1 files changed, 223 insertions, 0 deletions

diff --git a/arch/mn10300/kernel/fpu.c b/arch/mn10300/kernel/fpu.c
new file mode 100644
index 000000000000..e705f25ad5ff
--- /dev/null
+++ b/arch/mn10300/kernel/fpu.c
@@ -0,0 +1,223 @@
+/* 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>
+
+struct task_struct *fpu_state_owner;
+
+/*
+ * handle an exception due to the FPU being disabled
+ */
+asmlinkage void fpu_disabled(struct pt_regs *regs, enum exception_code code)
+{
+        struct task_struct *tsk = current;
+
+        if (!user_mode(regs))
+                die_if_no_fixup("An FPU Disabled exception happened in"
+                                " kernel space\n",
+                                regs, code);
+
+#ifdef CONFIG_FPU
+        preempt_disable();
+
+        /* transfer the last process's FPU state to memory */
+        if (fpu_state_owner) {
+                fpu_save(&fpu_state_owner->thread.fpu_state);
+                fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
+        }
+
+        /* the current process now owns the FPU state */
+        fpu_state_owner = tsk;
+        regs->epsw |= EPSW_FE;
+
+        /* load the FPU with the current process's FPU state or invent a new
+         * clean one if the process doesn't have one */
+        if (is_using_fpu(tsk)) {
+                fpu_restore(&tsk->thread.fpu_state);
+        } else {
+                fpu_init_state();
+                set_using_fpu(tsk);
+        }
+
+        preempt_enable();
+#else
+        {
+                siginfo_t info;
+
+                info.si_signo = SIGFPE;
+                info.si_errno = 0;
+                info.si_addr = (void *) tsk->thread.uregs->pc;
+                info.si_code = FPE_FLTINV;
+
+                force_sig_info(SIGFPE, &info, tsk);
+        }
+#endif  /* CONFIG_FPU */
+}
+
+/*
+ * 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 = fpu_state_owner;
+        siginfo_t info;
+
+        if (!user_mode(regs))
+                die_if_no_fixup("An FPU Operation exception happened in"
+                                " kernel space\n",
+                                regs, code);
+
+        if (!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;
+
+#ifdef CONFIG_FPU
+        {
+                u32 fpcr;
+
+                /* get FPCR (we need to enable the FPU whilst we do this) */
+                asm volatile("  or      %1,epsw         \n"
+#ifdef CONFIG_MN10300_PROC_MN103E010
+                             "  nop                     \n"
+                             "  nop                     \n"
+                             "  nop                     \n"
+#endif
+                             "  fmov    fpcr,%0         \n"
+#ifdef CONFIG_MN10300_PROC_MN103E010
+                             "  nop                     \n"
+                             "  nop                     \n"
+                             "  nop                     \n"
+#endif
+                             "  and     %2,epsw         \n"
+                             : "=&d"(fpcr)
+                             : "i"(EPSW_FE), "i"(~EPSW_FE)
+                             );
+
+                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;
+        }
+#endif
+
+        force_sig_info(SIGFPE, &info, tsk);
+}
+
+/*
+ * save the FPU state to a signal context
+ */
+int fpu_setup_sigcontext(struct fpucontext *fpucontext)
+{
+#ifdef CONFIG_FPU
+        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();
+
+        if (fpu_state_owner == tsk) {
+                fpu_save(&tsk->thread.fpu_state);
+                fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
+                fpu_state_owner = NULL;
+        }
+
+        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;
+#else
+        return 0;
+#endif
+}
+
+/*
+ * kill a process's FPU state during restoration after signal handling
+ */
+void fpu_kill_state(struct task_struct *tsk)
+{
+#ifdef CONFIG_FPU
+        /* disown anything left in the FPU */
+        preempt_disable();
+
+        if (fpu_state_owner == tsk) {
+                fpu_state_owner->thread.uregs->epsw &= ~EPSW_FE;
+                fpu_state_owner = NULL;
+        }
+
+        preempt_enable();
+#endif
+        /* 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;
+}