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From: "Tony Luck" <tony.luck@intel.com>
To: "David Miller" <davem@davemloft.net>
Cc: mingo@elte.hu, rdreier@cisco.com, linux-kernel@vger.kernel.org
Subject: Re: Strange hang on ia64 with CONFIG_PRINTK_TIME=y
Date: Wed, 13 Feb 2008 19:33:42 -0800	[thread overview]
Message-ID: <12c511ca0802131933g6aaaec9cidbfbfcac6f394c63@mail.gmail.com> (raw)
In-Reply-To: <20080213.170452.68851396.davem@davemloft.net>

> That's right.  I thought you guys had something that would handle that
> early on, but looking at how the trick works in the vmlinux.lds.S ia64
> uses that isn't the case.

We try to get things set up pertty early ... but I agree this is
fragile.  Adding code to printk() to not provide a timestamp
before some safe point in boot is a workaround to the
current problem.  But it may come back to haunt us if
other per-cpu data is added that needs to be accessed
early during boot.

There are some changes going on at the moment on how
we allocate the space for the per-cpu area.  It is likely that
for a non-boot cpu we might be able to get everything that
we need for per-cpu access to work done in head.S before
we can get to any C code.  Boot cpu may be harder unless
we statically allocate space for its per-cpu area in
vmlinux.lds.S

I'll take a closer look at what is needed tomorrow.

-Tony

  reply	other threads:[~2008-02-14  3:33 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-13  6:24 Roland Dreier
2008-02-13  7:01 ` David Miller
2008-02-13 12:57   ` Ingo Molnar
2008-02-13 13:02     ` Ingo Molnar
2008-02-14  0:26       ` Roland Dreier
2008-02-13 13:03     ` David Miller
2008-02-13 13:06       ` Ingo Molnar
2008-02-14  0:59       ` Tony Luck
2008-02-14  1:04         ` David Miller
2008-02-14  3:33           ` Tony Luck [this message]
2008-02-14  3:47             ` Roland Dreier
2008-02-14 18:24               ` Luck, Tony
2008-02-14 21:27               ` Tony Luck
2008-02-14 22:04                 ` Roland Dreier
2008-02-14 22:23                   ` Luck, Tony
2008-02-15  2:17                     ` Tony Luck
2008-02-19 22:40                       ` Tony Luck
2008-02-20  8:12                         ` Ingo Molnar
2008-02-20  8:15                           ` David Miller
2008-02-20 23:35                         ` Roland Dreier
2008-02-20 23:36                         ` Roland Dreier

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