[PATCH v2 1/3] remove CONFIG_DEBUG_INFO

[PATCH v2 1/3] remove CONFIG_DEBUG_INFO

[Rouven Czerwinski]

From: Oleksij Rempel <linux@rempel-privat.de>

The ELF file should have debug symbols, the binary should have no symbols any way.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 Makefile       | 4 +---
 common/Kconfig | 6 ------
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/Makefile b/Makefile
index 29347b6780..900117e727 100644
--- a/Makefile
+++ b/Makefile
@@ -457,9 +457,7 @@ endif # $(dot-config)
 
 include $(srctree)/arch/$(ARCH)/Makefile
 
-ifdef CONFIG_DEBUG_INFO
-CFLAGS		+= -g
-endif
+CFLAGS		+= -ggdb3
 
 # Force gcc to behave correct even for buggy distributions
 CFLAGS          += $(call cc-option, -fno-stack-protector)
diff --git a/common/Kconfig b/common/Kconfig
index 7832df5c55..ffb7537592 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -999,12 +999,6 @@ config DEFAULT_LOGLEVEL
 	  7    debug-level messages (debug)
 	  8    verbose debug messages (vdebug)
 
-config DEBUG_INFO
-	bool
-	prompt "enable debug symbols"
-	help
-	  Enable build of barebox with -g.
-
 config DEBUG_LL
 	bool
 	depends on HAS_DEBUG_LL
-- 
2.21.0


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[PATCH v2 2/3] add CONFIG_PBL_BREAK option

[Rouven Czerwinski]

From: Oleksij Rempel <linux@rempel-privat.de>

With this option barebox will be build with breakpoint instruction
in early pbl stage.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
---
 arch/arm/cpu/common.c              | 13 +++++++++++++
 arch/arm/cpu/start.c               |  2 ++
 arch/arm/include/asm/barebox-arm.h |  2 ++
 common/Kconfig                     |  7 +++++++
 4 files changed, 24 insertions(+)

diff --git a/arch/arm/cpu/common.c b/arch/arm/cpu/common.c
index 51fe7ed988..6fe3476aa2 100644
--- a/arch/arm/cpu/common.c
+++ b/arch/arm/cpu/common.c
@@ -30,6 +30,19 @@
 #define R_ARM_RELATIVE 23
 #define R_AARCH64_RELATIVE 1027
 
+void pbl_barebox_break(void)
+{
+	__asm__ __volatile__ (
+#ifdef CONFIG_PBL_BREAK
+		"bkpt #17\n"
+		"nop\n"
+#else
+		"nop\n"
+		"nop\n"
+#endif
+	);
+}
+
 /*
  * relocate binary to the currently running address
  */
diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
index 6573c2ef74..6bfc4da34c 100644
--- a/arch/arm/cpu/start.c
+++ b/arch/arm/cpu/start.c
@@ -168,6 +168,8 @@ __noreturn void barebox_non_pbl_start(unsigned long membase,
 
 	barrier();
 
+	pbl_barebox_break();
+
 	pr_debug("memory at 0x%08lx, size 0x%08lx\n", membase, memsize);
 
 	arm_endmem = endmem;
diff --git a/arch/arm/include/asm/barebox-arm.h b/arch/arm/include/asm/barebox-arm.h
index a11d34923d..12765b7277 100644
--- a/arch/arm/include/asm/barebox-arm.h
+++ b/arch/arm/include/asm/barebox-arm.h
@@ -55,6 +55,7 @@ static inline unsigned long global_variable_offset(void)
 }
 
 void setup_c(void);
+void pbl_barebox_break(void);
 void relocate_to_current_adr(void);
 void relocate_to_adr(unsigned long target);
 void __noreturn barebox_arm_entry(unsigned long membase, unsigned long memsize, void *boarddata);
@@ -177,6 +178,7 @@ static inline unsigned long arm_mem_barebox_image(unsigned long membase,
 				(uint32_t r0, uint32_t r1, uint32_t r2)	\
 		{							\
 			__barebox_arm_head();				\
+			pbl_barebox_break();				\
 			__##name(r0, r1, r2);				\
 		}							\
 		static void NAKED noinline __##name			\
diff --git a/common/Kconfig b/common/Kconfig
index ffb7537592..4124857a0a 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -1245,6 +1245,13 @@ config DEBUG_INITCALLS
 	help
 	  If enabled this will print initcall traces.
 
+
+config PBL_BREAK
+	bool "Execute software break on pbl start"
+	help
+	  If this enabled, barebox will be compiled with BKPT instruction
+	  on early pbl init. This option be used only with JTAG debugger!
+
 endmenu
 
 config HAS_DEBUG_LL
-- 
2.21.0


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[PATCH v2 3/3] add gdb helper scripts to load barebox symbols

[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 <r.czerwinski@pengutronix.de>
---
 Documentation/user/debugging.rst   | 21 +++++++++++
 Documentation/user/user-manual.rst |  1 +
 scripts/gdb/helper.py              | 60 ++++++++++++++++++++++++++++++
 3 files changed, 82 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/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


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