[PATCH v4 00/15] GDB script fixes and improvements

[Glenn Washburn]

v4 changes:
  * Fix issue where load_all_modules was only loading the last already loaded
    module.
  * Drastically simply runtime_load_module by using hardware break instead
    of software break. The previous work around didn't seem to be reliable on
    QEMU either.
  * Move early initialization symbol loading for i386-pc into its own patch
v3 changes:
  * Rebase on to latest master
  * Use correct automake macro for target cpu

There's been a lot of changes since v1. There are more fixes and more
features. The majority of the shell code has been moved to an external
file named gdb_helper.sh, instead of being inline in the GDB script. The
one (direct) PERL dependency in GRUB has been removed and converted to
shell script. Also a section on debugging is added to the developer docs.

Glenn

Glenn Washburn (15):
  gdb: Fix redirection issue in dump_module_sections
  gdb: Prevent wrapping when writing to .segments.tmp
  gdb: If no modules have been loaded, do not try to load module symbols
  gdb: Move runtime module loading into runtime_load_module
  gdb: Reliably load modules in runtime_load_module
  gdb: Add functions to make loading from dynamically positioned targets
    easier
  gdb: Remove Perl dependency for GRUB GDB script
  gdb: If enabled, print line used to load EFI kernel symbols when using
    gdb_grub script
  gdb: Conditionally run GDB script logic for dynamically or statically
    positioned GRUB
  gdb: Only connect to remote target once when first sourced
  gdb: Allow user defined "onload_<modname>" command to be run when
    module is loaded
  gdb: Allow running user-defined commands at GRUB start
  gdb: Add extra early initialization symbols for i386-pc
  gdb: Add ability to turn on shell tracing for gdb helper script
  docs: Add debugging chapter to development documentation

 config.h.in                 |   3 +
 docs/grub-dev.texi          | 191 ++++++++++++++++++++++++++++++++++++
 grub-core/Makefile.core.def |   4 +-
 grub-core/gdb_grub.in       | 162 +++++++++++++++++++++++++-----
 grub-core/gdb_helper.sh.in  | 108 ++++++++++++++++++++
 grub-core/gmodule.pl.in     |  30 ------
 grub-core/kern/efi/efi.c    |   4 +-
 grub-core/kern/efi/init.c   |  19 +++-
 include/grub/efi/efi.h      |   2 +-
 9 files changed, 465 insertions(+), 58 deletions(-)
 create mode 100644 grub-core/gdb_helper.sh.in
 delete mode 100644 grub-core/gmodule.pl.in

Range-diff against v3:
 1:  ec2b71c403 !  1:  9f273b8fa5 gdb: Fix redirection issue in 
dump_module_sections
    @@ Commit message
         which does the redirection and undoes the redirection when it finishes
         regardless of any errors in the command.
     
    +    Also, remove .segments.tmp file prior to loading modules in case one 
was
    +    left from a previous run.
    +
      ## grub-core/gdb_grub.in ##
     @@
      ###
    @@ grub-core/gdb_grub.in: define dump_module_sections
     -  set logging off
     -  # FIXME: restore logging status
     +define dump_module_sections
    -+  pipe dump_module_sections_helper $arg0 | sh -c 'cat >.segments.tmp'
    ++  pipe dump_module_sections_helper $arg0 | sh -c 'cat >>.segments.tmp'
      end
      document dump_module_sections
        Gather information about module whose mod structure was
    +@@ grub-core/gdb_grub.in: document load_module
    + end
    + 
    + define load_all_modules
    ++  shell rm -f .segments.tmp
    +   set $this = grub_dl_head
    +   while ($this != 0)
    +           dump_module_sections $this
 2:  f350ddf3c9 !  2:  85f68a8369 gdb: Prevent wrapping when writing to 
.segments.tmp
    @@ grub-core/gdb_grub.in: define dump_module_sections_helper
     +  # to .segments.tmp
     +  with width 0 -- \
     +  with trace-commands off -- \
    -   pipe dump_module_sections_helper $arg0 | sh -c 'cat >.segments.tmp'
    +   pipe dump_module_sections_helper $arg0 | sh -c 'cat >>.segments.tmp'
      end
      document dump_module_sections
 3:  75949e0d8e =  3:  88b3973cdb gdb: If no modules have been loaded, do not 
try to load module symbols
 4:  ed5599b842 =  4:  c0d7da87a8 gdb: Move runtime module loading into 
runtime_load_module
 5:  e00aa463bb <  -:  ---------- gdb: Get correct mod variable value
 6:  c1e0439012 <  -:  ---------- gdb: Do not run load_module if module has 
already been loaded
 -:  ---------- >  5:  4712465374 gdb: Reliably load modules in 
runtime_load_module
 7:  dc8ce82e27 =  6:  283021b7b9 gdb: Add functions to make loading from 
dynamically positioned targets easier
 8:  dc7338f00a =  7:  8f4b7c3bbd gdb: Remove Perl dependency for GRUB GDB 
script
 9:  0ee5cb7cc1 =  8:  055e968779 gdb: If enabled, print line used to load EFI 
kernel symbols when using gdb_grub script
10:  7ec11bff7e =  9:  64eccfc37e gdb: Conditionally run GDB script logic for 
dynamically or statically positioned GRUB
11:  e62defbaa7 = 10:  5064458dfd gdb: Only connect to remote target once when 
first sourced
12:  0101c41233 = 11:  c33e8f57b4 gdb: Allow user defined "onload_<modname>" 
command to be run when module is loaded
13:  94f4707b14 ! 12:  f8a26f3a56 gdb: Allow running user-defined commands at 
GRUB start
    @@ grub-core/gdb_grub.in: end
        # We may have been very late to loading the kernel.exec symbols and
        # and modules may already be loaded. So load symbols for any already
        # loaded.
    -@@ grub-core/gdb_grub.in: document num_modules
    -   Given a module name print its address or NULL if not loaded.
    +@@ grub-core/gdb_grub.in: document runtime_load_module
    +   Load module symbols at runtime as they are loaded.
      end
      
     +define run_on_start
    @@ grub-core/gdb_grub.in: document num_modules
      ###
      
      set confirm off
    -@@ grub-core/gdb_grub.in: set confirm off
    - # fail.
    - 
    - set $platform_efi = $_streq("@platform@", "efi")
    -+set $target = "@target_cpu@-@platform@"
    - 
    - if ! $runonce
    -   if $platform_efi
    -           # Only load the executable file, not the symbols
    +@@ grub-core/gdb_grub.in: if ! $runonce
                exec-file kernel.exec
        else
    -+          if $_streq($target, "i386-pc")
    -+                  add-symbol-file boot.image
    -+                  add-symbol-file diskboot.image
    -+                  add-symbol-file lzma_decompress.image
    -+          end
                file kernel.exec
     +          run_on_start
                runtime_load_module
 -:  ---------- > 13:  fbd217a89c gdb: Add extra early initialization symbols 
for i386-pc
14:  5fbef49d07 = 14:  973f24a485 gdb: Add ability to turn on shell tracing for 
gdb helper script
15:  b1f6f5861b = 15:  d6c6947762 docs: Add debugging chapter to development 
documentation
-- 
2.34.1