initial_commit

1 files changed, 176 insertions, 0 deletions

diff --git a/arch/mn10300/kernel/fpu.c b/arch/mn10300/kernel/fpu.c
new file mode 100644
index 00000000..bb5fa7df
--- /dev/null
+++ b/arch/mn10300/kernel/fpu.c
@@ -0,0 +1,176 @@
+/* MN10300 FPU management
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#include <asm/uaccess.h>
+#include <asm/fpu.h>
+#include <asm/elf.h>
+#include <asm/exceptions.h>
+#include <asm/system.h>
+
+#ifdef CONFIG_LAZY_SAVE_FPU
+struct task_struct *fpu_state_owner;
+#endif
+
+/*
+ * error functions in FPU disabled exception
+ */
+asmlinkage void fpu_disabled_in_kernel(struct pt_regs *regs)
+{
+	die_if_no_fixup("An FPU Disabled exception happened in kernel space\n",
+			regs, EXCEP_FPU_DISABLED);
+}
+
+/*
+ * handle an FPU operational exception
+ * - there's a possibility that if the FPU is asynchronous, the signal might
+ *   be meant for a process other than the current one
+ */
+asmlinkage void fpu_exception(struct pt_regs *regs, enum exception_code code)
+{
+	struct task_struct *tsk = current;
+	siginfo_t info;
+	u32 fpcr;
+
+	if (!user_mode(regs))
+		die_if_no_fixup("An FPU Operation exception happened in"
+				" kernel space\n",
+				regs, code);
+
+	if (!is_using_fpu(tsk))
+		die_if_no_fixup("An FPU Operation exception happened,"
+				" but the FPU is not in use",
+				regs, code);
+
+	info.si_signo = SIGFPE;
+	info.si_errno = 0;
+	info.si_addr = (void *) tsk->thread.uregs->pc;
+	info.si_code = FPE_FLTINV;
+
+	unlazy_fpu(tsk);
+
+	fpcr = tsk->thread.fpu_state.fpcr;
+
+	if (fpcr & FPCR_EC_Z)
+		info.si_code = FPE_FLTDIV;
+	else if	(fpcr & FPCR_EC_O)
+		info.si_code = FPE_FLTOVF;
+	else if	(fpcr & FPCR_EC_U)
+		info.si_code = FPE_FLTUND;
+	else if	(fpcr & FPCR_EC_I)
+		info.si_code = FPE_FLTRES;
+
+	force_sig_info(SIGFPE, &info, tsk);
+}
+
+/*
+ * save the FPU state to a signal context
+ */
+int fpu_setup_sigcontext(struct fpucontext *fpucontext)
+{
+	struct task_struct *tsk = current;
+
+	if (!is_using_fpu(tsk))
+		return 0;
+
+	/* transfer the current FPU state to memory and cause fpu_init() to be
+	 * triggered by the next attempted FPU operation by the current
+	 * process.
+	 */
+	preempt_disable();
+
+#ifndef CONFIG_LAZY_SAVE_FPU
+	if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
+		fpu_save(&tsk->thread.fpu_state);
+		tsk->thread.uregs->epsw &= ~EPSW_FE;
+		tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
+	}
+#else /* !CONFIG_LAZY_SAVE_FPU */
+	if (fpu_state_owner == tsk) {
+		fpu_save(&tsk->thread.fpu_state);
+		fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
+		fpu_state_owner = NULL;
+	}
+#endif /* !CONFIG_LAZY_SAVE_FPU */
+
+	preempt_enable();
+
+	/* we no longer have a valid current FPU state */
+	clear_using_fpu(tsk);
+
+	/* transfer the saved FPU state onto the userspace stack */
+	if (copy_to_user(fpucontext,
+			 &tsk->thread.fpu_state,
+			 min(sizeof(struct fpu_state_struct),
+			     sizeof(struct fpucontext))))
+		return -1;
+
+	return 1;
+}
+
+/*
+ * kill a process's FPU state during restoration after signal handling
+ */
+void fpu_kill_state(struct task_struct *tsk)
+{
+	/* disown anything left in the FPU */
+	preempt_disable();
+
+#ifndef CONFIG_LAZY_SAVE_FPU
+	if (tsk->thread.fpu_flags & THREAD_HAS_FPU) {
+		tsk->thread.uregs->epsw &= ~EPSW_FE;
+		tsk->thread.fpu_flags &= ~THREAD_HAS_FPU;
+	}
+#else /* !CONFIG_LAZY_SAVE_FPU */
+	if (fpu_state_owner == tsk) {
+		fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
+		fpu_state_owner = NULL;
+	}
+#endif /* !CONFIG_LAZY_SAVE_FPU */
+
+	preempt_enable();
+
+	/* we no longer have a valid current FPU state */
+	clear_using_fpu(tsk);
+}
+
+/*
+ * restore the FPU state from a signal context
+ */
+int fpu_restore_sigcontext(struct fpucontext *fpucontext)
+{
+	struct task_struct *tsk = current;
+	int ret;
+
+	/* load up the old FPU state */
+	ret = copy_from_user(&tsk->thread.fpu_state, fpucontext,
+			     min(sizeof(struct fpu_state_struct),
+				 sizeof(struct fpucontext)));
+	if (!ret)
+		set_using_fpu(tsk);
+
+	return ret;
+}
+
+/*
+ * fill in the FPU structure for a core dump
+ */
+int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpreg)
+{
+	struct task_struct *tsk = current;
+	int fpvalid;
+
+	fpvalid = is_using_fpu(tsk);
+	if (fpvalid) {
+		unlazy_fpu(tsk);
+		memcpy(fpreg, &tsk->thread.fpu_state, sizeof(*fpreg));
+	}
+
+	return fpvalid;
+}