hello:
I use linux-2.4.5 and I think VMALLOC may have some bugs which i don't
know how to fixup.
I try to replace some kernel functions with my own implementations.I
will explain it in the following:
Let's say:
void (*my_func)(void)=func1;
where "my_func" is a function pointer defined in kernel, and "func1" is
a function(void func1(void)) implemented in kernel.And "my_func" is an
EXPORTED SYMBOL in mips_ksyms.c.
Now I want to replace "func1" with my own "func2" in a module
my_module.o:
extern void (*my_func)(void);
my_func = func2;
where "func2" is a function (void fun2(void)) implemented in
"my_module.o".
If I do "insmod my_module.o", the kernel should run OK. In fact, it is
often met an "unhandled kernel unaligned access" or "do_page_fault"
exception and then panics.
We know "func1" should be in KSEG0(unmapped , cached) ,So it's address
should be 0x8XXXXXXX.And "my_func" should also pointed to this same address
before inserting
my_module.o. "func2" should be in KSEG2(mapped, cached) since it is
implemented in module, So it's address should be 0xCXXXXXXX.After inserting
my_module.o, "my_func" should be changed to pointed to this new address in
KSEG2. But kernel panics......
If I change "module_map()" in include/asm/module.h from vmalloc to
kmalloc, kernel runs ok after inserting my module. So I think vmalloc may
have some bugs.
Anyone knows how to fixup it?
machael
