Finishes basic paging support

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2876 42af7a65-404d-4744-a932-0658087f49c3

arch/arm/src/arm/pg_macros.h

@@ -91,6 +91,9 @@
 #  define MMU_L1_PGTABFLAGS    (PMD_TYPE_FINE|PMD_BIT4)
 #  define MMU_L2_PGTABFLAGS    (PTE_TYPE_TINY|PTE_EXT_AP_UNO_SRW)
 
+#  define MMU_L2_VECTRWFLAGS   (PTE_TYPE_TINY|PTE_EXT_AP_UNO_SRW)
+#  define MMU_L2_VECTROFLAGS   (PTE_TYPE_TINY|PTE_EXT_AP_UNO_SRO|PTE_CACHEABLE)
+
 #elif CONFIG_PAGING_PAGESIZE == 4096
 
    /* Number of pages in an L2 table per L1 entry */
@@ -115,6 +118,9 @@
 #  define MMU_L1_PGTABFLAGS    (PMD_TYPE_COARSE|PMD_BIT4)
 #  define MMU_L2_PGTABFLAGS    (PTE_TYPE_SMALL|PTE_SMALL_AP_UNO_SRW)
 
+#  define MMU_L2_VECTRWFLAGS   (PTE_TYPE_SMALL|PTE_SMALL_AP_UNO_SRW)
+#  define MMU_L2_VECTROFLAGS   (PTE_TYPE_SMALL|PTE_SMALL_AP_UNO_SRO|PTE_CACHEABLE)
+
 #else
 #  error "Need extended definitions for CONFIG_PAGING_PAGESIZE"
 #endif

arch/arm/src/lpc313x/lpc313x_boot.c

@@ -192,6 +192,56 @@ static void up_setupmappings(void)
 }
 #endif
 
+/************************************************************************************
+ * Name: up_vectorpermissions
+ *
+ * Description:
+ *   Set permissions on the vector mapping.
+ *
+ ************************************************************************************/
+
+#if !defined(CONFIG_ARCH_ROMPGTABLE) && defined(CONFIG_ARCH_LOWVECTORS) && defined(CONFIG_PAGING)
+static void  up_vectorpermissions(uint32 mmuflags)
+{
+  uint32_t *ptr = (uint3t*)PG_L2_VECT_VADDR;
+  uint32_t pte;
+
+  /* This is easily because we have already been told everything! */
+
+  pte = *ptr;
+#ifdef CONFIG_PAGING_VECPPAGE
+  /* We've been told to use a specify page for the vectors.  In this
+   * case, I expect the pte to be zero the first time this function is
+   * called (what if it is not?)
+   */
+
+  if (pte == 0)
+    {
+      pte = PG_VECT_PBASE;   
+    }
+  else
+    {
+      pte &= PG_L1_PADDRMASK;
+    }
+#else
+  /* Otherwise, we should be using the page at the beginning of the
+   * locked text region.
+   */
+
+  ASSERT(pte != 0);
+  pte &= PG_L1_PADDRMASK;
+#endif
+
+  /* Update the MMU flags and save */
+
+  *ptr = pte | mmuflags;
+
+  /* Invalid the TLB for this address */
+
+  tlb_invalidate_single(PG_L2_VECT_VADDR);
+}
+#endif
+
 /************************************************************************************
  * Name: up_vectormapping
  *
@@ -288,6 +338,14 @@ void up_boot(void)
 #ifndef CONFIG_ARCH_ROMPGTABLE
   up_setupmappings();
 
+  /* If we are using vectors in low memory but RAM in that area has been marked
+   * read only, then temparily mark the mapping write-able (non-buffered).
+   */
+
+#if defined(CONFIG_ARCH_LOWVECTORS) && defined(CONFIG_PAGING)
+  up_vectorpermissions(MMU_L2_VECTRWFLAGS);
+#endif
+
   /* Provide a special mapping for the IRAM interrupt vector positioned in high
    * memory.
    */
@@ -295,7 +353,7 @@ void up_boot(void)
 #ifndef CONFIG_ARCH_LOWVECTORS
   up_vectormapping();
 #endif
-#endif
+#endif /* CONFIG_ARCH_ROMPGTABLE */
 
   /* Setup up vector block.  _vector_start and _vector_end are exported from
    * up_vector.S
@@ -303,6 +361,12 @@ void up_boot(void)
 
   up_copyvectorblock();
 
+  /* Make the vectors read-only, cacheable again */
+
+#if !defined(CONFIG_ARCH_ROMPGTABLE) && defined(CONFIG_ARCH_LOWVECTORS) && defined(CONFIG_PAGING)
+  up_vectorpermissions(MMU_L2_VECTROFLAGS);
+#endif
+
   /* Reset all clocks */
 
   lpc313x_resetclks();