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From: Michael Ellerman <mpe@ellerman•id.au>
To: Daniel Axtens <dja@axtens•net>,
	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 10:43:42 +1100	[thread overview]
Message-ID: <1446767022.25265.2.camel@ellerman.id.au> (raw)
In-Reply-To: <87oaf8hwt2.fsf@gamma.ozlabs.ibm.com>

On Fri, 2015-11-06 at 10:05 +1100, Daniel Axtens wrote:

> 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?

If it's unused *and* broken then we should just remove it.

cheers

  parent reply	other threads:[~2015-11-05 23:43 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
2015-11-05 23:17   ` Michael Neuling
2015-11-05 23:17   ` Andrew Donnellan
2015-11-05 23:43   ` Michael Ellerman [this message]
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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