From: Sebastian Ott <sebott@linux.vnet.ibm.com>
Date: Tue, 16 Apr 2013 12:17:15 +0000 (+0200)
Subject: s390/pci: do not read data after failed load
X-Git-Tag: v3.10-rc1~201^2~20
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=b170bad40dab1a1684d629b37cb65a5281d35bd8;p=~emulex%2Finfiniband.git

s390/pci: do not read data after failed load

If a pci load instruction fails the content of the register where the
data is stored is possibly unchanged. Fix the inline assembly wrapper
__pcilg to not return stale data. Additionally fix the callers of this
function who access uninitialized variables.

Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

diff --git a/arch/s390/include/asm/pci_io.h b/arch/s390/include/asm/pci_io.h
index 0e0bec9a3fb..83a9caa6ae5 100644
--- a/arch/s390/include/asm/pci_io.h
+++ b/arch/s390/include/asm/pci_io.h
@@ -92,6 +92,9 @@ static inline int zpci_read_single(u64 req, u64 *dst, u64 offset, u8 len)
 	int cc;
 
 	cc = s390pci_load(&data, req, offset);
+	if (cc)
+		goto out;
+
 	switch (len) {
 	case 1:
 		*((u8 *) dst) = (u8) data;
@@ -106,6 +109,7 @@ static inline int zpci_read_single(u64 req, u64 *dst, u64 offset, u8 len)
 		*((u64 *) dst) = (u64) data;
 		break;
 	}
+out:
 	return cc;
 }
 
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 2b21749cc2b..51d16f1fb5e 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -281,11 +281,11 @@ static int zpci_cfg_load(struct zpci_dev *zdev, int offset, u32 *val, u8 len)
 	int rc;
 
 	rc = s390pci_load(&data, req, offset);
-	data = data << ((8 - len) * 8);
-	data = le64_to_cpu(data);
-	if (!rc)
+	if (!rc) {
+		data = data << ((8 - len) * 8);
+		data = le64_to_cpu(data);
 		*val = (u32) data;
-	else
+	} else
 		*val = 0xffffffff;
 	return rc;
 }
diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
index 4bc32f368f7..22eeb9d7ffe 100644
--- a/arch/s390/pci/pci_insn.c
+++ b/arch/s390/pci/pci_insn.c
@@ -103,7 +103,9 @@ static inline int __pcilg(u64 *data, u64 req, u64 offset, u8 *status)
 		:  "d" (__offset)
 		: "cc");
 	*status = __req >> 24 & 0xff;
-	*data = __data;
+	if (!cc)
+		*data = __data;
+
 	return cc;
 }