On 01/12, Will Drewry wrote: > > On Thu, Jan 12, 2012 at 11:23 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > > On 01/12, Will Drewry wrote: > >> > >> On Thu, Jan 12, 2012 at 10:22 AM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > >> >> + */ > >> >> + regs = seccomp_get_regs(regs_tmp, ®s_size); > >> > > >> > Stupid question. I am sure you know what are you doing ;) and I know > >> > nothing about !x86 arches. > >> > > >> > But could you explain why it is designed to use user_regs_struct ? > >> > Why we can't simply use task_pt_regs() and avoid the (costly) regsets? > >> > >> So on x86 32, it would work since user_regs_struct == task_pt_regs > >> (iirc), but on x86-64 > >> and others, that's not true. > > > > Yes sure, I meant that userpace should use pt_regs too. > > > >> If it would be appropriate to expose pt_regs to userspace, then I'd > >> happily do so :) > > > > Ah, so that was the reason. But it is already exported? At least I see > > the "#ifndef __KERNEL__" definition in arch/x86/include/asm/ptrace.h. > > > > Once again, I am not arguing, just trying to understand. And I do not > > know if this definition is part of abi. > > I don't either :/ My original idea was to operate on task_pt_regs(current), > but I noticed that PTRACE_GETREGS/SETREGS only uses the > user_regs_struct. So I went that route. Well, I don't know where user_regs_struct come from initially. But probably it is needed to allow to access the "artificial" things like fs_base. Or perhaps this struct mimics the layout in the coredump. > I'd love for pt_regs to be fair game to cut down on the copying! Me too. I see no point in using user_regs_struct. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
