When your emulator is connected at reset (or is used to load u-boot) it is possible to get the relocation address from the parameter passed to relocate_code() instead of building with -DDEBUG and extracting from the console messages.
Document this alternate method following the style of the original method written by Heiko Schocher.
Signed-off-by: Ben Gardiner bengardiner@nanometrics.ca CC: Heiko Schocher hs@denx.de --- doc/README.arm-relocation | 56 +++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 56 insertions(+), 0 deletions(-)
diff --git a/doc/README.arm-relocation b/doc/README.arm-relocation index c0957c2..1c2d783 100644 --- a/doc/README.arm-relocation +++ b/doc/README.arm-relocation @@ -192,3 +192,59 @@ Now running in RAM - U-Boot at: 8ff08000 ^^^^^^^^
Now you can use gdb as usual :-) + +An alternative to retrieving the relocated base address from the debug printfs +is to evaluate the 'addr' parameter of relocate_code() and use its value as the +argument to add-symbol-file. This method is only available when your emulator +is connected to the target on reset. + +----------------- + +a) [different than above] Compile as usual -- adding -DDEBUG can change the +relocated base address, this method will work on builds that do not have any +extra verbosity on boot + +----------------- +b) [same as above] start debugger +c) [same as above] connect to target +[remainder is different than above] +----------------- + +d) set breakpoint on relocate_code + +(gdb) b relocate_code +Breakpoint 1 at 0xc1080078: file start.S, line 196. + +----------------- + +e) run target until relocate_code + +(gdb) c +Breakpoint 2, relocate_code () at start.S:197 +197 mov r5, r1 /* save addr of gd */ +(gdb) d +Delete all breakpoints? (y or n) y + +----------------- + +f) discard symbol file + +(gdb) symbol-file +Discard symbol table from `/home/bengardiner/src/u-boot/u-boot'? (y or n) y +No symbol file now. +(gdb) + +----------------- + +g) load new symbol table using the addr parameter (aka $r2) + +(gdb) add-symbol-file u-boot $r2 +add symbol table from file "u-boot" at + .text_addr = 0xc7f53000 +(y or n) y +Reading symbols from /home/bengardiner/src/u-boot/u-boot...done. + +----------------- + +h) set breakpoints for any function after (and including) board_init_r +