pc, pc64: move all fpu specific code from main.c to fpu.c

1 files changed, 345 insertions, 0 deletions

diff --git a/sys/src/9/pc64/fpu.c b/sys/src/9/pc64/fpu.c
index 3af4d60e3..924a5752f 100644
--- a/sys/src/9/pc64/fpu.c
+++ b/sys/src/9/pc64/fpu.c
@@ -3,6 +3,8 @@
 #include "mem.h"
 #include "dat.h"
 #include "fns.h"
+#include "ureg.h"
+#include "io.h"
 
 enum {
 	CR4Osfxsr  = 1 << 9,
@@ -10,6 +12,252 @@ enum {
 	CR4Oxsave  = 1 << 18,
 };
 
+/*
+ * SIMD Floating Point.
+ * Assembler support to get at the individual instructions
+ * is in l.s.
+ */
+extern void _clts(void);
+extern void _fldcw(u16int);
+extern void _fnclex(void);
+extern void _fninit(void);
+extern void _fxrstor(void*);
+extern void _fxsave(void*);
+extern void _xrstor(void*);
+extern void _xsave(void*);
+extern void _xsaveopt(void*);
+extern void _fwait(void);
+extern void _ldmxcsr(u32int);
+extern void _stts(void);
+
+/*
+ * not used, AMD64 mandated SSE
+ */
+static void
+fpx87save(FPsave*)
+{
+}
+static void
+fpx87restore(FPsave*)
+{
+}
+
+static void
+fpssesave(FPsave *s)
+{
+	_fxsave(s);
+	_stts();
+}
+static void
+fpsserestore(FPsave *s)
+{
+	_clts();
+	_fxrstor(s);
+}
+
+static void
+fpxsave(FPsave *s)
+{
+	_xsave(s);
+	_stts();
+}
+static void
+fpxrestore(FPsave *s)
+{
+	_clts();
+	_xrstor(s);
+}
+
+static void
+fpxsaves(FPsave *s)
+{
+	_xsaveopt(s);
+	_stts();
+}
+static void
+fpxrestores(FPsave *s)
+{
+	_clts();
+	_xrstor(s);
+}
+
+static void
+fpxsaveopt(FPsave *s)
+{
+	_xsaveopt(s);
+	_stts();
+}
+
+static char* mathmsg[] =
+{
+	nil,	/* handled below */
+	"denormalized operand",
+	"division by zero",
+	"numeric overflow",
+	"numeric underflow",
+	"precision loss",
+};
+
+static void
+mathnote(ulong status, uintptr pc)
+{
+	char *msg, note[ERRMAX];
+	int i;
+
+	/*
+	 * Some attention should probably be paid here to the
+	 * exception masks and error summary.
+	 */
+	msg = "unknown exception";
+	for(i = 1; i <= 5; i++){
+		if(!((1<<i) & status))
+			continue;
+		msg = mathmsg[i];
+		break;
+	}
+	if(status & 0x01){
+		if(status & 0x40){
+			if(status & 0x200)
+				msg = "stack overflow";
+			else
+				msg = "stack underflow";
+		}else
+			msg = "invalid operation";
+	}
+	snprint(note, sizeof note, "sys: fp: %s fppc=%#p status=0x%lux",
+		msg, pc, status);
+	postnote(up, 1, note, NDebug);
+}
+
+/*
+ *  math coprocessor error
+ */
+static void
+matherror(Ureg *, void*)
+{
+	/*
+	 * Save FPU state to check out the error.
+	 */
+	fpsave(up->fpsave);
+	up->fpstate = FPinactive | (up->fpstate & (FPnouser|FPkernel|FPindexm));
+	mathnote(up->fpsave->fsw, up->fpsave->rip);
+}
+
+/*
+ *  SIMD error
+ */
+static void
+simderror(Ureg *ureg, void*)
+{
+	fpsave(up->fpsave);
+	up->fpstate = FPinactive | (up->fpstate & (FPnouser|FPkernel|FPindexm));
+	mathnote(up->fpsave->mxcsr & 0x3f, ureg->pc);
+}
+
+void
+fpinit(void)
+{
+	/*
+	 * A process tries to use the FPU for the
+	 * first time and generates a 'device not available'
+	 * exception.
+	 * Turn the FPU on and initialise it for use.
+	 * Set the precision and mask the exceptions
+	 * we don't care about from the generic Mach value.
+	 */
+	_clts();
+	_fninit();
+	_fwait();
+	_fldcw(0x0232);
+	_ldmxcsr(0x1900);
+}
+
+/*
+ *  math coprocessor emulation fault
+ */
+static void
+mathemu(Ureg *ureg, void*)
+{
+	ulong status, control;
+	int index;
+
+	if(up->fpstate & FPillegal){
+		/* someone did floating point in a note handler */
+		postnote(up, 1, "sys: floating point in note handler", NDebug);
+		return;
+	}
+	switch(up->fpstate & ~(FPnouser|FPkernel|FPindexm)){
+	case FPactive	| FPpush:
+		_clts();
+		fpsave(up->fpsave);
+	case FPinactive	| FPpush:
+		up->fpstate += FPindex1;
+	case FPinit	| FPpush:
+	case FPinit:
+		fpinit();
+		index = up->fpstate >> FPindexs;
+		if(index < 0 || index > (FPindexm>>FPindexs))
+			panic("fpslot index overflow: %d", index);
+		if(userureg(ureg)){
+			if(index != 0)
+				panic("fpslot index %d != 0 for user", index);
+		} else {
+			if(index == 0)
+				up->fpstate |= FPnouser;
+			up->fpstate |= FPkernel;
+		}
+		while(up->fpslot[index] == nil)
+			up->fpslot[index] = mallocalign(sizeof(FPsave), FPalign, 0, 0);
+		up->fpsave = up->fpslot[index];
+		up->fpstate = FPactive | (up->fpstate & (FPnouser|FPkernel|FPindexm));
+		break;
+	case FPinactive:
+		/*
+		 * Before restoring the state, check for any pending
+		 * exceptions, there's no way to restore the state without
+		 * generating an unmasked exception.
+		 * More attention should probably be paid here to the
+		 * exception masks and error summary.
+		 */
+		status = up->fpsave->fsw;
+		control = up->fpsave->fcw;
+		if((status & ~control) & 0x07F){
+			mathnote(status, up->fpsave->rip);
+			break;
+		}
+		fprestore(up->fpsave);
+		up->fpstate = FPactive | (up->fpstate & (FPnouser|FPkernel|FPindexm));
+		break;
+	case FPactive:
+		panic("math emu pid %ld %s pc %#p", 
+			up->pid, up->text, ureg->pc);
+		break;
+	}
+}
+
+/*
+ *  math coprocessor segment overrun
+ */
+static void
+mathover(Ureg*, void*)
+{
+	pexit("math overrun", 0);
+}
+
+void
+mathinit(void)
+{
+	trapenable(VectorCERR, matherror, 0, "matherror");
+	if(m->cpuidfamily == 3)
+		intrenable(IrqIRQ13, matherror, 0, BUSUNKNOWN, "matherror");
+	trapenable(VectorCNA, mathemu, 0, "mathemu");
+	trapenable(VectorCSO, mathover, 0, "mathover");
+	trapenable(VectorSIMD, simderror, 0, "simderror");
+}
+
+/*
+ * fpuinit(), called from cpuidentify() for each cpu.
+ */
 void
 fpuinit(void)
 {
@@ -43,3 +291,100 @@ fpuinit(void)
 		fprestore = fpx87restore;
 	}
 }
+
+void
+fpuprocsetup(Proc *p)
+{
+	p->fpstate = FPinit;
+	_stts();
+}
+
+void
+fpuprocfork(Proc *p)
+{
+	int s;
+
+	/* save floating point state */
+	s = splhi();
+	switch(up->fpstate & ~FPillegal){
+	case FPactive	| FPpush:
+		_clts();
+	case FPactive:
+		fpsave(up->fpsave);
+		up->fpstate = FPinactive | (up->fpstate & FPpush);
+	case FPactive	| FPkernel:
+	case FPinactive	| FPkernel:
+	case FPinactive	| FPpush:
+	case FPinactive:
+		while(p->fpslot[0] == nil)
+			p->fpslot[0] = mallocalign(sizeof(FPsave), FPalign, 0, 0);
+		memmove(p->fpsave = p->fpslot[0], up->fpslot[0], sizeof(FPsave));
+		p->fpstate = FPinactive;
+	}
+	splx(s);
+}
+
+void
+fpuprocsave(Proc *p)
+{
+	switch(p->fpstate & ~(FPnouser|FPkernel|FPindexm)){
+	case FPactive	| FPpush:
+		_clts();
+	case FPactive:
+		if(p->state == Moribund){
+			_fnclex();
+			_stts();
+			break;
+		}
+		/*
+		 * Fpsave() stores without handling pending
+		 * unmasked exeptions. Postnote() can't be called
+		 * here as sleep() already has up->rlock, so
+		 * the handling of pending exceptions is delayed
+		 * until the process runs again and generates an
+		 * emulation fault to activate the FPU.
+		 */
+		fpsave(p->fpsave);
+		p->fpstate = FPinactive | (p->fpstate & ~FPactive);
+		break;
+	}
+}
+
+void
+fpuprocrestore(Proc*)
+{
+}
+
+
+/*
+ * Fpusave and fpurestore lazily save and restore FPU state across
+ * system calls and the pagefault handler so that we can take
+ * advantage of SSE instructions such as AES-NI in the kernel.
+ */
+int
+fpusave(void)
+{
+	int ostate = up->fpstate;
+	if((ostate & ~(FPnouser|FPkernel|FPindexm)) == FPactive)
+		_stts();
+	up->fpstate = FPpush | (ostate & ~FPillegal);
+	return ostate;
+}
+void
+fpurestore(int ostate)
+{
+	int astate = up->fpstate;
+	if(astate == (FPpush | (ostate & ~FPillegal))){
+		if((ostate & ~(FPnouser|FPkernel|FPindexm)) == FPactive)
+			_clts();
+	} else {
+		if(astate == FPinit)	/* don't restore on procexec()/procsetup() */
+			return;
+		if((astate & ~(FPnouser|FPkernel|FPindexm)) == FPactive)
+			_stts();
+		up->fpsave = up->fpslot[ostate>>FPindexs];
+		if(ostate & FPactive)
+			ostate = FPinactive | (ostate & ~FPactive);
+	}
+	up->fpstate = ostate;
+}