[S390] cpcmd <-> __cpcmd calling issues
In case of reipl cpcmd gets called when all other cpus are not running
anymore. To prevent deadlocks change __cpcmd so that it doesn't take
any locks and call cpcmd or __cpcmd, whatever is correct in the current
context.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/cpcmd.c b/arch/s390/kernel/cpcmd.c
index 1eae74e..a5972f1 100644
--- a/arch/s390/kernel/cpcmd.c
+++ b/arch/s390/kernel/cpcmd.c
@@ -21,14 +21,15 @@
static char cpcmd_buf[241];
/*
- * the caller of __cpcmd has to ensure that the response buffer is below 2 GB
+ * __cpcmd has some restrictions over cpcmd
+ * - the response buffer must reside below 2GB (if any)
+ * - __cpcmd is unlocked and therefore not SMP-safe
*/
int __cpcmd(const char *cmd, char *response, int rlen, int *response_code)
{
- unsigned long flags, cmdlen;
+ unsigned cmdlen;
int return_code, return_len;
- spin_lock_irqsave(&cpcmd_lock, flags);
cmdlen = strlen(cmd);
BUG_ON(cmdlen > 240);
memcpy(cpcmd_buf, cmd, cmdlen);
@@ -74,7 +75,6 @@
: "+d" (reg3) : "d" (reg2) : "cc");
return_code = (int) reg3;
}
- spin_unlock_irqrestore(&cpcmd_lock, flags);
if (response_code != NULL)
*response_code = return_code;
return return_len;
@@ -82,15 +82,18 @@
EXPORT_SYMBOL(__cpcmd);
-#ifdef CONFIG_64BIT
int cpcmd(const char *cmd, char *response, int rlen, int *response_code)
{
char *lowbuf;
int len;
+ unsigned long flags;
if ((rlen == 0) || (response == NULL)
- || !((unsigned long)response >> 31))
+ || !((unsigned long)response >> 31)) {
+ spin_lock_irqsave(&cpcmd_lock, flags);
len = __cpcmd(cmd, response, rlen, response_code);
+ spin_unlock_irqrestore(&cpcmd_lock, flags);
+ }
else {
lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
if (!lowbuf) {
@@ -98,7 +101,9 @@
"cpcmd: could not allocate response buffer\n");
return -ENOMEM;
}
+ spin_lock_irqsave(&cpcmd_lock, flags);
len = __cpcmd(cmd, lowbuf, rlen, response_code);
+ spin_unlock_irqrestore(&cpcmd_lock, flags);
memcpy(response, lowbuf, rlen);
kfree(lowbuf);
}
@@ -106,4 +111,3 @@
}
EXPORT_SYMBOL(cpcmd);
-#endif /* CONFIG_64BIT */
