1 files changed, 16 insertions, 2 deletions

diff --git a/include/asm-s390/cpcmd.h b/include/asm-s390/cpcmd.h
index 1d33c5da083e..1fcf65be7a23 100644
--- a/include/asm-s390/cpcmd.h
+++ b/include/asm-s390/cpcmd.h
@@ -11,14 +11,28 @@
 #define __CPCMD__
 
 /*
+ * the lowlevel function for 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);
+extern int __cpcmd(const char *cmd, char *response, int rlen, int *response_code);
 
 #ifndef __s390x__
 #define cpcmd __cpcmd
 #else
-extern void cpcmd(char *cmd, char *response, int rlen);
+/*
+ * cpcmd is the in-kernel interface for issuing CP commands
+ *
+ * cmd:         null-terminated command string, max 240 characters
+ * response:    response buffer for VM's textual response
+ * rlen:        size of the response buffer, cpcmd will not exceed this size
+ *              but will cap the output, if its too large. Everything that
+ *              did not fit into the buffer will be silently dropped
+ * response_code: return pointer for VM's error code
+ * return value: the size of the response. The caller can check if the buffer
+ *              was large enough by comparing the return value and rlen
+ * NOTE: If the response buffer is not below 2 GB, cpcmd can sleep
+ */
+extern int cpcmd(const char *cmd, char *response, int rlen, int *response_code);
 #endif /*__s390x__*/
 
 #endif