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[PATCH] ARM: 2837/2: Re: ARM: Make NWFPE preempt safe
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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: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Richard Purdie authored and Russell King committed Aug 3, 2005
1 parent 1fcf844 commit f148af2
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Showing 11 changed files with 304 additions and 304 deletions.
24 changes: 12 additions & 12 deletions arch/arm/nwfpe/double_cpdo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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;

Expand All @@ -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;

Expand All @@ -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,
Expand All @@ -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;
Expand Down Expand Up @@ -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;
}
Expand Down
24 changes: 12 additions & 12 deletions arch/arm/nwfpe/extended_cpdo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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,
Expand All @@ -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;
Expand Down Expand Up @@ -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;
}
Expand Down
30 changes: 11 additions & 19 deletions arch/arm/nwfpe/fpa11.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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;
}

Expand Down
11 changes: 9 additions & 2 deletions arch/arm/nwfpe/fpa11.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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
28 changes: 17 additions & 11 deletions arch/arm/nwfpe/fpa11_cpdo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,23 +24,26 @@
#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. */
nDest = getDestinationSize(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,
Expand All @@ -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:
Expand All @@ -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;

Expand All @@ -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;

Expand All @@ -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;
}
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