From dd69967934106cec32fd9e281b10083d59c15fde Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Sat, 7 Nov 2015 09:35:23 -0600
Subject: [PATCH] SAMV7 protected mode:  Don't enable D-Cache until userspace
 data has been initialized

---
 arch/arm/src/samv7/sam_start.c     | 24 ++++++++++++------------
 arch/arm/src/samv7/sam_userspace.c |  3 +++
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/arch/arm/src/samv7/sam_start.c b/arch/arm/src/samv7/sam_start.c
index 985e24e181d..285e429b6b4 100644
--- a/arch/arm/src/samv7/sam_start.c
+++ b/arch/arm/src/samv7/sam_start.c
@@ -367,18 +367,6 @@ void __start(void)
 
   sam_boardinitialize();
 
-  /* Enable I- and D-Caches */
-
-  arch_dcache_writethrough();
-  arch_enable_icache();
-  arch_enable_dcache();
-
-  /* Perform early serial initialization */
-
-#ifdef USE_EARLYSERIALINIT
-  up_earlyserialinit();
-#endif
-
 #ifdef CONFIG_ARMV7M_MPU
   /* For the case of the separate user-/kernel-space build, perform whatever
    * platform specific initialization of the user memory is required.
@@ -398,6 +386,18 @@ void __start(void)
   sam_mpu_initialize();
 #endif
 
+  /* Enable I- and D-Caches */
+
+  arch_dcache_writethrough();
+  arch_enable_icache();
+  arch_enable_dcache();
+
+  /* Perform early serial initialization */
+
+#ifdef USE_EARLYSERIALINIT
+  up_earlyserialinit();
+#endif
+
   /* Then start NuttX */
 
 #ifdef CONFIG_STACK_COLORATION
diff --git a/arch/arm/src/samv7/sam_userspace.c b/arch/arm/src/samv7/sam_userspace.c
index 136c5ac1d75..255d59919a1 100644
--- a/arch/arm/src/samv7/sam_userspace.c
+++ b/arch/arm/src/samv7/sam_userspace.c
@@ -62,6 +62,9 @@
  *   Normally this just means initializing the user space .data and .bss
  *   segments.
  *
+ * Assumptions:
+ *   The D-Cache has not yet been enabled.
+ *
  ****************************************************************************/
 
 void sam_userspace(void)