[v4,01/13] scripts/gdb: Add infrastructure
diff mbox

Message ID 1e49f090f16f3e22711a27f473e2ed604f6a249f.1358787929.git.jan.kiszka@siemens.com
State New, archived
Headers show

Commit Message

Jan Kiszka Jan. 21, 2013, 5:06 p.m. UTC
This provides the basic infrastructure to load kernel-specific python
helper scripts when debugging the kernel in gdb.

The loading mechanism is based on gdb loading for <objfile>-gdb.py when
opening <objfile>. Therefore, this places a corresponding link to the
main helper script into the output directory that contains vmlinux.

The main scripts will pull in submodules containing Linux specific gdb
commands and functions. To avoid polluting the source directory with
compiled python modules, we link to them from the object directory.

Due to gdb.parse_and_eval, we depend on gdb >= 7.1. We need to
pre-process the version string returned by gdb as some distros tend to
prefix it with their name.

This feature depends on CONFIG_DEBUG_INFO.

CC: Michal Marek <mmarek@suse.cz>
CC: linux-kbuild@vger.kernel.org
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 Makefile                   |    5 ++++-
 scripts/Makefile           |    3 ++-
 scripts/gdb/Makefile       |    9 +++++++++
 scripts/gdb/utils.py       |   17 +++++++++++++++++
 scripts/gdb/vmlinux-gdb.py |   22 ++++++++++++++++++++++
 5 files changed, 54 insertions(+), 2 deletions(-)
 create mode 100644 scripts/gdb/Makefile
 create mode 100644 scripts/gdb/utils.py
 create mode 100644 scripts/gdb/vmlinux-gdb.py

Comments

Borislav Petkov Jan. 23, 2013, 11:41 a.m. UTC | #1
On Mon, Jan 21, 2013 at 06:06:08PM +0100, Jan Kiszka wrote:
> This provides the basic infrastructure to load kernel-specific python
> helper scripts when debugging the kernel in gdb.
> 
> The loading mechanism is based on gdb loading for <objfile>-gdb.py when
> opening <objfile>. Therefore, this places a corresponding link to the
> main helper script into the output directory that contains vmlinux.
> 
> The main scripts will pull in submodules containing Linux specific gdb
> commands and functions. To avoid polluting the source directory with
> compiled python modules, we link to them from the object directory.
> 
> Due to gdb.parse_and_eval, we depend on gdb >= 7.1. We need to
> pre-process the version string returned by gdb as some distros tend to
> prefix it with their name.
> 
> This feature depends on CONFIG_DEBUG_INFO.
> 
> CC: Michal Marek <mmarek@suse.cz>
> CC: linux-kbuild@vger.kernel.org
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>  Makefile                   |    5 ++++-
>  scripts/Makefile           |    3 ++-
>  scripts/gdb/Makefile       |    9 +++++++++
>  scripts/gdb/utils.py       |   17 +++++++++++++++++
>  scripts/gdb/vmlinux-gdb.py |   22 ++++++++++++++++++++++
>  5 files changed, 54 insertions(+), 2 deletions(-)
>  create mode 100644 scripts/gdb/Makefile
>  create mode 100644 scripts/gdb/utils.py
>  create mode 100644 scripts/gdb/vmlinux-gdb.py
> 
> diff --git a/Makefile b/Makefile
> index 253a455..fb18794 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -774,6 +774,9 @@ endif
>  ifdef CONFIG_BUILD_DOCSRC
>  	$(Q)$(MAKE) $(build)=Documentation
>  endif
> +ifdef CONFIG_DEBUG_INFO
> +	$(Q)ln -fsn $(srctree)/scripts/gdb/vmlinux-gdb.py
> +endif

I'm wondering whether it won't be a better idea to make this symlink
creation in the toplevel directory only when a user requires it.. I.e.,
not simply when CONFIG_DEBUG_INFO is enabled (it could be enabled for a
lot and different reasons) but only when user wants to really debug the
kernel with gdb.

Then, having a specific make target could arrange for all the setup like
the symlink, gdb version checking, etc, maybe something like this:

$ make gdb

and all is prepared (or errored out with a sensible message).

Hmm....
Jan Kiszka Jan. 23, 2013, 11:44 a.m. UTC | #2
On 2013-01-23 12:41, Borislav Petkov wrote:
> On Mon, Jan 21, 2013 at 06:06:08PM +0100, Jan Kiszka wrote:
>> This provides the basic infrastructure to load kernel-specific python
>> helper scripts when debugging the kernel in gdb.
>>
>> The loading mechanism is based on gdb loading for <objfile>-gdb.py when
>> opening <objfile>. Therefore, this places a corresponding link to the
>> main helper script into the output directory that contains vmlinux.
>>
>> The main scripts will pull in submodules containing Linux specific gdb
>> commands and functions. To avoid polluting the source directory with
>> compiled python modules, we link to them from the object directory.
>>
>> Due to gdb.parse_and_eval, we depend on gdb >= 7.1. We need to
>> pre-process the version string returned by gdb as some distros tend to
>> prefix it with their name.
>>
>> This feature depends on CONFIG_DEBUG_INFO.
>>
>> CC: Michal Marek <mmarek@suse.cz>
>> CC: linux-kbuild@vger.kernel.org
>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>> ---
>>  Makefile                   |    5 ++++-
>>  scripts/Makefile           |    3 ++-
>>  scripts/gdb/Makefile       |    9 +++++++++
>>  scripts/gdb/utils.py       |   17 +++++++++++++++++
>>  scripts/gdb/vmlinux-gdb.py |   22 ++++++++++++++++++++++
>>  5 files changed, 54 insertions(+), 2 deletions(-)
>>  create mode 100644 scripts/gdb/Makefile
>>  create mode 100644 scripts/gdb/utils.py
>>  create mode 100644 scripts/gdb/vmlinux-gdb.py
>>
>> diff --git a/Makefile b/Makefile
>> index 253a455..fb18794 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -774,6 +774,9 @@ endif
>>  ifdef CONFIG_BUILD_DOCSRC
>>  	$(Q)$(MAKE) $(build)=Documentation
>>  endif
>> +ifdef CONFIG_DEBUG_INFO
>> +	$(Q)ln -fsn $(srctree)/scripts/gdb/vmlinux-gdb.py
>> +endif
> 
> I'm wondering whether it won't be a better idea to make this symlink
> creation in the toplevel directory only when a user requires it.. I.e.,
> not simply when CONFIG_DEBUG_INFO is enabled (it could be enabled for a
> lot and different reasons) but only when user wants to really debug the
> kernel with gdb.
> 
> Then, having a specific make target could arrange for all the setup like
> the symlink, gdb version checking, etc, maybe something like this:
> 
> $ make gdb
> 
> and all is prepared (or errored out with a sensible message).
> 
> Hmm....

I wonder why we should do this, remove the convenience of the automatic
script setup, but I'm open for arguments.

Jan
Borislav Petkov Jan. 23, 2013, 12:01 p.m. UTC | #3
On Wed, Jan 23, 2013 at 12:44:04PM +0100, Jan Kiszka wrote:
> I wonder why we should do this, remove the convenience of the
> automatic script setup, but I'm open for arguments.

Only one: you get the symlink

vmlinux-gdb.py -> /..../scripts/gdb/vmlinux-gdb.py

created automatically when CONFIG_DEBUG_INFO is enabled and people who
enable CONFIG_DEBUG_INFO for other reasons and don't want to use gdb to
debug the kernel don't need it but will get it anyway.
Jan Kiszka Jan. 23, 2013, 12:04 p.m. UTC | #4
On 2013-01-23 13:01, Borislav Petkov wrote:
> On Wed, Jan 23, 2013 at 12:44:04PM +0100, Jan Kiszka wrote:
>> I wonder why we should do this, remove the convenience of the
>> automatic script setup, but I'm open for arguments.
> 
> Only one: you get the symlink
> 
> vmlinux-gdb.py -> /..../scripts/gdb/vmlinux-gdb.py
> 
> created automatically when CONFIG_DEBUG_INFO is enabled and people who
> enable CONFIG_DEBUG_INFO for other reasons and don't want to use gdb to
> debug the kernel don't need it but will get it anyway.

A lot of stuff is generated in the output directories during the kernel
build, so I wonder if this one really matters.

Jan

Patch
diff mbox

diff --git a/Makefile b/Makefile
index 253a455..fb18794 100644
--- a/Makefile
+++ b/Makefile
@@ -774,6 +774,9 @@  endif
 ifdef CONFIG_BUILD_DOCSRC
 	$(Q)$(MAKE) $(build)=Documentation
 endif
+ifdef CONFIG_DEBUG_INFO
+	$(Q)ln -fsn $(srctree)/scripts/gdb/vmlinux-gdb.py
+endif
 	+$(call if_changed,link-vmlinux)
 
 # The actual objects are generated when descending, 
@@ -1019,7 +1022,7 @@  MRPROPER_FILES += .config .config.old .version .old_version $(version_h) \
 		  Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS \
 		  signing_key.priv signing_key.x509 x509.genkey		\
 		  extra_certificates signing_key.x509.keyid		\
-		  signing_key.x509.signer
+		  signing_key.x509.signer vmlinux-gdb.py
 
 # clean - Delete most, but leave enough to build external modules
 #
diff --git a/scripts/Makefile b/scripts/Makefile
index 01e7adb..3204b91 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -37,6 +37,7 @@  subdir-$(CONFIG_MODVERSIONS) += genksyms
 subdir-y                     += mod
 subdir-$(CONFIG_SECURITY_SELINUX) += selinux
 subdir-$(CONFIG_DTC)         += dtc
+subdir-$(CONFIG_DEBUG_INFO)  += gdb
 
 # Let clean descend into subdirs
-subdir-	+= basic kconfig package selinux
+subdir-	+= basic kconfig package selinux gdb
diff --git a/scripts/gdb/Makefile b/scripts/gdb/Makefile
new file mode 100644
index 0000000..34ccd06
--- /dev/null
+++ b/scripts/gdb/Makefile
@@ -0,0 +1,9 @@ 
+always := gdb-scripts
+
+$(obj)/gdb-scripts:
+ifneq ($(KBUILD_SRC),)
+	$(Q)ln -fsn $(srctree)/$(obj)/*.py $(objtree)/$(obj)
+endif
+	@:
+
+clean-files := *.pyc $(if $(KBUILD_SRC),*.py)
diff --git a/scripts/gdb/utils.py b/scripts/gdb/utils.py
new file mode 100644
index 0000000..65a2e91
--- /dev/null
+++ b/scripts/gdb/utils.py
@@ -0,0 +1,17 @@ 
+#
+# gdb helper commands and functions for Linux kernel debugging
+#
+#  common utilities
+#
+# Copyright (c) Siemens AG, 2011, 2012
+#
+# Authors:
+#  Jan Kiszka <jan.kiszka@siemens.com>
+#
+# This work is licensed under the terms of the GNU GPL version 2.
+#
+
+import gdb
+import re
+
+gdb_version = re.sub("^[^0-9]*", "", gdb.VERSION)
diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py
new file mode 100644
index 0000000..bcb45cc
--- /dev/null
+++ b/scripts/gdb/vmlinux-gdb.py
@@ -0,0 +1,22 @@ 
+#
+# gdb helper commands and functions for Linux kernel debugging
+#
+#  loader module
+#
+# Copyright (c) Siemens AG, 2012
+#
+# Authors:
+#  Jan Kiszka <jan.kiszka@siemens.com>
+#
+# This work is licensed under the terms of the GNU GPL version 2.
+#
+
+import os
+
+sys.path = [ os.path.dirname(__file__) + "/scripts/gdb" ] + sys.path
+
+from utils import gdb_version
+
+if gdb_version < "7.1":
+	print "NOTE: gdb 7.1 or later required for Linux helper scripts " \
+	      "to work."