[PATCH V2 1/2] powerpc/kexec: Reset secondary cpu endianess before kexec

Samuel Mendoza-Jonas sam.mj at au1.ibm.com
Wed Jul 8 14:37:12 AEST 2015

If the target kernel does not inlcude the FIXUP_ENDIAN check, coming
from a different-endian kernel will cause the target kernel to panic.
All ppc64 kernels can handle starting in big-endian mode, so return to
big-endian before branching into the target kernel.

This mainly affects pseries as secondaries on powernv are returned to

Signed-off-by: Samuel Mendoza-Jonas <sam.mj at au1.ibm.com>
v2: Add an #ifdef for subarch-specific code
    Neaten the endian check (and extra call to mfmsr!) by modifying the msr and
    branching to the target kernel in the same call to rfid.
 arch/powerpc/kernel/misc_64.S | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 4e314b9..89f0600 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -475,9 +475,18 @@ _GLOBAL(kexec_wait)
 #ifdef CONFIG_KEXEC		/* use no memory without kexec */
 	lwz	r4,0(r5)
 	cmpwi	0,r4,0
-	bnea	0x60
+	beq	99b
+#ifdef CONFIG_PPC_BOOK3S_64
+	li	r10,0x60
+	mfmsr	r11
+	clrrdi	r11,r11,1	/* Clear MSR_LE */
+	mtsrr0	r10
+	mtsrr1	r11
+	rfid
+	b	0x60
-	b	99b
 /* this can be in text because we won't change it until we are
  * running in real anyways

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