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s390/pci: add exception table to load/store instructions
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Don't let pci_load and friends crash the kernel when called with
e.g. an invalid offset. Return -ENXIO instead.

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>
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Sebastian Ott authored and Martin Schwidefsky committed Apr 17, 2013
1 parent b2a9e87 commit f0bacb7
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Showing 2 changed files with 30 additions and 24 deletions.
2 changes: 1 addition & 1 deletion arch/s390/include/asm/pci_io.h
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Original file line number Diff line number Diff line change
Expand Up @@ -89,7 +89,7 @@ static inline int zpci_write_single(u64 req, const u64 *data, u64 offset, u8 len
static inline int zpci_read_single(u64 req, u64 *dst, u64 offset, u8 len)
{
u64 data;
u8 cc;
int cc;

cc = s390pci_load(&data, req, offset);
switch (len) {
Expand Down
52 changes: 29 additions & 23 deletions arch/s390/pci/pci_insn.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#include <linux/errno.h>
#include <linux/delay.h>
#include <asm/pci_insn.h>
#include <asm/processor.h>

#define ZPCI_INSN_BUSY_DELAY 1 /* 1 microsecond */

Expand Down Expand Up @@ -85,18 +86,20 @@ void set_irq_ctrl(u16 ctl, char *unused, u8 isc)
}

/* PCI Load */
static inline u8 __pcilg(u64 *data, u64 req, u64 offset, u8 *status)
static inline int __pcilg(u64 *data, u64 req, u64 offset, u8 *status)
{
register u64 __req asm("2") = req;
register u64 __offset asm("3") = offset;
int cc = -ENXIO;
u64 __data;
u8 cc;

asm volatile (
" .insn rre,0xb9d20000,%[data],%[req]\n"
" ipm %[cc]\n"
"0: ipm %[cc]\n"
" srl %[cc],28\n"
: [cc] "=d" (cc), [data] "=d" (__data), [req] "+d" (__req)
"1:\n"
EX_TABLE(0b, 1b)
: [cc] "+d" (cc), [data] "=d" (__data), [req] "+d" (__req)
: "d" (__offset)
: "cc");
*status = __req >> 24 & 0xff;
Expand All @@ -106,37 +109,36 @@ static inline u8 __pcilg(u64 *data, u64 req, u64 offset, u8 *status)

int s390pci_load(u64 *data, u64 req, u64 offset)
{
u8 cc, status;
u8 status;
int cc;

do {
cc = __pcilg(data, req, offset, &status);
if (cc == 2)
udelay(ZPCI_INSN_BUSY_DELAY);
} while (cc == 2);

if (cc) {
if (cc)
printk_once(KERN_ERR "%s: error cc: %d status: %d req: %Lx offset: %Lx\n",
__func__, cc, status, req, offset);
/* TODO: on IO errors set data to 0xff...
* here or in users of pcilg (le conversion)?
*/
}
return (cc) ? -EIO : 0;
return (cc > 0) ? -EIO : cc;
}
EXPORT_SYMBOL_GPL(s390pci_load);

/* PCI Store */
static inline u8 __pcistg(u64 data, u64 req, u64 offset, u8 *status)
static inline int __pcistg(u64 data, u64 req, u64 offset, u8 *status)
{
register u64 __req asm("2") = req;
register u64 __offset asm("3") = offset;
u8 cc;
int cc = -ENXIO;

asm volatile (
" .insn rre,0xb9d00000,%[data],%[req]\n"
" ipm %[cc]\n"
"0: ipm %[cc]\n"
" srl %[cc],28\n"
: [cc] "=d" (cc), [req] "+d" (__req)
"1:\n"
EX_TABLE(0b, 1b)
: [cc] "+d" (cc), [req] "+d" (__req)
: "d" (__offset), [data] "d" (data)
: "cc");
*status = __req >> 24 & 0xff;
Expand All @@ -145,7 +147,8 @@ static inline u8 __pcistg(u64 data, u64 req, u64 offset, u8 *status)

int s390pci_store(u64 data, u64 req, u64 offset)
{
u8 cc, status;
u8 status;
int cc;

do {
cc = __pcistg(data, req, offset, &status);
Expand All @@ -156,20 +159,22 @@ int s390pci_store(u64 data, u64 req, u64 offset)
if (cc)
printk_once(KERN_ERR "%s: error cc: %d status: %d req: %Lx offset: %Lx\n",
__func__, cc, status, req, offset);
return (cc) ? -EIO : 0;
return (cc > 0) ? -EIO : cc;
}
EXPORT_SYMBOL_GPL(s390pci_store);

/* PCI Store Block */
static inline u8 __pcistb(const u64 *data, u64 req, u64 offset, u8 *status)
static inline int __pcistb(const u64 *data, u64 req, u64 offset, u8 *status)
{
u8 cc;
int cc = -ENXIO;

asm volatile (
" .insn rsy,0xeb00000000d0,%[req],%[offset],%[data]\n"
" ipm %[cc]\n"
"0: ipm %[cc]\n"
" srl %[cc],28\n"
: [cc] "=d" (cc), [req] "+d" (req)
"1:\n"
EX_TABLE(0b, 1b)
: [cc] "+d" (cc), [req] "+d" (req)
: [offset] "d" (offset), [data] "Q" (*data)
: "cc");
*status = req >> 24 & 0xff;
Expand All @@ -178,7 +183,8 @@ static inline u8 __pcistb(const u64 *data, u64 req, u64 offset, u8 *status)

int s390pci_store_block(const u64 *data, u64 req, u64 offset)
{
u8 cc, status;
u8 status;
int cc;

do {
cc = __pcistb(data, req, offset, &status);
Expand All @@ -189,6 +195,6 @@ int s390pci_store_block(const u64 *data, u64 req, u64 offset)
if (cc)
printk_once(KERN_ERR "%s: error cc: %d status: %d req: %Lx offset: %Lx\n",
__func__, cc, status, req, offset);
return (cc) ? -EIO : 0;
return (cc > 0) ? -EIO : cc;
}
EXPORT_SYMBOL_GPL(s390pci_store_block);

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