The gdb operations using string-alike arguments require that the attached application implemented the funcion malloc. If not, the operations will fail and return the message: evaluation of this expression requires the program to have a function "malloc".
String-alike arguments are convenient for debugging, kernel-malloc-kgdb implement the funcions of malloc() and free() to support them.
kernel-malloc-kgdb uses a global char array as the memory area for sbrk(), the size is 8M.
GDB failed operations examples:
>>> p boot_command_line
$3 = 0x8094f014 <boot_command_line> "loglevel=0 root=/dev/mmcblk0 console=ttyAMA0"
>>> call strcmp("good",boot_command_line)
evaluation of this expression requires the program to have a function "malloc".
>>> find boot_command_line,+0x100,{char[7]}"console"
A syntax error in expression, near `sizeof("console"]}"console"'.GDB sucessful operations examples:
>>> p boot_command_line
$3 = 0x8094f014 <boot_command_line> "loglevel=0 root=/dev/mmcblk0 console=ttyAMA0"
>>> call strcmp("good",boot_command_line)
$4 = -1
>>> find boot_command_line,+0x100,{char[7]}"console"
0x8094f031 <boot_command_line+29>
1 pattern found.Suggest to put malloc.c into <kernel_root>/mm direcotry.
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