[PATCHv4,01/12] scripts/gdb: Provide linux constants

Commit Message

Kieran Bingham March 30, 2016, noon UTC

Some macro's and defines are needed when parsing memory, and without
compiling the kernel as -g3 they are not available in the debug-symbols.

We use the pre-processor here to extract constants to a dedicated module
for the linux debugger extensions

Top level Kbuild is used to call in and generate the constants file,
while maintaining dependencies on autogenerated files in
include/generated

CC: [e-mail]
CC: [e-mail]

Signed-off-by: Kieran Bingham <[e-mail]>
---
Changes since v1:

Kbuild:
 - Call to generate constants_py with dependancy on generated files

scripts/gdb/linux/Makefile:
 - Use call if_changed, and correct quiet invocation
 - Annouce "GEN  $@" instead of GDB PP

scripts/gdb/linux/constants.py.in:
 - Updated to use better macro implementations for one line defines
---
 Kbuild                            | 10 ++++++++++
 scripts/gdb/linux/Makefile        | 12 +++++++++++-
 scripts/gdb/linux/constants.py.in | 32 ++++++++++++++++++++++++++++++++
 scripts/gdb/vmlinux-gdb.py        |  1 +
 4 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 scripts/gdb/linux/constants.py.in

Comments

Jan Kiszka March 30, 2016, 9:02 p.m. UTC | #1

On 2016-03-30 14:00, Kieran Bingham wrote:
> Some macro's and defines are needed when parsing memory, and without
> compiling the kernel as -g3 they are not available in the debug-symbols.
> 
> We use the pre-processor here to extract constants to a dedicated module
> for the linux debugger extensions
> 
> Top level Kbuild is used to call in and generate the constants file,
> while maintaining dependencies on autogenerated files in
> include/generated
> 
> CC: [e-mail]
> CC: [e-mail]
> 
> Signed-off-by: Kieran Bingham <[e-mail]>
> ---
> Changes since v1:
> 
> Kbuild:
>  - Call to generate constants_py with dependancy on generated files
> 
> scripts/gdb/linux/Makefile:
>  - Use call if_changed, and correct quiet invocation
>  - Annouce "GEN  $@" instead of GDB PP
> 
> scripts/gdb/linux/constants.py.in:
>  - Updated to use better macro implementations for one line defines
> ---

Please only use a single separator line (i.e. remove this one), or the
history blob above makes it into the commit log. But there is no need to
resend if that will remain the only remark.

Jan

Patch

diff --git a/Kbuild b/Kbuild
index f55cefd9bf29..3d0ae152af7c 100644
--- a/Kbuild
+++ b/Kbuild
@@ -5,6 +5,7 @@ 
 # 2) Generate timeconst.h
 # 3) Generate asm-offsets.h (may need bounds.h and timeconst.h)
 # 4) Check for missing system calls
+# 5) Generate constants.py (may need bounds.h)
 
 # Default sed regexp - multiline due to syntax constraints
 define sed-y
@@ -96,5 +97,14 @@  quiet_cmd_syscalls = CALL    $<
 missing-syscalls: scripts/checksyscalls.sh $(offsets-file) FORCE
 	$(call cmd,syscalls)
 
+#####
+# 5) Generate constants for Python GDB integration
+#
+
+extra-$(CONFIG_GDB_SCRIPTS) += build_constants_py
+
+build_constants_py: $(obj)/$(timeconst-file) $(obj)/$(bounds-file)
+	@$(MAKE) $(build)=scripts/gdb/linux $@
+
 # Keep these three files during make clean
 no-clean-files := $(bounds-file) $(offsets-file) $(timeconst-file)
diff --git a/scripts/gdb/linux/Makefile b/scripts/gdb/linux/Makefile
index 6cf1ecf61057..cd129e65d1ff 100644
--- a/scripts/gdb/linux/Makefile
+++ b/scripts/gdb/linux/Makefile
@@ -8,4 +8,14 @@  ifneq ($(KBUILD_SRC),)
 endif
 	@:
 
-clean-files := *.pyc *.pyo $(if $(KBUILD_SRC),*.py)
+quiet_cmd_gen_constants_py = GEN     $@
+      cmd_gen_constants_py = \
+	$(CPP) -E -x c -P $(c_flags) $< > $@ ;\
+	sed -i '1,/<!-- end-c-headers -->/d;' $@
+
+$(obj)/constants.py: $(SRCTREE)/$(obj)/constants.py.in
+	$(call if_changed,gen_constants_py)
+
+build_constants_py: $(obj)/constants.py
+
+clean-files := *.pyc *.pyo $(if $(KBUILD_SRC),*.py) $(obj)/constants.py
diff --git a/scripts/gdb/linux/constants.py.in b/scripts/gdb/linux/constants.py.in
new file mode 100644
index 000000000000..79d9d0092452
--- /dev/null
+++ b/scripts/gdb/linux/constants.py.in
@@ -0,0 +1,32 @@ 
+/*
+ * gdb helper commands and functions for Linux kernel debugging
+ *
+ *  Kernel constants derived from include files.
+ *
+ * Copyright (c) 2016 Linaro Ltd
+ *
+ * Authors:
+ *  Kieran Bingham <[e-mail]>
+ *
+ * This work is licensed under the terms of the GNU GPL version 2.
+ *
+ */
+
+/* We need to stringify expanded macros so that they can be parsed */
+#define STRING(x) #x
+#define XSTRING(x) STRING(x)
+
+#define LX_VALUE(x) LX_##x = x
+#define LX_GDBPARSED(x) LX_##x = gdb.parse_and_eval(XSTRING(x))
+
+/*
+ * IS_ENABLED generates (a || b) which is not compatible with python
+ * We can only switch on configuration items we know are available
+ * Therefore - IS_BUILTIN() is more appropriate
+ */
+#define LX_CONFIG(x) LX_##x = IS_BUILTIN(x)
+
+/* The build system will take care of deleting everything above this marker */
+<!-- end-c-headers -->
+
+import gdb
diff --git a/scripts/gdb/vmlinux-gdb.py b/scripts/gdb/vmlinux-gdb.py
index d5943eca19cd..6e0b0afd888a 100644
--- a/scripts/gdb/vmlinux-gdb.py
+++ b/scripts/gdb/vmlinux-gdb.py
@@ -30,3 +30,4 @@  else:
     import linux.cpus
     import linux.lists
     import linux.proc
+    import linux.constants