microblaze: Add checking mechanism for MSR instruction

[safe/jmp/linux-2.6] / arch / microblaze / kernel / head.S

diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S
index e41c6ce..bfc7ea8 100644 (file)
--- a/arch/microblaze/kernel/head.S
+++ b/arch/microblaze/kernel/head.S
@@ -55,6 +55,19 @@ ENTRY(_start)
        andi    r1, r1, ~2
        mts     rmsr, r1
 
+/*
+ * Here is checking mechanism which check if Microblaze has msr instructions
+ * We load msr and compare it with previous r1 value - if is the same,
+ * msr instructions works if not - cpu don't have them.
+ */
+       or      r8, r0, r0 /* 0 - I have msr instr, 1 - I don't have */
+       or      r12, r0, r0
+       msrset  r12, 0  /* set nothing - just read msr for test */
+       cmpu    r12, r12, r1
+       beqi    r12, 1f
+       ori     r8, r0, 1 /* I don't have msr */
+1:
+
 /* r7 may point to an FDT, or there may be one linked in.
    if it's in r7, we've got to save it away ASAP.
    We ensure r7 points to a valid FDT, just in case the bootloader
@@ -209,8 +222,8 @@ start_here:
         * Please see $(ARCH)/mach-$(SUBARCH)/setup.c for
         * the function.
         */
-       la      r8, r0, machine_early_init
-       brald   r15, r8
+       la      r9, r0, machine_early_init
+       brald   r15, r9
        nop
 
 #ifndef CONFIG_MMU