Backout changes trying to inherit floating-point environment, although

POSIX (susv3) requires this, but it is unclear what should be inherited,
duplicating whole 387 stack for new thread seems to be unnecessary and
dangerous. Revert to previous code, force a new thread to be started with
clean FP state.

3 files changed, 1 insertions, 40 deletions

diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c
index f9b954b..26ed735 100644
--- a/sys/i386/i386/vm_machdep.c
+++ b/sys/i386/i386/vm_machdep.c
@@ -393,8 +393,7 @@ cpu_set_upcall(struct thread *td, struct thread *td0)
 	 * more analysis) (need a good safe default).
 	 */
 	bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
-	pcb2->pcb_flags &= ~PCB_NPXTRAP;
-	npx_fork_thread(td0, td);
+	pcb2->pcb_flags &= ~(PCB_NPXTRAP|PCB_NPXINITDONE);
 
 	/*
 	 * Create a new fresh stack for the new thread.
diff --git a/sys/i386/include/npx.h b/sys/i386/include/npx.h
index 792f75a..86b9af8 100644
--- a/sys/i386/include/npx.h
+++ b/sys/i386/include/npx.h
@@ -138,8 +138,6 @@ union	savefpu {
 
 #ifdef _KERNEL
 
-struct thread;
-
 #define	IO_NPX		0x0F0		/* Numeric Coprocessor */
 #define	IO_NPXSIZE	16		/* 80387/80487 NPX registers */
 
@@ -157,7 +155,6 @@ void	npxinit(u_short control);
 void	npxsave(union savefpu *addr);
 void	npxsetregs(struct thread *td, union savefpu *addr);
 int	npxtrap(void);
-void	npx_fork_thread(struct thread *td, struct thread *newtd);
 
 #endif
 
diff --git a/sys/i386/isa/npx.c b/sys/i386/isa/npx.c
index 129a853..bc39629 100644
--- a/sys/i386/isa/npx.c
+++ b/sys/i386/isa/npx.c
@@ -942,41 +942,6 @@ npxsetregs(td, addr)
 	curthread->td_pcb->pcb_flags |= PCB_NPXINITDONE;
 }
 
-/*
- * POSIX requires new thread to inherit floating-point environment.
- */
-void
-npx_fork_thread(struct thread *td, struct thread *newtd)
-{
-	union savefpu	*state;
-	u_int32_t	mxcsr;
-	u_int32_t	cw;
-
-	if (!(td->td_pcb->pcb_flags & PCB_NPXINITDONE)) {
-		newtd->td_pcb->pcb_flags &= ~PCB_NPXINITDONE;
-		return;
-	}
-		
-	state = &newtd->td_pcb->pcb_save;
-	/* get control word */
-	if (npxgetregs(td, state))
-		return;
-	if (cpu_fxsr) {
-		mxcsr = state->sv_xmm.sv_env.en_mxcsr;
-		cw = state->sv_xmm.sv_env.en_cw;
-	} else {
-		cw = state->sv_87.sv_env.en_cw;
-		mxcsr = 0;
-	}
-	bcopy(&npx_cleanstate, state, sizeof(*state));
-	if (cpu_fxsr) {
-		state->sv_xmm.sv_env.en_cw = cw;
-		state->sv_xmm.sv_env.en_mxcsr = mxcsr;
-	} else
-		state->sv_87.sv_env.en_cw = cw;
-	newtd->td_pcb->pcb_flags |= PCB_NPXINITDONE;
-}
-
 static void
 fpusave(addr)
 	union savefpu *addr;