patch-2.3.50 linux/arch/sh/kernel/fpu.c

• Lines: 267
• Date: Sun Mar 5 09:33:55 2000
• Orig file: v2.3.49/linux/arch/sh/kernel/fpu.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.49/linux/arch/sh/kernel/fpu.c linux/arch/sh/kernel/fpu.c
@@ -0,0 +1,266 @@
+/* $Id: fpu.c,v 1.27 2000/03/05 01:48:34 gniibe Exp $
+ *
+ * linux/arch/sh/kernel/fpu.c
+ *
+ * Save/restore floating point context for signal handlers.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
+ *
+ * FIXME! These routines can be optimized in big endian case.
+ */
+
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <asm/processor.h>
+#include <asm/io.h>
+
+void
+save_fpu(struct task_struct *tsk)
+{
+	asm volatile("sts.l	$fpul, @-%0\n\t"
+		     "sts.l	$fpscr, @-%0\n\t"
+		     "frchg\n\t"
+		     "fmov.s	$fr15, @-%0\n\t"
+		     "fmov.s	$fr14, @-%0\n\t"
+		     "fmov.s	$fr13, @-%0\n\t"
+		     "fmov.s	$fr12, @-%0\n\t"
+		     "fmov.s	$fr11, @-%0\n\t"
+		     "fmov.s	$fr10, @-%0\n\t"
+		     "fmov.s	$fr9, @-%0\n\t"
+		     "fmov.s	$fr8, @-%0\n\t"
+		     "fmov.s	$fr7, @-%0\n\t"
+		     "fmov.s	$fr6, @-%0\n\t"
+		     "fmov.s	$fr5, @-%0\n\t"
+		     "fmov.s	$fr4, @-%0\n\t"
+		     "fmov.s	$fr3, @-%0\n\t"
+		     "fmov.s	$fr2, @-%0\n\t"
+		     "fmov.s	$fr1, @-%0\n\t"
+		     "fmov.s	$fr0, @-%0\n\t"
+		     "frchg\n\t"
+		     "fmov.s	$fr15, @-%0\n\t"
+		     "fmov.s	$fr14, @-%0\n\t"
+		     "fmov.s	$fr13, @-%0\n\t"
+		     "fmov.s	$fr12, @-%0\n\t"
+		     "fmov.s	$fr11, @-%0\n\t"
+		     "fmov.s	$fr10, @-%0\n\t"
+		     "fmov.s	$fr9, @-%0\n\t"
+		     "fmov.s	$fr8, @-%0\n\t"
+		     "fmov.s	$fr7, @-%0\n\t"
+		     "fmov.s	$fr6, @-%0\n\t"
+		     "fmov.s	$fr5, @-%0\n\t"
+		     "fmov.s	$fr4, @-%0\n\t"
+		     "fmov.s	$fr3, @-%0\n\t"
+		     "fmov.s	$fr2, @-%0\n\t"
+		     "fmov.s	$fr1, @-%0\n\t"
+		     "fmov.s	$fr0, @-%0"
+		     : /* no output */
+		     : "r" ((char *)(&tsk->thread.fpu.hard.status))
+		     : "memory");
+
+	tsk->flags &= ~PF_USEDFPU;
+	release_fpu();
+}
+
+static void
+restore_fpu(struct task_struct *tsk)
+{
+	asm volatile("fmov.s	@%0+, $fr0\n\t"
+		     "fmov.s	@%0+, $fr1\n\t"
+		     "fmov.s	@%0+, $fr2\n\t"
+		     "fmov.s	@%0+, $fr3\n\t"
+		     "fmov.s	@%0+, $fr4\n\t"
+		     "fmov.s	@%0+, $fr5\n\t"
+		     "fmov.s	@%0+, $fr6\n\t"
+		     "fmov.s	@%0+, $fr7\n\t"
+		     "fmov.s	@%0+, $fr8\n\t"
+		     "fmov.s	@%0+, $fr9\n\t"
+		     "fmov.s	@%0+, $fr10\n\t"
+		     "fmov.s	@%0+, $fr11\n\t"
+		     "fmov.s	@%0+, $fr12\n\t"
+		     "fmov.s	@%0+, $fr13\n\t"
+		     "fmov.s	@%0+, $fr14\n\t"
+		     "fmov.s	@%0+, $fr15\n\t"
+		     "frchg\n\t"
+		     "fmov.s	@%0+, $fr0\n\t"
+		     "fmov.s	@%0+, $fr1\n\t"
+		     "fmov.s	@%0+, $fr2\n\t"
+		     "fmov.s	@%0+, $fr3\n\t"
+		     "fmov.s	@%0+, $fr4\n\t"
+		     "fmov.s	@%0+, $fr5\n\t"
+		     "fmov.s	@%0+, $fr6\n\t"
+		     "fmov.s	@%0+, $fr7\n\t"
+		     "fmov.s	@%0+, $fr8\n\t"
+		     "fmov.s	@%0+, $fr9\n\t"
+		     "fmov.s	@%0+, $fr10\n\t"
+		     "fmov.s	@%0+, $fr11\n\t"
+		     "fmov.s	@%0+, $fr12\n\t"
+		     "fmov.s	@%0+, $fr13\n\t"
+		     "fmov.s	@%0+, $fr14\n\t"
+		     "fmov.s	@%0+, $fr15\n\t"
+		     "frchg\n\t"
+		     "lds.l	@%0+, $fpscr\n\t"
+		     "lds.l	@%0+, $fpul\n\t"
+		     : /* no output */
+		     : "r" (&tsk->thread.fpu)
+		     : "memory");
+}
+
+/*
+ * Load the FPU with signalling NANS.  This bit pattern we're using
+ * has the property that no matter wether considered as single or as
+ * double precission represents signaling NANS.  
+ */
+/* Double presision, NANS as NANS, rounding to nearest, no exceptions */
+#define FPU_DEFAULT  0x00080000
+
+void fpu_init(void)
+{
+	asm volatile("lds	%0, $fpul\n\t"
+		     "lds	%1, $fpscr\n\t"
+		     "fsts	$fpul, $fr0\n\t"
+		     "fsts	$fpul, $fr1\n\t"
+		     "fsts	$fpul, $fr2\n\t"
+		     "fsts	$fpul, $fr3\n\t"
+		     "fsts	$fpul, $fr4\n\t"
+		     "fsts	$fpul, $fr5\n\t"
+		     "fsts	$fpul, $fr6\n\t"
+		     "fsts	$fpul, $fr7\n\t"
+		     "fsts	$fpul, $fr8\n\t"
+		     "fsts	$fpul, $fr9\n\t"
+		     "fsts	$fpul, $fr10\n\t"
+		     "fsts	$fpul, $fr11\n\t"
+		     "fsts	$fpul, $fr12\n\t"
+		     "fsts	$fpul, $fr13\n\t"
+		     "fsts	$fpul, $fr14\n\t"
+		     "fsts	$fpul, $fr15\n\t"
+		     "frchg\n\t"
+		     "fsts	$fpul, $fr0\n\t"
+		     "fsts	$fpul, $fr1\n\t"
+		     "fsts	$fpul, $fr2\n\t"
+		     "fsts	$fpul, $fr3\n\t"
+		     "fsts	$fpul, $fr4\n\t"
+		     "fsts	$fpul, $fr5\n\t"
+		     "fsts	$fpul, $fr6\n\t"
+		     "fsts	$fpul, $fr7\n\t"
+		     "fsts	$fpul, $fr8\n\t"
+		     "fsts	$fpul, $fr9\n\t"
+		     "fsts	$fpul, $fr10\n\t"
+		     "fsts	$fpul, $fr11\n\t"
+		     "fsts	$fpul, $fr12\n\t"
+		     "fsts	$fpul, $fr13\n\t"
+		     "fsts	$fpul, $fr14\n\t"
+		     "fsts	$fpul, $fr15\n\t"
+		     "frchg"
+		     : /* no output */
+		     : "r" (0), "r" (FPU_DEFAULT));
+}
+
+asmlinkage void
+do_fpu_error(unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7,
+	     struct pt_regs regs)
+{
+	struct task_struct *tsk = current;
+
+	regs.syscall_nr = -1;
+	regs.pc += 2;
+
+	grab_fpu();
+	save_fpu(tsk);
+	tsk->thread.trap_no = 11;
+	tsk->thread.error_code = 0;
+	force_sig(SIGFPE, tsk);
+}
+
+asmlinkage void
+do_fpu_state_restore(unsigned long r4, unsigned long r5, unsigned long r6,
+		     unsigned long r7, struct pt_regs regs)
+{
+	struct task_struct *tsk = current;
+
+	regs.syscall_nr = -1;
+
+	if (!user_mode(&regs)) {
+		if (tsk != &init_task) {
+			unlazy_fpu(tsk);
+		}
+		tsk = &init_task;
+		if (tsk->flags & PF_USEDFPU)
+			BUG();
+	}
+
+	grab_fpu();
+	if (tsk->used_math) {
+		/* Using the FPU again.  */
+		restore_fpu(tsk);
+	} else	{
+		/* First time FPU user.  */
+		fpu_init();
+		tsk->used_math = 1;
+	}
+	tsk->flags |= PF_USEDFPU;
+	release_fpu();
+}
+
+/*
+ * Change current FD flag to set FD flag back to exception
+ */
+asmlinkage void
+fpu_prepare_fd(unsigned long sr, unsigned long r5, unsigned long r6,
+	       unsigned long r7, struct pt_regs regs)
+{
+	__cli();
+	if (!user_mode(&regs)) {
+		if (init_task.flags & PF_USEDFPU)
+			grab_fpu();
+		else {
+			if (!(sr & SR_FD)) {
+				release_fpu();
+				BUG();
+			}
+		}
+		return;
+	}
+
+	if (sr & SR_FD) { /* Kernel doesn't grab FPU */
+		if (current->flags & PF_USEDFPU)
+			grab_fpu();
+		else {
+			if (init_task.flags & PF_USEDFPU) {
+				init_task.flags &= ~PF_USEDFPU;
+				BUG();
+			}
+		}
+	} else {
+		if (init_task.flags & PF_USEDFPU)
+			save_fpu(&init_task);
+		else {
+			release_fpu();
+			BUG();
+		}
+	}
+}
+
+/* Short cut for the FPU exception */
+asmlinkage void
+enable_fpu_in_danger(void)
+{
+	struct task_struct *tsk = current;
+
+	if (tsk != &init_task)
+		unlazy_fpu(tsk);
+
+	tsk = &init_task;
+	if (tsk->used_math) {
+		/* Using the FPU again.  */
+		restore_fpu(tsk);
+	} else	{
+		/* First time FPU user.  */
+		fpu_init();
+		tsk->used_math = 1;
+	}
+	tsk->flags |= PF_USEDFPU;
+}