Providing the space of a stack frame is the duty of the caller,
so we should reserve 160 bytes before jumping into the main function.
Otherwise the main() function might write past the stack array.

While we're at it, add a proper STACK_SIZE macro for the stack size
instead of using magic numbers (this is also required for the following
patch).

Reviewed-by: Christian Borntraeger <[email protected]>
Reviewed-by: Cédric Le Goater <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Eric Farman <[email protected]>
Reviewed-by: Claudio Imbrenda <[email protected]>
Reviewed-by: Marc Hartmayer <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Signed-off-by: Thomas Huth <[email protected]>
---
 pc-bios/s390-ccw/start.S | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pc-bios/s390-ccw/start.S b/pc-bios/s390-ccw/start.S
index d29de09cc6..abd6fe6639 100644
--- a/pc-bios/s390-ccw/start.S
+++ b/pc-bios/s390-ccw/start.S
@@ -10,10 +10,13 @@
  * directory.
  */
 
+#define STACK_SIZE        0x8000
+#define STACK_FRAME_SIZE  160
+
     .globl _start
 _start:
 
-    larl    %r15,stack + 0x8000     /* Set up stack */
+    larl    %r15,stack + STACK_SIZE - STACK_FRAME_SIZE   /* Set up stack */
 
     /* clear bss */
     larl    %r2,__bss_start
-- 
2.39.3


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