linux-kernel - Re: [PATCH v2 5/6] PCI: brcmstb: Add panic/die handler to RC driver

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, 1 Dec 2020 12:05:03 -0600
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Jim Quinlan <james.quinlan@...adcom.com>
Cc:     linux-pci@...r.kernel.org,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        broonie@...nel.org, bcm-kernel-feedback-list@...adcom.com,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-rpi-kernel@...ts.infradead.org>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 5/6] PCI: brcmstb: Add panic/die handler to RC driver

On Mon, Nov 30, 2020 at 04:11:42PM -0500, Jim Quinlan wrote:
> Whereas most PCIe HW returns 0xffffffff on illegal accesses and the like,
> by default Broadcom's STB PCIe controller effects an abort.  This simple
> handler determines if the PCIe controller was the cause of the abort and if
> so, prints out diagnostic info.

What happens during enumeration?  pci_bus_generic_read_dev_vendor_id()
assumes a read of Vendor ID returns 0xffffffff if the device doesn't
exist.

I assume this case doesn't cause the abort you're referring to here,
or nothing would work.  I think this enumeration case results in PCIe
Unsupported Request errors (PCIe r5.0, sec 2.3.2 implementation note).

Bjorn