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* [PATCH v2] ocxl: Fix endiannes bug in read_afu_name()
@ 2018-12-11 17:58 ` Greg Kurz
  0 siblings, 0 replies; 7+ messages in thread
From: Greg Kurz @ 2018-12-11 17:58 UTC (permalink / raw)
  To: linuxppc-dev
  Cc: Michael Ellerman, Frederic Barrat, Christophe Lombard,
	Andrew Donnellan, stable, Vaibhav Jain

The AFU Descriptor Template in the PCI config space has a Name Space
field which is a 24 Byte ASCII character string of descriptive name
space for the AFU. The OCXL driver read the string four characters at
a time with pci_read_config_dword().

This optimization is valid on a little-endian system since this is PCI,
but a big-endian system ends up with each subset of four characters in
reverse order.

This could be fixed by switching to read characters one by one. Another
option is to swap the bytes if we're big-endian.

Go for the latter with le32_to_cpu().

Cc: stable@vger.kernel.org      # v4.16
Signed-off-by: Greg Kurz <groug@kaod.org>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
---
v2: - silence sparse with (__force __le32) cast
    - new changelog
---
 drivers/misc/ocxl/config.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/ocxl/config.c b/drivers/misc/ocxl/config.c
index 57a6bb1fd3c9..8f2c5d8bd2ee 100644
--- a/drivers/misc/ocxl/config.c
+++ b/drivers/misc/ocxl/config.c
@@ -318,7 +318,7 @@ static int read_afu_name(struct pci_dev *dev, struct ocxl_fn_config *fn,
 		if (rc)
 			return rc;
 		ptr = (u32 *) &afu->name[i];
-		*ptr = val;
+		*ptr = le32_to_cpu((__force __le32) val);
 	}
 	afu->name[OCXL_AFU_NAME_SZ - 1] = '\0'; /* play safe */
 	return 0;

^ permalink raw reply related	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2018-12-23 13:52 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-12-11 17:58 [PATCH v2] ocxl: Fix endiannes bug in read_afu_name() Greg Kurz
2018-12-11 17:58 ` Greg Kurz
2018-12-12  2:26 ` Andrew Donnellan
2018-12-12  2:26   ` Andrew Donnellan
2018-12-20 14:53   ` Greg Kurz
2018-12-20 14:53     ` Greg Kurz
2018-12-23 13:28 ` [v2] " Michael Ellerman

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