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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86_64 ptrace orig_ax on ia32 task
Date: Fri, 7 Mar 2008 15:18:41 -0800 (PST)	[thread overview]
Message-ID: <alpine.LFD.1.00.0803071507240.3013@woody.linux-foundation.org> (raw)
In-Reply-To: <20080307225602.6491B26F990@magilla.localdomain>


On Fri, 7 Mar 2008, Roland McGrath wrote:
> 
> This makes 64-bit ptrace calls setting the 64-bit orig_ax field
> for a 32-bit task sign-extend the low 32 bits up to 64.  This
> matches what a 64-bit debugger expects when tracing a 32-bit task.

Hmm. Why make this conditional on CONFIG_IA32_EMULATION and TIF_IA32?

That field is never really 64-bit anyway. The only allowable values are
 - system call number (== small positive value)
 - a small negative number for traps

So I'd suggest just making it entirely unconditionally just do

	case offsetof(struct user_regs_struct, orig_ax):
		value = (long) (s32) value;
		break;

and be done with it. Why have arbitrarily different code on x86 and x86-64 
when there is no real reason for it?

		Linus

  reply	other threads:[~2008-03-07 23:20 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-29  3:57 [PATCH] x86_64 ia32 syscall restart fix Roland McGrath
2008-02-29 15:52 ` Ingo Molnar
2008-02-29 16:26   ` Linus Torvalds
2008-02-29 16:45     ` Ingo Molnar
2008-02-29 17:03       ` Linus Torvalds
2008-02-29 17:17         ` Ingo Molnar
2008-02-29 17:37           ` Ingo Molnar
2008-02-29 21:02             ` Andrew Morton
2008-02-29 21:20               ` Ingo Molnar
2008-03-01  5:48                 ` [stable] " Greg KH
2008-02-29 22:42     ` Roland McGrath
2008-02-29 23:18       ` Linus Torvalds
2008-03-07 22:56 ` [PATCH] x86_64 ptrace orig_ax on ia32 task Roland McGrath
2008-03-07 23:18   ` Linus Torvalds [this message]
2008-03-08  1:37     ` Roland McGrath
2008-03-10 19:19   ` Chuck Ebbert
2008-03-10 19:48     ` Linus Torvalds
2008-03-10 20:01       ` Roland McGrath
2008-03-11  9:32         ` Ingo Molnar

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