Commit e05c0e81 authored by Kevin Hao's avatar Kevin Hao Committed by Benjamin Herrenschmidt
Browse files

powerpc: split She math emulation into two parts 



For some SoC (such as the FSL BookE) even though there does have
a hardware FPU, but not all floating point instructions are
implemented. Unfortunately some versions of gcc do use these
unimplemented instructions. Then we have to enable the math emulation
to workaround this issue. It seems a little redundant to have the
support to emulate all the floating point instructions in this case.
So split the math emulation into two parts. One is for the SoC which
doesn't have FPU at all and the other for the SoC which does have the
hardware FPU and only need some special floating point instructions to
be emulated.

Signed-off-by: default avatarKevin Hao <haokexin@gmail.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 3a3b5aa6

arch/powerpc/Kconfig

+20 −0
Original line number Diff line number Diff line
@@ -312,6 +312,26 @@ config MATH_EMULATION 
	  such as fsqrt on cores that do have an FPU but do not implement

	  them (such as Freescale BookE).



choice

	prompt "Math emulation options"

	default MATH_EMULATION_FULL

	depends on MATH_EMULATION



config	MATH_EMULATION_FULL

	bool "Emulate all the floating point instructions"

	---help---

	  Select this option will enable the kernel to support to emulate

	  all the floating point instructions. If your SoC doesn't have

	  a FPU, you should select this.



config MATH_EMULATION_HW_UNIMPLEMENTED

	bool "Just emulate the FPU unimplemented instructions"

	---help---

	  Select this if you know there does have a hardware FPU on your

	  SoC, but some floating point instructions are not implemented by that.



endchoice



config PPC_TRANSACTIONAL_MEM

       bool "Transactional Memory support for POWERPC"

       depends on PPC_BOOK3S_64

arch/powerpc/math-emu/Makefile

+12 −12
Original line number Diff line number Diff line 


obj-$(CONFIG_MATH_EMULATION)	+= fabs.o fadd.o fadds.o fcmpo.o fcmpu.o \

					fctiw.o fctiwz.o fdiv.o fdivs.o \

					fmadd.o fmadds.o fmsub.o fmsubs.o \

					fmul.o fmuls.o fnabs.o fneg.o \

					fnmadd.o fnmadds.o fnmsub.o fnmsubs.o \

					fres.o fre.o frsp.o fsel.o lfs.o \

					frsqrte.o frsqrtes.o \

					fsqrt.o	fsqrts.o fsub.o fsubs.o \

					mcrfs.o mffs.o mtfsb0.o mtfsb1.o \

					mtfsf.o mtfsfi.o stfiwx.o stfs.o \

					math.o fmr.o lfd.o stfd.o

math-emu-common-objs = math.o fre.o fsqrt.o fsqrts.o frsqrtes.o mtfsf.o mtfsfi.o

obj-$(CONFIG_MATH_EMULATION_HW_UNIMPLEMENTED) += $(math-emu-common-objs)

obj-$(CONFIG_MATH_EMULATION_FULL) += $(math-emu-common-objs) fabs.o fadd.o \

					fadds.o fcmpo.o fcmpu.o fctiw.o \

					fctiwz.o fdiv.o fdivs.o  fmadd.o \

					fmadds.o fmsub.o fmsubs.o fmul.o \

					fmuls.o fnabs.o fneg.o fnmadd.o \

					fnmadds.o fnmsub.o fnmsubs.o fres.o \

					frsp.o fsel.o lfs.o frsqrte.o fsub.o \

					fsubs.o  mcrfs.o mffs.o mtfsb0.o \

					mtfsb1.o stfiwx.o stfs.o math.o \

					fmr.o lfd.o stfd.o



obj-$(CONFIG_SPE)		+= math_efp.o

arch/powerpc/math-emu/math.c

+14 −6
Original line number Diff line number Diff line
@@ -13,6 +13,20 @@ 


#define FLOATFUNC(x)	extern int x(void *, void *, void *, void *)



/* The instructions list which may be not implemented by a hardware FPU */

FLOATFUNC(fre);

FLOATFUNC(frsqrtes);

FLOATFUNC(fsqrt);

FLOATFUNC(fsqrts);

FLOATFUNC(mtfsf);

FLOATFUNC(mtfsfi);



#ifdef CONFIG_MATH_EMULATION_HW_UNIMPLEMENTED

#undef FLOATFUNC(x)

#define FLOATFUNC(x)	static inline int x(void *op1, void *op2, void *op3, \

						 void *op4) { }

#endif



FLOATFUNC(fadd);

FLOATFUNC(fadds);

FLOATFUNC(fdiv);
@@ -42,8 +56,6 @@ FLOATFUNC(mcrfs); 
FLOATFUNC(mffs);

FLOATFUNC(mtfsb0);

FLOATFUNC(mtfsb1);

FLOATFUNC(mtfsf);

FLOATFUNC(mtfsfi);



FLOATFUNC(lfd);

FLOATFUNC(lfs);
@@ -58,13 +70,9 @@ FLOATFUNC(fnabs); 
FLOATFUNC(fneg);



/* Optional */

FLOATFUNC(fre);

FLOATFUNC(fres);

FLOATFUNC(frsqrte);

FLOATFUNC(frsqrtes);

FLOATFUNC(fsel);

FLOATFUNC(fsqrt);

FLOATFUNC(fsqrts);





#define OP31		0x1f		/*   31 */

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