extra/stack_analyzer: Configurable exception frame size.

Make the size of extra stack needed by exceptions configurable.
It can be set in the annotation file.

BUG=chromium:648840
BRANCH=none
TEST=extra/stack_analyzer/stack_analyzer_unittest.py
     make BOARD=elm SECTION=RW \
         ANNOTATION=./extra/stack_analyzer/example_annotation.yaml \
         analyzestack

Change-Id: Idf2a59650dd20257a0291f89d788c0c83b91a7c9
Signed-off-by: Che-yu Wu <cheyuw@google.com>
Reviewed-on: https://chromium-review.googlesource.com/649454
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>

4 files changed, 17 insertions, 8 deletions

diff --git a/extra/stack_analyzer/README.md b/extra/stack_analyzer/README.md
index 0933959249..b809ccc5a2 100644
--- a/extra/stack_analyzer/README.md
+++ b/extra/stack_analyzer/README.md
@@ -41,6 +41,7 @@ The callsites to the next function will be shown like below,
    - handle_request[common/usb_pd_protocol.c:1191]
      - handle_data_request[common/usb_pd_protocol.c:798]
 -> pd_task[common/usb_pd_protocol.c:2672] 1008c222
+-> [annotation]
 ```
 This means one callsite to the next function is at `usb_pd_protocol.c:798`,
 but it is inlined to the current function and you can follow the trace:
diff --git a/extra/stack_analyzer/example_annotation.yaml b/extra/stack_analyzer/example_annotation.yaml
index 92dff8922f..084fabc2d1 100644
--- a/extra/stack_analyzer/example_annotation.yaml
+++ b/extra/stack_analyzer/example_annotation.yaml
@@ -1,3 +1,6 @@
+# Size of extra stack frame needed by exception context switch.
+exception_frame_size: 64
+
 # Add some missing calls.
 add:
   # console_task also calls command_display_accel_info and command_accel_init.
diff --git a/extra/stack_analyzer/stack_analyzer.py b/extra/stack_analyzer/stack_analyzer.py
index af58ef7ef0..f08470bafc 100755
--- a/extra/stack_analyzer/stack_analyzer.py
+++ b/extra/stack_analyzer/stack_analyzer.py
@@ -26,9 +26,9 @@ import yaml
 
 SECTION_RO = 'RO'
 SECTION_RW = 'RW'
-# TODO(cheyuw): This should depend on the CPU and build options.
-# The size of extra stack frame needed by interrupts. (on cortex-m with FPU)
-INTERRUPT_EXTRA_STACK_FRAME = 224
+# Default size of extra stack frame needed by exception context switch.
+# This value is for cortex-m with FPU enabled.
+DEFAULT_EXCEPTION_FRAME_SIZE = 224
 
 
 class StackAnalyzerError(Exception):
@@ -1259,13 +1259,15 @@ class StackAnalyzer(object):
     cycle_functions = self.AnalyzeCallGraph(function_map, remove_list)
 
     # Print the results of task-aware stack analysis.
+    extra_stack_frame = self.annotation.get('exception_frame_size',
+                                            DEFAULT_EXCEPTION_FRAME_SIZE)
     for task in self.tasklist:
       routine_func = function_map[task.routine_address]
       print('Task: {}, Max size: {} ({} + {}), Allocated size: {}'.format(
           task.name,
-          routine_func.stack_max_usage + INTERRUPT_EXTRA_STACK_FRAME,
+          routine_func.stack_max_usage + extra_stack_frame,
           routine_func.stack_max_usage,
-          INTERRUPT_EXTRA_STACK_FRAME,
+          extra_stack_frame,
           task.stack_max_size))
 
       print('Call Trace:')
diff --git a/extra/stack_analyzer/stack_analyzer_unittest.py b/extra/stack_analyzer/stack_analyzer_unittest.py
index a3bd80a186..cac4383906 100755
--- a/extra/stack_analyzer/stack_analyzer_unittest.py
+++ b/extra/stack_analyzer/stack_analyzer_unittest.py
@@ -590,18 +590,21 @@ class StackAnalyzerTest(unittest.TestCase):
     )
 
     addrtoline_mock.return_value = [('??', '??', 0)]
-    self.analyzer.annotation = {'remove': [['fake_func']]}
+    self.analyzer.annotation = {
+        'exception_frame_size': 64,
+        'remove': [['fake_func']],
+    }
 
     with mock.patch('__builtin__.print') as print_mock:
       checkoutput_mock.return_value = disasm_text
       self.analyzer.Analyze()
       print_mock.assert_has_calls([
           mock.call(
-              'Task: HOOKS, Max size: 232 (8 + 224), Allocated size: 2048'),
+              'Task: HOOKS, Max size: 72 (8 + 64), Allocated size: 2048'),
           mock.call('Call Trace:'),
           mock.call('    hook_task (8) [??:0] 1000'),
           mock.call(
-              'Task: CONSOLE, Max size: 240 (16 + 224), Allocated size: 460'),
+              'Task: CONSOLE, Max size: 80 (16 + 64), Allocated size: 460'),
           mock.call('Call Trace:'),
           mock.call('    console_task (8) [??:0] 2000'),
           mock.call('        -> ??[??:0] 2002'),