propagate additional process loading errors to main.rs

kernel/src/process.rs

@@ -31,6 +31,16 @@ pub enum ProcessLoadError {
     /// Not enough flash remaining to parse an app and its header.
     NotEnoughFlash,
 
+    /// Not enough memory to meet the amount requested by an app.
+    /// Modify your app to request less memory or flash fewer apps or
+    /// increase the size of the region your board reserves for app memory.
+    NotEnoughMemory,
+
+    /// An app was loaded with a length in flash that the MPU does not support.
+    /// The fix is probably to correct the app size, but this could also be caused
+    /// by a bad MPU implementation.
+    MpuInvalidFlashLength,
+
     /// Process loading error due (likely) to a bug in the kernel. If you get
     /// this error please open a bug report.
     InternalError,
@@ -58,6 +68,14 @@ impl fmt::Debug for ProcessLoadError {
                 write!(f, "Not enough flash available for app linked list")
             }
 
+            ProcessLoadError::NotEnoughMemory => {
+                write!(f, "Not able to meet memory requirements requested by apps")
+            }
+
+            ProcessLoadError::MpuInvalidFlashLength => {
+                write!(f, "App flash length not supported by MPU")
+            }
+
             ProcessLoadError::InternalError => write!(f, "Error in kernel. Likely a bug."),
         }
     }
@@ -1595,13 +1613,13 @@ impl<C: 'static + Chip> Process<'a, C> {
         {
             if config::CONFIG.debug_load_processes {
                 debug!(
-                    "[!] flash=[{:#010X}:{:#010X}] process={:?} - couldn't allocate flash region",
+                    "[!] flash=[{:#010X}:{:#010X}] process={:?} - couldn't allocate MPU region for flash",
                     app_flash.as_ptr() as usize,
                     app_flash.as_ptr() as usize + app_flash.len(),
                     process_name
                 );
             }
-            return Ok((None, 0));
+            return Err(ProcessLoadError::MpuInvalidFlashLength);
         }
 
         // Determine how much space we need in the application's
@@ -1656,7 +1674,7 @@ impl<C: 'static + Chip> Process<'a, C> {
                         min_total_memory_size
                     );
                 }
-                return Ok((None, 0));
+                return Err(ProcessLoadError::NotEnoughMemory);
             }
         };
 
@@ -1793,7 +1811,7 @@ impl<C: 'static + Chip> Process<'a, C> {
                         process_name
                     );
                 }
-                return Ok((None, 0));
+                return Err(ProcessLoadError::InternalError);
             }
         };