From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: "Pali Rohár" <pali@kernel.org>,
"Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Marek Behún" <kabel@kernel.org>,
linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/15] PCI: mvebu: Handle invalid size of read config request
Date: Fri, 7 Jan 2022 19:15:26 +0000 [thread overview]
Message-ID: <YdiRTjGGWelHZ9rA@shell.armlinux.org.uk> (raw)
In-Reply-To: <20220107184548.GA390934@bhelgaas>
On Fri, Jan 07, 2022 at 12:45:48PM -0600, Bjorn Helgaas wrote:
> On Thu, Nov 25, 2021 at 01:45:54PM +0100, Pali Rohár wrote:
> > Function mvebu_pcie_hw_rd_conf() does not handle invalid size. So correctly
> > set read value to all-ones and return appropriate error return value
> > PCIBIOS_BAD_REGISTER_NUMBER like in mvebu_pcie_hw_wr_conf() function.
> >
> > Signed-off-by: Pali Rohár <pali@kernel.org>
> > Cc: stable@vger.kernel.org
>
> Is there a bug that this fixes? If not, I would drop the stable tag
> (as I see Lorenzo already did, thanks!).
>
> > ---
> > drivers/pci/controller/pci-mvebu.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
> > index 08274132cdfb..19c6ee298442 100644
> > --- a/drivers/pci/controller/pci-mvebu.c
> > +++ b/drivers/pci/controller/pci-mvebu.c
> > @@ -261,6 +261,9 @@ static int mvebu_pcie_hw_rd_conf(struct mvebu_pcie_port *port,
> > case 4:
> > *val = readl_relaxed(conf_data);
> > break;
> > + default:
> > + *val = 0xffffffff;
> > + return PCIBIOS_BAD_REGISTER_NUMBER;
>
> Might be the right thing to do, but there are many config accessors
> that do not set *val to ~0 before returning
> PCIBIOS_BAD_REGISTER_NUMBER:
I think a better question would be - how can this function be called
with a size that isn't 1, 2 or 4? I suppose if someone were to add
another PCI_OP_READ/PCI_OP_WRITE. However... they really need to audit
every implementation if they do that.
The generic implementation does this:
if (size == 1)
*val = readb(addr);
else if (size == 2)
*val = readw(addr);
else
*val = readl(addr);
and therefore completely ignores the size if it isn't 1 or 2. So I
don't think this is something that needs fixing.
If we're going to fix this in drivers, shouldn't we fix the generic
implementation too?
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
next prev parent reply other threads:[~2022-01-07 19:15 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-25 12:45 [PATCH 00/15] pci: mvebu: Various fixes Pali Rohár
2021-11-25 12:45 ` [PATCH 01/15] PCI: mvebu: Check for valid ports Pali Rohár
2021-11-25 12:45 ` [PATCH 02/15] PCI: mvebu: Check for errors from pci_bridge_emul_init() call Pali Rohár
2021-11-25 12:45 ` [PATCH 03/15] PCI: mvebu: Check that PCI bridge specified in DT has function number zero Pali Rohár
2022-01-07 18:15 ` Bjorn Helgaas
2022-01-07 18:18 ` Pali Rohár
2022-01-07 21:09 ` Bjorn Helgaas
2022-01-07 21:58 ` Pali Rohár
2021-11-25 12:45 ` [PATCH 04/15] PCI: mvebu: Handle invalid size of read config request Pali Rohár
2022-01-07 18:45 ` Bjorn Helgaas
2022-01-07 19:15 ` Russell King (Oracle) [this message]
2021-11-25 12:45 ` [PATCH 05/15] PCI: mvebu: Disallow mapping interrupts on emulated bridges Pali Rohár
2022-01-07 21:32 ` Bjorn Helgaas
2022-01-07 22:13 ` Pali Rohár
2022-01-07 23:01 ` Bjorn Helgaas
2022-01-07 23:11 ` Pali Rohár
2021-11-25 12:45 ` [PATCH 06/15] PCI: mvebu: Fix support for bus mastering and PCI_COMMAND on emulated bridge Pali Rohár
2021-11-25 12:45 ` [PATCH 07/15] PCI: mvebu: Do not modify PCI IO type bits in conf_write Pali Rohár
2021-11-25 12:45 ` [PATCH 08/15] PCI: mvebu: Propagate errors when updating PCI_IO_BASE and PCI_MEM_BASE registers Pali Rohár
2022-01-07 21:55 ` Bjorn Helgaas
2022-01-07 22:28 ` Pali Rohár
2022-01-07 23:16 ` Bjorn Helgaas
2022-01-07 23:46 ` Pali Rohár
2022-01-13 0:19 ` Bjorn Helgaas
2022-01-13 10:35 ` Pali Rohár
2022-01-20 17:50 ` Bjorn Helgaas
2022-01-20 19:08 ` Pali Rohár
2022-01-20 19:37 ` Bjorn Helgaas
2021-11-25 12:45 ` [PATCH 09/15] PCI: mvebu: Setup PCIe controller to Root Complex mode Pali Rohár
2021-11-25 12:46 ` [PATCH 10/15] PCI: mvebu: Set PCI Bridge Class Code to PCI Bridge Pali Rohár
2021-11-25 12:46 ` [PATCH 11/15] PCI: mvebu: Fix configuring secondary bus of PCIe Root Port via emulated bridge Pali Rohár
2021-11-25 12:46 ` [PATCH 12/15] PCI: mvebu: Fix support for PCI_BRIDGE_CTL_BUS_RESET on " Pali Rohár
2021-11-25 12:46 ` [PATCH 13/15] PCI: mvebu: Fix support for PCI_EXP_DEVCTL " Pali Rohár
2021-11-25 12:46 ` [PATCH 14/15] PCI: mvebu: Fix support for PCI_EXP_RTSTA " Pali Rohár
2021-11-25 12:46 ` [PATCH 15/15] PCI: mvebu: Fix support for DEVCAP2, DEVCTL2 and LNKCTL2 registers " Pali Rohár
2022-01-04 15:04 ` [PATCH 00/15] pci: mvebu: Various fixes Lorenzo Pieralisi
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