linux-kernel - [PATCH 4.2.y-ckt 009/268] cxl: use correct operator when writing pcie config space values

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Message-Id: <1453926929-17663-10-git-send-email-kamal@canonical.com>
Date:	Wed, 27 Jan 2016 12:31:10 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Andrew Donnellan <andrew.donnellan@....ibm.com>,
	Michael Ellerman <mpe@...erman.id.au>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 4.2.y-ckt 009/268] cxl: use correct operator when writing pcie config space values

4.2.8-ckt3 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Andrew Donnellan <andrew.donnellan@....ibm.com>

commit 48f0f6b717e314a30be121b67e1d044f6d311d66 upstream.

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@...erman.id.au>
Fixes: 6f7f0b3df6d4 ("cxl: Add AFU virtual PHB and kernel API")
Signed-off-by: Andrew Donnellan <andrew.donnellan@....ibm.com>
Acked-by: Ian Munsie <imunsie@....ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Kamal Mostafa <kamal@...onical.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 2eba002..15f154e 100644
--- a/drivers/misc/cxl/vphb.c
+++ b/drivers/misc/cxl/vphb.c
@@ -171,7 +171,7 @@ 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;
-- 
1.9.1