From: Daniel Axtens <dja@axtens•net>
To: Andrew Donnellan <andrew.donnellan@au1•ibm.com>, linuxppc-dev@ozlabs•org
Cc: mikey@neuling•org, imunsie@au1•ibm.com
Subject: Re: [PATCH] cxl: use correct operator when writing pcie config space values
Date: Fri, 06 Nov 2015 10:05:13 +1100 [thread overview]
Message-ID: <87oaf8hwt2.fsf@gamma.ozlabs.ibm.com> (raw)
In-Reply-To: <1446603849-26796-1-git-send-email-andrew.donnellan@au1.ibm.com>
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Andrew Donnellan <andrew.donnellan@au1•ibm.com> writes:
> When writing a value to config space, cxl_pcie_write_config() calls
> cxl_pcie_config_info() to obtain a mask and shift value, shifts the new
> value accordingly, then uses the mask to combine the shifted value with the
> existing value at the address as part of a read-modify-write pattern.
>
> Currently, we use a logical OR operator rather than a bitwise OR operator,
> which means any use of this function results in an incorrect value being
> written. Replace the logical OR operator with a bitwise OR operator so the
> value is written correctly.
>
> Reported-by: Michael Ellerman <mpe@ellerman•id.au>
> Cc: stable@vger•kernel.org
Given that there are no current users of this function, does this need
to go to stable? Does it actually fix a real (as opposed to theoretical)
bug?
Regards,
Daniel
> Fixes: 6f7f0b3df6d4 ("cxl: Add AFU virtual PHB and kernel API")
> Signed-off-by: Andrew Donnellan <andrew.donnellan@au1•ibm.com>
> ---
> drivers/misc/cxl/vphb.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/misc/cxl/vphb.c b/drivers/misc/cxl/vphb.c
> index 94b5208..9be09bb 100644
> --- a/drivers/misc/cxl/vphb.c
> +++ b/drivers/misc/cxl/vphb.c
> @@ -203,7 +203,7 @@ static int cxl_pcie_write_config(struct pci_bus *bus, unsigned int devfn,
> mask <<= shift;
> val <<= shift;
>
> - v = (in_le32(ioaddr) & ~mask) || (val & mask);
> + v = (in_le32(ioaddr) & ~mask) | (val & mask);
>
> out_le32(ioaddr, v);
> return PCIBIOS_SUCCESSFUL;
> --
> Andrew Donnellan Software Engineer, OzLabs
> andrew.donnellan@au1•ibm.com Australia Development Lab, Canberra
> +61 2 6201 8874 (work) IBM Australia Limited
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists•ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
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next prev parent reply other threads:[~2015-11-05 23:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-04 2:24 [PATCH] cxl: use correct operator when writing pcie config space values Andrew Donnellan
2015-11-04 4:07 ` Ian Munsie
2015-11-05 23:05 ` Daniel Axtens [this message]
2015-11-05 23:17 ` Michael Neuling
2015-11-05 23:17 ` Andrew Donnellan
2015-11-05 23:43 ` Michael Ellerman
2015-11-09 6:45 ` Andrew Donnellan
2015-11-12 2:26 ` Daniel Axtens
2015-11-26 12:15 ` Michael Ellerman
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