linux-kernel - Re: pci error recovery procedure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 5 Sep 2006 14:01:15 -0500
From:	linas@...tin.ibm.com (Linas Vepstas)
To:	"Zhang, Yanmin" <yanmin_zhang@...ux.intel.com>
Cc:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	linuxppc-dev@...abs.org,
	linux-pci maillist <linux-pci@...ey.karlin.mff.cuni.cz>,
	Yanmin Zhang <yanmin.zhang@...el.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Rajesh Shah <rajesh.shah@...el.com>
Subject: Re: pci error recovery procedure

On Tue, Sep 05, 2006 at 10:32:08AM +0800, Zhang, Yanmin wrote:
> Is it the exclusive reason to have multi-steps?

I don't understand the question. A previous email explained the reason
to have mutiple steps.

> 1) Here link reset and hard reset are hardware operations, not the
> link_reset and slot_reset callback in pci_error_handlers.

I don't understand the comment.

> 2) Callback error_detected will notify drivers there is PCI errors. Drivers
> shouldn't do any I/O in error_detected.

It shouldn't matter. If it is truly important for a particular platform
to make sure that there is no i/o, then the low-level i/o routines
could be modified to drop any accidentally issued i/o on the floor.
This doesn't require a change to either the API or the policy.

> 3) If both the link and slot are reset after all error_detected are called,
> the device should go back to initial status and all DMA should be stopped
> automatically. Why does the driver still need a chance to stop DMA? 

As explained previously, not all drivers may want to have a full
electrical device reset.

> The
> error_detected of the drivers in the latest kernel who support err handlers
> always returns PCI_ERS_RESULT_NEED_RESET. They are typical examples.

Just because the current drivers do it this way does not mean that this is
the best way to do things. A full reset is time-consuming. Some drivers
may want to implement a faster and quicker reset.

--linas
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/