Re: [PATCH 2/3] x86: Pass in pt_regs pointer for syscalls that needit
From: Tejun Heo
Date: Wed Feb 11 2009 - 02:42:15 EST
Hello, Brian.
Brian Gerst wrote:
> Some syscalls need to access the pt_regs structure, either to copy
> user register state or to modifiy it. This patch adds stubs to load
> the address of the pt_regs struct into the %eax register, and changes
> the syscalls to regparm(1) to receive the pt_regs pointer as the
> first argument.
Heh... neat. Just one question.
> -asmlinkage long sys_iopl(unsigned long regsp)
> +ptregscall long sys_iopl(struct pt_regs *regs, unsigned int level)
> {
> - struct pt_regs *regs = (struct pt_regs *)®sp;
> - unsigned int level = regs->bx;
Here and at other places where the function takes more than one
arguments, wouldn't it be better to just take *regs and use other
parameters from regs? That way we won't have to worry about gcc
corrupting register frame at all and I think it's cleaner that way.
Thanks.
--
tejun
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