Subject: Re: [RFC][PATCH 2/4] checkpoint/restart: x86 support
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Oren Laadan <orenl@cs.columbia.edu>
Cc: containers@lists.linux-foundation.org, Theodore Tso <tytso@mit.edu>,
       linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>
In-Reply-To: <489CF0CE.1000603@cs.columbia.edu>
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Date: Fri, 08 Aug 2008 19:20:58 -0700
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On Fri, 2008-08-08 at 21:20 -0400, Oren Laadan wrote:
> hehehe .. both; I meant that while it doesn't change per architecture, it
> varies between architectures. So "struct pt_regs" compiled for x86-32 is
> different than that compiled for x86-64. Therefore we can't just dump the
> structure as is and expect that 64 bit would be able to parse the 32 bit.
> In other words, we need an intermediate representation.

Surely we already handle this, though.  Don't we allow a 32-bit app
running on a 64-bit kernel to PTRACE_GETREGS and get the 32-bit version?
A 64-bit app will get the 64-bit version making the same syscall.  It's
all handled in the syscall compatibility code.

-- Dave

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