Blackfin: do not configure the UART early if on wrong processor

Before we configure the early UART, check to make sure we are running on
the expected processor - otherwise, we cause problems by configuring pins
that don't exist (and causing an infinite loop of faults).

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 6 insertions, 2 deletions

diff --git a/arch/blackfin/kernel/early_printk.c b/arch/blackfin/kernel/early_printk.c
index 3302719173ca..2ab56811841c 100644
--- a/arch/blackfin/kernel/early_printk.c
+++ b/arch/blackfin/kernel/early_printk.c
@@ -202,11 +202,15 @@ asmlinkage void __init init_early_exception_vectors(void)
 asmlinkage void __init early_trap_c(struct pt_regs *fp, void *retaddr)
 {
         /* This can happen before the uart is initialized, so initialize
-         * the UART now
+         * the UART now (but only if we are running on the processor we think
+         * we are compiled for - otherwise we write to MMRs that don't exist,
+         * and cause other problems. Nothing comes out the UART, but it does
+         * end up in the __buf_log.
          */
-        if (likely(early_console == NULL))
+        if (likely(early_console == NULL) && CPUID == bfin_cpuid())
                 setup_early_printk(DEFAULT_EARLY_PORT);
 
+        printk(KERN_EMERG "Early panic\n");
         dump_bfin_mem(fp);
         show_regs(fp);
         dump_bfin_trace_buffer();