linux-kernel - RE: [PATCH] arm64: fix /proc/cpuinfo for elf32

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Date:	Wed, 27 Apr 2016 02:13:01 +0000
From:	"Zengtao (B)" <prime.zeng@...ilicon.com>
To:	Suzuki K Poulose <Suzuki.Poulose@....com>,
	Catalin Marinas <catalin.marinas@....com>
CC:	"will.deacon@....com" <will.deacon@....com>,
	"mark.rutland@....com" <mark.rutland@....com>,
	"yang.shi@...aro.org" <yang.shi@...aro.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"james.morse@....com" <james.morse@....com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: RE: [PATCH] arm64: fix /proc/cpuinfo for elf32

> -----Original Message-----
> From: Suzuki K Poulose [mailto:Suzuki.Poulose@....com]
> Sent: Tuesday, April 26, 2016 5:21 PM
> To: Zengtao (B); Catalin Marinas
> Cc: will.deacon@....com; mark.rutland@....com; yang.shi@...aro.org;
> linux-kernel@...r.kernel.org; james.morse@....com;
> linux-arm-kernel@...ts.infradead.org
> Subject: Re: [PATCH] arm64: fix /proc/cpuinfo for elf32
> 
> On 26/04/16 03:21, Zengtao (B) wrote:
> >
> > So you mean the 64-bit grep should see the same cpuinfo as its father process
> > which is 32-bit?
> >
> > For 32-bit process running on 64-bit kernel, we have to explicitly call the
> personality
> > syscall to get the right cpuinfo, but how to deal with the old 32-bit binaries?
> 
> Yes, you could use the syscall to switch the personality. Alternately, you could
> run
> "linux32" command to switch the personality to PER_LINUX32 and then
> execute
> 64/32 bit applications.
>

Any plan to place the personality syscall in libc? It is not nessary for each 32-bit process 
to do the personality syscall or linux32 command. 
 
> Suzuki
> 
>