fpu_kernel_{enter,exit}; Functions to allow the use of

the FPU in the kernel.

From Mike Belopuhov; Little bits by myself.

Comments/OK kettenis@

4 files changed, 136 insertions, 5 deletions

diff --git a/sys/arch/amd64/amd64/fpu.c b/sys/arch/amd64/amd64/fpu.c
index e8deedcbba2..51515478f97 100644
--- a/sys/arch/amd64/amd64/fpu.c
+++ b/sys/arch/amd64/amd64/fpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fpu.c,v 1.15 2010/06/07 08:23:58 thib Exp $	*/
+/*	$OpenBSD: fpu.c,v 1.16 2010/06/29 21:13:43 thib Exp $	*/
 /*	$NetBSD: fpu.c,v 1.1 2003/04/26 18:39:28 fvdl Exp $	*/
 
 /*-
@@ -322,3 +322,66 @@ fpusave_proc(struct proc *p, int save)
 	fpusave_cpu(ci, save);
 #endif
 }
+
+void
+fpu_kernel_enter(void)
+{
+	struct cpu_info	*oci, *ci = curcpu();
+	struct proc	*p = curproc;
+	uint32_t	 cw;
+	int		 s;
+
+	KASSERT(p != NULL && (p->p_flag & P_SYSTEM));
+
+	/*
+	 * Fast path. If we were the last proc on the FPU,
+	 * there is no work to do besides clearing TS.
+	 */
+	if (ci->ci_fpcurproc == p) {
+		p->p_addr->u_pcb.pcb_cr0 &= ~CR0_TS;
+		clts();
+		return;
+	}
+
+	s = splipi();
+
+	if (ci->ci_fpcurproc != NULL) {
+		fpusave_cpu(ci, 1);
+		uvmexp.fpswtch++;
+	}
+
+	/*
+	 * If we were switched away to the other cpu, cleanup
+	 * an fpcurproc pointer.
+	 */
+	oci = p->p_addr->u_pcb.pcb_fpcpu;
+	if (oci != NULL && oci != ci && oci->ci_fpcurproc == p)
+		oci->ci_fpcurproc = NULL;
+
+	/* Claim the FPU */
+	ci->ci_fpcurproc = p;
+	p->p_addr->u_pcb.pcb_fpcpu = ci;
+	p->p_addr->u_pcb.pcb_cr0 &= ~CR0_TS;
+
+	splx(s);
+
+	/* Disables DNA exceptions */
+	clts();
+
+	/* Initialize the FPU */
+	fninit();
+	cw = __INITIAL_NPXCW__;
+	fldcw(&cw);
+	cw = __INITIAL_MXCSR__;
+	ldmxcsr(&cw);
+}
+
+void
+fpu_kernel_exit(void)
+{
+	/*
+	 * Nothing to do.
+	 * TS is restored on a context switch automatically
+	 * as long as we use hardware assisted task switching.
+	 */
+}
diff --git a/sys/arch/amd64/include/fpu.h b/sys/arch/amd64/include/fpu.h
index f7da949e8e0..69f77ee812f 100644
--- a/sys/arch/amd64/include/fpu.h
+++ b/sys/arch/amd64/include/fpu.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fpu.h,v 1.3 2006/10/01 10:52:10 kettenis Exp $	*/
+/*	$OpenBSD: fpu.h,v 1.4 2010/06/29 21:13:43 thib Exp $	*/
 /*	$NetBSD: fpu.h,v 1.1 2003/04/26 18:39:40 fvdl Exp $	*/
 
 #ifndef	_AMD64_FPU_H_
@@ -51,11 +51,12 @@ struct cpu_info;
 
 void fpuinit(struct cpu_info *);
 void fpudrop(void);
-void fpusave(struct proc *);
 void fpudiscard(struct proc *);
 void fputrap(struct trapframe *);
 void fpusave_proc(struct proc *, int);
 void fpusave_cpu(struct cpu_info *, int);
+void fpu_kernel_enter(void);
+void fpu_kernel_exit(void);
 
 #endif
 
diff --git a/sys/arch/i386/include/npx.h b/sys/arch/i386/include/npx.h
index a3b787214b6..f2e63403439 100644
--- a/sys/arch/i386/include/npx.h
+++ b/sys/arch/i386/include/npx.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: npx.h,v 1.11 2009/10/03 21:51:01 kettenis Exp $	*/
+/*	$OpenBSD: npx.h,v 1.12 2010/06/29 21:13:43 thib Exp $	*/
 /*	$NetBSD: npx.h,v 1.11 1994/10/27 04:16:11 cgd Exp $	*/
 
 /*-
@@ -167,5 +167,7 @@ struct trapframe;
 
 void	npxinit(struct cpu_info *);
 void	npxtrap(struct trapframe *);
+void	fpu_kernel_enter(void);
+void	fpu_kernel_exit(void);
 
 #endif /* !_I386_NPX_H_ */
diff --git a/sys/arch/i386/isa/npx.c b/sys/arch/i386/isa/npx.c
index 49d376ecd31..232886c0788 100644
--- a/sys/arch/i386/isa/npx.c
+++ b/sys/arch/i386/isa/npx.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: npx.c,v 1.47 2009/10/28 21:12:18 deraadt Exp $	*/
+/*	$OpenBSD: npx.c,v 1.48 2010/06/29 21:13:43 thib Exp $	*/
 /*	$NetBSD: npx.c,v 1.57 1996/05/12 23:12:24 mycroft Exp $	*/
 
 #if 0
@@ -859,3 +859,68 @@ npxsave_proc(struct proc *p, int save)
 	npxsave_cpu(ci, save);
 #endif
 }
+
+void
+fpu_kernel_enter(void)
+{
+	struct cpu_info	*oci, *ci = curcpu();
+	struct proc	*p = curproc;
+	uint32_t	 cw;
+	int		 s;
+
+	KASSERT(p != NULL && (p->p_flag & P_SYSTEM));
+
+	/*
+	 * Fast path. If we were the last proc on the FPU,
+	 * there is no work to do besides clearing TS.
+	 */
+	if (ci->ci_fpcurproc == p) {
+		p->p_addr->u_pcb.pcb_cr0 &= ~CR0_TS;
+		clts();
+		return;
+	}
+
+	s = splipi();
+
+	if (ci->ci_fpcurproc != NULL) {
+		npxsave_cpu(ci, 1);
+		uvmexp.fpswtch++;
+	}
+
+	/*
+	 * If we were switched away to the other cpu, cleanup
+	 * an fpcurproc pointer.
+	 */
+	oci = p->p_addr->u_pcb.pcb_fpcpu;
+	if (oci != NULL && oci != ci && oci->ci_fpcurproc == p)
+		oci->ci_fpcurproc = NULL;
+
+	/* Claim the FPU */
+	ci->ci_fpcurproc = p;
+	p->p_addr->u_pcb.pcb_fpcpu = ci;
+	p->p_addr->u_pcb.pcb_cr0 &= ~CR0_TS;
+
+	splx(s);
+
+	/* Disables DNA exceptions */
+	clts();
+
+	/* Initialize the FPU */
+	fninit();
+	cw = __INITIAL_NPXCW__;
+	fldcw(&cw);
+	if (i386_has_sse || i386_has_sse2) {
+		cw = __INITIAL_MXCSR__;
+		ldmxcsr(&cw);
+	}
+}
+
+void
+fpu_kernel_exit(void)
+{
+	/*
+	 * Nothing to do.
+	 * TS is restored on a context switch automatically
+	 * as long as we use hardware assisted task switching.
+	 */
+}