[Skiboot] [PATCH] asm/head: Loop after attn

[Oliver O'Halloran]

We use the attn instruction to raise an error in early boot if OPAL
don't recognise the PVR. It's possible for hostboot to disable the
attn instruction before entering OPAL so add an extra busy loop after
the attn to prevent attempting to boot on an unknown processor.

Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
---
 asm/head.S | 1 +
 1 file changed, 1 insertion(+)

diff --git a/asm/head.S b/asm/head.S
index d82e4e5e7c66..ccf0948273d2 100644
--- a/asm/head.S
+++ b/asm/head.S
@@ -270,6 +270,7 @@ boot_entry:
 	cmpwi	cr0,%r3,PVR_TYPE_P9
 	beq 	1f
 	attn		/* Unsupported CPU type... what do we do ? */
+	b 	.	/* loop here, just in case attn is disabled */
 
 	/* P8 -> 8 threads */
 2:	li	%r26,7
-- 
2.9.5