From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from magratgarlick.emantor.de ([2a01:4f8:c17:c88::2] helo=margratgarlick.emantor.de) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hYAb0-0002VZ-Ae for barebox@lists.infradead.org; Tue, 04 Jun 2019 14:39:28 +0000 From: Rouven Czerwinski Date: Tue, 4 Jun 2019 16:38:53 +0200 Message-Id: <20190604143851.11928-3-r.czerwinski@pengutronix.de> In-Reply-To: <20190604143851.11928-1-r.czerwinski@pengutronix.de> References: <20190604143851.11928-1-r.czerwinski@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 3/3] add gdb helper scripts to load barebox symbols To: barebox@lists.infradead.org Cc: Rouven Czerwinski Add a gdb script with two helper functions which use the new pbl_barebox_break symbol to calculate the current barebox load address on the device and loads a barebox ELF file to this address. Signed-off-by: Rouven Czerwinski --- Documentation/user/debugging.rst | 21 +++++++++++ Documentation/user/user-manual.rst | 1 + common/Kconfig | 9 +++++ scripts/gdb/helper.py | 60 ++++++++++++++++++++++++++++++ 4 files changed, 91 insertions(+) create mode 100644 Documentation/user/debugging.rst create mode 100644 scripts/gdb/helper.py diff --git a/Documentation/user/debugging.rst b/Documentation/user/debugging.rst new file mode 100644 index 0000000000..15cb439043 --- /dev/null +++ b/Documentation/user/debugging.rst @@ -0,0 +1,21 @@ +Debugging with OpenOCD +====================== + +Barebox can be configured to break on prebootloader and main barebox entry. This +breakpoint can not be resumed and will stop the board to allow the user to +attach a JTAG debugger with OpenOCD. Additionally, barebox provides helper +scripts to load the symbols from the ELF binaries. +The python scripts require `pyelftools`. +To load the scripts into your gdb session, run the following command in the +barebox directory: + +.. code-block:: none + + (gdb) source scripts/gdb/helper.py + +This makes two new commands available in gdb, `bb-load-symbols` and +`bb-skip-break`. `bb-load-symbols` can load either the main `barebox` file or +one of the .pbl files in the image directories. The board needs to be stopped in +either the prebootloader or main barebox breakpoint, and gdb needs to be +connected to OpenOCD. To continue booting the board, `bb-skip-break` jumps over +the breakpoint and continues the barebox execution. diff --git a/Documentation/user/user-manual.rst b/Documentation/user/user-manual.rst index 516b760b1b..f04981c3f0 100644 --- a/Documentation/user/user-manual.rst +++ b/Documentation/user/user-manual.rst @@ -33,6 +33,7 @@ Contents: system-reset state random + debugging * :ref:`search` * :ref:`genindex` diff --git a/common/Kconfig b/common/Kconfig index 4124857a0a..c766e1ef64 100644 --- a/common/Kconfig +++ b/common/Kconfig @@ -1252,6 +1252,15 @@ config PBL_BREAK If this enabled, barebox will be compiled with BKPT instruction on early pbl init. This option be used only with JTAG debugger! +config GDB_SCRIPTS + bool "Provide GDB scripts for barebox debugging" + help + This creates the required links to GDB helper scripts in the + build directory. If you load barebox into gdb, the helper + scripts will be automatically imported by gdb as well, and + additional functions are available to analyze a Linux kernel + instance. + endmenu config HAS_DEBUG_LL diff --git a/scripts/gdb/helper.py b/scripts/gdb/helper.py new file mode 100644 index 0000000000..4041789890 --- /dev/null +++ b/scripts/gdb/helper.py @@ -0,0 +1,60 @@ +#!/usr/bin/env python + +import gdb + +try: + from elftools.elf.elffile import ELFFile + from elftools.common.exceptions import ELFError +except ImportError: + gdb.write("The barebox helper requires pyelftools\n", gdb.STDERR) + exit(1) + + +class BBSymbols(gdb.Command): + + def __init__(self): + super(BBSymbols, self).__init__("bb-load-symbols", gdb.COMMAND_FILES, + gdb.COMPLETE_FILENAME) + + def invoke(self, argument, from_tty): + path = argument + f = open(path, 'rb') + + try: + elf = ELFFile(f) + except ELFError: + gdb.write("Selected file is not an ELF file\n", gdb.STDERR) + return + + section = elf.get_section_by_name(".symtab") + if section is None: + gdb.write("Section .symtab not found\n", gdb.STDERR) + return + symbol = section.get_symbol_by_name("pbl_barebox_break") + if not symbol: + gdb.write("Symbol pbl_barebox_break in section {} in file {} not found\n" + .format(section.name, self.path), gdb.STDERR) + return + symbol = symbol[0] + pc = gdb.parse_and_eval("$pc") + symbol_address = int(symbol.entry.st_value) + address = int(pc) - symbol_address + 1 + gdb.execute("symbol-file") + gdb.execute("add-symbol-file {} {}".format(path, address)) + + +BBSymbols() + + +class BBSkip(gdb.Command): + + def __init__(self): + super(BBSkip, self).__init__("bb-skip-break", gdb.COMMAND_BREAKPOINTS) + + def invoke(self, arg, from_tty): + pc = gdb.parse_and_eval("$pc") + nop_address = int(pc) + 2 + gdb.execute("jump *{}".format(nop_address)) + + +BBSkip() -- 2.21.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox