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s390/pci: do not read data after failed load

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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>
This commit is contained in:
Sebastian Ott 2013-04-16 14:17:15 +02:00 committed by Martin Schwidefsky
parent f0bacb7fc4
commit b170bad40d
3 changed files with 11 additions and 5 deletions
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4
arch/s390/include/asm/pci_io.h
View file

@ -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;
}

8
arch/s390/pci/pci.c
View file

@ -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;
}

4
arch/s390/pci/pci_insn.c
View file

@ -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;
}