Hi,
I am trying to work in a special configuration where the thread_info is
above the stack pointer. The SP though, start from the 
base stack address + THREAD_SIZE - THREAD_INFO_SECTION_SIZE (that is 128
bytes). 
The INIT_TSS macro looks like:
.esp0           = sizeof(init_stack)-THREAD_INFO_SECTION_SIZE +
(long)&init_stack,      \
So far it works.


When I am trying to move the init_thread_info to the top of the stack
the computer restart itself. What I am doing is replacing the union of
the init_thread_info with the following structure:

-union thread_union {
-        struct thread_info thread_info;
-        unsigned long stack[THREAD_SIZE/sizeof(long)];
-};

+struct thread_union {
+unsigned stack[(THREAD_SIZE-THREAD_INFO_SECTION_SIZE)/sizeof(long)];
+        struct thread_info thread_info;
+};

it means that when I am referencing the thread_info it is in offset
(THREAD_SIZE-THREAD_INFO_SECTION_SIZE)/sizeof(long) and not the base
address as it was when declared with a union.

I have changed other relevant places as in fork.c and so, although the
computer even doesn't start, I think its related to the init thread.
any clues?

-- 
Eliad