[ros-dev] Kernel-mode stack layout (FPU save area, trap frames,
blight at blight.eu.org
Thu Oct 21 17:47:51 CEST 2004
I have changed all the places you mentioned (I hope) and even more - still the
area gets written into... when I did a backtrace from the place where the
memory was written it seemed to be in irq_handler_0. I did not see where the
CPU was pointed to a TSS which it would take the stack pointer for the irq
handler from, but I have changed all places where a stack pointer is setup in
a TSS I think.
I have attached the changes which I have made so far, it's very unstable, some
things are wrong and it does none of the important work (fsave on taskswitch
is commented out because it crashed everytime, frstor with a corrupted FPU
save area caused math-faults to raise after the not-present fault which also
crashed somewhere in KiDispatchException - maybe because they were raised in
KernelMode and not handled, so I replaced it by finit for now, ...)
In ke/i386/exp.c ExceptionToNtStatus and ExceptionTypeStrings are wrong I
think, interrupt #15 is reserved by intel, #16 is math fault and #17 is
alignment check. At the moment #15 is missing in the table, so #15 is math
fault, #16 is alignment check and so on.
Maybe "if (ExceptionNr < 16)" (around line 170) should be changed to something
like "if (ExceptionNr < ARRAY_SIZE(ExceptionToNtStatus)" (there are two other
places where "ExceptionNr < 19" is hardcoded, and we could use "ExceptionNr <
Do we have any macro like ARRAY_SIZE(x) (sizeof(x) / sizeof(x)) ?
I was also wondering about line 137 in tss.c (Tss->Esp0 =
(ULONG)Ki386InitialStackArray[Id];) because it sets the stack pointer of the
Tss to Ki386InitialStackArray[Id], which is set to &init stack on line 217
(Ki386InitialStackArray = (PVOID)&init_stack;) - shouldn't it be set to
On Saturday 16 October 2004 14:33, Hartmut Birr wrote:
> you must change all position where a kernel stack is initialized:
> - In multiboot.S is setup the initial stack
> - In tss.c is setup the tss with the initial stack
> - In w32call.c is setup a new kernel stack for the callback function.
> - In kthread.c are setup some values on the top of the stack
> - In bthread.S starts the execution of a new thread
> It seems that you have changed only the last two points. The size of the
> stack must not be changed.
> - Hartmut
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