s390/pci: add exception table to load/store instructions

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>

2 files changed, 30 insertions, 24 deletions

diff --git a/arch/s390/include/asm/pci_io.h b/arch/s390/include/asm/pci_io.h
index a312c7e5a71e..0e0bec9a3fb7 100644
--- a/arch/s390/include/asm/pci_io.h
+++ b/arch/s390/include/asm/pci_io.h
@@ -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) {
diff --git a/arch/s390/pci/pci_insn.c b/arch/s390/pci/pci_insn.c
index d9b573bf4eb7..4bc32f368f7d 100644
--- a/arch/s390/pci/pci_insn.c
+++ b/arch/s390/pci/pci_insn.c
@@ -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 */
 
@@ -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;
@@ -106,7 +109,8 @@ 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);
@@ -114,29 +118,27 @@ int s390pci_load(u64 *data, u64 req, u64 offset)
                         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;
@@ -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);
@@ -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;
@@ -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);
@@ -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);