leandrof/u-boot
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

doc/qemu_mips: add doc howto debug u-boot with gdb

Browse Source 
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
This commit is contained in:
Jean-Christophe PLAGNIOL-VILLARD 2008-09-02 02:58:32 +02:00 committed by Shinya Kuribayashi
parent 628ffd73bc
commit 7007c5975e
1 changed files with 63 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
doc/README.qemu_mips
View File

@ -1,7 +1,7 @@
Notes for the Qemu MIPS port
Example usage:
I) Example usage:
# ln -s u-boot.bin mips_bios.bin
start it:
@ -16,3 +16,65 @@ create image:
# dd of=flash bs=1k conv=notrunc if=u-boot.bin
start it:
# qemu-system-mips -M mips -pflash flash -monitor null -nographic
II) How to debug U-Boot
In order to debug U-Boot you need to start qemu with gdb server support (-s)
and waiting the connection to start the CPU (-S)
# qemu-system-mips -S -s -M mips -pflash flash -monitor null -nographic
in an other console you start gdb
1) Debugging of U-Boot Before Relocation
Before relocation, the addresses in the ELF file can be used without any problems
buy connecting to the gdb server localhost:1234
# mipsel-unknown-linux-gnu-gdb u-boot
GNU gdb 6.6
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "--host=i486-linux-gnu --target=mipsel-unknown-linux-gnu"...
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
_start () at start.S:64
64 RVECENT(reset,0) /* U-boot entry point */
Current language: auto; currently asm
(gdb) b board.c:289
Breakpoint 1 at 0xbfc00cc8: file board.c, line 289.
(gdb) c
Continuing.
Breakpoint 1, board_init_f (bootflag=<value optimized out>) at board.c:290
290 relocate_code (addr_sp, id, addr);
Current language: auto; currently c
(gdb) p/x addr
$1 = 0x87fa0000
2) Debugging of U-Boot After Relocation
For debugging U-Boot after relocation we need to know the address to which
U-Boot relocates itself to 0x87fa0000 by default.
And replace the symbol table to this offset.
(gdb) symbol-file
Discard symbol table from `/private/u-boot-arm/u-boot'? (y or n) y
Error in re-setting breakpoint 1:
No symbol table is loaded. Use the "file" command.
No symbol file now.
(gdb) add-symbol-file u-boot 0x87fa0000
add symbol table from file "u-boot" at
.text_addr = 0x87fa0000
(y or n) y
Reading symbols from /private/u-boot-arm/u-boot...done.
Breakpoint 1 at 0x87fa0cc8: file board.c, line 289.
(gdb) c
Continuing.
Program received signal SIGINT, Interrupt.
0xffffffff87fa0de4 in udelay (usec=<value optimized out>) at time.c:78
78 while ((tmo - read_c0_count()) < 0x7fffffff)