/6] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default.
Date: Mon, 2 Sep 2019 11:42:39 +0200	[thread overview]
Message-ID: <20190902114239.32bd81f4@naga> (raw)
In-Reply-To: <87ftlftpy7.fsf@mpe.ellerman.id.au>

On Mon, 02 Sep 2019 12:03:12 +1000
Michael Ellerman <mpe@ellerman.id.au> wrote:

> Michal Suchanek <msuchanek@suse.de> writes:
> > On bigendian ppc64 it is common to have 32bit legacy binaries but much
> > less so on littleendian.  
> 
> I think the toolchain people will tell you that there is no 32-bit
> little endian ABI defined at all, if anything works it's by accident.

I have seen a piece of software that workarounds code issues on 64bit
by always compiling 32bit code. So it does work in some way. Also it
has been pointed out that you can still switch to BE even with the
'fast-switch' removed.

> 
> So I think we should not make this selectable, unless someone puts their
> hand up to say they want it and are willing to test it and keep it
> working.

I don't really care either way.

Thanks

Michal

> 
> cheers
> 
> > v3: make configurable
> > ---
> >  arch/powerpc/Kconfig | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index 5bab0bb6b833..b0339e892329 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -264,8 +264,9 @@ config PANIC_TIMEOUT
> >  	default 180
> >  
> >  config COMPAT
> > -	bool
> > -	default y if PPC64
> > +	bool "Enable support for 32bit binaries"
> > +	depends on PPC64
> > +	default y if !CPU_LITTLE_ENDIAN
> >  	select COMPAT_BINFMT_ELF
> >  	select ARCH_WANT_OLD_COMPAT_IPC
> >  	select COMPAT_OLD_SIGACTION
> > -- 
> > 2.22.0  


  reply	other threads:[~2019-09-02  9:42 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-30 21:03 [PATCH v7 0/6] Disable compat cruft on ppc64le v7 Michal Suchanek
2019-08-30 21:03 ` [PATCH v7 1/6] powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro Michal Suchanek
2019-08-30 21:03 ` [PATCH v7 2/6] powerpc: move common register copy functions from signal_32.c to signal.c Michal Suchanek
2019-08-30 21:03 ` [PATCH v7 3/6] powerpc/perf: consolidate read_user_stack_32 Michal Suchanek
2019-09-02  3:53   ` Michael Ellerman
2019-09-02  4:01     ` Michael Ellerman
2019-09-02  8:26       ` Michal Suchánek
2019-09-02 23:45         ` Michael Ellerman
2019-08-30 21:03 ` [PATCH v7 4/6] powerpc/64: make buildable without CONFIG_COMPAT Michal Suchanek
2019-08-31  6:43   ` Christophe Leroy
2019-08-31 13:02   ` Michal Suchánek
2019-08-30 21:03 ` [PATCH v7 5/6] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default Michal Suchanek
2019-09-02  2:03   ` Michael Ellerman
2019-09-02  9:42     ` Michal Suchánek [this message]
2019-09-03  0:00       ` Michael Ellerman
2019-09-14 10:22         ` Michal Suchánek
2019-09-18  5:36           ` Michael Ellerman
2019-09-02 13:00     ` Segher Boessenkool
2019-09-02 23:53       ` Michael Ellerman
2019-09-03  5:21         ` Christophe Leroy
2019-08-30 21:03 ` [PATCH v7 6/6] powerpc/perf: split callchain.c by bitness Michal Suchanek
2019-08-31 18:51   ` Michal Suchánek
2019-08-31  6:41 ` [PATCH v7 0/6] Disable compat cruft on ppc64le v7 Christophe Leroy
2019-08-31 18:03   ` Michal Suchánek

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