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Commit f148af25 authored by Richard Purdie's avatar Richard Purdie Committed by Russell King
Browse files

[PATCH] ARM: 2837/2: Re: ARM: Make NWFPE preempt safe 



Patch from Richard Purdie

NWFPE used global variables which meant it wasn't safe for use with
preemptive kernels. This patch removes them and communicates the
information between functions in a preempt safe manner. Generation
of some exceptions was broken and this has also been corrected.
Tests with glibc's maths test suite show no change in the results
before/after this patch.

Signed-off-by: default avatarRichard Purdie <rpurdie@rpsys.net>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 1fcf8448

arch/arm/nwfpe/double_cpdo.c

+12 −12
Original line number Diff line number Diff line
@@ -40,17 +40,17 @@ float64 float64_arccos(float64 rFm); 
float64 float64_pow(float64 rFn, float64 rFm);

float64 float64_pol(float64 rFn, float64 rFm);



static float64 float64_rsf(float64 rFn, float64 rFm)

static float64 float64_rsf(struct roundingData *roundData, float64 rFn, float64 rFm)

{

	return float64_sub(rFm, rFn);

	return float64_sub(roundData, rFm, rFn);

}



static float64 float64_rdv(float64 rFn, float64 rFm)

static float64 float64_rdv(struct roundingData *roundData, float64 rFn, float64 rFm)

{

	return float64_div(rFm, rFn);

	return float64_div(roundData, rFm, rFn);

}



static float64 (*const dyadic_double[16])(float64 rFn, float64 rFm) = {

static float64 (*const dyadic_double[16])(struct roundingData*, float64 rFn, float64 rFm) = {

	[ADF_CODE >> 20] = float64_add,

	[MUF_CODE >> 20] = float64_mul,

	[SUF_CODE >> 20] = float64_sub,
@@ -65,12 +65,12 @@ static float64 (*const dyadic_double[16])(float64 rFn, float64 rFm) = { 
	[FRD_CODE >> 20] = float64_rdv,

};



static float64 float64_mvf(float64 rFm)

static float64 float64_mvf(struct roundingData *roundData,float64 rFm)

{

	return rFm;

}



static float64 float64_mnf(float64 rFm)

static float64 float64_mnf(struct roundingData *roundData,float64 rFm)

{

	union float64_components u;
@@ -84,7 +84,7 @@ static float64 float64_mnf(float64 rFm) 
	return u.f64;

}



static float64 float64_abs(float64 rFm)

static float64 float64_abs(struct roundingData *roundData,float64 rFm)

{

	union float64_components u;
@@ -98,7 +98,7 @@ static float64 float64_abs(float64 rFm) 
	return u.f64;

}



static float64 (*const monadic_double[16])(float64 rFm) = {

static float64 (*const monadic_double[16])(struct roundingData *, float64 rFm) = {

	[MVF_CODE >> 20] = float64_mvf,

	[MNF_CODE >> 20] = float64_mnf,

	[ABS_CODE >> 20] = float64_abs,
@@ -108,7 +108,7 @@ static float64 (*const monadic_double[16])(float64 rFm) = { 
	[NRM_CODE >> 20] = float64_mvf,

};



unsigned int DoubleCPDO(const unsigned int opcode, FPREG * rFd)

unsigned int DoubleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd)

{

	FPA11 *fpa11 = GET_FPA11();

	float64 rFm;
@@ -151,13 +151,13 @@ unsigned int DoubleCPDO(const unsigned int opcode, FPREG * rFd) 
		}



		if (dyadic_double[opc_mask_shift]) {

			rFd->fDouble = dyadic_double[opc_mask_shift](rFn, rFm);

			rFd->fDouble = dyadic_double[opc_mask_shift](roundData, rFn, rFm);

		} else {

			return 0;

		}

	} else {

		if (monadic_double[opc_mask_shift]) {

			rFd->fDouble = monadic_double[opc_mask_shift](rFm);

			rFd->fDouble = monadic_double[opc_mask_shift](roundData, rFm);

		} else {

			return 0;

		}

arch/arm/nwfpe/extended_cpdo.c

+12 −12
Original line number Diff line number Diff line
@@ -35,17 +35,17 @@ floatx80 floatx80_arccos(floatx80 rFm); 
floatx80 floatx80_pow(floatx80 rFn, floatx80 rFm);

floatx80 floatx80_pol(floatx80 rFn, floatx80 rFm);



static floatx80 floatx80_rsf(floatx80 rFn, floatx80 rFm)

static floatx80 floatx80_rsf(struct roundingData *roundData, floatx80 rFn, floatx80 rFm)

{

	return floatx80_sub(rFm, rFn);

	return floatx80_sub(roundData, rFm, rFn);

}



static floatx80 floatx80_rdv(floatx80 rFn, floatx80 rFm)

static floatx80 floatx80_rdv(struct roundingData *roundData, floatx80 rFn, floatx80 rFm)

{

	return floatx80_div(rFm, rFn);

	return floatx80_div(roundData, rFm, rFn);

}



static floatx80 (*const dyadic_extended[16])(floatx80 rFn, floatx80 rFm) = {

static floatx80 (*const dyadic_extended[16])(struct roundingData*, floatx80 rFn, floatx80 rFm) = {

	[ADF_CODE >> 20] = floatx80_add,

	[MUF_CODE >> 20] = floatx80_mul,

	[SUF_CODE >> 20] = floatx80_sub,
@@ -60,24 +60,24 @@ static floatx80 (*const dyadic_extended[16])(floatx80 rFn, floatx80 rFm) = { 
	[FRD_CODE >> 20] = floatx80_rdv,

};



static floatx80 floatx80_mvf(floatx80 rFm)

static floatx80 floatx80_mvf(struct roundingData *roundData, floatx80 rFm)

{

	return rFm;

}



static floatx80 floatx80_mnf(floatx80 rFm)

static floatx80 floatx80_mnf(struct roundingData *roundData, floatx80 rFm)

{

	rFm.high ^= 0x8000;

	return rFm;

}



static floatx80 floatx80_abs(floatx80 rFm)

static floatx80 floatx80_abs(struct roundingData *roundData, floatx80 rFm)

{

	rFm.high &= 0x7fff;

	return rFm;

}



static floatx80 (*const monadic_extended[16])(floatx80 rFm) = {

static floatx80 (*const monadic_extended[16])(struct roundingData*, floatx80 rFm) = {

	[MVF_CODE >> 20] = floatx80_mvf,

	[MNF_CODE >> 20] = floatx80_mnf,

	[ABS_CODE >> 20] = floatx80_abs,
@@ -87,7 +87,7 @@ static floatx80 (*const monadic_extended[16])(floatx80 rFm) = { 
	[NRM_CODE >> 20] = floatx80_mvf,

};



unsigned int ExtendedCPDO(const unsigned int opcode, FPREG * rFd)

unsigned int ExtendedCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd)

{

	FPA11 *fpa11 = GET_FPA11();

	floatx80 rFm;
@@ -138,13 +138,13 @@ unsigned int ExtendedCPDO(const unsigned int opcode, FPREG * rFd) 
		}



		if (dyadic_extended[opc_mask_shift]) {

			rFd->fExtended = dyadic_extended[opc_mask_shift](rFn, rFm);

			rFd->fExtended = dyadic_extended[opc_mask_shift](roundData, rFn, rFm);

		} else {

			return 0;

		}

	} else {

		if (monadic_extended[opc_mask_shift]) {

			rFd->fExtended = monadic_extended[opc_mask_shift](rFm);

			rFd->fExtended = monadic_extended[opc_mask_shift](roundData, rFm);

		} else {

			return 0;

		}

arch/arm/nwfpe/fpa11.c

+11 −19
Original line number Diff line number Diff line
@@ -51,48 +51,42 @@ static void resetFPA11(void) 
	fpa11->fpsr = FP_EMULATOR | BIT_AC;

}



void SetRoundingMode(const unsigned int opcode)

int8 SetRoundingMode(const unsigned int opcode)

{

	switch (opcode & MASK_ROUNDING_MODE) {

	default:

	case ROUND_TO_NEAREST:

		float_rounding_mode = float_round_nearest_even;

		break;

		return float_round_nearest_even;



	case ROUND_TO_PLUS_INFINITY:

		float_rounding_mode = float_round_up;

		break;

		return float_round_up;



	case ROUND_TO_MINUS_INFINITY:

		float_rounding_mode = float_round_down;

		break;

		return float_round_down;



	case ROUND_TO_ZERO:

		float_rounding_mode = float_round_to_zero;

		break;

		return float_round_to_zero;

	}

}



void SetRoundingPrecision(const unsigned int opcode)

int8 SetRoundingPrecision(const unsigned int opcode)

{

#ifdef CONFIG_FPE_NWFPE_XP

	switch (opcode & MASK_ROUNDING_PRECISION) {

	case ROUND_SINGLE:

		floatx80_rounding_precision = 32;

		break;

		return 32;



	case ROUND_DOUBLE:

		floatx80_rounding_precision = 64;

		break;

		return 64;



	case ROUND_EXTENDED:

		floatx80_rounding_precision = 80;

		break;

		return 80;



	default:

		floatx80_rounding_precision = 80;

		return 80;

	}

#endif

	return 80;

}



void nwfpe_init_fpa(union fp_state *fp)
@@ -103,8 +97,6 @@ void nwfpe_init_fpa(union fp_state *fp) 
#endif

 	memset(fpa11, 0, sizeof(FPA11));

	resetFPA11();

	SetRoundingMode(ROUND_TO_NEAREST);

	SetRoundingPrecision(ROUND_EXTENDED);

	fpa11->initflag = 1;

}

arch/arm/nwfpe/fpa11.h

+9 −2
Original line number Diff line number Diff line
@@ -37,6 +37,13 @@ 
/* includes */

#include "fpsr.h"		/* FP control and status register definitions */

#include "milieu.h"



struct roundingData {

    int8 mode;

    int8 precision;

    signed char exception;

};



#include "softfloat.h"



#define		typeNone		0x00
@@ -84,8 +91,8 @@ typedef struct tagFPA11 { 
				   initialised. */

} FPA11;



extern void SetRoundingMode(const unsigned int);

extern void SetRoundingPrecision(const unsigned int);

extern int8 SetRoundingMode(const unsigned int);

extern int8 SetRoundingPrecision(const unsigned int);

extern void nwfpe_init_fpa(union fp_state *fp);



#endif

arch/arm/nwfpe/fpa11_cpdo.c

+17 −11
Original line number Diff line number Diff line
@@ -24,15 +24,16 @@ 
#include "fpa11.h"

#include "fpopcode.h"



unsigned int SingleCPDO(const unsigned int opcode, FPREG * rFd);

unsigned int DoubleCPDO(const unsigned int opcode, FPREG * rFd);

unsigned int ExtendedCPDO(const unsigned int opcode, FPREG * rFd);

unsigned int SingleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);

unsigned int DoubleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);

unsigned int ExtendedCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd);



unsigned int EmulateCPDO(const unsigned int opcode)

{

	FPA11 *fpa11 = GET_FPA11();

	FPREG *rFd;

	unsigned int nType, nDest, nRc;

	struct roundingData roundData;



	/* Get the destination size.  If not valid let Linux perform

	   an invalid instruction trap. */
@@ -40,7 +41,9 @@ unsigned int EmulateCPDO(const unsigned int opcode) 
	if (typeNone == nDest)

		return 0;



	SetRoundingMode(opcode);

	roundData.mode = SetRoundingMode(opcode);

	roundData.precision = SetRoundingPrecision(opcode);

	roundData.exception = 0;



	/* Compare the size of the operands in Fn and Fm.

	   Choose the largest size and perform operations in that size,
@@ -63,14 +66,14 @@ unsigned int EmulateCPDO(const unsigned int opcode) 


	switch (nType) {

	case typeSingle:

		nRc = SingleCPDO(opcode, rFd);

		nRc = SingleCPDO(&roundData, opcode, rFd);

		break;

	case typeDouble:

		nRc = DoubleCPDO(opcode, rFd);

		nRc = DoubleCPDO(&roundData, opcode, rFd);

		break;

#ifdef CONFIG_FPE_NWFPE_XP

	case typeExtended:

		nRc = ExtendedCPDO(opcode, rFd);

		nRc = ExtendedCPDO(&roundData, opcode, rFd);

		break;

#endif

	default:
@@ -93,9 +96,9 @@ unsigned int EmulateCPDO(const unsigned int opcode) 
			case typeSingle:

				{

					if (typeDouble == nType)

						rFd->fSingle = float64_to_float32(rFd->fDouble);

						rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble);

					else

						rFd->fSingle = floatx80_to_float32(rFd->fExtended);

						rFd->fSingle = floatx80_to_float32(&roundData, rFd->fExtended);

				}

				break;
@@ -104,7 +107,7 @@ unsigned int EmulateCPDO(const unsigned int opcode) 
					if (typeSingle == nType)

						rFd->fDouble = float32_to_float64(rFd->fSingle);

					else

						rFd->fDouble = floatx80_to_float64(rFd->fExtended);

						rFd->fDouble = floatx80_to_float64(&roundData, rFd->fExtended);

				}

				break;
@@ -121,12 +124,15 @@ unsigned int EmulateCPDO(const unsigned int opcode) 
#else

		if (nDest != nType) {

			if (nDest == typeSingle)

				rFd->fSingle = float64_to_float32(rFd->fDouble);

				rFd->fSingle = float64_to_float32(&roundData, rFd->fDouble);

			else

				rFd->fDouble = float32_to_float64(rFd->fSingle);

		}

#endif

	}



	if (roundData.exception)

		float_raise(roundData.exception);



	return nRc;

}