On Thu, Jul 11, 2013 at 10:45:21PM +1000, Benjamin Herrenschmidt wrote: > On Thu, 2013-07-11 at 20:21 +0800, Kevin Hao wrote: > > Some cores (such as Freescale BookE) don't implement all floating > > point instructions in ISA. But some gcc versions do use these > > instructions. So we would have to enable the math emulation in this > > case. Add this to emulated instructions tracking statistics so that > > the user has a way to know that its toolcahin emit these unimplemented > > floating point instructions. > > That patch is gross, it makes the function even more nasty than it > already is. Besides, CONFIG_PPC_FPU doesn't mean you have a HW FPU, > you need to check the CPU feature bits. > > Also the caller already does PPC_WARN_EMULATED, so this patch makes > you call it twice or am I missing something ?
There are two invocations of do_mathemu() in the traps.c. The one in the
function program_check_exception() doesn't call the PPC_WARN_EMULATED.
This is also the one I try to fix. Of course my patch will definitely corrupt
the one in function SoftwareEmulation(). I will respin a new patch to
fix this. Sorry for my mistake.
Thanks,
Kevin
>
> Cheers,
> Ben.
>
> > Signed-off-by: Kevin Hao <haoke...@gmail.com>
> > ---
> > arch/powerpc/math-emu/math.c | 50
> > +++++++++++++++++++++++++++-----------------
> > 1 file changed, 31 insertions(+), 19 deletions(-)
> >
> > diff --git a/arch/powerpc/math-emu/math.c b/arch/powerpc/math-emu/math.c
> > index 18ce6a7..9a98b6c 100644
> > --- a/arch/powerpc/math-emu/math.c
> > +++ b/arch/powerpc/math-emu/math.c
> > @@ -10,6 +10,7 @@
> >
> > #include <asm/sfp-machine.h>
> > #include <math-emu/double.h>
> > +#include <asm/emulated_ops.h>
> >
> > #define FLOATFUNC(x) extern int x(void *, void *, void *, void *)
> >
> > @@ -222,10 +223,17 @@ do_mathemu(struct pt_regs *regs)
> > int idx = 0;
> > int (*func)(void *, void *, void *, void *);
> > int type = 0;
> > - int eflag, trap;
> > + int eflag, trap, ret = -ENOSYS;
> > + int has_hw_fpu = 0;
> >
> > - if (get_user(insn, (u32 *)pc))
> > - return -EFAULT;
> > +#ifdef CONFIG_PPC_FPU
> > + has_hw_fpu = 1;
> > +#endif
> > +
> > + if (get_user(insn, (u32 *)pc)) {
> > + ret = -EFAULT;
> > + goto out;
> > + }
> >
> > switch (insn >> 26) {
> > case LFS: func = lfs; type = D; break;
> > @@ -249,7 +257,7 @@ do_mathemu(struct pt_regs *regs)
> > case STFDUX: func = stfd; type = XEU; break;
> > case STFIWX: func = stfiwx; type = XE; break;
> > default:
> > - goto illegal;
> > + goto out;
> > }
> > break;
> >
> > @@ -267,7 +275,7 @@ do_mathemu(struct pt_regs *regs)
> > case FNMSUBS: func = fnmsubs; type = ABC; break;
> > case FNMADDS: func = fnmadds; type = ABC; break;
> > default:
> > - goto illegal;
> > + goto out;
> > }
> > break;
> >
> > @@ -287,7 +295,7 @@ do_mathemu(struct pt_regs *regs)
> > case FNMSUB: func = fnmsub; type = ABC; break;
> > case FNMADD: func = fnmadd; type = ABC; break;
> > default:
> > - goto illegal;
> > + goto out;
> > }
> > break;
> > }
> > @@ -309,12 +317,12 @@ do_mathemu(struct pt_regs *regs)
> > case MFFS: func = mffs; type = X; break;
> > case MTFSF: func = mtfsf; type = XFLB; break;
> > default:
> > - goto illegal;
> > + goto out;
> > }
> > break;
> >
> > default:
> > - goto illegal;
> > + goto out;
> > }
> >
> > switch (type) {
> > @@ -347,7 +355,7 @@ do_mathemu(struct pt_regs *regs)
> > case DU:
> > idx = (insn >> 16) & 0x1f;
> > if (!idx)
> > - goto illegal;
> > + goto out;
> >
> > sdisp = (insn & 0xffff);
> > op0 = (void *)¤t->thread.TS_FPR((insn >> 21) & 0x1f);
> > @@ -375,7 +383,7 @@ do_mathemu(struct pt_regs *regs)
> > if (((insn >> 1) & 0x3ff) == STFIWX)
> > op1 = (void *)(regs->gpr[(insn >> 11) & 0x1f]);
> > else
> > - goto illegal;
> > + goto out;
> > } else {
> > op1 = (void *)(regs->gpr[idx] + regs->gpr[(insn >> 11)
> > & 0x1f]);
> > }
> > @@ -417,7 +425,7 @@ do_mathemu(struct pt_regs *regs)
> > break;
> >
> > default:
> > - goto illegal;
> > + goto out;
> > }
> >
> > /*
> > @@ -425,9 +433,8 @@ do_mathemu(struct pt_regs *regs)
> > * if flushed into the thread_struct before attempting
> > * emulation
> > */
> > -#ifdef CONFIG_PPC_FPU
> > - flush_fp_to_thread(current);
> > -#endif
> > + if (has_hw_fpu)
> > + flush_fp_to_thread(current);
> >
> > eflag = func(op0, op1, op2, op3);
> >
> > @@ -437,8 +444,10 @@ do_mathemu(struct pt_regs *regs)
> > }
> >
> > trap = record_exception(regs, eflag);
> > - if (trap)
> > - return 1;
> > + if (trap) {
> > + ret = 1;
> > + goto out;
> > + }
> >
> > switch (type) {
> > case DU:
> > @@ -451,8 +460,11 @@ do_mathemu(struct pt_regs *regs)
> > }
> >
> > regs->nip += 4;
> > - return 0;
> > + ret = 0;
> > +
> > +out:
> > + if (has_hw_fpu && ret >= 0)
> > + PPC_WARN_EMULATED(math, regs);
> >
> > -illegal:
> > - return -ENOSYS;
> > + return ret;
> > }
>
>
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