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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Anatolij Gustschin <agust@denx.de>,
        Alan Tull <atull@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.20 039/352] fpga: altera-cvp: fix bad IO access on x86_64
Date:   Mon, 11 Feb 2019 15:14:26 +0100
Message-Id: <20190211141848.807196746@linuxfoundation.org>
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4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 187fade88ca0ff2df9d360ca751d948d73db7095 ]

If mapping the CvP BAR fails, we still can configure the FPGA via
PCI config space access. In this case the iomap pointer is NULL.
On x86_64, passing NULL address to pci_iounmap() generates
"Bad IO access at port 0x0" output with stack call trace. Fix it.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/fpga/altera-cvp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
index 36d79b039c57..35c3aa5792e2 100644
--- a/drivers/fpga/altera-cvp.c
+++ b/drivers/fpga/altera-cvp.c
@@ -478,7 +478,8 @@ static int altera_cvp_probe(struct pci_dev *pdev,
 	return 0;
 
 err_unmap:
-	pci_iounmap(pdev, conf->map);
+	if (conf->map)
+		pci_iounmap(pdev, conf->map);
 	pci_release_region(pdev, CVP_BAR);
 err_disable:
 	cmd &= ~PCI_COMMAND_MEMORY;
@@ -493,7 +494,8 @@ static void altera_cvp_remove(struct pci_dev *pdev)
 	u16 cmd;
 
 	fpga_mgr_unregister(mgr);
-	pci_iounmap(pdev, conf->map);
+	if (conf->map)
+		pci_iounmap(pdev, conf->map);
 	pci_release_region(pdev, CVP_BAR);
 	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
 	cmd &= ~PCI_COMMAND_MEMORY;
-- 
2.19.1