Re: [CONT PROBLEM] 2.4.1-pre3 - Undefined symbol `__buggy_fxsr_alignment'

Shawn Starr
2001-01-12T21:31:10Z

Well, when i Make bzImage it uses -O2 for optimization. Is there any fix? change
the optimization to -O0 ?

Matti Aarnio wrote:

> On Fri, Jan 12, 2001 at 03:02:15PM -0500, Shawn Starr wrote:
> > Nope, its not ;/
> >
> > Im on a Intel Pentium 200Mhz PC, 64MB RAM,
> >
> > init/main.o: In function `check_fpu':
> > init/main.o(.text.init+0x53): undefined reference to `__buggy_fxsr_alignment'
> > make: *** [vmlinux] Error 1
> >
> > same fatal error. Where is this function defined in the i386 asm header?
>
> It should not be present at all in the objects.
> The compiler optimizer should remove that call,
> which is just an example of similar kind of "if
> optimizer fails, here is cannon-fodder to alert
> users about it."
>
> > If so, I could fix this and submit a patch.
>
> > /* Enable FXSR and company _before_ testing for FP problems. */
> > /*
> > * Verify that the FXSAVE/FXRSTOR data will be 16-byte aligned.
> > */
> > if (offsetof(struct task_struct, thread.i387.fxsave) & 15) {
> > extern void __buggy_fxsr_alignment(void);
> > __buggy_fxsr_alignment();
> >
> > Where is this function? Where is it defined? When i grep the whole dir
> > i dont see this function anywhere?
>
> See the comment above the offsetof() call.
> Now think. Figure out why things are at wrong offset.
> Has something been added into task_struct lately ?
> Or to thread_struct, which actually is processor context
> data where this 'thread.i386.fxsave' thing resides ?
>
> Oh yes, if compilation DOES NOT happen with -O flag,
> this will also happen..
>
> > Shawn.
>
> /Matti Aarnio
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