| Sumit Garg | 444bd73 | 2019-04-09 18:40:02 +0530 | [diff] [blame^] | 1 | .. _ftrace: |
| 2 | |
| 3 | Ftrace |
| 4 | ###### |
| 5 | This section describes how to generate function call graph for user Trusted |
| 6 | Applications using ``ftrace``. |
| 7 | |
| 8 | The configuration option ``CFG_TA_FTRACE_SUPPORT=y`` enables OP-TEE to collect |
| 9 | function graph information from Trusted Applications running in user mode and |
| 10 | compiled with ``-pg``. Once collected, the function graph data is formatted |
| 11 | in the ``ftrace.out`` format and sent to ``tee-supplicant`` via RPC, so they |
| 12 | can be saved to disk, later processed and displayed using helper script called |
| 13 | ``symbolize.py`` present as part of ``optee_os`` repo. |
| 14 | |
| 15 | Usage |
| 16 | ***** |
| 17 | |
| 18 | - Build OP-TEE OS and OP-TEE Client with ``CFG_TA_FTRACE_SUPPORT=y``. You |
| 19 | may also set ``CFG_ULIBS_MCOUNT=y`` in OP-TEE OS to instrument the |
| 20 | user TA libraries (libutee, libutils, libmpa). |
| 21 | |
| 22 | - Build user TAs with ``-pg``, for instance enable ``CFG_TA_MCOUNT=y`` to |
| 23 | instrument whole TA. Also, in case user wants to set ``-pg`` for a |
| 24 | particular file, following should go in corresponding sub.mk: |
| 25 | ``cflags-<file-name>-y+=-pg``. Note that instrumented TAs have a larger |
| 26 | ``.bss`` section. The memory overhead depends on ``CFG_FTRACE_BUF_SIZE`` |
| 27 | macro which can be configured specific to user TAs using config: |
| 28 | ``CFG_FTRACE_BUF_SIZE=4096`` (default value: 2048, refer to the TA linker |
| 29 | script for details: ``ta/arch/arm/ta.ld.S``). |
| 30 | |
| 31 | - Run the application normally. When the current session exits or there is |
| 32 | any abort during TA execution, ``tee-supplicant`` will write function |
| 33 | graph data to ``/tmp/ftrace-<ta_uuid>.out``. If the file already exists, |
| 34 | a number is appended, such as: ``ftrace-<ta_uuid>.1.out``. |
| 35 | |
| 36 | - Run helper script called ``symbolize.py`` to translate the function graph |
| 37 | addresses into function names: ``cat ftrace-<ta_uuid>.out | |
| 38 | ./optee_os/scripts/symbolize.py -d <ta_uuid>.elf`` |