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

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Message-ID: <571F32F3.7080005@arm.com>
Date:	Tue, 26 Apr 2016 10:20:51 +0100
From:	Suzuki K Poulose <Suzuki.Poulose@....com>
To:	"Zengtao (B)" <prime.zeng@...ilicon.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

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.

Suzuki