patch #2 to add pointer to errno in TCB (Re: The time has come for a kernel interfacing library layer)
Sepherosa Ziehau
sepherosa at gmail.com
Tue May 10 03:21:24 PDT 2005
On 5/10/05, YONETANI Tomokazu <qhwt+dfly at xxxxxxxxxx> wrote:
> Not essential for this patch, but before it looses its context,
>
> On Tue, May 10, 2005 at 12:19:27AM -0700, Matthew Dillon wrote:
> > @@ -78,14 +81,7 @@
> > {
> > void *self;
> >
> > -#if 0
> > - __asm __volatile ("movl %%gs:%1, %0"
> > - : "=r" (self)
> > - : "i" (__offsetof(struct tls_tcb, tcb_pthread)));
> > -#else
> > __asm __volatile ("movl %%gs:8, %0" : "=r" (self));
> > -#endif
> > -
> > return(self);
> > }
> >
>
> this part(and other similar parts) could be written to avoid hard-coded
> constants in __asm code by using an "m" constraint and a faked lvalue
> for a member of the structure whose base address is zero:
>
> __asm __volatile ("movl %%gs:%1, %0"
> : "=r" (self)
> : "m" (((struct tls_tcb *)0)->tcb_pthread));
>
Why not move __offsetof() from machine/stdint.h to sys/cdefs.h and
resurrect `#if 0' code in tls.h
--
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