powerpc: Fix TLB cleanup at boot on POWER8

The TLB has 512 congruence classes (2048 entries 4 way set associative)
while P7 had 128

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

diff --git a/arch/powerpc/kernel/cpu_setup_power.S b/arch/powerpc/kernel/cpu_setup_power.S
index a283b6442b266544235e11bc061d33d58f321b05..18b5b9cf8e3730f4608ca6ff997810d5cc47df9a 100644 (file)
--- a/arch/powerpc/kernel/cpu_setup_power.S
+++ b/arch/powerpc/kernel/cpu_setup_power.S
@@ -135,8 +135,12 @@ __init_HFSCR:
        blr
 
 __init_TLB:
-       /* Clear the TLB */
-       li      r6,128
+       /*
+        * Clear the TLB using the "IS 3" form of tlbiel instruction
+        * (invalidate by congruence class). P7 has 128 CCs, P8 has 512
+        * so we just always do 512
+        */
+       li      r6,512
        mtctr   r6
        li      r7,0xc00        /* IS field = 0b11 */
        ptesync