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-rw-r--r--arch/mn10300/kernel/fpu.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/arch/mn10300/kernel/fpu.c b/arch/mn10300/kernel/fpu.c
new file mode 100644
index 000000000..064fa194d
--- /dev/null
+++ b/arch/mn10300/kernel/fpu.c
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+/* 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>
+
+#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;
+}