powerpc: Perform an isync to synchronize CPUs coming out of secondary_hold

We need to do that to guarantee they see any code change done by
dynamic patching during boot.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
index 0700e1135c91a63eb5fa90dedf376e3c479cb030..6d17c37f22a144dc542a383b5e02cce076e5d700 100644 (file)
--- a/arch/powerpc/kernel/head_64.S
+++ b/arch/powerpc/kernel/head_64.S
@@ -147,6 +147,8 @@ __secondary_hold:
        mtctr   r4
        mr      r3,r24
        li      r4,0
+       /* Make sure that patched code is visible */
+       isync
        bctr
 #else
        BUG_OPCODE