[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: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/nwfpe/fpa11_cpdt.c b/arch/arm/nwfpe/fpa11_cpdt.c
index 95fb63f..b0db5cb 100644
--- a/arch/arm/nwfpe/fpa11_cpdt.c
+++ b/arch/arm/nwfpe/fpa11_cpdt.c
@@ -96,7 +96,7 @@
}
}
-static inline void storeSingle(const unsigned int Fn, unsigned int __user *pMem)
+static inline void storeSingle(struct roundingData *roundData, const unsigned int Fn, unsigned int __user *pMem)
{
FPA11 *fpa11 = GET_FPA11();
union {
@@ -106,12 +106,12 @@
switch (fpa11->fType[Fn]) {
case typeDouble:
- val.f = float64_to_float32(fpa11->fpreg[Fn].fDouble);
+ val.f = float64_to_float32(roundData, fpa11->fpreg[Fn].fDouble);
break;
#ifdef CONFIG_FPE_NWFPE_XP
case typeExtended:
- val.f = floatx80_to_float32(fpa11->fpreg[Fn].fExtended);
+ val.f = floatx80_to_float32(roundData, fpa11->fpreg[Fn].fExtended);
break;
#endif
@@ -122,7 +122,7 @@
put_user(val.i[0], pMem);
}
-static inline void storeDouble(const unsigned int Fn, unsigned int __user *pMem)
+static inline void storeDouble(struct roundingData *roundData, const unsigned int Fn, unsigned int __user *pMem)
{
FPA11 *fpa11 = GET_FPA11();
union {
@@ -137,7 +137,7 @@
#ifdef CONFIG_FPE_NWFPE_XP
case typeExtended:
- val.f = floatx80_to_float64(fpa11->fpreg[Fn].fExtended);
+ val.f = floatx80_to_float64(roundData, fpa11->fpreg[Fn].fExtended);
break;
#endif
@@ -259,8 +259,11 @@
{
unsigned int __user *pBase, *pAddress, *pFinal;
unsigned int nRc = 1, write_back = WRITE_BACK(opcode);
+ struct roundingData roundData;
- SetRoundingMode(ROUND_TO_NEAREST);
+ roundData.mode = SetRoundingMode(opcode);
+ roundData.precision = SetRoundingPrecision(opcode);
+ roundData.exception = 0;
pBase = (unsigned int __user *) readRegister(getRn(opcode));
if (REG_PC == getRn(opcode)) {
@@ -281,10 +284,10 @@
switch (opcode & MASK_TRANSFER_LENGTH) {
case TRANSFER_SINGLE:
- storeSingle(getFd(opcode), pAddress);
+ storeSingle(&roundData, getFd(opcode), pAddress);
break;
case TRANSFER_DOUBLE:
- storeDouble(getFd(opcode), pAddress);
+ storeDouble(&roundData, getFd(opcode), pAddress);
break;
#ifdef CONFIG_FPE_NWFPE_XP
case TRANSFER_EXTENDED:
@@ -295,6 +298,9 @@
nRc = 0;
}
+ if (roundData.exception)
+ float_raise(roundData.exception);
+
if (write_back)
writeRegister(getRn(opcode), (unsigned long) pFinal);
return nRc;