[PATCH v2 2/3] ppc64: Avoid rfid if no need to clear MSR_LE

[Scott Wood <scottwood@freescale.com>]

Commit a304e2d82a8c3 ("ppc64: purgatory: Reset primary cpu endian to
big-endian) changed bctr to rfid.  rfid is book3s-only and will cause a
fatal exception on book3e.

Purgatory is an isolated environment which makes importing information
about the subarch awkward, so instead rely on the fact that MSR_LE
should never be set on book3e, and the rfid is only needed if MSR_LE is
set (and thus needs to be cleared).  In theory that MSR bit is reserved
on book3e, rather than zero, but in practice I have not seen it set.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Samuel Mendoza-Jonas <sam.mj@au1.ibm.com>
---
v2: new patch

 purgatory/arch/ppc64/v2wrap.S | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/purgatory/arch/ppc64/v2wrap.S b/purgatory/arch/ppc64/v2wrap.S
index 179ade9..3534080 100644
--- a/purgatory/arch/ppc64/v2wrap.S
+++ b/purgatory/arch/ppc64/v2wrap.S
@@ -116,9 +116,17 @@ master:
 	stw	7,0x5c(4)	# and patch it into the kernel
 	mr      3,16            # restore dt address
 
+	mfmsr	5
+	andi.	10,5,1		# test MSR_LE
+	bne	little_endian
+
+	li	5,0		# r5 will be 0 for kernel
+	mtctr	4		# prepare branch to
+	bctr			# start kernel
+	
+little_endian:			# book3s-only
 	mtsrr0	4		# prepare branch to
 
-	mfmsr	5
 	clrrdi	5,5,1		# clear MSR_LE
 	mtsrr1	5
 
-- 
2.1.4