linux-kernel - Re: [PATCH 05/20] arm64: rename COMPAT to AARCH32

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170608224059.fi4a5urcjoxhbgwb@yury-thinkpad>
Date:   Fri, 9 Jun 2017 01:40:59 +0300
From:   Yury Norov <ynorov@...iumnetworks.com>
To:     Catalin Marinas <catalin.marinas@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Andrew Pinski <Andrew.Pinski@...iumnetworks.com>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Chris Metcalf <cmetcalf@...hip.com>,
        philipp.tomsich@...obroma-systems.com,
        Joseph Myers <joseph@...esourcery.com>,
        zhouchengming1@...wei.com,
        Steve Ellcey <sellcey@...iumnetworks.com>,
        Prasun.Kapoor@...iumnetworks.com, Andreas Schwab <schwab@...e.de>,
        agraf@...e.de, szabolcs.nagy@....com, geert@...ux-m68k.org,
        Adam Borowski <kilobyte@...band.pl>,
        manuel.montezelo@...il.com, Chris Metcalf <cmetcalf@...lanox.com>,
        Andrew Pinski <pinskia@...il.com>, linyongting@...wei.com,
        klimov.linux@...il.com, broonie@...nel.org,
        Bamvor Zhangjian <bamvor.zhangjian@...wei.com>,
        Bamvor Jian Zhang <bamvor.zhangjian@...aro.org>,
        Maxim Kuvyrkov <maxim.kuvyrkov@...aro.org>,
        Florian Weimer <fweimer@...hat.com>, Nathan_Lynch@...tor.com,
        Andrew Pinski <apinski@...ium.com>,
        Ramana Radhakrishnan <ramana.gcc@...glemail.com>,
        schwidefsky@...ibm.com, davem@...emloft.net,
        christoph.muellner@...obroma-systems.com
Subject: Re: [PATCH 05/20] arm64: rename COMPAT to AARCH32_EL0 in Kconfig

Hi Catalin, thanks for review.

On Thu, Jun 08, 2017 at 03:09:12PM +0100, Catalin Marinas wrote:
> On Sun, Jun 04, 2017 at 02:59:54PM +0300, Yury Norov wrote:
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -402,7 +402,7 @@ config ARM64_ERRATUM_834220
> >  
> >  config ARM64_ERRATUM_845719
> >  	bool "Cortex-A53: 845719: a load might read incorrect data"
> > -	depends on COMPAT
> > +	depends on AARCH32_EL0
> >  	default y
> >  	help
> >  	  This option adds an alternative code sequence to work around ARM
> > @@ -784,7 +784,7 @@ config FORCE_MAX_ZONEORDER
> >  
> >  menuconfig ARMV8_DEPRECATED
> >  	bool "Emulate deprecated/obsolete ARMv8 instructions"
> > -	depends on COMPAT
> > +	depends on AARCH32_EL0
> >  	help
> >  	  Legacy software support may require certain instructions
> >  	  that have been deprecated or obsoleted in the architecture.
> > @@ -1062,9 +1062,15 @@ menu "Userspace binary formats"
> >  source "fs/Kconfig.binfmt"
> >  
> >  config COMPAT
> > +	bool
> > +	depends on AARCH32_EL0
> 
> You could just use "def_bool y" here
> 
> > +
> > +config AARCH32_EL0
> >  	bool "Kernel support for 32-bit EL0"
> > +	def_bool y
> >  	depends on ARM64_4K_PAGES || EXPERT
> >  	select COMPAT_BINFMT_ELF if BINFMT_ELF
> > +	select COMPAT
> 
> and avoid the explicit select.

in patch 20 COMPAT becomes depending also on ARM64_ILP32, like this:
-       depends on AARCH32_EL0
+       depends on AARCH32_EL0 || ARM64_ILP32

So this is a preparation for it. If it looks confusing, I think it's
better to underline it in the description to the patch in addition to
this:

> From now, AARCH32_EL0 (former COMPAT) config option means the support of
> AARCH32 userspace, ARM64_ILP32 - support of ILP32 ABI (see next patches),
> and COMPAT indicates that one of them, or both, is enabled.

But if you prefer, I can do like you suggested here and make COMPAT
depend on AARCH32_EL0 in the last patch.

> 
> >  	select HAVE_UID16
> >  	select OLD_SIGSUSPEND3
> >  	select COMPAT_OLD_SIGACTION
> [...]
> > --- a/arch/arm64/kernel/cpuinfo.c
> > +++ b/arch/arm64/kernel/cpuinfo.c
> > @@ -139,15 +139,17 @@ static int c_show(struct seq_file *m, void *v)
> >  		 */
> >  		seq_puts(m, "Features\t:");
> >  		if (compat) {
> > -#ifdef CONFIG_COMPAT
> > -			for (j = 0; compat_hwcap_str[j]; j++)
> > -				if (compat_elf_hwcap & (1 << j))
> > -					seq_printf(m, " %s", compat_hwcap_str[j]);
> > -
> > -			for (j = 0; compat_hwcap2_str[j]; j++)
> > -				if (compat_elf_hwcap2 & (1 << j))
> > -					seq_printf(m, " %s", compat_hwcap2_str[j]);
> > -#endif /* CONFIG_COMPAT */
> > +#ifdef CONFIG_AARCH32_EL0
> > +			if (personality(current->personality) == PER_LINUX32) {
> > +				for (j = 0; compat_hwcap_str[j]; j++)
> > +					if (compat_elf_hwcap & (1 << j))
> > +						seq_printf(m, " %s", compat_hwcap_str[j]);
> > +
> > +				for (j = 0; compat_hwcap2_str[j]; j++)
> > +					if (compat_elf_hwcap2 & (1 << j))
> > +						seq_printf(m, " %s", compat_hwcap2_str[j]);
> > +			}
> > +#endif /* CONFIG_AARCH32_EL0 */
> 
> I don't understand this hunk. Why do you need another check on
> personality? "compat" is already true if PER_LINUX32.

I think it's rebase issue. I'll fix it.

Yury