In the code of
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
in arch/i386/kernel/process.c
as can be seen in the code here, a system call is made by trigerring the 0x80 interrupt.
this function kernel_thread() is used to launch the init process during booting by
start_kernel() //in init/main.c
But at that time, the process 0 which calls kernel_thread is executing in Kernel mode, so why should some process in kernel mode make a system call??
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
long retval, d0;
__asm__ __volatile__(
"movl %%esp,%%esi\n\t"
"int $0x80\n\t" /* Linux/i386 system call */
"cmpl %%esp,%%esi\n\t" /* child or parent? */
"je 1f\n\t" /* parent - jump */
/* Load the argument into eax, and push it. That way, it does
* not matter whether the called function is compiled with
* -mregparm or not. */
"movl %4,%%eax\n\t"
"pushl %%eax\n\t"
"call *%5\n\t" /* call fn */
"movl %3,%0\n\t" /* exit */
"int $0x80\n"
"1:\t"
:"=&a" (retval), "=&S" (d0)
:"0" (__NR_clone), "i" (__NR_exit),
"r" (arg), "r" (fn),
"b" (flags | CLONE_VM)
: "memory");
return retval;
}
On Sat, Feb 02, 2002 at 10:46:20PM +0530, Alpha Beta wrote:
> In the code of
> int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
> in arch/i386/kernel/process.c
>
> as can be seen in the code here, a system call is made by trigerring the 0x80 interrupt.
> this function kernel_thread() is used to launch the init process during booting by
> start_kernel() //in init/main.c
> But at that time, the process 0 which calls kernel_thread is executing in Kernel mode, so why should some process in kernel mode make a system call??
Easy way to get the registers dumped into memory
--
Mark Zealey
[email protected]
[email protected]
UL++++>$ G!>(GCM/GCS/GS/GM) dpu? s:-@ a16! C++++>$ P++++>+++++$ L+++>+++++$
!E---? W+++>$ N- !o? !w--- O? !M? !V? !PS !PE--@ PGP+? r++ !t---?@ !X---?
!R- b+ !tv b+ DI+ D+? G+++ e>+++++ !h++* r!-- y--
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