[uClinux-dev] SAVE_STACK_SWITCH in system call.
amit_bhor at hotpop.com
Fri Mar 14 16:12:48 EST 2003
On Fri, 14 Mar 2003 11:22:20 -0800 (PST), Deepa Sivasankarane
<sdeepa69 at yahoo.com> wrote:
> This is the extended stack (switch_stack: asm-m68knommu/include/ptrace.h)
> that gets saved, after pt_regs (SAVE_ALL), before calling signal
> handlers or context switching (within system_call handler).
But in the system call , if and when it sleeps , these registers will be
saved anyways(in SWITCH_TO() ). Like i said, i thought the whole idea was
to *not save* registers that C functions save. So as long as you dont use
these registers in your system call handler,there should not be a need to
save them unless you actually sleep.
> amit bhor <amit_bhor at hotpop.com> wrote:hi,
> I was looking through the uClinux m68k code and i see a SAVE_STACK_SWITCH
> before every system call. I thought the whole idea was to not save the
> scratch registers (callee saved). Am i right here ? I am looking at
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