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Date: Thu, 15 Nov 2012 21:55:29 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>, linux-kernel@vger.kernel.org,
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Subject: Re: new execve/kernel_thread design
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On Thu, Nov 15, 2012 at 05:41:16PM +0100, Michal Simek wrote:
> Here is the branch based on rc5 (information below)
> and here is giweb.
> http://developer.petalogix.com/git/gitweb.cgi?p=linux-2.6-microblaze.git;a=shortlog;h=refs/heads/viro/arch-microblaze-rc5
> 
> I have also looked at your sys_fork / sys_vfork / sys_clone unification
> and I have fixed it for Microblaze.
> 
> Also I have done some tests on it for sure.
> 
> I would add sys_execve/kernel_execve/kernel_thread patches to my next branch.
> Are you OK with that?

Umm...  In principle - yes, but I've a couple of question abouts those.

1) What's that set_fs(USER_DS) in start_thread() for?  Note that we do the same
thing in flush_old_exec(), at the same time we remove PF_KTHREAD from
current->flags.

While we are at it, if we *ever* hit do_signal() with KERNEL_DS, we are
very deep in trouble.  set_fs(USER_DS) in setup_{rt_,}frame() is pointless.

2) your definition of current_pt_regs() is an exact copy of on in
include/linux/ptrace.h; why is "microblaze: Define current_pt_regs"
needed at all?  IOW, I'd rather added #include <linux/ptrace.h> to
arch/microblaze/kernel/process.c instead...

From mboxrd@z Thu Jan  1 00:00:00 1970
From: Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: new execve/kernel_thread design
Date: Thu, 15 Nov 2012 21:55:29 +0000
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To: Michal Simek <monstr@monstr.eu>
Cc: Jonas Bonn <jonas@southpole.se>, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Linus Torvalds <torvalds@linux-foundation.org>, Catalin Marinas <catalin.marinas@arm.com>, Haavard Skinnemoen <hskinnemoen@gmail.com>, Mike Frysinger <vapier@gentoo.org>, Jesper Nilsson <jesper.nilsson@axis.com>, David Howells <dhowells@redhat.com>, Tony Luck <tony.luck@intel.com>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Hirokazu Takata <takata@linux-m32r.org>, Geert Uytterhoeven <geert@linux-m68k.org>, "James E.J. Bottomley" <jejb@parisc-linux.org>, Richard Kuo <rkuo@codeaurora.org>, Martin Schwidefsky <schwidefsky@de.ibm.com>, Lennox Wu <lennox.wu@gmail.com>, "David S. Miller" <davem@davemloft.net>, Paul Mundt <lethal@linux-sh.org>, Chris Zankel <chris@zankel.net>, Chris Metcalf <cmetcalf@tilera.com>, Yoshinori Sato <ysato@users.sourceforge.jp>, Guan Xuetao <gx>

On Thu, Nov 15, 2012 at 05:41:16PM +0100, Michal Simek wrote:
> Here is the branch based on rc5 (information below)
> and here is giweb.
> http://developer.petalogix.com/git/gitweb.cgi?p=linux-2.6-microblaze.git;a=shortlog;h=refs/heads/viro/arch-microblaze-rc5
> 
> I have also looked at your sys_fork / sys_vfork / sys_clone unification
> and I have fixed it for Microblaze.
> 
> Also I have done some tests on it for sure.
> 
> I would add sys_execve/kernel_execve/kernel_thread patches to my next branch.
> Are you OK with that?

Umm...  In principle - yes, but I've a couple of question abouts those.

1) What's that set_fs(USER_DS) in start_thread() for?  Note that we do the same
thing in flush_old_exec(), at the same time we remove PF_KTHREAD from
current->flags.

While we are at it, if we *ever* hit do_signal() with KERNEL_DS, we are
very deep in trouble.  set_fs(USER_DS) in setup_{rt_,}frame() is pointless.

2) your definition of current_pt_regs() is an exact copy of on in
include/linux/ptrace.h; why is "microblaze: Define current_pt_regs"
needed at all?  IOW, I'd rather added #include <linux/ptrace.h> to
arch/microblaze/kernel/process.c instead...