[S390] add mini sclp driver

This adds a mini sclp device driver for very early use. The primary
and probably only use will be to emit a message to the console if the
cpu doesn't provide the minimum required capabilities to run the kernel.
After printing the message a disabled wait will be loaded and the
machine stops operating.
Printing the message is also part of this patch.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 14 insertions, 4 deletions

diff --git a/arch/s390/kernel/head.S b/arch/s390/kernel/head.S
index bf8cf1caeffc..6d227413cbe7 100644
--- a/arch/s390/kernel/head.S
+++ b/arch/s390/kernel/head.S
@@ -1,7 +1,5 @@
 /*
- *  arch/s390/kernel/head.S
- *
- * Copyright (C) IBM Corp. 1999,2006
+ * Copyright IBM Corp. 1999,2009
  *
  *    Author(s): Hartmut Penner <hp@de.ibm.com>
  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
@@ -494,7 +492,19 @@ startup:basr	%r13,0			# get base
         n       %r0,2f+12-.LPG0(%r13)
         cl      %r0,2f+12-.LPG0(%r13)
         je      3f
-1:      lpsw    2f-.LPG0(13)            # machine type not good enough, crash
+1:      l       %r15,.Lstack-.LPG0(%r13)
+        ahi     %r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union+THREAD_SIZE
+        ahi     %r15,-96
+        la      %r2,.Lals_string-.LPG0(%r13)
+        l       %r3,.Lsclp_print-.LPG0(%r13)
+        basr    %r14,%r3
+        lpsw    2f-.LPG0(%r13)          # machine type not good enough, crash
+.Lals_string:
+        .asciz  "The Linux kernel requires more recent processor hardware"
+.Lsclp_print:
+        .long   _sclp_print_early
+.Lstack:
+        .long   init_thread_union
         .align 16
 2:      .long   0x000a0000,0x8badcccc
 #if defined(CONFIG_64BIT)