[Buildroot] [PATCH] linux: Add helping kernel gdb functions compilation

* [Buildroot] [PATCH] linux: Add helping kernel gdb functions compilation
@ 2023-12-09 10:10 Michael Trimarchi
  2023-12-09 18:47 ` Yann E. MORIN
  0 siblings, 1 reply; 3+ messages in thread
From: Michael Trimarchi @ 2023-12-09 10:10 UTC (permalink / raw)
  To: buildroot; +Cc: Dario Binacchi, linux-amarula, Michael Trimarchi

In order to use all the features of KGDB it's nice to have
the possibility to source the vmlinux-gdb.py file. The
generation of this file it's a target of linux kernel. Add it
in order to use gdb of vmlinux in output directory including
tx-* linux script

gdb-multiarch --tui output/build/<linux dir>/vmlinux
add-auto-load-safe-path output/build/<linux dir>
source output/build/<linux dir>/vmlinux-gdb.py

Linux needs to be compiled with DEBUG_INFO (without restrict
DEBUG_INFO) and kernel cmdline should be modified to wait
of kgdb if needed. As example

kgdboc_earlycon=ns16550a kgdboc=/dev/ttyS2 kgdbwait nokaslr

The test was done on am62x board over serial line. In order
to have it running properly we need to compile the agent-proxy

./output/host/bin/agent-proxy 4440 4441 0 /dev/ttyUSB0 115200

gdb can now having the debugging uart available using:

target remote localhost:4441

the 4440 is used by the console and 4441 is used to debug

Tested-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
---
 linux/Config.in | 7 +++++++
 linux/linux.mk  | 7 +++++++
 2 files changed, 14 insertions(+)

diff --git a/linux/Config.in b/linux/Config.in
index ae734c49a0..71ab27bbcb 100644
--- a/linux/Config.in
+++ b/linux/Config.in
@@ -486,6 +486,13 @@ config BR2_LINUX_KERNEL_NEEDS_HOST_PAHOLE
 	  such as "BTF: .tmp_vmlinux.btf: pahole (pahole) is not
 	  available".
 
+config BR2_LINUX_KERNEL_ADD_HOST_GDB_SCRIPTS
+	bool "Need tools for debugging with kgdb"
+	help
+	  Add helping script to be used with gdb and kgdb in order to
+	  debug linux kernel. Those convinients scripts add some feature
+	  command to gdb with specific python script
+
 # Linux extensions
 source "linux/Config.ext.in"
 
diff --git a/linux/linux.mk b/linux/linux.mk
index 1db5c6046d..e8cdb26793 100644
--- a/linux/linux.mk
+++ b/linux/linux.mk
@@ -488,6 +488,12 @@ LINUX_APPEND_DTB += ; \
 endif
 endif
 
+ifeq ($(BR2_LINUX_KERNEL_ADD_HOST_GDB_SCRIPTS),y)
+define LINUX_BUILD_GDB_SCRIPTS
+	$(LINUX_MAKE_ENV) $(BR2_MAKE) $(LINUX_MAKE_FLAGS) -C $(@D) scripts_gdb
+endef
+endif
+
 # Compilation. We make sure the kernel gets rebuilt when the
 # configuration has changed. We call the 'all' and
 # '$(LINUX_TARGET_NAME)' targets separately because calling them in
@@ -503,6 +509,7 @@ define LINUX_BUILD_CMDS
 	$(LINUX_MAKE_ENV) $(BR2_MAKE) $(LINUX_MAKE_FLAGS) -C $(@D) all
 	$(LINUX_MAKE_ENV) $(BR2_MAKE) $(LINUX_MAKE_FLAGS) -C $(@D) $(LINUX_TARGET_NAME)
 	$(LINUX_BUILD_DTB)
+	$(LINUX_BUILD_GDB_SCRIPTS)
 	$(LINUX_APPEND_DTB)
 endef
 
-- 
2.40.1

_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot

^ permalink raw reply related	[flat|nested] 3+ messages in thread