ARM: let CPUs not being able to run in ARM mode enter in THUMB mode

Some ARM cores are not capable to run in ARM mode (e.g. Cortex-M3). So
obviously these cannot enter the kernel in ARM mode. Make an exception
for them and let them enter in THUMB mode.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Message-Id: 1358162123-30113-1-git-send-email-u.kleine-koenig@pengutronix.de
Acked-by: Nicolas Pitre <nico@linaro.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index 2c228a07e58c..6a2e09c952c7 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -32,15 +32,21 @@
  * numbers for r1.
  *
  */
-        .arm
 
         __HEAD
+
+#ifdef CONFIG_CPU_THUMBONLY
+        .thumb
+ENTRY(stext)
+#else
+        .arm
 ENTRY(stext)
 
  THUMB( adr     r9, BSYM(1f)    )       @ Kernel is always entered in ARM.
  THUMB( bx      r9              )       @ If this is a Thumb-2 kernel,
  THUMB( .thumb                  )       @ switch to Thumb now.
  THUMB(1:                       )
+#endif
 
         setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
                                                 @ and irqs disabled