Re: [PATCH V2] PCI: rcar: Add L1 link state fix into data abort hook

From: Marek Vasut <marek.vasut@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-pci <linux-pci@vger.kernel.org>,
	Marek Vasut <marek.vasut+renesas@gmail.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Wolfram Sang <wsa@the-dreams.de>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH V2] PCI: rcar: Add L1 link state fix into data abort hook
Date: Sun, 4 Oct 2020 16:14:55 +0200	[thread overview]
Message-ID: <1431d12a-0e19-6795-b2e0-fb652f8a95c1@gmail.com> (raw)
In-Reply-To: <CAMuHMdURuSsYRwi10FT+s-rVjok0f-FgS6G8rmpg46u98scMkQ@mail.gmail.com>

On 9/28/20 11:35 AM, Geert Uytterhoeven wrote:
[...]
>> +static int __init rcar_pcie_init(void)
>> +{
>> +#ifdef CONFIG_ARM_LPAE
>> +       hook_fault_code(17, rcar_pcie_aarch32_abort_handler, SIGBUS, 0,
>> +                       "asynchronous external abort");
>> +#else
>> +       hook_fault_code(22, rcar_pcie_aarch32_abort_handler, SIGBUS, 0,
>> +                       "imprecise external abort");
>> +#endif
> 
> As there can be only a single handler, this may interfere with a handler
> for another platform in a multi-platform kernel.
> Hence I think this should not be done unconditionally, but be moved to
> the driver's .probe() callback.

Why is nobody doing this in the probe code then ? It seems all the other
drivers which hook fault code do it in init as well. I can imagine that
something might trip the fault handler even before probe is called, e.g.
some PM handling or simply user accessing that PCIe area using setpci.

[...]