[PATCH] s390: cpcmd interface

- Diagnose 8 needs a response buffer below 2GB real storage.
  As the caller cannot always allocate the buffer with GFP_DMA the best
  solution is to rewrite cpcmd to use a bounce buffer if necessary.
  The old function was renamed to __cpcmd and can be called if appropriate.
  The early boot code does not provide kmalloc but need cpcmd functionality.
  These places have been converted to use __cpcmd, as the init code and data
  are below 2GB.
- In case of an 31 bit system, cpcmd is defined as __cpcmd.
- EXPORT_SYMBOL(cpcmd) moved into cpcmd.c
- some whitespace fixes in cpcmd.[c/h]
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/s390/kernel/cpcmd.c

@@ -4,20 +4,26 @@
  *  S390 version
  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ *               Christian Borntraeger (cborntra@de.ibm.com),
  */
 
-#include <linux/stddef.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stddef.h>
 #include <linux/string.h>
 #include <asm/ebcdic.h>
-#include <linux/spinlock.h>
 #include <asm/cpcmd.h>
 #include <asm/system.h>
 
 static DEFINE_SPINLOCK(cpcmd_lock);
 static char cpcmd_buf[240];
 
-void cpcmd(char *cmd, char *response, int rlen)
+/*
+ * the caller of __cpcmd has to ensure that the response buffer is below 2 GB
+ */
+void __cpcmd(char *cmd, char *response, int rlen)
 {
 	const int mask = 0x40000000L;
 	unsigned long flags;
@@ -25,11 +31,12 @@ void cpcmd(char *cmd, char *response, int rlen)
 
 	spin_lock_irqsave(&cpcmd_lock, flags);
 	cmdlen = strlen(cmd);
-	BUG_ON(cmdlen>240);
+	BUG_ON(cmdlen > 240);
 	strcpy(cpcmd_buf, cmd);
 	ASCEBC(cpcmd_buf, cmdlen);
 
 	if (response != NULL && rlen > 0) {
+		memset(response, 0, rlen);
 #ifndef CONFIG_ARCH_S390X
 		asm volatile ("LRA   2,0(%0)\n\t"
                               "LR    4,%1\n\t"
@@ -78,3 +85,27 @@ void cpcmd(char *cmd, char *response, int rlen)
 	spin_unlock_irqrestore(&cpcmd_lock, flags);
 }
 
+EXPORT_SYMBOL(__cpcmd);
+
+#ifdef CONFIG_ARCH_S390X
+void cpcmd(char *cmd, char *response, int rlen)
+{
+	char *lowbuf;
+	if ((rlen == 0) || (response == NULL)
+	    || !((unsigned long)response >> 31))
+		__cpcmd(cmd, response, rlen);
+	else {
+		lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA);
+		if (!lowbuf) {
+			printk(KERN_WARNING
+				"cpcmd: could not allocate response buffer\n");
+			return;
+		}
+		__cpcmd(cmd, lowbuf, rlen);
+		memcpy(response, lowbuf, rlen);
+		kfree(lowbuf);
+	}
+}
+
+EXPORT_SYMBOL(cpcmd);
+#endif		/* CONFIG_ARCH_S390X */

arch/s390/kernel/s390_ksyms.c

@@ -63,4 +63,3 @@ EXPORT_SYMBOL(console_mode);
 EXPORT_SYMBOL(console_devno);
 EXPORT_SYMBOL(console_irq);
 EXPORT_SYMBOL(sys_wait4);
-EXPORT_SYMBOL(cpcmd);

arch/s390/kernel/setup.c

@@ -191,11 +191,11 @@ static void __init conmode_default(void)
 	char *ptr;
 
         if (MACHINE_IS_VM) {
-		cpcmd("QUERY CONSOLE", query_buffer, 1024);
+		__cpcmd("QUERY CONSOLE", query_buffer, 1024);
 		console_devno = simple_strtoul(query_buffer + 5, NULL, 16);
 		ptr = strstr(query_buffer, "SUBCHANNEL =");
 		console_irq = simple_strtoul(ptr + 13, NULL, 16);
-		cpcmd("QUERY TERM", query_buffer, 1024);
+		__cpcmd("QUERY TERM", query_buffer, 1024);
 		ptr = strstr(query_buffer, "CONMODE");
 		/*
 		 * Set the conmode to 3215 so that the device recognition 
@@ -204,7 +204,7 @@ static void __init conmode_default(void)
 		 * 3215 and the 3270 driver will try to access the console
 		 * device (3215 as console and 3270 as normal tty).
 		 */
-		cpcmd("TERM CONMODE 3215", NULL, 0);
+		__cpcmd("TERM CONMODE 3215", NULL, 0);
 		if (ptr == NULL) {
 #if defined(CONFIG_SCLP_CONSOLE)
 			SET_CONSOLE_SCLP;

arch/s390/mm/extmem.c

@@ -576,8 +576,8 @@ segment_save(char *name)
 			segtype_string[seg->range[i].start & 0xff]);
 	}
 	sprintf(cmd2, "SAVESEG %s", name);
-	cpcmd(cmd1, NULL, 80);
-	cpcmd(cmd2, NULL, 80);
+	cpcmd(cmd1, NULL, 0);
+	cpcmd(cmd2, NULL, 0);
 	spin_unlock(&dcss_lock);
 }
 

include/asm-s390/cpcmd.h

@@ -4,11 +4,21 @@
  *  S390 version
  *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ *               Christian Borntraeger (cborntra@de.ibm.com),
  */
 
 #ifndef __CPCMD__
 #define __CPCMD__
 
+/*
+ * the caller of __cpcmd has to ensure that the response buffer is below 2 GB
+ */
+extern void __cpcmd(char *cmd, char *response, int rlen);
+
+#ifndef __s390x__
+#define cpcmd __cpcmd
+#else
 extern void cpcmd(char *cmd, char *response, int rlen);
+#endif /*__s390x__*/
 
 #endif