Messages in this thread | | | From | Avery Pennarun <> | Date | Tue, 13 Mar 2012 02:00:30 -0400 | Subject | Re: [PATCH 0/5] Persist printk buffer across reboots. |
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On Tue, Mar 13, 2012 at 1:53 AM, David Miller <davem@davemloft.net> wrote: > From: Avery Pennarun <apenwarr@gmail.com> > Date: Tue, 13 Mar 2012 01:36:36 -0400 > >> The last patch in this series implements a new CONFIG_PRINTK_PERSIST option >> that, when enabled, puts the printk buffer in a well-defined memory location >> so that we can keep appending to it after a reboot. The upshot is that, >> even after a kernel panic or non-panic hard lockup, on the next boot >> userspace will be able to grab the kernel messages leading up to it. It >> could then upload the messages to a server (for example) to keep crash >> statistics. > > On some platforms there are formal ways to reserve areas of memory > such that the bootup firmware will know to not touch it on soft resets > no matter what. For example, on Sparc there are OpenFirmware calls to > set aside such an area of soft-reset preserved memory. > > I think some formal agreement with the system firmware is a lot better > when available, and should be explicitly accomodated in these changes > so that those of us with such facilities can very easily hook it up.
Sounds good to me. Do you have any pointers? Just use an early_param? If we see the early_param but we can't reserve the requested address, should we fall back to probing or disable the PRINTK_PERSIST mode entirely?
Thanks,
Avery -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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